पत स च / Address List

Transcription

1

2 पत स च / Address List 1. मह ब धक, एसआरएलड स, प स क, बगल र/ GM, SRLDC, POSOCO, Bengaluru 2. म U य अ भय त (एचप स व जल पEरय जन ) एप ज नक, 4व म जल, ग णदल, वजयव ड आ / Chief Engineer (Generation), APGENCO, 4 th Floor, Vidyut Soudha, Eluru Road, Gunadala, Vijayawada, AP म ख य अ भय त (पEरय जन ), एप ज नक, 4व म जल, ग णदल, वजयव ड आ / Chief Engineer (Projects), APGENCO, 4 th Floor, Vidyut Soudha, Eluru Road, Gunadala, Vijayawada, AP म ख य अ भय त (आईप स व वय त ण ल), एप \ न स क,3र म जल, ग णदल, वजयव ड आ / Chief Engineer (IPC & Power Systems), APTRANSCO, 3 rd Floor, Vidyut Soudha, Eluru Road, Gunadala, Vijayawada, AP म ख य अ भय त ( उत प दन), टएसज नक, ह दर ब द/ Chief Engineer (Generation), TSGENCO, Hyderabad 6. म ख य अ भय त (पEरय जन ), टएसज नक, ह दर ब द/ Chief Engineer (Projects), TSGENCO, Hyderabad 7. म ख य अ भय त (वय त ण ल), टएस\ न स क, ह दर ब द/ Chief Engineer (Power System), TSTRANSCO, Hyderabad 8. म ख य अ भय त (इल._डज़ ईन), क प स एल, बगल र/ Chief Engineer (Ele. Designs), KPCL, Bangalore 9. म ख य अ भय त ( आर ट और आर & ड ), क प टस एल, बगल र/ Chief Engineer (RT and R&D), KPTCL, Bangalore 10. म ख य अ भय त, एसएलड स, क प टस एल, बगल र/ Chief Engineer, SLDC, KPTCL, Bangalore 11. म ख य अ भय त (एम.ट.एस), ट नज डक, च न न / Chief Engineer (MTS), TANGEDCO, Chennai (Fax No: ) 12. म ख य अ भय त (जल वय त), ट नज डक, च न न / Chief Engineer (Hydro),TANGEDCO, Chennai (Fax No: ) 13. म ख य अ भय त (स रण एव स च र), ट एन ई ब, च न न / Chief Engineer (Protection & Communication), TANTRANSCO, Chennai 14. म ख य अ भय त (प र षण), ण ल च लन, एचएमट क ल न, क एसईब, कलमस स र / Chief Engineer (Transmission) System Operation, HMT Colony, KSEB, Kalamassery अध क अ भय त -, वय त वभ ग, 137, एनएसस ब स स ल, प द च र / Superintending Engineer I, Electricity Department, 137, NSC Bose Salai, Puducherry (Fax No: ) 16. ज एम ( च व अन ) द -, प वरdड, सक दर ब द/ GM (O&M), SR-I, PGCIL, Secunderabad 17. ज एम ( च व अन ) द -, प वरdड, बगल र/ GM (O&M), SR-II, PGCIL, Bengaluru 18. मह ब धक (ओ एस), एनटप स, दण य म ख य लय, सक दर ब द/ General Manager (OS), NTPC SRHQ, Secunderabad 19. म ख य मह ब धक,टप एस- वस त र,एनएलस आईएल,न व ल / Chief General Manager, TPS-I Expn. NLCIL, Neyveli (Fax No: ) 20. म ख य अ भय त (प र षण) एनप स आईएल, म बई/ Chief Engineer (Transmission), NPCIL, Mumbai. 21. क "नद शक, क ज एस, क ग, कन #टक/ Station Director, KGS, Kaiga, Karnataka 22. क "नद शक, एमएप एस, कल पक कम/ Station Director, MAPS, Kalpakkam 23. क "नद शक, क क एनप प, "तfनल व ल जल, त मलन ड / Station Director, KKNPP, Thirunelveli Dist,TamilNadu

3 24. g प प ज स टन, एज एम (ईएम), एनटईस एल, च न न -103/ Shri P.P. Gestine, AGM (EM), NTECL, Chennai g एम भ कर, मह ब धक ( व अ), एनटप एल, ह ब#र ए ट ट, त त क ड / Sh. M. Prabhakar, GM (O&M), NTPL, Harbour Estate, Tuticorin (Fax No: ) 26. g स य# क श, उप h य (च लन व अन रण), ज एसडi j य एनजk ल. त रणगj ल, बj ल र / Shri Surya Prakash, Vice President (Operations & Maintenance), M/s JSW Energy Ltd, Toranagallu, Bellary g श त र म प, सह उप h य (वय त एव पEरय जन ), ज एसडi j य एनजk ल. त रणगj ल, बj ल र / Shri Shantharam Pai, Associate Vice President (Electrical & Projects), M/s JSW Energy Ltd, Toranagallu, Bellary g आर व भoए, उप ध य ( च लन) य प स एल, बगल र/ Shri R.V.Bhat, Vice President (Operations), UPCL, Bangalore 29. सह उप h य ( स रण व म टEर ग), अद न प वर ल, 8-ए, 'स भव' जज भवन क स मन, ब दकद व, अहमद ब द , ग जर त / Associate Vice President (Protection & Metering), Adani Power Ltd, 8- A, Sambhav, Opp. Judge s Bungalow, Bodakdev, Ahmedabad , Gujarat, India 30. g pबय त च$बतk (ध न वय त एव स आई अन रण) टप स आईएल, q य नप रम / न ल9 त f d म, म त क र म डल, एसप एसआर न j ल र / Sh. Bidyut Chakraborty (Head Electrical and C&I Maintenance), TPCIL, Pyanampuram/ Nelaturu Village, Muthukur Mandal, SPSR Nellore (Fax No: ) 31. g आर एस क म र व म, सल ह र(वय त), स ईप एल, म लमरड र d म, ओ+oपदरम त j ल क, त त क ड , त मलन ड / Sh. R.S. Kumaraswamy, Advisor (Electrical), CEPL, Melamarudur Village, Ottipidaram Taluk, Tuticorin , Tamil Nadu (Fax No: ) 32. g <कश र आक# ट, वEर. उप h य ( व अ), आईएल व एफएस, टप स एल, स प द प o ड क, परनग प o, भ वनगEर त j ल क, क डल र जल, त मलन ड / Sh. Kishore Arcot, Sr. Vice President (O&M), IL&FS Tamilnadu Power Company Ltd., C.Pudhupettai (post), Parnagipettai, Bhuvanagiri Taluk, Cuddalore Dist, Tamilnadu (Fax No: ) 33. g सi यस च म खजk, वEर. उप h य ( एव अ) +ह द ज एनप स एल, प टग rयड म डल, वश खपrनम, आ / Sh. Sabyasachi Mukherjee, Sr. Vice President (O&M), Hinduja NPCL, Pedagantyada Mandal, Visakhapatnam, AP g एस स दरम "त#, उप h य ( च लन), ल नक कCडपj ल प वर ल मट ड, आईड ए कCडपj ल, इs +हमपrनम म डल, क t ण जj ल, आ u द श / Sh. S. Sundaramoorthy-Vice President (operations), Lanco Kondapalli Power Limited, IDA Kondapalli, Ibrahimpatnam Mandal, Krishna district, Andhra Pradesh , (Fax No: ) 35. "नद शक (एन प स भ ग), क व, नई +दल ल / Director (NPC Division), CEA, New Delhi *****

4 SOUTHERN REGIONAL POWER COMMITTEE BENGALURU Minutes of the 73 rd Meeting of Protection Coordination Sub-Committee (PCSC 73) of SRPC held on 26 th April, Introduction The 73 rd meeting of Protection Coordination Sub-Committee (PCSC-73) of SRPC was held on 26 th April, 2018 at SRPC Secretariat, Bengaluru. The list of participants is enclosed at Annexure-I. Sh. S. R. Bhat, Member Secretary (MS), SRPC welcomed Members and Participants to the meeting and briefed them on the following points: Apprised Members that a special meeting on Gajuwaka HVDC Pole trippings was held on [Minutes circulated vide SRPC letter dated ] at PGCIL (SRTS-I) RHQ, Hyderabad to deliberate & finalize on various measures required to be taken to deal with Pole-1 trippings on auxiliary supply failure and Pole-2 trippings on ferro-resonance detection. PGCIL (SR-I) was requested to take necessary action as per the recommendations given & within agreed timelines, and submit a compliance report for the same. Expressed concern at the increased no. of trippings in SR and requested Constituents to exercise due vigilance w.r.t. healthiness of protection systems put in place, adopting stipulated line maintenance practices, and undertaking condition-based monitoring of substation equipment & transmission lines. Specifically, Members attention was drawn to the Grid Disturbances at 400 kv Sriperambudur SS on and those involving KPTCL stations on & , and requested concerned Constituents to present in detail the cause of the trippings & the mitigating measures taken when the issue was taken up for discussion later in the meeting. Informed members that in accordance with CERC Order dated in respect of APTRANSCO Petition No.95/MP/2015 dated , protection audit of 400/ 220 kv Palavady SS of TANTRANSCO was proposed to be conducted during May, 2018, and requested TANTRANSCO to furnish required details as sought vide SRPC letter dated , and extend necessary cooperation to conduct the said audit. Stated that a protocol on implementing & using Protection Management System in Southern Region was circulated to all SR-Constituents vide SRPC letter dated , and requested all Constituents to stick to different time-lines specified therein for completing various tasks & cooperate with PRDC in this regard. Expressed concern at the repeated absence of APGENCO representatives to PCSC meetings despite inclusion of tripping events relating to their system in the meeting Agendas. It was also noted that action required to be taken to attend to their pending protections issues had also not been forthcoming as desired. Minutes of the 73 rd Meeting of PCSC held on 26 th April, 2018 Page 1

5 2. Confirmation of the Minutes of the 72 nd meeting of PCSC held on 15 th March, 2018 The minutes of the 72 nd meeting of PCSC were circulated vide SRPC letter No. SRPC/SE-III/ PCSC-72/ 2018/ dated Since no comments had been received from any of the Constituents, the minutes of the 72 nd meeting of PCSC were confirmed. 3. Details of Grid Disturbances (GD s), Grid Incidents (GI s), and Line Trippings due to Auto- Reclose (A/R) failure/ non-operation & PLCC mal-operation The trippings due to GD s, GI s, A/R failure/ non-operation, and PLCC mal-operation that had occurred during February-March, 2018 were discussed in the Meeting. The deliberations and recommendations of the PCSC Forum are enclosed at Annexure II for further needful action. The details of the tripping events including relevant PMU plots presented by SRLDC in the meeting are also enclosed at Annexure-VIII for kind reference. 4. Status of pending PCSC Recommendations (P-REC) The status of implementation of pending PCSC recommendations was discussed in the meeting. The updated status of the same as on is enclosed at Annexure III. The Constituents were asked to take steps to comply with the same, and requested to submit the status of their compliance latest by Remedial measures/ Action taken for the tripping incidents of the transmission elements under forced outage (PRM) The tripping incidents of the transmission elements under forced outage for which the remedial action taken had not been furnished were discussed in the meeting. The Constituents were asked to kindly furnish specific remedial measures/ action taken covering one or the other items from the following indicative list in time so as to forward the same to Central Electricity Authority: Brief details of line patrolling carried out (with tower location) Brief details of RoW maintenance (by proper Tree-cutting) resorted to De-capped insulators replacement DC earth fault removal PLCC cards replacement Relay settings modification Steps taken to put A/R or CB into service after they have been locked-out Faulty equipment replacement Reference to OEM in case of equipment failure Brief Details of tests carried out to ascertain the healthiness of various equipment (Power Transformer/ Reactors/ Surge Arrestors/ Circuit Breakers/ CT's/ PT's/CVT's) like Insulation Resistance (IR) test, Winding Resistance test, Capacitance test, Tan delta test, DGA test, Leakage current test, CRM/ DCRM test, etc. Any other appropriate remedial measure The updated list of PRM as on is enclosed at Annexure-IV. Minutes of the 73 rd Meeting of PCSC held on 26 th April, 2018 Page 2

6 6. Certificate for Healthiness of Batteries As per MoP/ CEA direction given in pursuant to recommendations of the Enquiry Committee (NEW Grid Disturbance on 30 th & 31 st July, 2012), RPC s are required to obtain from their respective Constituents a monthly certificate for healthiness of batteries installed at 220 KV & above voltage level Substations (for power supply to Relays, RTUs and PLCC equipment) and furnish the same to CEA/ MoP. With reference to above, the Constituents were requested to submit the certificate on healthiness of batteries on monthly basis (i.e. status for a month shall be sent by the 7 th day of the following month) to SRPC as per the format given below: Sl. No. Station Name Station Application Battery Battery Charger Remarks Code Type (PS/ SS) Protection/ Communication 1 Station-A Protection (Bank-1) 2 Station-B Protection (Bank-2) Communication (Bank-1) Communication (Bank-2) Details Status (Healthy/ Unhealthy) Details Status (Healthy/ Unhealthy) Brief Details of unhealthy battery banks and/ or DC leakage along with proposed timelines for rectifying the same shall be mentioned. Note: 1. Code is the short name of the Station 2. PS Power Station; SS Substation The sought status for the month of March, 2018 had not been received from the following SR- Constituents: TANTRANSCO, KSEBL & UPCL 7. MAPS Agenda Item on 230 kv grid Voltage fluctuations due to CT failure at Sriperumbudur Substation MAPS vide their letter dated (copy enclosed at Annexure-V) had requested to include above Agenda Item due to Grid Disturbance at Sriperumbudur Substation at 18:01:32 hrs on All pertinent issues in this regard were discussed as part of Grid Disturbance - 6 (reference may be made to Annexure-II). TANTRANSCO and PGCIL (SR-II) were asked to take necessary action to comply with the recommendations given therein. Minutes of the 73 rd Meeting of PCSC held on 26 th April, 2018 Page 3

7 8. Adoption of New Over Voltage Relay (OVR) Gradings for 400 kv and 765 kv Transmission Lines of Southern Region - reg. In the past one year, a number of new 400 kv and 765 kv transmission lines have been added to SR-Grid in addition to reconfiguration (including LILO) works of the existing 400 kv and 765 kv transmission lines. In this regard, a comprehensive exercise of OVR (Stage-I) grading for 400 kv and 765 kv transmission lines of Southern Region (existing as in March, 2018 and few lines expected in April-May, 2018) has been carried out, and the new OVR Gradings proposed to be adopted for these lines (along with study results) have been circulated to all Constituents for modifications/ omissions/ comments, if any, vide SRPC mail dated [The general concepts involved in OVR grading and study results are enclosed at Annexure-VI for kind reference]. After duly incorporating Constituents' comments, the final OVR gradings to be adopted for 400 kv and 765 kv lines in the Southern Region were issued vide SRPC letter no: SRPC/ SE-III/ OVR/ 2018/ dated (copy enclosed at Annexure-VII) for implementation with immediate effect, and confirm the same by The above OVR gradings have also been kept in SRPC Website for easy reference. 9. Network Configuration Changes As per the information furnished by SR-Constituents to the OCC forum in their 142 nd meeting held on (Minutes circulated vide SRPC letter dated ), it is formed that the following network configuration changes (additions/ deletions/ modifications of transmission elements) took place in the southern grid during March, LILO of 220 kv ADR Palem Bobbli Dc Line from loc. No.43 to proposed 400kV SS to Garividi in Vizianagaram district of 2 Ckm was commissioned on by APTRANSCO. 220kV DC line from 400kV SS Gani to 220kV SS Somayajulapalli to in Kurnool district of 34.6 Ckm was commissioned on by APTRANSCO. 220kV SS Gundala in Krishna Dist of Existing 3x50 MVA was commissioned on by APTRANSCO with augmented capacity of 1x80+2x50 MVA. 220kV DC line with Moose conductor from 220/132 kv Narketpally SS to Udaya Samudram 220/11 kv SS in Nalgonda dist of Ckm was commissioned on by TSTRANSCO. 220kV Chandrayagutta in Rangareddy Dist of Existing 2x160+2x100 MVA was commissioned on by TSTRANSCO with augmented capacity of 3x160 +1x100 MVA. PGCIL (SR-II) vide letter dated had informed that consequent to the successful completion of Trial Operation, the following asset under Transmission System for Ultra Mega Solar Power Park at Tumkur (Pavagada), Karnataka-Phase-I were put under commercial operation w.e.f. 00:00 hrs of 31st March 2018 in terms of Clause 4 of CERC (Terms and conditions of Tariff Regulations, 2014) 1x 125 MVAR 400kV Bus Reactor along with its associated bays and equipments at Tumkur (Pavagada) pooling station. PGCIL (SR-II) vide letter dated had informed that consequent to the successful completion of Trial Operation, the following assets under Augmentation of transformation capacity in Southern Region were put under Commercial Operation w.e.f. 00:00 hrs of 31st March 2018 in terms of clause 4 of CERC (Terms and Conditions of Tariff Regulations, 2014). Minutes of the 73 rd Meeting of PCSC held on 26 th April, 2018 Page 4

8 1x500 MVA 400/230kV ICT along with associated bays and equipment at Tirunelveli 400/230 kv substation. PGCIL (SR-II) vide letter dated had informed that consequent to the successful completion of Trial Operation, the following assets under Transmission System for Ultra Mega Solar Power Park at Tumkur (Pavagada), Karnataka-Phase-I were put under Commercial Operation w.e.f. 00:00 hrs of 31st March 2018 in terms of clause 4 of CERC (Terms and Conditions of Tariff Regulations, 2014). LILO of 400 Kv D/C Bellary-Tumkur (Vasantnarasapur) (Quad Moose) TL at Tumkur (Pavagada) pooling station along with associated bays and equipments PGCIL (SR-II) vide letter dated had informed that consequent to the successful completion of Trial Operation, the following assets under Augmentation of transformation capacity in Southern Region were put under Commercial Operation w.e.f. 00:00 hrs of 2nd April 2018 in terms of clause 4 of CERC (Terms and Conditions of Tariff Regulations, 2014). 1x500 MVA 400/230kV ICT along with associated bays and equipment at Karaikudi 400/230 kv substation PGCIL (SR-II) vide letter dated had informed that consequent to the successful completion of Trial Operation, the following assets under Augmentation of transformation capacity in Southern Region were put under Commercial Operation w.e.f. 00:00 hrs of 31st March 2018 in terms of clause 4 of CERC (Terms and Conditions of Tariff Regulations, 2014). 1x500 MVA 400/230kV ICT along with associated bays and equipment at Arasur 400/230 kv substation 10. Instances of SPS Operation Based on the information furnished by SRLDC, it is informed that no SPS operations took place in SR during the period Status of Implementation of Protection Audit Recommendations (Phase-I & Phase-II) With reference to the petitions filed by KSEB (88/MP/2016) and KPTCL (135/MP/2016) for seeking further time-extension for completing their respective Protection Audit Recommendations (PAR), the final Order of Hon ble CERC disposing of petitions was issued on In this Order, the Commission, apart from granting last-chance time-extensions to various SR-Constituents, had also directed SRPC to monitor the status of completion of PAR regularly in PCSC meetings and submit bimonthly report to the Commission confirming the completion of Phase-I and Phase-II of PAR of the Constituents of Southern Region. In this regard, based on the information furnished by various Constituents, a summary table showing the compliance status of various SR-Constituents as on is given below: Sl. No. Constituent PAR (Phase-I) Activities PAR (Phase-II) Activities Stipulated Stipulated Completion Date Completion Date PAR (Ph-I & Ph-II) Compliance (%) Remarks 1 APGENCO (Hydel) Based on the status furnished, timeline for complying with the remaining pending recommendations (5 in no.) is Minutes of the 73 rd Meeting of PCSC held on 26 th April, 2018 Page 5

9 2 APGENCO (Thermal) Based on the status furnished, timeline for complying with the remaining pending recommendations (2 in no.) is APTRANSCO Based on the status furnished, the lone pending recommendation is expected to be completed by April, TSGENCO (Hydel) Based on the status furnished, timeline for complying with the remaining pending recommendations (3 in no.) is June, TSTRANSCO Based on the status furnished, timeline for complying with the remaining pending recommendations (12 in no.) is June, KPTCL Based on the status furnished, timeline for complying with the remaining pending recommendations (22 in no.) is May, TANGEDCO Based on the status furnished, timeline for complying with the remaining pending recommendations (9 in no.) is June, TANTRANSCO Based on the status furnished, timeline for complying with the remaining pending recommendations (60 in no.) is December, TANTRANSCO has been asked to approach Hon ble CERC to get required time-extension 9 KSEBL Based on the status furnished, timeline for complying with the remaining pending recommendations (2 in no.) is July, NPCIL (MAPS) Based on the status furnished, timeline for complying with the lone pending recommendation is September, All above SR-Constituents are requested to complete their respective pending PAR. The IPP s for whom there are pending PAR [viz., Spectrum PGL, Konaseema GPL, APGPCL Vijjeswaram (Stage-I & Stage-II), & LANCO-Kondapalli PL] are also requested to complete them at the earliest. 12. Nomenclature for naming various files uploaded in web-based Tripping Monitoring System of SRLDC Portal The nomenclature to be followed by the Constituents in naming various files (FIR, DR, EL, TR) corresponding to a tripping incident was brought out in the SRPC letter No. SRPC/ SE-III/ PCSC-45/ dated and in the minutes of PCSC-45 issued vide SRPC letter No. SRPC/SE-III/ PCSC-45/ 2015/ dated As illustrated therein, the format to be followed for the user entered part-name is given below: Minutes of the 73 rd Meeting of PCSC held on 26 th April, 2018 Page 6

10 Transmission Element Transmission Line Inter-connecting Transformer Generating Transformer Generating Unit File Name to be given by the user SSN_DSN_line#_FT SSN_ICT#_FT SSN_GT#_FT SSN_Unit#_FT Where, SSN = Source Station Name/ From end Station Name/ Sending end Station Name DSN = Destination Station Name/ To end Station Name/ Receiving end Station Name FT = File Type (FIR/ DR/ EL/ TR) The following Constituents were found to be not using the above File Naming Nomenclature (FNN) for the tripping files uploaded in TMS portal for January February, 2018: NPCIL (KGS), KPTCL & PGCIL (SR-II) All SR-Constituents are requested to kindly intimate the above file naming nomenclature to all the concerned and ensure that it is strictly followed at all the stations in their respective control areas so that tripping analysis can be done systematically. 13. Date & Venue of the next PCSC Meeting It is informed that the 74 th meeting of PCSC will be held on 24 th May, 2018 (Thursday) from 10:30 hrs onwards in the Conference Hall of SRPC Secretariat, Bengaluru. ***** Minutes of the 73 rd Meeting of PCSC held on 26 th April, 2018 Page 7

11 Annexure-I

12 Annexure-I

13 Annexure-I

14 Annexure-I

15 Annexure-I

16 Annexure-I

17 Analysis of Grid Occurrences - 73 Annexure-II I. Details of Grid Disturbances: Sl. No. Details of Event Date &Time Reason Remarks Category 1 Complete outage of 220kV Hubli, Ambewadi and Nagjheri substations of KPTCL at 06:45 hrs 220 kv Hubli - Bidnal and 220kV Nagjhari-Bidnal also tripped on over current protection which resulted in tripping of running units at Nagjhari on over frequency protection. Complete outage of 220kV Hubli, Ambewadi and Nagjhari stations occurred due to cascaded tripping. As per Report furnished by KPTCL vide their mail dated : Gen Loss: 642 MW Load Loss: 136 MW GD-1 Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

18 Annexure-II For the above disturbance, there occurred a generation loss of 642 MW [550MW (NPH) + 92 MW (Supa)], and Load Loss of 136 MW [ Ambewadi (90MW), Hubli ( 46 MW)]. Outage of 220 kv Nagjheri PH: Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

19 Annexure-II Deliberations: It was noted that the above GD was primarily due to operational issues rather than protection issues as brought out below: It was clear that by 06:15 hrs the area under consideration was under depleted conditions due to tripping of various lines on transient faults on account of prevailing thick fog conditions, and was connected to grid by only five 220 kv lines, viz., 220 kv Hubli Narendra D/C line, 220 Hubli Bidnal D/C line, and 220 kv Nagjheri Bidnal S/C line. This was further accetuated by tripping of 220 kv Hubli Bidnal line-1 at 06:18 hrs followed by tripping of 220 kv Hubli Narendra line-2 at 06:44 hrs on transient faults. Around this time (06:45 hrs), instead of effecting generation reduction at Nagjheri, the 220 kv Hubli Narendra line-1 was hand-tripped to contain overloading as per SLDC, KPTCL instructions. With this, the only connecting link of the subject area with the grid, viz., 220 kv Nagjheri Bidnal line got heavily overloaded and tripped on backup O/C protection. Finally, with no lines left for evacuation, running Units of Nagjheri also got tripped on overspeed protection. From above, it was noted that since the subject area was prone to tripping of the lines on transient faults due to thick fog conditions, replacement of the existing insulators at identified locations with composite polymer type insulators would have helped alleviate the issue. Similarly, providing of A/R on all 220 kv lines in the area would have also helped mitigate the issue. It was also noted that due diligence (& vigilance) by SLDC, KPTCL in giving right/ timely instructions for the area under deplted conditions [effecting generation reduction in stead of tripping link lines) would have tackled the overloading issues from exacerbating. In this regard, KPTCL was enquired about (i) the status of A/R implementation on the 220 kv lines in the area under consideration, and (ii) the review of existing SPS at Nagjheri as recommended to them way back in February, To this, KPTCL replied that were actively pursuing A/R implementation on all 220 kv lines in the area, and planeed to put it in service within two-month period. As regards implementing modified SPS at Nagjheri PH, KPTCL assured that the scheme would be finalized in a couple of weeks, and would be submitted to PCSC forum in the next meeting for approval. In this regard, the status of implementation of Protection Audit Works at 220 kv Ambewadi SS was also discussed. As clarified in the recently held SRPC-33 meeting, KPTCL was asked to attend to them on priority basis without linking them with their new station proposal at Ambewadi. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

20 Annexure-II Complete outage of 220kV Narendra-PG (KPTCL), Belgaum, Chikkodi, 2 Ghataprabha, MKHubli, Mahalingapura, Soundatti, Athani and Kudachi Connectivity Diagram: at 09:13 hrs Triggering incident was tripping of 500 MVA ICT at Narendra. This resulted in overloading of downstream Karnataka system. Load Loss: 460 MW GD-1 Tripping of 400/ 220 kv ICT-1 from 220 kv side at Narendra SS : As per FIR/EL/TR, ICT-1 tripped from 220 kv side at 09:13: hrs on operation of HV side DOC protection. As per DR, ICT-1 tripped from 220 kv side at 09:16: hrs on operation of Over Load protection. Karnataka Partial GD: No tripping files (FIR/DR/EL/TR) were furnished. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

21 KPTCL: Antecedent conditions: Annexure-II At 9.13 Hrs, 220kV Mahalingapura line 1 &2 tripped at Vajramatti end on OCR due to over load (Flow was towards Mahalingapura prior to tripping). Due to this, 500MVA ICT tripped at Narendra Sub Station on over current protection and power supply to following 220kV substations failed: Narendra(KPTCL), Belgaum, Chikkodi, Gataprabha, MKHubli, Mahalingapura, Soudatti, Athani and Kudachi. Deliberations: It was noted that the above GD was again primarily due to operational issues rather than protection issues. It was noted that the present GD had occurred at 09:13 hrs before the system could fully recuperate from the GD that had occurred at 6:45 hrs on the same day. In fact, at the time of occurrence of the instant GD, the depleted conditions (forced outage of various lines) in the area were observed to be continuing. Here again, the role of SLDC, KPTCL in containing above kind of GD s was emphasized, since when 220 kv Vajramatti Mahalingapura D/C line started experiencing overloading conditions, and got tripped on back-up O/C protection, timely instructions to carry out load shedding at suitable locations would have prevented overloading of Narendra ICT-1 and its subsequent tripping on backup O/C protection. In this regard, KPTCL was asked to operationalize the SPS scheme finalized in OCC forum to contain overloading of Narendra ICT s at the earliest. To this, KPTCL replied in affirmative; and also informed that the pick-up value of back-up O/C protection of Narendra ICT s had been changed from 1.2 PU to 1.5 PU. Further, KPTCL was enquired about (i) the status of A/R implementation on the 220 kv lines in the area under consideration, and (ii) the review of existing SPS at Nagjheri as recommended to them in February, To this, KPTCL replied that were actively pursuing A/R implementation on all 220 kv lines in the area, and planeed to put it in service within two-month period. As regards implementing modified SPS at Nagjheri PH, KPTCL assured that the scheme would be finalized in a couple of weeks, and would be submitted to PCSC forum in the next meeting for approval. It was also conveyed to all that operation of back-up directional O/C or E/F protection on HV/ LV side of an ICT should result in tripping of the CB s on the same side or both sides of ICT. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

22 Annexure-II Complete outage of following 220kV stations of KPTCL Narendra (KPTCL), Bidnal, SRS Hubballi, Ambewadi 3 Haveri, Karwar, Belgaum, Chikkodi, Soudatti, ML Pura, Athani, Kudachi, Ghataprabha, MK Hubli, NPH, Kodasalli and Kadra Connectivity Diagram: at 10:01 hrs 220kV Kaiga-kadra and 220kV Kadra-Kodasalli lines tripped on backup over-rcurrent protection. 400/220kV Narendra ICT tripped on over load protection. Running units at Nagjhari and Kodasalli tripped due to non-availability of evacuation lines. Cascaded tripping occurred due to overloading of 220 kv network and there was complete outage of several stations of KPTCL. Gen Loss: 290 MW Load Loss: 500 MW GD-1 Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

23 A. Tripping of 400/ 220 kv ICT-1 at Narendra-PG: As per FIR/EL/TR, ICT-1 tripped from 220 kv side at 10:00: hrs due to operation of HV side OC protection. As per DR, ICT-1 tripped at 10:03: hrs due to operation of HV side Over Load protection (with delay of 400 msec). B. Tripping of 220 kv Kodasalli Kadra line: Kadra (KPCL) end: As per FIR, the line was kept holding from Kadra end. Kodasalli (KPCL) end: As per FIR/DR/EL/TR, line tripped at 10:01: hrs due to O/C operation. C. Tripping of 220 kv Kaiga Kodasalli line KPCL and KGS informed in the meeting that the line was holding from Kaiga end, and tripped at Kodasalli end on Directional O/C protection. D. Tripping of 220 kv Kaiga Kadra line: Kadra (KPCL) end: As per FIR, the line was kept holding from Kadra end. Kaiga (NPCIL) end: The FIR and TR formats were not the prescribed ones. The FIR format was the filled FIR of As per FIR/DR/TR, line tripped at 10:03: hrs due to backup DOC operation. In DR, the digital signal names were not configured. From the furnished EL, operation of Directional O/C protection could not be found. E. Outage at Nagjheri PH: As per FIR, the following was stated: Annexure-II DR & EL not furnished. E. Outage at Kodasalli PH: No tripping files (FIR/DR/EL/TR) furnished. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

24 KPTCL: Annexure-II Deliberations: Here again, the role of SLDC, KPTCL in operating the depleted system with extra care was emphasized. In this regard, KPTCL was asked to operationalize the SPS scheme finalized in OCC forum to contain overloading of Narendra ICT s at the earliest. KPTCL was also asked to provide A/R on all 220 kv lines in the area under consideration at the earliest, and to operationalize the modified SPS at Nagjheri as recommended to them way back in February, To this, KPTCL replied that were actively pursuing A/R implementation on all 220 kv lines in the area, and planeed to put it in service within two-month period. As regards implementing modified SPS at Nagjheri PH, KPTCL assured that the scheme would be finalized in a couple of weeks, and would be submitted to PCSC forum in the next meeting for approval. Recommendations: NPCIL (KGS) to use stipulated formats for furnishing FIR and TR. NPCIL (KGS) to configure DR s & EL s of all protection relays at their 400 kv & 220 kv Kaiga GS for recording all mandated protections. 4 Complete outage of 220kV Kemar, MSEZ Bajpe, Kavoor, Netlamandur (Puttur) and 400/ 220 kv ICT-2 at UPCL Connectivity Diagram: at 18:45 hrs Fault in 220 kv Kemar Bajpe line- 2 led to tripping of 220kV UPCL- Kemar Line-2 due to faulty LBB operation. Subsequently, lnie faults on 220 kv Varahi Kemar lines and UPCL Kemar line-1 led to complete outage of 220kV Kemar, MSEZ Bajpe, Kavoor, Netlamandur (Puttur). Load Loss: 500 MW GD-1 Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

25 A. Tripping of 220 kv Kemar Bajpe line-2: As informed by KPTCL, the line was tripped on B-E fault due to operation of O/C protection. B. Tripping of UPCL-Kemar line-2: UPCL end: No tripping files (FIR/DR/EL/TR) furnished. As per EL (furnished for ICT-2 tripping), line tripped at 18:33: hrs on B-E fault due to DPR, Z2 operation. From EL, it was also observed that LBB protection for 220 kv Bus-2 got operated at 18:33: hrs. Kemar (KPTCL) end: As per FIR, line was kept holding from Kemar end. C. Tripping of 400/ 220 kv ICT-2 at UPCL: As per FIR/DR/EL/TR, ICT-2 tripped from 220 kv side at 18:33: hrs due to LBB operation of 220 kv Bus-2. D. Tripping of UPCL-Kemar line-1: UPCL end: As per EL, line tripped at 18:45: hrs on B-E fault due to DPR, Z2 operation. Annexure-II KPTCL: Pre-fault conditions: Heavy lightning and rain around Kemar Sub Station area. Nature of fault: Tripping of all the lines emanating from Kemar Sub Station due to heavy lightning around that area. Sequence of tripping of lines which led to complete outage of Kemar Substation were as follows: : At hrs, 220 kv Kemar-Bajape line -2 tripped at Kemar end on OCR B-phase. Along with this, 220 kv UPCL-Kemar line-2 also got tripped at UPCL end on distance protection with following indication: DPR Zp (programmable zone) and Z2 Operated Dist kms, Ib=2.63 KA; Further, LBB which was enabled in MICOM P442 distance relay suspected to be mal-operated during the instance and tripped the elements connected to the bus at UPCL. Due to continued heavy lightning, at hrs, the remaining 220kV lines tripped at Kemar end with following relay indications: Kemar Varahi line-1: Tripped on DPR ABC Trip, Zone-1, RYN, Fault location= km; Kemar- Varahi line-2: Tripped on DPR,Zone-1, RYN, fault location L= km; Kemar- Varahi line-3: Tripped on DPR, Zone-1 fault. Kemar- UPCL line-1: Tripped on DPR, Z1 fault. (UPCL line-2 was already in open condition) The above trippings resulted in 220kV bus shut down to Kemar, MSEZ Bajpe, Netlamandur(Puttur) and Kavoor Sub stations. Remedial action: At Kemar, the distance relay of 220 kv Bajpe line - 2 checked and found to be in order. Resistive reaches have been reviewed. At UPCL, the programmable Zone Zp in MICOM P442 relay had been disabled. Load Loss: 500 MW [Radial Load of Kemar, MSEZ Bajpe, Netlamandur (Puttur), and Kavoor]. As per TR furnished by UPCL, the reasons for LBB operation at UPCL were brought out as given below: 18:33:44:959 Zp Operated. 18:33:45:165 Z2 Operated 18:33:45:287 Any Trip and 3P Trip operated. 18:33:45:289 Any Trip, 3P trip and other trip reset. 18:33:45:487- tbf1 Trip ON indicating circuit breaker failure protection operation. The BOs connected with Bus Bar Protection BU, operated to trigger external CB fail protection for 220 kv Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

26 Annexure-II Bus-2. All feeders connected to Bus-2 tripped on operation of LBB protection for Line-2. As per OEM scheme CB fail function is active in Line Protection relay. The CB fail protection output from Line relay is wired with Bay Unit of Bus bar Protection relay to operate bus LBB operation to trip connected bays directly. The above sequence of operation is explained as under. Micom P442 relay detected fault in Zp initially and on moving impedance, Z2 operated and initiated Relay internal Trip action for only 2 ms duration and turned reset. With Internal trip initiation the Breaker Failure Protection configured in Micom P442 relay as a art of OEM scheme configuration also initiated the CBF operation cycle. With only 2 ms of trip pulse from relay due to moving impedance, Trip Coil of Circuit breaker and also Master Trip relay could not be operated. The initiation for CBF function is of latch type as per function algorithm. Further line current was persisting as no physical tripping took place due to short trip pulse. Due to latched initiation through internal trip and persisting current, line CBF function operated after set time of 200 ms, which made Binary Input high for External CBF trip for BusBar Protection Bay Unit and extended LBB trip to bays connected with Bus-2. Remedial action taken: The CBF function in Line Protection relays and other feeder protection relay had been disabled. Individual feeder LBB protection is now available only with Bus Bar protection BU of each feeder. ZP function had been disabled since it was not necessary for line protection and to configure Z3 as per existing revised setting philosophy adopted. Deliberations: It was noted that the instant GD proceeded in stages first with tripping of lines on account of improper settings, then on account of transient line faults due to thunderstorms. First it all started with a high resistance fault on 220 kv Kemar Bajpe line-2 which was momentarily detected in Zone-2 (for about 2 msec) at UPCL end on 220 kv UPCL Kemar line-2. Though this did not result result in tripping of the corresponding line breaker at UPCL end, this did initiate LBB protection implemented from the line protection relay. Since this initiation was of latch type, its persistence combined with the presence of current at the end of LBB time setting of 200 msec had resulted in operation of LBB protection for 220 kv Bus-2 at UPCL. Consequently, all breakers connected to 220 kv Bus-2 including that of 220 kv UPCL Kemar line-2 got tripped. Here, it was noted that had re-trip feature of LBB been provided, it would have come to rescue under these circumstances. Subsequently, 220 kv UPCL Kemar lines 1 & 2 & 3 and 220 kv UPCL Kemar line-1 also got tripped on transient line faults. Here, it was noted that since Varahi Kemar area was prone to frequent line trippings on transient faults due to fog & thunderstorms, providing of A/R on all 220 kv lines and replacement of the existing insulators with composite polymer type insulators at suitable locations would have come to rescue under these circumstances. On this, KPTCL replied that they were actively pursuing A/R implementation on all 220 kv lines in the area, and planned to put it in service within two-month period. It was also assured that replacement of existing insulators with composite polymer type insulators, wherever required, would be undertaken. Recommendations: UPCL to provide re-trip feature for LBB protection of all breakers at their 220 kv Udupi power plant. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

27 5 Complete outage of 220kV Varahi power station at 22:36 hrs There was Y-phase to ground fault on 220 kv Varahi - Shimoga line-2. Consequent to persisting fault in Y phase, the breaker failure protection operated resulting in operation of 220KV bus bar protection at Varahi, tripping all the connected lines and Varahi running units. Gen Loss: 459 MW SLD: The single line diagram of 220 kv Varahai PH as furnished by KPCL is attached at the end. Bus Configuration: Double Bus with Bus-Coupler in OPEN position. --- (effectively single-bus operation) All elements, viz., Units 1 & 2 & 3 & 4 and Shimoga lines 1 & 2 & 3 and Kemar (Mangalore) lines 1 & 2 & 3 were on Bus (single-bus operation) 220 kv Varahi Shimoga line-2: Varahi (KPCL) end: As per FIR/DR/EL/TR, line tripped at 22:36: hrs on Y-E fault due to DPR, Z1 operation. It was stated in TR that even though A/R was initiated, due to non-transmitting of 1-ph trip command, LBB protection operated tripping all the connected 220 kv elements. KPCL: At 22:36:26 hrs on Y-phase to ground fault occurred on 220kV Varahi Shimoga-2 Line & Auto-reclose function initiated Single pole trip command for VS-2 Breaker along with LBB/CBF initiation command for Busbar Protection Panel. As the 1-phase Trip command was not extended to Y-phase Breaker pole, Busbar Protection CBF was activated thereby tripping all 6 Nos 220kV Lines & all 4 Nos running Units Remedial action: On thorough inspection of the Control panel of the VS2 line it was found that there was slight improper contact in the common terminal of Main-I and Main-II single phase tripping loop (Y-phase). The same was rectified and the line was charged. KPTCL: On at 22:36 hrs the 220KV bus shut down occurred at Varahi GS due to LBB operation. The single phase Y to G fault occurred in 220 KV Varahi-2 line at a distance of 8 km from MRS Shimoga fault and current was 7.6 KA in Y phase. At MRS Shimoga only V-2 line breaker had tripped and other two lines i.e V-1 & V-3 breakers were is closed condition. At Varahi Generating Station the distance relays connected to Varahi Shimoga-2 line had sensed that fault and extended the trip signal, but the pole has not opened, the DR recorded at Varahi end is Zone-1, FL-64.86km Ia=434.2A, Ib=2.629KA, Ic=383.7A. Consequent to persisting of fault in Y phase the breaker failure relay has operated and resulted in operation of 220KV bus bar protection at Varahi, tripping all the lines and Generators. Recommendations: KPCL to take steps to put double-bus operation into service at their 220 kv Varahi PH. Annexure-II GD-1 Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

28 6 Complete outage of 400 kv Sriperumbudur station at 18:01 hrs There was HV side Y-phase CT failure of 400/ 230 kv ICT-2 at Sriperumbudur. This resulted in tripping of all connected feeders and ICTs GD-1 Lower Voltage level events which are the root-cause of outage of higher voltage level station should also be included in TMS portal by SRLDC. SLD: Annexure-II The single line diagram of 400/ kv Sriperambudur SS as furnished by TANTRANSCO is attached at the end. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

29 Annexure-II A. BBP operation of 400 kv Bus-2: As per FIR/EL, BBP of 400 kv Bus-2 (Zone-2) operated at 17:49: hrs. It was stated in FIR that the failure (bursting) of 400/230 kv, 315 MVA, CGL MAKE, ICT-2 HV side Y-ph Main-CB CT had led to BBP operation. It was also noticed that LBB protection for HV side CB had acted. DR not furnished. In EL, CB poles status was not shown. B. Tripping of 315 MVA, 400/ 230 kv ICT-2: As per FIR/EL, ICT-2 tripped at 17:49: hrs on differential protection and at 17:49: hrs on Bus Bar Protection (BBP) operation. DR not furnished. In EL, CB poles status was not shown. C. Tripping of 315 MVA, 400/ 230 kv ICT-1: As per FIR, subsequent to above tripping, the ICT-1 connected to Bus-1 got tripped at 17:57 hrs on Pressure Relief Valve operation. DR & EL not furnished. D. Tripping of 200 MVA, 400/ 110 kv ICT-5: As per FIR, 400kV breaker connected to Bus 2 got tripped at 17:49: hrs on BBP operation. The LV breaker was stuck up and hence LBB protection operated. All the 110kV breakers got tripped due to this resulting in 110kV supply failure at Sriperumpudur. The 33kV tertiary Y-phase clamp also got cut. DR & EL not furnished. E. Tripping of 315 MVA, 400/ 230 kv ICT-3: As per FIR (& EL of that furnished for BBP operation of 400 kv Bus-2), ICT-3 tripped at 17:49: hrs on Bus Bar Protection (BBP) operation. The 400kV breaker connected to Bus-2 (CB-1752) got tripped on BBP. The 230kV LV breaker got tripped due to operation of LV O/C protection. As per DR/EL, the 230 kv CB got tripped at 17:47: hrs due to operation of O/C protection (with Toc = sec). Time sync of PR s with GPS needed to be ensured. As per Report furnished by PGCIL (SR-II) vide their mail dated : Sriperumbudur 400 kv Station commissioned in 1987 comprises 5 nos of 400kV lines and one Bus Reactor and 400kV Bus Extended to TANTRANSCO, where 3 ICTs of 315 MVA, 400/230kV rating and 2 ICTS of 200 MVA, 400/ 110 kv rating were connected in Utility Station. The 400 kv feeders connected to Sriperambudur are given below: Nellore-1 & km; SVC km; Tiruvalam km; Chittoor km; 5) 63 MVAR Bus Reactor. On , all the feeders at Sriperumbudur Switching Station were in Service. At 18:02 hrs, POWERGRID Switching Station & TANTRASCO 400/230/110kV Station became dead due to failure of Y-ph of Main CT Connected to ICT-2 (near 252 CB) failed. Upon failure, the Bus Bar Protection of 400 kv Bus-1 at TANTRANSCO operated and tripped its inter-tie CB (1152). However since the fault was not cleared successfully, it continued to be fed through 400 kv feeders (Nellore-1, Nellore-2, Tiruvalam & Chittoor, and SV Chatram) connected to Sriperumbudur (through the other inter-tie CB), and finally got cleared with the tripping of those lines on DPR, Z2 operation from the remote ends. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

30 Annexure-II Also Zone-4 protection operated in Nellore-1, Nellore-2, Tiruvalam & Chittoor lines and tripped at local end ( Zone-4 time kept at 0.5 Sec). In Sriperumbudur, all CBs except Bus sectionalizer CB of Bus-2 (1052), SVC Main CB (952) and Bus Reactor Main CB tripped at Sriperumbudur end. As per Report furnished by TANTRANSCO vide their mail dated : The 400kV HV Y phase, Mehru make CT of ICT -2 got burst on at hrs resulting in the following trippings. ICT-2 (400/230kV 315MVA): Tripped on differential protection (87) and Bus Bar Protection (BBP) operated to clear the fault. The breakers connected to Bus 2 got tripped on BBP. The 400 kv tie breaker dia & LV breaker got tripped due to operation of differential protection. The 400kV supply from PGCIL 400kV bus is extended to TANTRANSCO grid through Inter-tie breakers 1&2. The inter-tie Breaker-2 connected to Bus 2 got tripped on BBP. The 400kV breakers at PGCIL SS got tripped on Zone-2 from remote ends and on Zone-4 (reverse) in 500msec at Sriperambudur end. However, the SV Chatram feeder did not trip at Sriprambudur end. This breaker and Inter-tie Breaker-1 were hand-tripped ultimately due to absence of source. ICT-3 (400/230kV 315MVA): The 400kV breaker connected to Bus 2 got tripped on BBP operation. Due to this, the 230 kv LV breaker got tripped on LV O/C protection and the 400 kv tie breaker also got tripped through master relay. ICT-5 (400/110kV 200 MVA): The ICT-5 was connected to Bus2. Due to 400KV BBP, ICT-5 HV&LV and TIE got tripped thro 86-1&2 master relay and 96 relay respectively. LV-5 breaker LBB protection acted due to severe arcing in Y-phase unit tertiary bushing end clamp. All the 110kV breakers got tripped, resulting in 110kV supply failure at Sriperumpudur. The 33kV tertiary Y phase clamp also got cut. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

31 ICT-1 (400/230kV 315MVA): Subsequent to the above tripping the ICT-1 connected to Bus-1 got tripped on Pressure Relief Valve operation. ICT-4 (400/110kV 200 MVA): The HV breaker of ICT 4 was hand tripped since there was no source due to tripping of Intertie breaker connecting to PGCIL bus and LV breaker got tripped on LBB. 230 kv bus was fed from remote end substation and hence there was no interruption to 230 kv supply. Remedial measure: ICT-1 - Routine test, SFRA, Tan delta and DGA tests were conducted and found normal. ICT-2 was normalized through Tie-CB. The Main-CB CT yet to be replaced. Annexure-II Deliberations: It was noted that the same set of Bus and its Inter-tie CB are being regarded differently by TANTRANSCO and PGCIL (SR-II). What Bus-2 & CB-1052 for TANTRANSCO are regarded as Bus-1 & CB-1152 by PGCIL (SR-II); and what Bus-1 & CB-1152 for TANTRANSCO are regarded as Bus-2 & CB by PGCIL (SR-II) creating unwarranted confusion in analysing the things. Accordingly, TANTRANSCO and PGCIL (SR-II) were asked to adopt same nomenclature by discussing with each other. It was noted that the triggering cause of the GD, viz., blasting of HV side Y-ph CT of ICT-2 led to BBP operation of 400 kv Bus-2 (as per TANTRANSCO) resulting in tripping of all CB s connected to it. However, from the fact that ICT-3 LV (230 kv) side CB tripped on operation of O/C protection, it was clear that it s HV (400 kv) side CB-1752 connected to 400 kv Bus-2 had not tripped on BBP operation. It was also noted that the LBB protection employed for 400 kv side CB of ICT-3, which should have acted under these circumstances, had not acted. Hence, TANTRANSCO was asked to look into the healthiness of HV side CB of ICT-3 (CB-1752) and its LBB protection. It was also noted that blasting of HV side Y-ph CT of ICT-2 had resulted in LBB operation of its HV side CB connected to 400 kv Bus-2 (as per TANTRANSCO). When enquired about the same, TANTRANSCO replied that since the fault was not cleared, persistence of fault current at the end of LBB time setting had led to its operation. It was further noted that tripping of 110 kv Bus on LBB operation of LV (110 kv) side CB of ICT-5 was not in order. When enquired about the reasons for the same, TANTRANSCO replied that for operation of HV (400 kv) side protections, LBB trip had been wrongly configured for LV (110 kv) side breakers. Thus, in the instant case with BBP operation of 400 kv Bus-2, 110 kv side LBB protection was initiated. Then due to presence of current on 110 kv side (which in turn was due to nonclearance of fault) at the end of LBB time-setting, LBB trip was extended to all CB s connected to 110 kv Bus. As a remedial action, TANTRANSCO informed that this wrong configuration of LBB operation for HV side protections had been set right on Again when asked about the reasons for tripping of ICT-1, TANTRANSCO informed that they were suspecting that mechanical vibrations caused by CT blast might have increased the pressure inside the transformer tank leading to operation of PRV protection. It was also informed that the matter had been referred to its OEM (TELK) for suitable advice. Regarding the nature of the fault and its clearance, it can be seen from the event PMU plots given below that the fault got isolated from 400 kv side in about 550 msec from the instant of its occurrence, which validates Zone-2 operation from remote ends of 400 kv connected feeders at Sriperambudur: Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

32 Annexure-II Similarly from the DR corresponding to 230 kv side O/C protection operation of ICT-3 as given below, it can be seen that after isolation of fault from 400 kv side (which happened in about 550 msec from the instant of CT blast), balanced current began to flow through all phases after about 650 msec from the instant of CT blast: Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

33 Annexure-II However, by this time since 400 kv side, 110 kv side, ICT-1 & ICT-2 got isolated from the fault path, it can be seen that the load on ICT-3 was entirely due to fault; therefore it can be deduced that its balanced nature could be due to development of Y-ph arc (from CT blast) into a 3-ph one, which ultimately got interrupted by the operation of 230 kv side backup O/C protection of ICT-3. Recommendations: TANTRANSCO to ensure healthiness of 400 kv side CB of ICT-3 (CB-1752) and integrity of its LBB protection. TANTRANSCO to furnish equipment failure report of the current incident (CT blast) to PSE&TD Division of CEA with a copy marked to SRPC. TANTRANSCO to refer the instant case of PRV operation of ICT-1 to its OEM, and take appropriate action based on their advice. 7 Complete outage of 220 kv Vizag (Gazuwaka) switching station Connectivity Diagram: at 16:14 hrs Triggering incident was R-ph CT failure Bus-Coupler. This resulted in tripping of all the connected elements due to operation of bus bar protection. Load Loss: 700 MW GD-1 Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

34 Annexure-II Grid disturbance occurred at 16:14 hrs on in Vizag area PGCIL Gajuwaka MRS 1 ICT-1 Kakinada Kalapaka 1 Pendurthy kv VSS open Bus 1 220KV Kalapaka 220 KV Upper Sileru R ph C.T blast at 16:14 hrs C.T 1 BHEL make C.B 2 Bph -G,Z1 at 16:26 hrs 1 B ph-n,z1 at 16:15 hrs C.T kv VSS open Pendurthy 1 Bus 2 Dairy farm mva 100 mva PGCIL ICT-2 Kalapaka 2 Gangavaram MRS 2 Parwada H.T H.T H.T H.T 220KV Pendurthy mva 160 mva 160 mva 132 KV H.T H.T H.T 220KV Gajuwaka 220KV B.D.palem 220KV Garividi KV Kasimkota 132 KV Anandapuram BBP operation of 220 kv Buses - 1 & 2: As per DR/EL/TR, BBP for Buses 1 & 2 operated at 15:49: hrs on R-ph fault. Time-sync of PR s with GPS needed to be ensured at VSS. The following was stated in the furnished TR: Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

35 Annexure-II Tripping of 315 MVA, 400/ 220 kv ICTs 1 & 2: As per FIR/EL/TR, ICT s tripped at 16:14: hrs on 220 kv side only due to BBP operation on 220kV Buses, which in turn was due to Bus-Coupler s R-Phase CT blast at VSS. As per DR, ICT s tripped at 16:14: hrs on 220 kv side due to BBP operation on 220 kv Buses of VSS. It was noted that the triggering cause was the failure of Bus-Coupler s R-ph CT towards 220 kv Bus-1. When enquired about the reasons for its failure, APTRANSCO informed that the failed CT (BHEL make) was an old one (YoM: 2003), and were investigating the same. Subsequently, it was replaced by another CT of CGL make. In this regard, APTRANSCO s attention was brought to PGCIL (SRTS-I) concerns regarding the health of their HVDC equipment at their Gajuwaka station being effected on account of frequent disturbances on 220 kv side, and enquired about following required maintenance activities for substation equipment & line maintenance practices as mandated by CEA Grid Standards and IEGC Regulations. It was also pointed out that subsequent tripping of 220 kv VSS Dairyfarm lines 1 & 2 on jumper cuts indicates the need for APTRANSCO to put concrete efforts in this direction. At this juncture, APTRANSCO s attention was also brought to earlier recommendation of SRPC given in the context of multiple trippings in Kalpaka-Gajuwaka-NTPC corridor in April, 2016 to provide one more thermo-vision camera to Vizag division for use exclusively on 400 kv & 220 & 132 kv transmission lines emanating from Kalpaka, Gajuwaka, VSS, Pendurti and other adjoining substations of APTRANSCO. When enquired about its compliance, APTRANSCO replied that they would revert on the issue soon. Recommendations: APTRANSCO to furnish equipment failure report of the current incident (CT blast) to PSE&TD Division of CEA with a copy marked to SRPC. APTRANSCO to take steps to provide one more thermo-vision camera to Vizag division for use exclusively on 400 kv & 220 & 132 kv transmission lines emanating from Kalpaka, Gajuwaka, VSS, Pendurti and other adjoining substations of APTRANSCO. 8 Complete outage of 220 kv Sedam station. Connectivity Diagram: at 17:55 hrs For the faults on 220 kv Humnabad Sedam line-2 and 220 kv Shahapur Sedam line, the breakers at Seadam did not trip, due to which the fault had to be got cleared from remote ends. Load loss: 44 MW GD-1 Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

36 Antecedent conditions: At Sedam, all 220kV lines and Transformers were taken on Bus-2 as Bus-1 selector Isolator jump was cut in Bus coupler bay at Sedam SS. (effectively single-bus operation) 220 kv Sedam SS outage: As per FIR, for the RY fault on 220 kv Sedam Shahapur line, the Sedam end CBB did not trip. Due to this the fault was continued to be fed from remote ends, and resulted in tripping of them on back-up protections (DPR, Z2 / DPR, Z3). 220 kv Sedam Shahapur line-1: Tripping event not added in TMS. SRLDC should add triggering cause event for the main event in TMS portal. 220 kv Sedam Tandur line: Sedam (KPTCL) end: As per FIR, line tripped at 7:55 hrs on RY fault due to DPR, Z1 (9.6 km) operation. DR/EL/TR not furnished. Tandur (TSTRANSCO) end: As per FIR/DR/EL, line tripped at 17:56: hrs on R-Y-E fault due to DPR, Zp (Tzp = 600 msec) operation. KPTCL: Annexure-II Remedial action: After detailed inspection, it was found that R phase PT found burn at PT terminal and the same was replaced on Action was also taken to enable non directional OC/EF protection to get activated automatically in the event of PT fuse fail condition. In this regard, KPTCL was enquired about the time-frame for providing LBB and BBP protections and double-bus operation at 220 kv Sedam SS, to which it was informed that the works are under progress, and are targeted to be completed by May, SLD: Disturbance North Kerala. in at 17:15 hrs 400/220 ICT# 1&2 tripped at Kozhikode station while carrying out CT testing works pertaining to 400/220kV ICT-3 at Kozhikode Load Loss: 800 MW GD-1 The single line diagram of 400/ 220 kv Kozhikode SS as furnished by PGCIL (SR-II) is attached at the end. Bus Configuration of 400/ 220 kv Kozhikode SS: Double Main Bus and Transfer Bus (with Bus Coupler) Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

37 Bus arrangement at 220 kv Areacode SS: Annexure-II Tripping of 400/ 220 kv ICT-2: As per FIR/ DR/EL, ICT-2 tripped at 17:14: hrs on LBB (Main-CB) protection. It was stated in TR that along with ICT-2, ICT-temporary also got tripped. It was also seen in EL that BBP operation of 400 kv Bus-1 occurred at 17:14: hrs. Tripping of 400/ 220 kv ICT-1: As per FIR/ DR/EL, ICT-1 tripped at 17:14: hrs on HV DOC protection. It was also seen in EL that BBP operation of 400 kv Bus-1 occurred at 17:14: hrs. It was noted that the time delay of sec observed above was in order as brought out below: Outage of 220 kv Areacode SS: As per FIR/DR/EL/TR, total power failure occurred at 17:15: hrs on 220 kv PGCIL#1, PGCIL#2 and PGCIL#3 feeders due to LBB operation on ICT-2 and ICT-3 at 400 kv Power grid Kozhikode SS; and consequent DOC operation on ICT-1 due to over load. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

38 From SRLDC s preliminary report, the following was noted: Annexure-II Tripping of 400 kv Kozhikode Mysore line2: Mysore (PGCIL-SR2) end: As per FIR/ DR/EL/TR, line tripped at 17:15: hrs due to DT receipt from remote end. Kozhikode (PGCIL-SR2) end: As per FIR/ DR/EL/TR, line tripped at 17:15: hrs due to OVR, Stage-I operation. In EL, OVR-I_Start and OVR-I_Trip signals were not found. (Not configured?) As per Report furnished by PGCIL (SR-II) vide their mail dated : Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

39 Annexure-II In this context, KSEBL was enquired about the reasons for non-operation of SPS operationalized for preventing over-loading of the remaining ICT upon tripping of one of the in-service ICT s. To this, KSEBL replied that the said SPS was put in place when there were only two ICT s. But after commissioning of ICT-temporary in parallel with ICT-2 in early 2017, the SPS was kept out of service to prevent unwarranted trippings (in case of tripping of ICT-1, the parallel combination of the other two ICT s would be sufficient to feed the loads). On this, SRPC/ SRLDC pointed out that such unilateral action was not in good faith. Because any SPS finalized through SRPC fora cannot be kept out of service without approval of the same from SRPC. In this regard, it was decided to have to a review of various Special Protection Schemes in SR in OCC forum to avoid unwanted surprises such as above in the nick of time to facilitate integrated grid operation. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

40 II. Details of Grid Incidents: Annexure-II Sl. No. Details of Event Date &Time Reason Category 1 Tripping of HVDC Kolar-Talcher Pole at 16:15 hrs Pole-1 tripped due to clogging of the mechanical filter of valve cooling system at Talcher. Emergency Switch Off (ESOF) was received at Kolar end. Pole 2 went into metallic return mode after the tripping of Pole-1. Kolar (PGCIL-SR2) end: As per FIR, ESOF signal was received at 16:14 hrs from Talcher end. Due to this, Pole-1 got tripped resulting in loss of power from 1500 MW to 1018 MW at Talcher end. This in turn resulted in transmission of trip signals Trip-1, Trip-2 & Trip-3 from Kolar end to obtain load relief. As per TR furnished by Kolar (PGCIL-SR2) end: Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

41 Annexure-II As per Preliminary Report of SRLDC: Pole-1 of HVDC Talcher-Kolar got tripped due to clogging of the mechanical filter of Pole-1 valve cooling system at Talcher. Emergency switch off (ESOF) was received at Kolar end. Pole 2 went into metallic return mode after the tripping of Pole-1. SPS of HVDC Talcher-Kolar (Trip 1) got operated resulting in load loss of 973 MW. SPS operation details: 2 Tripping of 400/220 kv ICT-1 at N Sagar at 16:43 hrs ICT-1 got tripped due operation of Sudden Pressure Relief Device. Suspected mal-operation. Nagarjunasagar (PGCIL-SR1) end: As per FIR/DR/EL/TR, ICT-1 tripped at 16:43:43:148 hrs due to operation of SPRD (Sudden Pressure Relief Device). In EL time-resolution was configured up to msec. only. Reasons for SPRD operation? GI-2 Remedial action taken by PGCIL (SR-I): During checking of mechanical protections of ICT-1 unit after major O/H, spurious Buchholtz trip signal was extended to ICT-1. Instructed the site to ensure isolation of mechanical protection of spare unit before starting any work. 3 Tripping of HVDC Talcher-Kolar pole at 09:38 Hrs Pole-1 tripped due to external protection operation at Talcher end. Emergency Switch Off (ESOF) was received at Kolar end. Pole 2 went into metallic return mode after tripping of Pole-1. Kolar (PGCIL-SR2) end: As per FIR, ESOF signal was received at 09:38 hrs from Talcher end. Due to this, Pole-1 got tripped resulting in loss of power from 2300 MW to 996 MW at Talcher end. This in turn resulted in transmission of trip signals Trip-1 from Kolar end to obtain load relief. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

42 As per TR furnished by Kolar (PGCIL-SR2) end: Annexure-II As per Preliminary Report of SRLDC: Pole-1 of HVDC Talcher-Kolar got tripped due to external protection operation at Talchar end. Emergency switch off (ESOF) was received at Kolar end. Pole 2 went into metallic return mode after the tripping of pole-1. SPS of HVDC Talcher-Kolar (Trip 1) got operated resulting in load loss of 935 MW. SPS operation details: Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

43 4 Tripping of 765 kv Kurnool-Tiruvalam line at 11:08 hrs DT Received at Kurnool. 86A, 86B operated due to 705 bay CB gas compartment lock-out at Tiruvalam Annexure-II Kurnool (PGCIL-SR1) end: As per FIR/DR/EL/TR, line tripped at 11:08: hrs due to DT receipt from remote end. Tiruvalam (PGCIL-SR2) end: As per FIR/DR/EL/TR, line tripped at 11:08: hrs due to 705 CB gas compartment Gp-1 lockout-1 operation. GI-2 Remedial action taken by PGCIL (SR-I): PGCIL (SR-I) informed that the tripping was due to wrong configuration of Gas Density Monitor s different Stages (with Stage-I for Trip and Stage-II for Alarm). This was subsequently rectified. In DR, it was observed that B-ph current became zero immediately. However, currents in the other two phases were persisting (shown interval was 1.15 sec) albeit at a lower value. PGCIL (SR-I) was asked to examine reasons for the same, and inform the action taken to PCSC forum. 5 Multiple trippings at 220 kv Guttur SS at 06:45 Hrs There was a Y-phase to ground fault on 220 kv Guttur Haveri line-1. This triggered bus bar protection operation and Bus-1 tripped. As reported 220 kv Guttur was on single bus operation. Reverse FNN followed by KPTCL SLD: The single line diagram of 220 kv Guttur SS as furnished by KPTCL is attached at the end. Connectivity Diagram: GI-1 Antecedent conditions: Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

44 220 kv Guttur Haveri line-1: Guttur (KPTCL) end: As per FIR/DR/EL/TR, line tripped (in 3-ph) at 06:41:19:025 hrs on Y-E fault due to DPR, Z1 (30.99 km; ka) operation. It was stated in FIR that 220 kv BBP also got operated during the incident. KPTCL: Annexure-II Due to this, Complete outage on 220kV side occurred at Guttur and Haveri Sub Stations during the instance. Load loss due to the incident was around 80 MW Remedial action: Feedback of OEM M/s GE was sought for making necessary modification in the PSL logic; till such time dead zone protection has been disabled in the newly commissioned 220kV bus bar Protection scheme at Guttur. It was noted that the KPTCL has presently employed 1.2 PU as the current setting for dead-zone protection. Since this resulted in operation dead-zone protection of Busbar scheme, it would do good to increase this setting after comparing the short circuit contribution of individual lines with their respective normal load currents. Alternatively, KPTCL was also suggested to explore the possibility of providing line-side Isolators after CT so that the effect of lines under outage on the in-service elements can be avoided. In this regard, KPTCL was enquired about the status of providing numerical BBP on 400 kv side, to which it was informed that the works have almost been completed except for want of some control cables, whose procurement will be taken up after completion of Karnataka state elections. 6 Multiple trippings at 220 kv Sharavathy Power station at 22:05 hrs The incident happened during shifting of Unit-8 from 220 kv North West bus to 220 kv South West Bus. The 220 kv buses got tied together without synchronizing which resulted in operation of bus bar protection. SLD: The single line diagram of 220 kv SGS as furnished by KPCL is attached at the end. GI-1 Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

45 Annexure-II Bus-Configuration: Two main 220 KV buses- 220 KV North and South buses these 2 buses are bifurcated in to four by providing a bus sectionalizer arrangement - North East, South East, North West and South West. Antecedent conditions: North West bus and South bus were in Split bus operation. North East bus was under shutdown. 220 kv BBP operation of 220 kv NW-Bus Section and SW-Bus Section: As per FIR/DR/EL/TR, BBP operation of 220 kv 220 kv NW-Bus Section and SW-Bus Section took place at 22:02: hrs. In FIR, the following was stated: At SGS Split BUS was in service (In NW BUS Unit Nos. 8,9,10 and 220kV Lines SS1 & SS2). Station was running under source SOUTH Bus. (Unit Nos. 1,2,3,4,5,6,7 and 220kV lines S1,S3,S4, ST1,ST2, ST3, SB) were in service. At 19:27 Hrs. SS1-220kV line tripped on Zone-1, Y-phase, DPR Dist=15Km, I=2.41KA. SS1 line charged but line again tripped on R-ph, Dist=16.1Km. In North West- Bus, only SS2-220kV line of 200MW capacity was in service. But the Generators No.8, 9 and 10 totaling 300MW was tied on NW Bus. To maintain stability at SGS NW Bus, decision was taken to put Unit No. 8 on SOUTH Bus as per the directions of LDC. Hence Unit No.8 220kV breaker was opened. Then 89S Isolator (U#8) was closed while 89N Isolator (U#8) was in closed condition. Bus tied through Isolators and Bus bar operated. Remedial action: Standard operating procedures (SOP) not followed in spite of having SCADA interlocks. SOP shall be followed. KPTCL: Sharavathi Generating Station there are two main 220 KV buses namely 220 KV North and South buses these 2 buses are bifurcated in to four by providing a bus sectionalizer arrangement and named as North East, South East, North West and South West respectively. On , 220 KV South bus was main load bus, unit nos 1, 2, 3, 4, 5, 6, 7 and 220 KV lines Shimoga 1,3 &4 Talaguppa 1,2 and 3 and Belligavi (Shiralakoppa) lines were on South bus. Unit Nos 8, 9,10 and 220 KV Sirsi 1 &2 lines were on North West bus section of 220 KV North bus. 220kV Sharavathy- Sirsi -1 was under LC due to line fault. Due to tripping Sirsi-1 line, only 220 KV Sirsi-2 line and 3 units were on North west bus. As informed by KPCL it was intended to shift unit no-8 on 220 KV South West section of south bus in order to maintain stability. The breaker of unit no-8 was opened and without opening the 220 KV North West bus isolator the 220 KV South West bus isolator was closed as a result both 220 KV buses were tied together without synchronizing and phase to phase fault has developed (B&C phase) resulting in operation of bus bar protection. The operation of bus bar protection has resulted in tripping of 220KV SS1, SS2, S3, S4 & ST2 and unit are 6, 7, 8, 9 & 10 connected to faulty North West and South West buses. However simultaneously the 220 KV ST-1 & ST-3 lines connected to 400 KV Station Talaguppa tripped at Talaguppa end on DPR in Zone-1. The distance recorded is 26 km and 16 km in MICOM P442 distance relays at Talaguppa. The actual full line distance of 220KV ST-1 & ST-3 line is 30 km & 20 km respectively. Reason for tripping of these lines in Zone-1 is being investigated. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

46 Annexure-II Deliberations: It was noted that even though the instant GD was due to more of an operational issue, the protection aspect to be addressed in above kind of outages had long been brought to KPCL s attention, which was about implementing full-fledged double-bus operation at Sharavathy GS. Even though the Bus-Configuration for Sharavathy GS has been designed for a full-fledged doublebus operation with four sections, it is mostly run on single-bus operation with two sections with both the bus-couplers in OPEN condition and the other bus being used solely as a transfer bus. The disadvantages of split-bus operation such as one practiced at SGS were noted as follows: It permanently results in sort of two mini-stations operating independently. One would have to de-energize a running Unit in order to move it from one Bus to another Bus Buses will not be in sync with each other The purpose of B/C CB s can never be realized. It was therefore once again emphasized on the need to using full-fledged Double Main-Bus system with four sections instead of the present Single Main-Bus with two sections. KPCL s reason behind resorting to above split-bus operation, viz., the need to undertake maintenance activities for the elements can be addressed by bringing the element to be attended on to a particular bus-section, and then by isolating it from the rest of the system by opening corresponding Bus-Sectionalizer CB and Bus Coupler CB. It was also noted that at least bringing in Bus-Coupler CB (into service) before effecting changeover of a running Unit from one Bus to another Bus would have helped in preventing the above GD. W.r.t. tripping of 220 kv Talaguppa Sharavathy lines 1 & 3 due to DPR, Z1 operation for the fault at SGS, it was noted that it was a typical case of over-reach of the distance relay. However, since the subject area was not very critical (fault currents are well below switchgear ratings), KPTCL was asked to check the settings employed for distance protection for these lines at Talaguppa, and revise them suitably considering the latest fault levels. Recommendations: KPCL to take steps to using full-fledged Double Main-Bus system with four sections instead of the present Single Main-Bus with two sections at their 220 kv Sharavathy GS. 7 Multiple trippings at 400 kv Guttur Substation at 08:25 hrs 400 kv Guttur-Kaiga-1 Breaker was in lock-out condition. It was intended to take Kaiga line-1 on tie CB. While carrying out this operation bus bar protection operated at Guttur resulting in tripping of all connected elements. FNN not followed by KGS Reverse FNN followed by KPTCL SLD: The single line diagram of 400 kv Guttur SS as furnished by KPTCL is attached at the end. Bus-Configuration: Two Main Bus and Transfer Bus. GI-2 Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

47 Annexure-II Antecedent conditions: 400kV Kaiga-Guttur line-2 was under outage since 4th March 2018 (04:28 Hrs) due to insulator flashover (B-phase to ground fault). The line was restored at 13:37 hrs on 23rd March kv Kaiga-Guttur line-1: Kaiga (NPCIL) end As per FIR/EL/TR, line tripped at 08:10: hrs due to DT receipt from the remote end. As per DR, line got tripped at 08:08: hrs. In DR, DT receipt event was not configured. Guttur (KPTCL) end: As per FIR/DR/EL/TR, line tripped repeatedly starting from 08:17: hrs to 08:34: hrs due to continuous DT receipt in channel-1, and at 08:24: hrs due to LBB operation with 400 kv Bus-1 No load loss was reported due to the event. From PMU data plots of phase voltages and sequence currents for the event, no fault was observed. From the PMU data voltage plot, considerable difference was observed between B-phase and R&Y phase voltages of 400kV Guttur Bus. KPTCL: At Guttur, 400kV Kaiga line-1 Circuit Breaker went into lock out due to low oil pressure. It was intended to take 400kV Kaiga Line-1 on Tie-CB. For this, first Transfer Bus was charged, then the pantograph type Transfer Bus Isolator was closed. Then, after closing Tie-CB, the Isolator across it was opened. During this process, due to improper contact making of Transfer Bus Isolator, severe arcing took place, and BBP got operated tripping all breakers connected to 400 kv Bus-1 along with sending of DT to the remote end. However, since operation of 86X trip relay at Kaiga end had been configured to send DT to the remote end, DT was also received at Guttur end from Kaiga end. This mutual sending of DT between both ends continued several times due to PLCC link problem at Guttur end. At this juncture, when it was pointed out there was no actual fault in the system, and tripping of 400 kv Bus-1 connected elements was recorded as due to LBB operation, KPTCL replied that they would find out the proper reasons for the same and revert soon. Remedial action: The matter was referred to our TCD wing for rectifying the problem with PLCC of Guttur-Kaiga lines. Recommendations: NPCIL (KGS) to take steps to disable sending of DT to remote ends upon 86X operation for any line protection operation at its 400 kv KGS. KPTCL to resolve PLCC issues on 400 kv Guttur Kaiga lines at the earliest. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

48 8 Tripping of 400 kv Pavagada-Tumkur line- 1, 400/ 220 kv ICT-1&2 at 400 kv Pavagada SS at 14:18 Hrs Multiple trippings occurred during charging of 400 kv Pavagada-Tumkur line- 2. Annexure-II SRLSC should ensure that usage of Names for various tripping events/ elements in TMS portal and PCSC Agenda match. SLD: The single line diagram of 400/220 kv Pavagada SS as furnished by PGCIL (SR-II) is attached at the end. GI-2 Antecedent conditions: At Pavagada station, Gooty D/C lines, Tumkur 3 & 4 D/C lines along with 2 No s 500MVA transformers were in service. At Tumkur station, Kudgi line-2, Bidadi D/C Lines, Pavagada 3&4 DC lines were in service. Kudgi-1 line was out of service due to system conditions. Tumkur Pavagada Line-1 was charged from Tumkur end at 12:41Hrs and synchronized at Pavagada end at 12:44Hrs. A. Tripping of 400 kv Pavagada-Tumkur line-1: Tumkur (PGCIL-SR2) end: As per FIR, line was kept holding from Tumkur end. Pavagada (PGCIL-SR2) end: As per FIR/DR/TR, line tripped at 14:18: hrs on Y-E fault due to DPR, Z2 (with tz2 = 0.39 sec) operation. EL not furnished. (Furnished EL was the event summary of DR) B. Tripping of 400 kv Kudgi-Tumkur line-2: Tumkur (PGCIL-SR2) end: As per FIR/DR/EL/TR, line tripped at 14:18: hrs due to DT receipt from remote end. In DR, DT receipt event was not configured (this signal was shown as Virtual Output7). Kudgi (PGCIL-SR2) end: As per FIR/DR/EL/TR, line tripped at 14:18: hrs due to DEF (Main-2) operation. The observed time delay for DEF operation was about sec. C. Tripping of 400/ 220 kv ICT-1 at Pavagada SS: As per FIR/DR/EL/TR, ICT-1 tripped at 14:18: hrs due to operation of backup E/F protection. The observed time delay for DEF operation was about sec. D.Tripping of 400/ 220 kv ICT-2 at Pavagada: As per FIR/DR/EL/TR, ICT-2 tripped at 14:18: hrs due to operation of backup E/F protection. The observed time delay for DEF operation was about sec. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

49 Annexure-II E. Tripping of 400 kv Pavagada Tumkur line2: As informed by PGCIL (SR-II), line tripped due to operation of OVR, Stage-II protection (2.145 sec after occurrence of the fault) at Pavagada end. As per Report furnished by PGCIL (SR-II) vide their mail dated : Sequence of Important Events are as following: a) At 12:41 hrs, Tumkur Pavagada Line-1 was charged from Tumkur end and synchronized at Pavagada end at 12:44Hrs. b) At 14:18:08:050 hrs, Pavagada Tumkur Line-2 Charged from Tumkur End c) At 14:18:08:605 hrs, Pavagada Tumkur Line-1 tripped from Pavagada end on Zone 2 Y-G fault (505 ms) d) 14:18: ICT-2 at Pavagada Tripped on LV side Earth Fault Protection (1.175s) e) 14:18: ICT-1 at Pavagada Tripped on LV side Earth Fault Protection (1.964s) f) 14:18: Tumkur- Kudgi line tripped on DEF protection at Kudgi end. g) 14:18: Tumkur-Pavagada line-2 got tripped on OV protection stage-2 operation at Pavagada end ( 2.145sec) Observations at Pavagada end: a) Tumkur-Pavagada Line-1 tripped on Y-G fault in Zone-2. b) ICT-1 & 2 tripped on operation of Back up Earth fault Protection c) Even though Tumkur-Pavagada Line-1 tripped on Zone-2, Tumkur-Pavagada Line 3 & 4 were not tripped either in Zone-2 or Zone-3 or DEF protection. d) Tripping of Pavagada-Tumkur Line-1: The Zone Settings of Line-1&2 of Pavagada line (159.7Km) is (LILO of Tumkur-BTPS D/C line of KPTCL): Z1: Ohms, Z2: 50 Ohms(td:500ms) Z-3 is 84.2 Ohms(Td:1.5s) As the Fault in Line-2 was not cleared at Tumkur end. The fault was seen by the line-1 in Zone-2 (Tumkur-Pawagada-1 is highest Zone -2 setting among the other lines in service at that time). The fault impedance was found to be around 48 to 51 ohms, which is almost equal to Zone-2 Setting. Hence the tripping of Line-1 is found to be in order. e) Tripping of ICTs 1 & 2: The ICT-1 &2 Backup Earth fault settings as per the CC-Engg is TMS: 0.13 & PMS-0.2. As per the IEC normal inverse timing: (0.14 * TMS/(Falut current PU/PMS)^0.02-1) comes to 1.1 sec for Earth Fault current of 733 A. As the current was varying from 733A to 360A, based on the overall effective Disc simulation time, the 67IN trip element picked up after Sec for ICT-2 and sec for ICT-1. It is to mention that the Impedance values of ICT-1 & 2 is different. ICT-1 (12.1%), ICT-2 (11.6%) as per the name plate and load sharing is observed around 217 MW & 230 MW respectively. Hence ICT-1 & ICT-2 tripped accordingly with corresponding delay time. Hence the tripping of ICTs was found to be in order. f) Reason for Non-tripping of Pavagada-Tumkur lines - 3&4: The Zone Settings of Line-3&4 of Pavagada line (104.7Km) is (LILO of Gooty-Tumkur D/C line) is as follows: Z1: 14.8 Ohms, Z2: (Td:500 ms) Ohms Z-3 is 84.2 Ohms(Td:1.5s) The reason for non-operation of Tumkur -Pavagada lines - 3 & 4 on Zone-2/3 or DEF could be due to the fault impedance seen by Pavagada -1 line which is around 50 ohms which is greater than zone-2 but less than zone-3 setting. As per the fault characteristic, the fault current reduced after 500ms after tripping of Line-1. As the Zone-3 timing is 1.5 Sec and the fault impedance was varying which seems to have increased as per DR, the Zone-3 element might have been reset after initial pickup. Also, the DEF setting for line is TMS:0.49, PMS:0.1 with the fault current comes to around 2.48 sec, whereas the fault cleared in 2.14 sec. It was observed that DEF has picked up at 14:18:08:059 for both lines. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

50 Observations at Tumkur end: Annexure-II Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

51 Annexure-II Remedial measures taken: The Y-Ph CVT Capacitance and Tan delta and Y-Ph LA IR value were tested and found healthy at Tumkur end. Secondary injection was done and the mutual compensation circuit neutral discrepancy in termination was corrected at Tumkur end. Both Main-1 & Main-2 Relay testing of Tumkur Line 1 &2 carried out for critical parameters like SOTF & DEF etc. Detailed Zone testing would be carried out by site. Tumkur Line Settings and ICT settings checked with Standard Template for correctness at Pavagada end. The BPS-Tumkur line ownership pertaining to KPTCL and the LILO portion pertaining to POWERGRID. The Line was kept charged from BPS-Tumkur for very Short period and kept out of Service. It was understood that in the KPTCL portion a tamarind tree was lying below the line caused the fault. The same was removed on Station personnel were advised to check the Mutual compensation scheme to avoid such type of unintended operations. Site people were also instructed to ensure thorough patrolling in the entire line before charging of the same is undertaken. Recommendations: PGCIL (SR-II) to review SOTF settings at Tumkur end on Tumkur Pavagada lines considering the least expected fault current levels. 9 Tripping of HVDC Talcher-Kolar Pole at 15:12 hrs As per TR furnished by Kolar (PGCIL-SR2) end: Talcher Kolar Pole-1 tripped due to mal operation of DC protection system at Talcher end and Emergency Switch OFF (ESOF) signal received at Kolar end. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

52 Annexure-II As per Preliminary Report of SRLDC: The recovery sequences operated several times from 13:45 hrs prior to tripping of Pole-1. Pole-1 came automatically to RVO mode at 14:20 hrs due to repeated recovery sequences. In Reduced Voltage Operation (RVO) mode, pole operates at 80% of the rated voltage and the power transfer capability of the pole also reduces to 80% of the rated capability. Normally HVDC pole switches automatically to RVO mode after unsuccessful recovery from DC line fault. Subsequently at 15:12 hrs, Talcher-Kolar Pole-1 tripped due to mal-operation of DC protection system at Talcher end and Emergency Switch OFF (ESOF) signal was received at Kolar end. Recovery sequences can be observed from the SCADA data plot prior to tripping of Pole-1 at 15:12 hrs. Talcher-Kolar Pole-1 went into Reduced Voltage Mode of operation at 14:19 hrs and after several recovery attempts, the Pole-1 tripped at 15:12 hrs. At the same time, Pole -2 went to metallic return mode. At around 20:28 hrs on , while attempting to charge Pole-1, Pole-2 went to ground return mode due to sequence failure with a power flow ~ 140MW. Pole-2 was in ground return mode for around 46 mins. Pole-1 was successfully de-blocked at 21:09 hrs and normal operation of Talcher-Kolar bi-pole was restored. Deliberations: It was noted that the reasons for repeated voltage recovery sequences were not brought out in the report furnished by Kolar HVDC. Further, if this was due to any DC fault, the reasons for Kolar end not experiencing the same also needed to be explained. Weather this DC fault was local to Talcher or on the Pole was also needed to be clarified. It was also noted that the reasons for Pole-2 going into ground-return mode while attempting to de-block Pole-1 at around 20:28 hrs were not furnished. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

53 Annexure-II It was further noted that SPS operation did not take place both at the time of tripping of Pole-1 at 15:12 hrs and also at the time of Pole-1 de-blocking when Pole-2 went into ground-return mode. The same needed proper explanation. Recommendations: PGCIL (SR-II) to furnish a detailed report on the instant tripping explaining clearly the reasons for repeated voltage recovery sequences, reasons for Pole-2 going into ground return mode while attempting Pole-1 de-block around 20:28 hrs, and non-operation of SPS (i) at around 15:12 hrs when the Pole-1 was blocked, and (ii) at around 20:28 hrs when Pole-2 went into ground return mode. 10 Tripping of HVDC Talcher-Kolar Pole at 13:31 Hrs As per TR furnished by Kolar (PGCIL-SR2) end: HVDC Talcher - Kolar Pole-1 got tripped due to failure of measurement in DC protection system at Talchar end. Emergency switch off (ESOF) was received at Kolar end. Pole 2 went into metallic return mode after the tripping of Pole-1. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

54 11 Multiple trippings at 220 kv Trichur station at 21:27 hrs Triggering incident was bus section Y-phase CT flashover. This resulted in tripping of all the elements connected to bus section 1A and 1B. Annexure-II SLD: The single line diagram of 400/ 220/ 110 kv Trichur SS as furnished by KSEBL is attached at the end. Outage of 220 kv Trichur station: As per FIR, Bus Zones A & B tripped at 21:26:55 hrs due to BBP operation, which in turn was due to failure of Y-ph CT of Bus-Sectionalizer. It was stated that since BBP relay was static, DR & EL were not available. Tripping 315 MVA, 400/ 220 kv ICTs -2 & 3: As per FIR/EL/TR, ICT s tripped at 21:26: hrs due to BBP operation of 220 kv Bus Zones A & B. As per Report submitted by KSEBL vide their mail dated : Antecedent conditions: 220kV feeders 2MDMR, and 2LPMD2 were under permit to work A portion of the 220kV C bus (2A) was under shutdown for bus up gradation works ICT#1, 2MDAR and 200MVA#2 were on Zone C ( bus 2B) ICT#2,ICT#3 and 2LPMD1 were on Zone-A (bus 1A) 2ELMD,2MDPK,2SHMD AND 200MVA#1 were on Zone-B (bus 1B) Bus-sectionalizer and Bus-coupler 1 were in closed condition, Bus-coupler 2 in open condition The Incident: At 21:26 hrs, the Y phase CT of 220kV sectionalizer bay flashed. Zone A and Zone B bus differential relays operated. All the bays connected to Zone 1A and zone 1B tripped along with Bus-sectionalizer and Bus-coupler 1. ICT#1, 2MDAR and 200MVA#2 which were on Zone-C remained in service. Tripping of ICT#2 & #3 resulted overloading of ICT #1. SPS for the ICT overloading operated and tripped some 110kV feeders. Restoration Details: Bus-sectionalizer was isolated and after extinguishing the fire, Bus 1B and corresponding feeders were put back in service. To reduce the overloading of ICT #1, split bus operation was resorted to. Since Bus-sectionalizer CT was faulted and Bus 2A was in permit to work for bus strengthening, there was no provision to restore ICT#2 & 3 and LPMD1 immediately. Analysis: Operation of Zone A and Zone B differential relays were in order as the fault was in the overlapping zone. The fault was also seen cleared by the protection in around 50 ms. The flashed CT was of SCT make with 2000A rating which was commissioned during The SCT make CTs have a bad performance history. Remedial measures: The CTs were replaced (these CTs were already intended for replacement as part of bus upgradation works) and ICT #2,ICT#3 and LPMD1 restored. GI-1 It was noted that the BBP relay was a static one, due to which DR & EL events corresponding to BBP operation had not been captured. It was therefore suggested that KSEBL should go for Numerical BBP at their 220 kv Trichur SS. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

55 Annexure-II 12 Tripping of 400 kv RTPS - Mehbubnagar line at 20:11 Hrs Line tripped on operation of SOTF protection from RTPS end during BBP operation of 400 kv Bus-1. GI-2 Mehboobnagar (TSTRANSCO) end: As per FIR/EL/TR, line tripped at 20:11: hrs due to DT receipt from remote end. RTPS (KPCL) end: As per FIR/EL/TR, line tripped at 20:11: hrs due to SOTF operation. The following was stated in TR: Remedial action: Tripping of RTPS-Mahbubnagar line-1 on initiation of SOTF was not appropriate. Due to the frequent ON/OFF detection of Line closure from Main-1 distance relay at the time of Bus-1 fault, line got tripped on SOTF protection. Charged the RTPS-Mahbubnagar line with Tie Breaker at 22:02:41 Hrs after getting the clearance from SLDC. It was informed that SOTF issue had been referred to OEM, an assured that it would be sorted before next PCSC meeting. Charged the Bus-1 at 22:31:50 Hrs after isolating the Main Breaker of ICT-2 (552-1) and getting clearance from LDC. III. Details of Trippings due to Failure or Non-operation of Auto-Reclose: Sl. No. Element Date & Time Reason 1 Tripping of 400 kv Gooty-Narnoor line at 07:20 hrs Line tripped on Y-phase to earth fault due to agricultural fire. Auto-reclose attempt was unsuccessful. Tripping of 400 kv Gooty-Narnoor line-1 Gooty (PGCIL-SR1) end: As per FIR/DR/EL, line tripped (Y-ph) at 07:20: hrs on Y-E fault due to DPR, Z1 (A/R; 5km) operation, and tried to auto-reclose after about 1.1 sec; but tripped in 3-ph due to persistent fault. It was noted from DR that Tie-CB tried for A/R after 2 sec even though Main-CB got tripped in 3- ph on unsuccessful A/R attempt. Narnoor (APTRANSCO) end: As per FIR/DR/EL, line tripped (Y-ph) at 07:20: hrs on Y-E Fault due to DPR, Z2 (CAT, A/R) operation, and tried to auto-reclose after about 1 sec; but tripped in 3-ph due to persistent fault. It was noted from DR that the roles of Main-CB and Tie-CB got interchanged in that Tie-CB tried for A/R with dead-time of 1 sec; while Main-CB tried for A/R with dead-time of 2 sec. Further, both CB s tried for A/R independently even though one of them had tripped in 3-ph due to unsuccessful A/R attempt. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

56 Annexure-II Remedial action taken by PGCIL (SR-I): Line was tripped on Y-N fault due to agri-fire at Loc No. 768 & 769 near Gooty (GTY End: 5KM, 11KA & KLN End: KM, 4.21KA). Ground patrolling carried out from Loc No. 756 to 799 and found agri waste fire marks were observed below the conductor in between loc No. 768 to 769. Marks were observed on Y-Ph conductor. Already preventive measures were taken like distributing pamphlets to the villagers/ land owners not to fire the waste below the line. Complaint raised in local police station. Recommendations: PGCIL (SR-I) and APTRANSCO set right the observed discrepancy in A/R operation for Main-CB & Tie-CB at Gooty and Narnoor ends respectively at 05:40 Hrs (Line-2) Line tripped on R-G fault. Autoreclose 400kV Krishnapatnam at 2 successful at Krishnapatnam end but Nellore-1 & 2 07:51 Hrs (Line-2) unsuccessful at Nellore end at 6:27 Hrs (Line-1) Tripping of 400kV Krishnapatnam Nellore-Line-2 at 05:40 hrs: Krishnapatnam (APGENCO) end: As per FIR/DR/EL, line tripped (in R-ph) at 05:40: hrs on R-E fault due to DPR, Z1 (A/R; 13km) operation, and successfully auto-reclosed after about 1 sec. Nellore-AP (APTRANSCO) end: As per FIR/DR/EL, line tripped (in 3-ph) at 05:40:16:380 hrs on R-B fault due to DPR, Z1 operation. Tripping of 400kV Krishnapatnam Nellore-Line-2 at 07:51 hrs: Krishnapatnam (APGENCO) end: As per FIR/DR/EL, line tripped (in R-ph) at 07:51: hrs on R-E fault due to DPR, Z1 (A/R; km) operation, and successfully auto-reclosed after about 1 sec. Nellore (APTRANSCO) end: As per FIR/DR/EL, line tripped (in 3-ph) at 07:51:23:733 hrs on R-B fault due to DPR, Z1 operation. Remedial action taken by APTRANSCO for Line-2: The flashed over Insulators changed at Loc.No.49 (All three phases) & Loc.no 66 (Top-phase) on & Tripping of 400kV Krishnapatnam Nellore-Line-1 at 06:27 hrs Krishnapatnam (APGENCO) end: As per FIR/DR/EL, line tripped (in R-ph) at 06:27: hrs on R-E fault due to DPR, Z1 (A/R; 17 km) operation, and successfully auto-reclosed after about 1 sec. Nellore (APTRANSCO) end: As per FIR/DR/EL, line tripped (in 3-ph) at 06:27: hrs on R-B fault due to DPR, Z1 operation. Remedial action taken by APTRANSCO for Line-1: The flashed over Insulators at Loc.No.49 on had been changed It was noted that in all above trippings, the fault was detected as RE fault from Krishnapatnam end and R-B fault from Nellore-AP (Manubolu) end. APTRANSCO was asked to take up the issue with the relays OEM, and take appropriate action including replacing the concerned distance relays (REL-670). Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

57 3 Tripping of 400kV Kaiga- Narendra line at 13:25 hrs FNN not followed by KGS (NPCIL) and PGCIL (SR-II) 400 kv Kaiga- Narendra Line-2 tripped on R-E fault. At Narendra end auto reclose could not be attempted due to direct trip receive from Kaiga. From EL of Kaiga, R-phase Zone-1 trip and A/R lock out were observed. Tripping of 400kV Kaiga-Narendra line-2 Narendra(PGCIL-SR2): As per FIR/EL, line tripped at 13:25: hrs on R-E fault due to DPR, Zone-1 (101.2 km) operation & DT receipt from Kaiga end. DR furnished was irrelevant (02:53: hrs on 01/09/1980) and nothing could be deciphered from it. Kaiga (NPCIL) end: As per FIR/DR/EL, line tripped (in 3-ph) at 13:24: hrs on RY fault due to DPR, Z1 (32.38 km) operation. It was noted that whenever operation of 86X trip relay takes place at Kaiga on account of any 400 kv line protection operation, DT would be sent to the remote end. The same had happened in the instant case. Recommendations: NPCIL (KGS) to take steps to disable sending of DT to remote ends upon 86X operation for any line protection operation at its 400 kv KGS. 4 Tripping of 400 kv ILFS- Nagapattinam PS line at 10:32 Hrs Annexure-II R-phase to earth fault had occurred in line. Autoreclose attempt could not be validated with submitted DR of Nagapattinam end. ILFS end: As per FIR, line tripped (in R-ph) at 10:32:14 hrs on R-E fault due to DPR, Z1 (A/R; 46.5 km) operation, and auto-reclosed successfully. From the furnished DR & EL, successful A/R operation of the line could not be established (due to restricted time-scales; in DR this was 0.6 sec). Nagapattinam PS (PGCIL-SR2) end: As per FIR/DR, line tripped (in R-ph) at 10:32: hrs on R-E Fault due to DPR, Z1 (8.1 km) operation. But within 40 msec into A/R dead-time, the other two poles also got opened. In DR, time scale was restricted to 200 msec. ILFS and PGCIL (SR-II) were asked to configure DR s for capturing complete A/R operation (pretrigger 500 msec; post-trigger 2.5 sec) Recommendations: PGCIL (SR-II) to furnish a report on the reasons for A/R non-operation, and the remedial action taken to rectify the same. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

58 IV. Details of Trippings due to PLCC mal-operation: Annexure-II Sl. No. Element Date & Time Reason 1 Tripping of 400kV Kaiga- Guttur line at 17:23 hrs Line tripped on operation of direct trip received at both ends due to suspected PLCC mal operation. Kaiga (NPCIL) end: As per FIR/DR, Line tripped at 17: hrs due to DT received from other end. As per EL line tripped at 17:21: hrs. Guttur (KPTCL) end: As per FIR/DR/EL, Line tripped at 17:21: hrs due to receipt of DT from Kaiga end. NPCIL(KGS): On at 17:21 hours, 400kV Kaiga-Guttur (Line-2) tripped on receipt of direct trip at both end. During the event at KGS end the Guttur line-2 PLCC channel-1 Tx-A and Rx A counter are increased by one digit and no changes in Channel-2. As per information from Guttur end the PLCC channel-1 was increased abnormally and channel-2 increased by 3 digits. On same day, Line was taken into service at 18:42 hours vide CPCC-CP-02/723 and SRLDC - CR-02/917 codes. It was noted that DT sending from Guttur end was due to PLCC link problem. Therefore, KPTCL was asked to resolve PLCC issues on 400 kv Guttur Kaiga lines at the earliest. It was also noted that DT sending from Kaiga end was due to operation of 86X trip relay at Kaiga end, which has been configured to send DT to the remote end on its operation. Therefore, NPCIL (KGS) was asked to take steps to disable sending of DT to remote ends upon 86X operation for any line protection operation at its 400 kv KGS. 2 Tripping of 400kV Srisailam-Narnoor line at 14:54 Hrs Tripped on direct trip receive at Srisailam and line was holding from Narnoor. Suspected PLCC maloperation. Narnoor (APTRANSCO) end: As per FIR, line was kept holding from Narnoor end. Srisailam (TSGENCO) end: As per FIR/DR/EL/TR, line Tripped at 11:29: hrs due to DT receipt from NARNOOR end. Remedial action: W.r.t. above tripping, TSGENCO and APTRANSCO informed that they had conducted PLCC endto-end testing on , and the link was found to be healthy. Further, APTRARNSCO also informed that the PLCC voltage pick-up settings were increased from 75 V to 143 V, and Narnoor station was thoroughly checked for D/C earth fault. Since this kind of event occurred for the first time, and the required precautions had already been taken, it was decided to keep the line under observation for behavior of PLCC link. Tripping of 400 kv 3 Pondicherry-S.V.Chatram line. Pondicherry (PGCIL-II) end: S.V. Chatram (PGCIL-SR2) end: at 17:58 hrs As per FIR, line was kept holding from Pondy end. Line tripped at SVChatram end only and was holding from Puducherry. No fault was observed from DR of S.V.Chatram. Suspected PLCC mal-operation. As per FIR/DR, the line tripped at 17:58:52:092 hrs due to DT rreceipt from Puducherry end. As per EL, DT was received at 17:58:55:334 hrs. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

59 Annexure-II Recommendations: For the line under consideration, the following shall be carried out by PGCIL (SR-II), in coordination with TSTRANSCO: (i) End-to-end communication for DT/ permissive & other signals may be ensured by testing at both the ends. (ii) Healthiness of PLCC system components (hardware and software) at both ends shall be checked and faulty components shall be repaired/ replaced. 4 Tripping of 400 kv Vijaywada Vemagiri (PG) line-2 and 400 kv Vijaywada Vemagiri (PG) line at 18:02 Hrs Line tripped on receipt of DT at Vemagiri from Vijayawada end. Line was holding from Vijaywada end. Due to severe DC earth fault at Vijaywada DT was initiated. Tripping of 400kV Vijayawada-Vemagiri (AP) Line-2: Vijayawada (PGCIL-I): As per FIR, line was kept holding from Vijayawada end. Vemagir(PGCIL-I): As per FIR/DR, line tripped at 18:02:51:642 hrs due to DT receipt from remote end. As per EL, line tripped at 18:02:52:132 hrs due to DT receipt from remote end. Tripping of 400kV Vijayawada-Vemagiri (PG) Line-3: Vijayawada(PGCIL-I): As per FIR, line was kept holding from Vijayawada end. Vemagir(PGCIL-I): As per FIR/DR/EL, line tripped at 18:02:52:161 hrs due to DT receipt from remote end. Remedial action taken by PGCIL (SR-I): Due to severe DC earth leakage, DT was initiated from VJA end. DC E/F rectified immediately. The spurious DT signal during DC E/F taken up with OEM 5 Tripping of 400 kv Kaiga- Guttur line at 16:44 Hrs Direct trip was sent while Changing over from Tie- Breaker (transfer CB) to Normal Breaker (Line breaker) at Guttur end. Reverse FNN used by KPTCL Kaiga (NPCIL) end: As per FIR/DR, line tripped at 16:41: hrs due to DT receipt from remote end. Guttur (KPTCL) end: As per FIR/DR/EL, line tripped at 16:44: hrs due to DT receipt while effecting change-over from Tie-CB to Main-CB. KPTCL: At Guttur, Kaiga line-1 was taken on Tie-CB due to lock out of line CB on While restoring normalcy by changing over to line s Main-CB from Tie CB, Direct Trip signal was sent to remote end. This was due to manual error, as the trip command was given with NIT switch in Normal bus mode instead of in Transfer bus mode. Due to this, trip command went straight to Main-CB along with sending of DT to the remote end. Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

60 6 Tripping of 400 kv Ghanapur-Mamidapalli line at 11:00 Hrs Line tripped at Mamidipally end only & line was holding from Hyderabad end. Severe DC earth leakage in source-1&2 initiated DT from Hyderabad end. Ghanapur (PGCIL-SR1) end: As per FIR, As per FIR, line was kept holding from Ghanapur end. Mamidapalli (TSTRANSCO) end: As per FIR/EL, line tripped at 10:59: hrs due to DT receipt from remote end. As per DR, line tripped at 10:58: hrs due to DT receipt from remote end. Annexure-II PGCIL (SR-I): Line tripped due to DT send from HYD end. DT was initiated due to severe DC E/F in DC System-1&2 at HYD end. The DC E/F was subsequently removed. There were two DTPC s at Ghanapur (these belong to TSTRANSCO). To attend to above kind of maloperations, recently an external fast acting relay that acts at higher voltage levels was placed in one of the DTPC extension circuit. TSTRANSCO should take steps to replicate the same for the other DTPC also. Alternatively, they may also increase the voltage pick-up settings of DTPC suitably by modifying its relevant internal logics. On this, TSTRANSCO was asked to consider PGCIL (SR-I) suggestions, and take appropriate action to prevent above kind of mal-operations in future at Tripping of 400 kv Line-1&2 got tripped on Direct Trip receive at 17:17 hrs (Line-1) 7 Arasur-Karamadai line- Karamadai end and the line was in service from at 1&2 Arasur end. Suspected PLCC mal-operation. 18:11 hrs (Line-2) Tripping of 400kV Karamadai- Arasur Line-1 at 17:17 hrs: Arasur (PGCIL-SR2) end: As per FIR, line was kept holding from Arasur end. Karamadai (TANTRANSCO) end: As per FIR/EL, line tripped at 17:17: hrs due to DT receipt from remote end. Tripping of 400kV Karamadai- Arasur line-2 at 18:11 hrs: Arasur (PGCIL-SR2) end: As per FIR, line was kept holding from Arasur end. Karamadai (TANTRANSCO) end: As per FIR/EL, line tripped at 18:10: hrs due to DT receipt from remote end. As informed by TANTRANSCO, it was noted that the lines had been put into service without thoroughly checking the integrity of PLCC link. Recommendations: For the line under consideration, the following shall be carried out by PGCIL (SR-II), in coordination with TANTRANSCO: (i) End-to-end communication for DT/ permissive & other signals may be ensured by testing at both the ends. (ii) Healthiness of PLCC system components (hardware and software) at both ends shall be checked and faulty components shall be repaired/ replaced. ***** Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

61 Single Line Diagram of 220 kv Varahi PH of KPCL (Ref: I.5) Annexure-II Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

62 Single Line Diagram of 400/ kv Sriperambudur SS of TANTRANSCO (Ref: I.6) Annexure-II Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

63 Connectivity Diagram of 220 kv Vizag SS of APTRANSCO (Ref: I.7) Annexure-II Grid disturbance occurred at 16:14 hrs on in Vizag area PGCIL Gajuwaka MRS 1 ICT-1 Kakinada Kalapaka 1 Pendurthy kv VSS open Bus 1 220KV Kalapaka 220 KV Upper Sileru R ph C.T blast at 16:14 hrs C.T 1 BHEL make C.B 2 Bph -G,Z1 at 16:26 hrs 1 B ph-n,z1 at 16:15 hrs C.T kv VSS open Pendurthy 1 Bus 2 Dairy farm mva 100 mva PGCIL ICT-2 Kalapaka 2 Gangavaram MRS 2 Parwada H.T H.T H.T H.T 220KV Pendurthy mva 160 mva 160 mva 132 KV H.T H.T H.T 220KV Gajuwaka 220KV B.D.palem 220KV Garividi KV Kasimkota 132 KV Anandapuram Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

64 Single Line Diagram of 400/ 220 kv Kozhikode SS of PGCIL (SR-II) (Ref: I.9) Annexure-II Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

65 Single Line Diagram of 220 kv Sharavathy GS of KPCL (Ref: II. 5 & II.7) Annexure-II Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

66 Single Line Diagram of 220 kv Sharavathy GS of KPCL (Ref: II.6) Annexure-II Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

67 Single Line Diagram of 400/ 220 kv Pavagada SS of PGCIL (SR-II) (Ref: II.8) Annexure-II Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

68 Single Line Diagram of 400/220/ 110 kv Trichur (Madakathara) SS of KSEBL (Ref: II.11) Annexure-II Grid Occurrences to be discussed in the 73r d Meeting of PCSC scheduled to be held on 26 th April, /52

69 Annexure-III Status of Pending Implementation of PCSC Recommendations as on (up to 73rd Meeting) Meeting No / Index Details of Event Date & Time Reason PCSC Recommendations Utility responsible for Implementation Status of Implementation of PCSC Recommendations Remarks Latest Status (To be filled up by the Constituent) Multi-Utilities 34/I/6 400/220 kv ICT-1 & 2 at Munirabad As reported directional over current relay of ICT s operated due to snapping of line jumper in 220kV Lingapur line. 1. Bus bar protection shall be provided by asset owner ( i.e KPTCL). 2. Settings for main distance protection & Overcurrent protection shall be examined and reviewed. 3. Time synchronization of the Substation shall be ensured. KPTCL/ PGCIL (SR-I) KPTCL Mail dated : 1. KPTCL has taken action to provide bus bar protection to 220kV buses. --- Pending 2. Over current relay Settings of ICTs to be reviewed by PGCIL. --- Pending Pending KPTCL Mail dated : 1. Initial Tendering stage. --- Pending Pending Pending Pending (with KPTCL) KPTCL Mail dated on : 1. Detailed estimate prepared for taking up the work. CEE, Transmission Zone, Gulbarga will take up necessary procurement and further execution. --- Pending Pending with PGCIL (SR-I) Pending PGCIL (SR-I) Mail dated : 2. Relay settings of all the stations in SRTS-1 were derived as per Ramakrishna Commettee recomendations and implemented" --- Completed. KPTCL Mail dated : 1) & 3). DPR is approved. Tender is to be called by CEE,TZ Kalaburgi --- Pending Review Meeting dated : 1. KPTCL informed that Tenders for providing BBP would be called in Jan-Feb, 2018; Supply of the same is targeted by September, 2018; Erection & Commissioning is targeted by January, Pending 3. PGCIL (SR-I) informed that time-synchronization of 220 kv side is in place. --- Completed. 47/I/2 Complete outage of Krishnapatnam TPS at 18:20 hrs As per FIR submitted, CT damage observed in Chitoor- Main bay (404). Main breakers connected to bus-1 (401, 404, 407, 410) got tripped on operation of bus bar protection. Unit-1 tripped on operation of MFT. Unit-2 was not in service 1. APGENCO to furnish to PCSC forum (i) A3-size Single Line Diagram of SDSTPS, and (ii) the sequence of events with time stamp showing the protection that opened Tie-CB (405) at SDSTPS. 2. APGENCO to review STUB/TEED protection in all dias at SDSTPS and ensure that they are configured for instantaneous operation. 3. APGENCO to properly configure the STATE of the tripping events so that they get recorded appropriately like TRIP/ OPERATED in their corresponding Event Loggers. 4. APGENCO to ensure time sync of all DR s and EL s at SDSTPS. 5. PGCIL (SR-I) to provide line differential protection for 400 kv NPS Nellore-PG lines 1 & 2. APGENCO/ PGCIL (SR-I) APGENCO letter dated : Pending 1.SOE and SLD are attached. The DR of 405 CB is not generated during the incident. Now the [with problem is identified and rectified. PGCIL (SR-I)] Completed 2.All the 3 lines i.e CHTR-2, MNBL-I & II tripped in zone protection. The fault was in Blind zone i.e P2 side of CT, where it was covered under Bus fault by the time fault moved on to P1 side when the fault comes under STUB/TEED zone after 330msec all the feeders expect CHTR-1 tripped in Zone-II and total fault persisted for 500msec before the 405 TIE CB opens and clear the fault. As a remedial the STUB protection operation also checked and found OK Completed 3.The Time Sync was missed on the day and found there was problem with LAN Timer same was rectified. Now found OK Completed 4.Now the DR Time scale changed to 1 sec for Pre fault and 3 sec for Post fault and STATE of events are corrected wherever found wrong/or misguiding during analysis completed. PGCIL-SR1 RVMD : 5. Procurement of differential protection for 400kV NPS-NLR D/C and 400kV RCR-RTPS-D/C is under tendering. PGCIL-SR1 RVMD : 5. The proposal for procurement of Line differential Protections for 400kV Raichur - RTPS-1 & 2 and 400kV Nellore - NPS - 1 & 2 lines has been approved and tender is under technical evaluation PGCIL (SR-I) Mail dated : PGCIL: On LDP relays commissioned in place of Main-1 distance relay in 400kV NPS- Nellore line-2 & In line-1 installation of LDP relay is planned in Dec-2017/Jan Review Meeting dated : Page 1 of 38

70 Review Meeting dated : 5. PGCIL (SR-I) informed that LDP commissioning on both lines would be completed by February, In this regard, PCSC made it clear that the recommendation pertains to providing LDP as both Main-I & Main-II on both the lines, and asked PGCIL (SR-I) to ensure & comply with the same. Annexure-III 47/II/7 Tripping of 220 kv Kadra-Karwar at 220kV Kadra-Karwar lines-1&2 tripped 1. KPTCL/ KPCL to see the possibility of implementing Weak KPTCL/ KPCL/ KPTCL Mail recieved on : lines - 1&2 and 220kV Kaiga- Kadra line 11:44 hrs on earth fault in B-phase in zone-2. Kaiga-Kadra line tripped at Kaiga end only on operation of directional eath Infeed logic with Echo feature enabled by Under Voltage (27) element on Kadra-Karwar lines 1 &2, and implement the same if feasible. NPCIL (KAPS) fault protection. 2. NPCIL to time-coordinate Kaiga s DEFR settings with (i) Zone-2 settings at Kaiga, and (ii) primary protections of the lines emanating from Kadra and Kodasalli. 1. Availability of week end infeed with eco feature to be confirmed by SEE,RTC,Hubli --- Pending. NPCIL (KGA) Mail recieved on : 2. The 200 ms Definite time DEFR element in both Kaiga Kadra and Kaiga Kodasally lines were disabled. IDMT DEFR is retained. The 200 ms Definite time back up o/c element in both Kaiga Kadra and Kaiga Kodasally lines were disabled. IDMT is retained. --- Completed. Pending [with KPTCL] 3. KPCL to ensure time-sync of EL s, and healthiness of the Fault Locators at Kadra. Status received vide KPCL mail dated & : 1. Since PT blasted (B phase) at Karwar end, resistive over reach occurred. hence Backup protecion operated at Kadra end (zone-2 not sensed) --- Pending Completed 3.Newly commissioned micom P444 relay time synchronised with GPS Completed. KPTCL Mail dated : 1. Week end infeed logic will be enabled in the new numerical relays supplied to Karwar under R&U during retrofitting works. --- Pending Review Meeting dated : 1. KPTCL informed that since the line is a double circuit, there may not be need for implementing Weak Infeed logic with Echo feature at Karwar end. However, the same would be looked into w.r.t. the newly commissioned NR's at Karwar, and final action taken would be informed by March, /I/2 Complete outage of TPCIL power station at 06:02hrs Running units at Thermal Powertech power Station tripped due to tripping of 400kV Nellore pooling station 1.PGCIL (SR-I) to furnish Action Taken Report on the findings of OEM on relay mal-operation at NPS end on 400 kv NPS PGCIL (SR-I), MEPL, SEL, TPCIL, (NPS)-TPCIL line and 400kV Nellore pooling station (NPS)- NCC line to PCSC forum. NCC NCC line 2. PGCIL (SR-I) to appropriately configure Station Event Logger at NPS to record events at msec interval. 3. PGCIL (SR-I) to carry out PLCC end-to-end testing in coordination with TPCIL for 400 kv NPS TPCIL line. 4.PGCIL (SR-I), MEPL, SEL, TPCIL & NCC to take steps to provide line differential protection at their respective ends on all 400 kv lines (except Gooty line) emanating from Nellore Pooling Station, and furnish an action plan to implement the same. PGCIL (SR-I) mail received on : 1. The firmware of REL670 is being upgraded Completed. 2. The recording of events in msec interval is being taken up with OEM. Henceforth, for analysis purpose, we will provide larm list which has msec time stamp Completed. 3. End to end testing of PLCC code transmision and tuning of channels carried out Completed. 4. Procurement of differential protection for 400kV NPS-NLR D/C and 400kV RCR-RTPS-D/C is under tendering. The legends modified in Event/alarm list. Provision of diff. relay for all short lines emanating from NPS is being taken up with our corporate Pending. PGCIL(SR-I) RVMD : 4. The proposal for procurement of Line differential Protections for 400kV Raichur - RTPS-1 & 2 and 400kV Nellore - NPS - 1 & 2 lines has been approved and tender is under technical evaluation --- Pending Pending PGCIL (SR-I) Mail dated : 4. LDP relays procurement is under process. Procurement will be completed by Feb TPCIL has to give written confirmation for LDP relay procurement. For want of written confirmation from TPCIL, PGCIL approving authority has withheld the LDP proposal. Review Meeting dated : 4. PGCIL (SR-I) informed that they are waiting for written confirmation from TPCIL to complete procurement of LDP relays. To this, PCSC forum asked TPCIL to submit written confirmation to PGCIL (SR-I) by PGCIL (SR-I) assured that with receipt of above confirmation from TPCIL by Dec, 2017, they would be able to complete the work by FEbruary, APTRANSCO informed that they would be able to implement LDP from their & APGENCO side by April, In this regard, PCSC forum made it clear that the recommendation is about providing LDP as both Main-I & Main-II relays on all stated lines in Nellore Complex, ans asked all stakeholders to ensure & comply with the same. Page 2 of 38

71 Annexure-III 51/II/6 Tripping of 400kV Sattenapalli- Vijayawada line at 3:01 hrs Line tripped due to operation of over voltage protection at Vijayawada end and Direct Trip was received at Sattenapalli end 1. PGCIL (SR-I), in co-ordination with APTRANSCO, to address the problem with CB at the earliest opportune time. 2. APTRANSCO to take steps to replace the faulty Event Logger at Vijayawada (Nunna) SS. PGCIL (SR-I)/ APTRANSCO PGCIL mail received on : Being pursued with APTRANSCO APTRANSCO mail dated on : AS maintenance being carrired out by PGCIL(SR-1), the required relay replacement (wiring/programming) may also be carried out by PGCIL(SR-1). PGCIL RVMD : 1. The CB problem has been attended by POWERGRID by using OEM M/s BHEL services & POWERGRID's O&M spares Completed. 2. Being pursued with APTRANSCO to replace the faulty Event Logger at Vijayawada (Nunna) SS Pending APTRANSCO mail dated on & & : As maintenance being carrired out by PGCIL(SR-1), the required relay replacement (wiring/programming) may also be carried out by PGCIL(SR-1). APTRANSCO mail dated : May be coordinated with PGCIL APTRANSCO mail dated : PGCIL may be requested to take necessary action Pending [with APTRANSCO] APTRANSCO mail dated : 2. EL procured and drawn. Configuration to be done by Alstorm company engineer. Will be configured in four weeks. ---Pending PGCIL (SR-I) Mail dated : 2. APTRANSCO is to replace the faulty/outdated relays & POWERGRID has to maintain the relays after retrofitting. Review Meeting dated : 2. APTRANSCO informed that the recommended works would be completed in one-month period. APTRANSCO Mail dated As per the requirement of PGCIL.Event logger(bcu) with data base is configured and handed over to PGCIL/Nunna on 27 th dec 17.PGCIL is requested to take action for taking event logger (BCU) into service. 56/I/2 Complete outage of 220kV Sedam Substation of KPTCL at 15:27hrs 220kV Sedam-Humnabad-2 tripped at Sedam on Distance protection, Zone-2. Sedam-RTPS-1 &2 lines tripped at RTPS end only. 220kV Tandoor inter-state line was hand tripped due to incoming supply failure KPTCL and TSTRANSCO to take steps to provide A/R feature on 220 kv Sedam Tandur inter-state line at their respective ends at the earliest. KPTCL/ TSTRANSCO KPTCL Mail dated : Carrier protection is to be restored. B/U OC and EF relay is to be replaced by M-II distance relay. Required materials like wave trap, M-II distance relay are already supplied. The work will be taken up on top priority through GE Ltd. --- Pending Pending [with KPTCL] Review Meeting dated : TSTRANSCO informed that they have kept A/R in service from Tandur end. KPTCL informed that the works relating to put A/R in service are going on at their Sedam SS, and assured that it would be put into service by February, Page 3 of 38

72 Annexure-III 56/II/13 Tripping at 220 kv Gooty Substation of APTRANSCO at 16:04 hrs LBB protection got operated for 400/220kV ICT-2 breaker which had resulted in tripping of 220kV Bus-2 at 220kV Gooty Substation 1.APTRANSCO to check the healthiness of the connecting cable between Gooty (PGCIL) and Gooty (APTRANSCO), and replace it, if required. 2.APTRANSCO to ensure that the distributed architecture employed in implementing busbar protection at their Gooty 220 kv SS does not introduce any unwarranted delays in transmitting the triggering signals to the Central Unit. APTRANSCO/ PGCIL (SR-I) APTRANSCO mail dated on : To avoid the unwanted malopeartions due to the external LBB trip initiation from PGCIL, Vide letter Dt: , APTRANSCO has requsted the PGCIL to arrange the Master trip relay and breaker contacts of ICT-1 &2 LV side to enable the internal LBB feature in the Busbar protection scheme at 220kV Gooty Switching station. Waiting for the PGCIL response. APTRANSCO mail dated on : To avoid the unwanted maloperations due to the external LBB trip initiation from PGCIL, vide letter Dt: , ARTRANSCO has requested the PGCIL to arrange the Master trip relay and breaker contacts of ICT-1&2 LV side to enable the internal LBB feature in the Busbar protection scheme at 220kV Gooty Switching station. Waiting for the PGCIL response. APTRANSCO mail dated on : Waiting for the PGCIL response. Pending APTRANSCO mail dated & SRPC is requested to coordinate with PGCIL in takind necessary action. APTRANSCO mail dated & PGCIL may be requested to take necessary action APTRANSCO maild ated : 1. Cable healthiness checked and found ok. But it is proposed to replace the cable with armored cable. --Completed 2. After replacing the cable contactors will be removed so as to avoid unwarrented delays in transmitting trigging signal to the central unit. ---Pending Review Meeting dated : APTRANSCO informed that replacement of the existing cable with armoured cable and subsequent removal of cable contactors would be completed by In this regard, PGCIL (SR-I) also assured that they would render all required help from their side to complete the stated works in time. APTRANSCO Mail Dated : New armoured cable is laid from 220 kv Gooty (AP) to 400/220 kv Gooty (PGCIL) for replacing the existing cable connected to ICT-2.PGCIL is requested to provide spare contacts from trip relays of 315 mva LV-1 and LV-2 for providing internal CB failure in busbar protection scheme. APTRANSCO Mail Dated : As requested by PGCIL the busbar drawings Were submitted for providing spare contacts from trip relays of 315 mva LV-1 and LV-2 for providing LBB in busbar protection scheme. 56/III/4 Tripping of 220 kv Sedam- Tandur line at 21:52 hrs Line tripped on B-phase to earth fault. Auto-reclose is not enabled for line. KPTCL and TSTRANSCO to fast-track providing A/R on 220 kv Sedam Tandur line, and furnish an action plan of providing the same by next PCSC meeting (PCSC-57). KPTCL/ TSTRANSCO KPTCL Mail dated : Carrier protection is to be restored. B/U OC and EF relay is to be replaced by M-II distance relay. Required materials like wave trap, M-II distance relay are already supplied. The work will be taken up on top priority through GE Ltd. Pending (With KPTCL) Review Meeting dated : TSTRANSCO informed that they have kept A/R in service from Tandur end. KPTCL informed that the works relating to put A/R in service are gonig on at their Sedam SS, and assured that it would be put into service by February, TSTRANSCO MAIL DATED : As discussed in the review meeting on , A/R is kept in service from Tandur(TSTRANSCO) end.---pending TSTRANSCO MAIL DATED : Issue is not pending from TSTRANSCO side. Page 4 of 38

73 Annexure-III 57/I/1 Complete outage of 220 kv Karwar Substation of KPTCL at 11:36 hrs Triggering incident was failure of R phase PT in Bus-1 at 1.NPCIL (KAPS) to disable DefiniteTime O/C relay, and put in 220kV Karwar substation. 220kV Kaiga-Kodasalli tripped its place by IDMT O/C relay for backup protection on both 220 during the incident. Also bus shut down occurred at kv Kaiga Kadra line and 220 kv Kaiga Kodasalli line at Kadra and Kodasally stations. Kaiga end. 2.KPTCL to put bus bar protection in service at their 220 kv Karwar SS at the earliest. KPTCL/ KPCL/ NPCIL (KAPS) NPCIL(KGS) mail dated on & : 1.The 200 ms Definite time DEFR element in both Kaiga Kadra and Kaiga Kodasally lines were disabled. IDMT DEFR is retained. --- Completed Pending Pending Pending Pending [with KPCL & KPTCL] 3.KPCL/ KPTCL to implement Weak In-feed Logic with Echo feature enabled by Under Voltage (27) element on Kadra Karwar lines 1 & 2. 4.KPTCL to furnish equipment failure report of the current incident to PSE&TD Division of CEA with a copy marked to SRPC. KPTCL Mail dated : 2) Bus-bar protection panel is supplied under R&U. Replacement work will be taken up after priority Sub stations. --- Pending 3] Weak end Infeed logic available in new relays supplied; Will be enabled During R&U works Pending 4] Equipement failure reports are being sent to CEA regularly. --- Completed Review Meeting dated : 2. KPTCL informed that the works relating to providing BBP are targeted to be completed by March, KPTCL informed that since the line is a double circuit, there may not be need for implementing Weak Infeed logic with Echo feature at Karwar end. However, the same would be looked into w.r.t. the newly commissioned NR's at Karwar, and final action taken would be informed by March, /II/9 Tripping of 400 kv Nellore (PG) NPS line-1, 400 kv at 19:05 hrs Krishnapatnam-Nellore (AP) lines -1&2 and 400kV NPS - MEPL line Triggering incident was snapping of Y phase conductor in 400kV Nellore (PG) - NPS line-1. Distance relay at Krishnapatnam end over-reached in Zone-1, and resulted in tripping of 400kV Krishnapatnam Nellore (AP) lines - 1&2 from Krishnapatnam end. Distance relay at MEPL over-reached and resulted in tripping of MEPL-NPS line from MEPL end. PGCIL (SR-I), TPCIL, MEPL, SEL, SGPL, APTRANSCO, APGENCO and SDSTPS to implement line differential protection on all 400 kv transmission lines (of length less than 50 km) emanating from Nellore PS, Nellore (PG) SS, and Nellore (AP) SS. [It may be noted here that the cut-off length of 50 km has been specified with a view to exclude only long transmission lines]. APGENCO/ PGCIL(SR-I)/ TPCIL/MEPL/SEL/ SGPL/ APTRANSCO APTRANSCO mail dated on : Issue was addressed to the concerned for necessary action. APTRANSCO mail dated on : Meeting was conducted and the relays procurement for all the loctions is under progress. APTRANSCO mail dated on & : Relays procurement for all the locations is under progress. APTRANSCO Mail dated : Technical bids opened. PQ evaluation under progress. Price bids expected to open in next week. PGCIL (SR-I) Mail dated : LDP relays procurement is under process. Procurement will be completed by Feb TPCIL has to give written confirmation for LDP relay procurement. For want of written confirmation from TPCIL, PGCIL approving authority has withheld the LDP proposal. Pending Review Meeting dated : PGCIL (SR-I) informed that they are waiting for written confirmation from TPCIL to complete procurement of LDP relays. To this, PCSC forum asked TPCIL to submit written confirmation to PGCIL (SR-I) by PGCIL (SR-I) assured that with receipt of above confirmation from TPCIL by Dec, 2017, they would be able to complete the work by FEbruary, APTRANSCO informed that they would be able to implement LDP from their & APGENCO side by April, In this regard, PCSC forum made it clear that the recommendation is about providing LDP as both Main-I & Main-II relays on all stated lines in Nellore Complex, ans asked all stakeholders to ensure & comply with the same. APTRANSCO MAIL DATED Technical & financial bids are opened. Tenders will be awarded shortly. APTRANSCO Mail Dated : ABB make LDP relays inspection is completed. SNEIDER make LDP relays inspection yet to be completed. Delivery of relays expected in the 1st weak of May Page 5 of 38

74 Annexure-III 63/II/9 Tripping of 400 kv YTPS-BTPS at 19:11 R-phase to earth had occurred in 400kV BTPS-JSWEL line line and 400 kv BTPS-JSWEL line hrs and protection issued a 3 phase trip 1. JSWEL to follow file naming terminology provided by SRPC for various tripping files uploaded in SRLDC s TMS portal. 2.JSWEL to furnish reasons for AR-BLOCK observed during the instant tripping and remedial action taken by them to keep A/R in service. 3. KPCL to configure DR & EL properly to record OVR Stage-I & Stage-II protections at their BTPS station. KPCL/ JSWEL Status received vide mail dated : Pending 1. JSWEL will follow the file naming terminology provided by SRPC during future uploads Completed 2. Auto-reclosure is in service for JSW BTPS line. The reason for AR-Block was due to carrier fail signal which was after the fault clearance. As per the attached event list, the fault occurred at 7:11:21:550 PM & the AR block appeared around 7:11:21:586 PM, after the clearance of the fault at around 7:11:21:583 PM (3PH-TRIP) -----Completed Pending with KPCL Review Meeting dated : 3. KPCL informed that DR's & EL's had been configured for OVR (Stage-I & Stage-II) protections at their BTPS sttaion, and the exact date of completion of the same would be intimated soon. JSWEL Status received vide mail dated : 1. JSWEL will follow the file naming terminology provided by SRPC during future uploads. 2. Auto-reclosure is in service for JSW BTPS line. The reason for AR-Block was due to carrier fail signal which was after the fault clearance. As per the attached event list, the fault occurred at 7:11:21:550 PM & the AR block appeared around 7:11:21:586 PM, after the clearance of the fault at around 7:11:21:583 PM (3PH-TRIP) 64/I/1 Complete outage of North Chennai TPS STG at 21:02hrs Tripping of evacuating lines due to fault led to tripping of Units TANTRANSCO and PGCIL (SR-II) to take steps to complete insulator replacement works on the 400 kv lines owned by them in Chennai area within 3 months. TANTRANSCO/ PGCIL(SR-II) Status received vide TANTRANSCO mail dated & & & : 1. All the Porcelain insulators of 400kV NCTPS-II - Vallur feeders-1&2 were replaced with Polymer insulators by Completed 2. Existing Porcelain insulators of all other 400kV feeders are being replaced with Polymer insulators in a phased manner. --- Pending Pending [with TANTRANSCO] PGCIL (SR-II) Mail dated : Pertaining to POWERGRID all the porceleing insulators in the polluted streches has been completed. - Completed. 64/I/2 Complete outage of North Chennai TPS STG at 18:27hrs Tripping of evacuating lines due to fault led to tripping of Unit Review Meeting dated : TANTRANSCO informed that a total of 597 insulators ahd alreeady been replaced, and the total replacement would take another 9-month period. In this regard, TANTRANSCO was asked to furnish detailed plan of action regarding replacement of insulators on all 400 kv lines owned by them in Chennai area. TANTRANSCO MAIL DATED : Existing Porcelain insulators of all other 400kV feeders are being replaced with Polymer Page 6 of 38

75 64/I/3 Complete outage of North Chennai TPS STG at 21:09 hrs Tripping of evacuating lines due to fault led to tripping of running Unit at NCTPS Stg-2 Existing Porcelain insulators of all other 400kV feeders are being replaced with Polymer insulators in a phased manner. Timeline: Sep Detailed plan of action will be submitted. Annexure-III 66/ II/ 5 Tripping of 400 kv Ramagundam at 19:15 Triggering incident was fault in 400kV Nizamabad GIS Dichipally line, 400kV Nizamabad hrs - Dichipally line-1 and 400/220 kv ICT-1 1. TSTRANSCO/ NTPC to adopt proper Zone-2 time settings NTPC- (say, Ramagundam end --> 500 msec; Dichipally end --> 350 Ramagundam/ msec in line with Ramakrishna Committee recommendations) TSTRANSCO/ on 400 kv Ramagundam Dichipally line and 400 kv PGCIL (SR-I) Dichipally - Nizamabad lines respectively. 2. For the 400 kv Dichipally - Nizamabad D/C line, TSTRANSCO, in coordination with PGCIL (SR-I), to carry out the following: (i) End-to-end communication for DT/ permissive & other signals may be ensured by testing at both the ends. (ii) Healthiness of PLCC system components (hardware and software) at both ends shall be checked and faulty components shall be repaired/ replaced. PGCIL (SR-I) Mail dated : 1. In 400kV Nizamabad-Dichpally lines Zone-2 trip time delay of 0.35 sec was already implemented at Nizamabad end. 2. For 400kV NZB-Dichpally D/C lines PLCC commissioned with LDP relays & Line-1 tested on & Line-2 tested on found ok. --- Completed Review Meeting dated : 1. It was agreed that TSTRANSCO would provide revised settings to NTPC-Ramagundam for implementation in one-week time. In this regard, PCSC forum also asked TSTRANSCO to revise their Zone-2 settings of their 220 kv & 400 kv lines in line with Ramakrishna Committee guidelines. To this, TSTRANSCO replied in affirmative and assured that they would comply with the same by January, Pending TSTRANSCO MAIL DATED : 1. Revised relay settings for Dichpally-Ramagundam line is given as per the Lr.No.CE/PS/SE/PS/SP-1/111/Relays 400kV Dichpally/Vol-2/D.No. 11/18, Dt: As per the Ramakrishna Committee guidelines and same will be adopted in field in coordination with NTPC/PGCIL and based on Line Clearance availability. 2. Instructions for revising Zone-2 settings for 220kV and 400kV lines will be issued to the concerned field officials shortly. ---Pending NTPC Ramagundam MAIL DATED : Zone -2 timing implemented at NTPC end is 0.4 Sec. Same has been communicated to TSTRANSCO on 30/01/2018. TSTRANSCO MAIL DATED : With regard to Point No.2, instructions have already been issued vide letter dated to all field officials to revise the Zonal timings of 220/400kV EHV transmission lines with proper coordination at both ends. TSTRANSCO MAIL DATED : TSTRANSCO: Revised Zonal timings of Distance scheme for all 400kV, 220kV EHV transmission lines were already communicated to the field vide letter in compliance to the recommendations of Ramakrishna committee. Page 7 of 38

76 Annexure-III 66/ II/ 8 Tripping of 400 kv Khammam KTPS lines 1 & at 18:32 hrs Lines 1 & 2 tripped on B-phase to earth faults 1. TSGENCO to keep uniform A/R dead-time of 1 sec on the lines emanating from their KPTS station. 2. PGCIL (SR-I) to enable Trip-on-Reclose (TOR) functionality for Zone-2 faults for Khammam KTPS lines at Khammam end, if such a feature is available in the concerned relay, and to configure it for sending Direct Trip (DT) Command to KTPS end. 3. PGCIL (SR-I) to set right time-sync issues w.r.t. Khammam end Event Loggers on Khammam KTPS lines. 4. For 400 kv Khammam KTPS line-1, PGCIL (SR-I), in coordination with TSGENCO, shall carry out the following: (i) End-to-end communication for DT/ permissive & other signals may be ensured by testing at both the ends. (ii) Healthiness of PLCC system components (hardware and software) at both ends shall be checked and faulty components shall be repaired/ replaced. TSGENCO/ PGCIL (SR-I) Pending with TSGENCO Pending [with PGCIL (SR-I) Mail dated : PGCIL (SR-I)] 2). TOR feature in MiCOM P444 relay enabled for 400kV KMM-KTPS lines at Khammam end. DT send on TOR trip is not as per protection philosopy. However if SRPC/SRLDC gives separate instructions exclusively for this line, the same shall be imoplemented after getting our CC approval. --- Pending 3). At Khammam SS all DR & ELs are time synched. --- Completed. 4). --- Pending TSGENCO Mail dated : 1). If the auto reclose function dead time kept same at both ends as 1 sec uniformly. In case of persistent fault, it leads to feed the fault from both ends and cause the generator breaker switching on to high fault current and chances of pole slip. To avoid this time differentiated A/R scheme to be implemented. In KTPS 400KV Line I & II at KTPS end dead time is 1.2sec and at KMM end it is 1sec. In our relay 7SA522 does not have the adaptive dead time function A/R. Hence, it is requested to send DT in case of on 3-phase trip and A/R unsuccessful at KMM end to avoid reclose attempt from KTPS end after dead time (1.2Sec) for persistent faults. We communicated to M/s Siemens to upgrade the firmware version regarding adaptive dead time. Hence, it is requested to review these settings to reduce the stress on Generating Station --- Completed Review Meeting dated : 2. It was made clear to PGCIL (SR-I) that this is a specific case of those 400 kv lines where one one of the ends is a generating station, and the other end is grid-connected substation having TOR feature in line protection relays. The said recommendation of enabling TOR along with sending DT to the other end is basically to ensure safety of Generating Units at the other end. Accordingly, PGCIL (SR-I) was asked to take steps to ensure the same. --- Pending 4. PGCIL (SR-I) informed that shutdown was availed by TSGENCO on , and all issues relating to PLCC including end-to-end testing were carried out. --- Completed Page 8 of 38

77 Annexure-III 66/ II/ 10 Tripping of 400/ 220 kv ICT s & 4 at Ramagundam STPS at 19:46hrs Triggering incident was failure of 220 kv B-phase LA in ICT-3 LV extension feeder (220KV line-2) at Malayalapalli substation 1. NTPC to disable high-set of DEFR on the 220 kv lines emanating from their Ramagundam STPS. 2. NTPC/ TSTRANSCO to provide Line Differential Protection (with or without pilot) on 220 kv Ramagundam Malayalapalli lines 1 & 2 & 3. NTPC- Ramagundam/ TSTRANSCO NTPC mail dated : 1. High set DEFR on 220 KV lines is disabled ----Completed Pending Review Meeting dated : TSTRANSCO informed that the works are under progress, and are targeted to be completed in 3 months time. Pending TSTRANSCO MAIL DATED : Line Differential Protection will be provided within 3 months i.e., by end of March, TSTRANSCO MAIL DATED : Line Differential Protection relays are under procurement and will be provided by end of May, /I/2 Complete outage of 220 kv Kadra Power Station of KPCL at 11:41hrs Triggering incident was tripping of 220 kv Kadra- Kodasalli and 220 kv Kadra-Kaiga line. There was no generation at Kadra in antecedent condition. 1. KPCL to investigate the reasons for non-tripping of 220 kv Kadra Kodasalli line from Kadra end by any of the Main protection relays, and opening of only B-ph pole at Kodasalli end, and furnish an action taken report on the same. 2.KPCL to sort out issues relating to downloading of DR s & EL s at Kadra PH at the earliest. KPCL/ NPCIL (KGS) Pending Pending Pending Status received vide NPCIL mail dated : 4. The event logger(escada) has inherent time resolution of 10 millisecond for digital inputs. In future higesht resultion event logger history will be extratced for submission to grid authorities..--npcil-kaiga ----Completed Pending 3. KPCL to use both the 220 kv buses as main buses under normal operation, and to go for single bus operation only during emergencies at their Kadra PH. 4. NPCIL (KGS) to configure time resolution of Event Loggers to milli seconds at their Kaiga GS. Review Meeting dated : 1). Kadra-kaiga 220KV line tripped on both end in Zone-1 distance protection. Fault distance is 0.9KM from kadra end. Kodasalli-Kadra 220KV tripped at Kodasalli end only in Zone-1 fault. Reason for tripping is the both Kadra-kodasalli, kadra-kaiga line are in same tower, hence same fault reflected adjuscent line. Because of no Bus source, Kadra end relay stopped to detect, hence Kadra end breaker was intact Completed 2). Issue relating to downloading of DRs & Els at Kadra PH rectified. --- Completed 3). KPCL informed that they have planned to take up providing double-bus operation at their 220 kv Kadra PH, 220 kv Gersoppa PH, and 220 kv Raichur TPS through PSDF funding, and DPR for the same is under preparation. After obtaining approval of the same from their management, other activities inluding tenders floating, approaching PSDF would be taken up. All these activites are targeted to be completed within 2 years. --- Pending Page 9 of 38

78 Annexure-III 69/I/2 Complete outage of 400kV TPCIL station at 21:37 hrs 400kV TPCIL - Nellore line-1 got tripped at TPCIL end during failure of LA of Station Transformer-2 at TPCIL. Running Units at TPCIL got tripped due to loss of evacuating line. 400kV TPCIL - Nellore PS line-2 was under emergency shutdown 1. TPCIL to configure DEF protection such that it remains in TPCIL/ blocked condition as long as Distance Protection is active, and PGCIL (SR-I) becomes active only when distance protection does not pickup. 2.PGCIL (SR-I) to ensure healthiness of Carrier communication, and the set PUP mode of carrier aided scheme operates reliably on TPCIL lines 1 & 2. Review Meeting dated : PGCIL (SR-I) informed that they are waiting for written confirmation from TPCIL to complete procurement of LDP relays. To this, PCSC forum asked TPCIL to submit written confirmation to PGCIL (SR-I) by PGCIL (SR-I) assured that with receipt of above confirmation from TPCIL by Dec, 2017, they would be able to complete the work by February, APTRANSCO informed that they would be able to implement LDP from their & APGENCO side by April, Pending In this regard, PCSC forum made it clear that the recommendation is about providing LDP as both Main-I & Main-II relays on all stated lines in Nellore Complex, ans asked all stakeholders to ensure & comply with the same. 69/III/3 Tripping of 400 kv Kurnool(PG) Kurnool(AP) line at 02:03 hrs Line tripped on B-ph to ground fault. A/R was unsuccessful at both Kurnool (AP) and Kurnool (PG) ends. 1) PGCIL (SR-I) and APTRANSCO to provide for Line Differential Protection as both the Main protections on 400 kv Kurnool (AP) Kurnool (PG) lines 1 & 2 lines. 2) APTRANSCO to furnish an action taken report w.r.t. resolving A/R non-operation at Kurnool-AP end for the subject trippings and configure EL for capturing PDR operation at their 400 kv Kurnool-AP SS. APTRANSCO/ PGCIL (SR-I) APTRANSCO maild ated : A/R scheme on 400kV Kurnool (PGCIL) feeder-2 will be checked after getting LC. APTRANSCO maild ated : B Ph auxilary trip relay is found defective. The same is to be replaced by M/S PGCIL. Ii) PD relay event is configured in the EL as per the recommendation. Pending 69/III/7 Tripping of 220 kv Ragulapadu Alipura line at 01:30 hrs Line tripped on B-Ph to earth fault. A/R was successful at Regulapadu and breakers at Alipura end got tripped. KPTCL and APTRANSCO to sort out issues relating to APTRANSCO/ incongruence in denoting R, Y, B phases of the electric supply KPTCL on their respective sides. APTRANSCO maild ated : APTRANSCO would extend support and requirements if any,for the rectification proposed by KPTCL. Pending Review Meeting dated : It was noted that the original Gooty - Lingapur line got LILOed at BTPS, Alipura, and Ragulapadu. It was also noted that Phase Discrepancy is being observed in Ragulapadu - Alipira section only. When enquired about the same, KPTCL informed that they would examine the issue in detail, and would inform the action lan proposed by next PCSC-71 meeting. On this, APTRANSCO was also asked to render all help required from their side to KPTCL. APTRANSCO maild ated : APTransco world extend required support. APTRANSCO maild ated : AP Transco would extend required support for attending, phase discrepancy issue in ragulapadu-alipura line by KPTCL. 71/III/2 Tripping of 400 kv Suryapet- VTPS line at 14:39 hrs Line tripped on Y-phase to earth fault. Zone-2 operated at VTPS due to non-receipt of carrier 1. APGENCO and TSTRANSCO to put A/R into service from APGENCO/ their respective ends on 400 VTPS Suryapet line. TSTRANSCO 2. For the line under consideration, the following shall be carried out by APGENCO, in coordination with TSTRANSCO: (i) End-to-end communication for DT/ permissive & other signals may be ensured by testing at both the ends. (ii) Healthiness of PLCC system components (hardware and software) at both ends shall be checked and faulty components shall be repaired/ replaced. TSTRANSCO MAIL DATED : End to end testing will be carried out by availing Line Clearance by the end of March, TSTRANSCO MAIL DATED : 1) Pending... 2) On , end to end testing was carried out and checked the healthiness of PLCC System. Along with that the A/R function was also checked at both ends. Pending Page 10 of 38

79 Annexure-III 72/II/4 Tripping of 400/ 220 kv Hoody ICT-3 and 400 kv Kolar-Hoody line at 17:42 hrs Triggering incident was failure of Y-phase lightning arrestor of 400kV Hoody-Kolar line-2 at Hoody end due to which 400 kv Kolar Hoody line-2 tripped on operation of distance protection. At the same time 400/220 kv, 500 MVA ICT-3 at Hoody also tripped on earth fault protection. For the Hoody Kolar line-2, the following shall be carried out by KPTCL, in coordination with PGCIL (SR-II): (i) End-to-end communication for DT/ permissive & other signals may be ensured by testing at both the ends. KPTCL / PGCIL (SR- II) Yet to be informed Pending (ii) Healthiness of PLCC system components (hardware and software) at both ends shall be checked and faulty components shall be repaired/ replaced. KPTCL to keep A/R in service on Hoody Kolar line-2 after verifying the healthiness of PLCC communication. 72/III/5 Tripping of 400 kv HNPCL - K.V. Kota line at 11:46 hrs Tripped due to R-phase to ground fault. Line did not reclose at HNPCL. HNPCL/ HNPCL to configure DEF protection such that it remains in APTRANSCO blocked condition as long as Distance Protection is active, and becomes active only when distance protection does not pickup. APTRANSCO maild ated : To be attended by HNPCL Pending HNPCL to ensure healthiness of A/R scheme implemented on all 400 kv lines at their station. 73/II/7 Multiple trippings at 400 kv Guttur Substation at 08:25 hrs 400 kv Guttur-Kaiga-1 Breaker was in lock-out condition. It was intended to take Kaiga line-1 on tie CB. While carrying out this operation bus bar protection operated at Guttur resulting in tripping of all connected elements. 1) NPCIL (KGS) to take steps to disable sending of DT to remote ends upon 86X operation for any line protection operation at its 400 kv KGS. 2) KPTCL to resolve PLCC issues on 400 kv Guttur Kaiga lines at the earliest. KPTCL/ NPCIL Yet to be informed Pending 73/III/1 Tripping of 400 kv Gooty- Narnoor line at 07:20 hrs Line tripped on Y-phase to earth fault due to agricultural fire. Auto-reclose attempt was unsuccessful PGCIL (SR-I) and APTRANSCO set right the observed APTRANSCO/ PGCIL Yet to be informed discrepancy in A/R operation for Main-CB & Tie-CB at Gooty (SR-I) and Narnoor ends respectively. Pending 73/IV/3 Tripping of 400 kv Pondicherry- S.V.Chatram line at 17:58 hrs Line tripped at SVChatram end only and was holding from Puducherry. No fault was observed from DR of S.V.Chatram. Suspected PLCC mal-operation. For the line under consideration, the following shall be carried out by PGCIL (SR-II), in coordination with TSTRANSCO: (i) End-to-end communication for DT/ permissive & other signals may be ensured by testing at both the ends. TSTRANSCO/ PGCIL Yet to be informed (SR-II) Pending (ii) Healthiness of PLCC system components (hardware and software) at both ends shall be checked and faulty components shall be repaired/ replaced. 73/IV/ at 17:17 hrs (Line-1) Line-1&2 got tripped on Direct Trip receive at Karamadai end and the line was in service from Arasur end. Suspected PLCC mal-operation. For the line under consideration, the following shall be TANTRANSCO/ carried out by PGCIL (SR-II), in coordination with PGCIL(SR-II) TANTRANSCO: Yet to be informed Pending (i) End-to-end communication for DT/ permissive & other signals may be ensured by testing at both the ends. (ii) Healthiness of PLCC system components (hardware and software) at both ends shall be checked and faulty components shall be repaired/ replaced at 18:11 hrs (Line-2) Page 11 of 38

80 Annexure-III 52/I/2 (GD) Complete outage of 220 kv Yerraguntla substation and tripping of running Units at Rayalaseema TPS at 10:39 hrs HV B-Ph Current transformer of 100MVA Power Transformer -1 failed resulting into a bus fault on 220KV Bus-1. Unit-1 and Unit-5 at RYTPS tripped during the fault at Yerraguntla substation Andhra Pradesh 1. APGENCO to check associated logic for lube oil pump for correct operation under transient low voltage conditions at Rayalaseema TPS, Unit APGENCO to keep appropriate time delay/ fault ride through delay (typically 2 sec) in VFD speed sensor relay at all its generating Units including Rayalaseema TPS Units. APGENCO Mail received on : 1.The drop out relays of reducer oil pumps time setting was increased for all mills.so there will not be any trip under transient low voltage condition.----complied 2.The recommendation regarding 2 sec time delay will be implemented during unit shut down and will be intimated immediately after implementation pending Review Meeting dated : It was noted that no APGENCO representative had come to attend the meeting. Pending Page 12 of 38

81 Annexure-III 57/II/9 Tripping of 400 kv Nellore (PG) NPS line-1, 400 kv at 19:05 hrs Krishnapatnam-Nellore (AP) lines -1&2 and 400kV NPS - MEPL line Triggering incident was snapping of Y phase conductor in APGENCO to furnish a report on the remedial action 400kV Nellore (PG) - NPS line-1. Distance relay at implemented w.r.t. overreaching of Krishnapatnam end Krishnapatnam end over-reached in Zone-1, and resulted distance relays during the tripping of 400 kv Nellore (PG) - in tripping of 400kV Krishnapatnam Nellore (AP) lines - NPS line-1 1&2 from Krishnapatnam end. Distance relay at MEPL over-reached and resulted in tripping of MEPL-NPS line from MEPL end. APGENCO Review Meeting dated : It was noted that no APGENCO representative had come to attend the meeting. APGENCO Mail dated : Procurement of relays is under progress Pending 69/II/1 Multiple trippings at Tripping at 220 kv Srisailam Right Bank power station at 14:39 hrs 220kV Srisailam RB Markapuram S/C line and 220 kv Srisailam Podili S/C line tripped on operation of distance protection. Srisailam Units - 3, 4, 6 and 7 got tripped during the incident. 1.APGENCO to furnish compliance report on the recommendations given by PSAG-9 team that had visited Srisailam RB PH on October, APGENCO to carry out the following: (i)removal of DC earth leakage in station switchyard on priority basis (latest by ) (ii)integration of Station earth-mat and Switchyard earthmat. 3. APGENCO to provide for numerical relays (as both Main-I & Main-II) on all 220 kv feeders emanating from Srisailam RB PH. 4.APGENCO to put A/R into service on all 220 kv feeders emanating from Srisailam RB PH. APGENCO APGENCO Mail dated : 1. Complainance report on PSAG -9 recommendations is enclosed in next sheet. --Completed 2. i ) Attended and removed the earth leakage. --Completed 2 ii) Procurement of material is under progress. --Pending 3. Material received at site. Work will be completed by April Pending 4. Will be provided at the time of commissioning of new protection panels. --Pending 5. i) Time synchronization for Unit-4 both MAin- I & II relays was provided through SNTP. --Completed ii) Time synchronization for Unit-1,2,3,5,6, & 7 RET- 670 Main -II Relays was provided through SNTP. --Completed iii) Time synchronization for Unit -1,2,3,5,6, & 7 REG- 670 Main - I & II Relays was provided through PPM. --Completed Pending 5.APGENCO to provide for Time Synchronization equipment at their Srisailam RB PH to synchronize all protection relays with GPS. 68/III/9 Tripping of 400 kv Kalpaka Asupaka line at 10:48 hrs Y-phase to earth fault. Auto reclose was stated to be successful at Kalpaka end. At Asupaka end Auto-reclose had not operated due to problem in configuration settings. For the subject line relay at Kalpaka end, APTRANSCO to configure DR for a post-triggering period of 2 sec and EL for all required protection (analog & digital) events APTRANSCO APTRANSCO Mail dated : Post triggering period of 2 see for DR is configured. Wiring under the scope of retrofitting works is being carryout by EMC. EL will be configured on completion to wiring works. Review Meeting dated : APTRANSCO informed that the recommedned works would be completed by APTRANSCO maild ated : Informed to EMC to complete retrofitting work on top priority Pending 69/II/7 Tripping of 400 kv Uravakonda Jamalamadugu line at 10:22 hrs Line tripped on overvoltage at Uravakonda end and Direct Trip received at Jamalamadugu end. DR & EL of Uravakonda end not furnished. APTRANSCO to complete configuration of DR s & EL s for all APTRANSCO APTRANSCO Mail dated & Review Meeting dated : protections relays at their 400 kv Uravakonda SS, and render Instructions were issued for taking necessary action. them suitable for extraction/downloading of relevant tripping records/ events within a month s time. APTRANSCO maild ated : Configuration of DR & EL s in the relays completed configuration of DR & EL at SAS is to be verified. Pending 72/I/2 Complete outage of 400 kv Uravakonda Substation of APTRANSCO at 4:48 hrs 400kV Uravakonda- Jammalmadugu line-1 tripped at APTRANSCO to get checked Auto-Reclosure scheme APTRANSCO Yet to be informed Pending 4:48hrs due to Y-phase to ground fault at both the ends. provided on 400 kv & 220 kv lines for correctness of 400kV Uravakonda Jammalmadugu line-2, functionality & healthiness of the logic employed by April, Mahabubnagar line-1 and 2 were in open condition due to high voltage. After tripping of 400kV UV Konda- Jammalmadugu line-1, 400/220kV ICT #1,2,3 and 4 at 400kV UV Konda were hand tripped due to loss of evacuating lines. Page 13 of 38

82 Annexure-III 73/I/7 Complete outage of 220 kv Vizag (Gazuwaka) switching station at 16:14 hrs Triggering incident was R-ph CT failure Bus-Coupler. This resulted in tripping of all the connected elements due to operation of bus bar protection. 1) APTRANSCO to furnish equipment failure report of the current incident (CT blast) to PSE&TD Division of CEA with a copy marked to SRPC. APTRANSCO Yet to be informed Pending 2) APTRANSCO to take steps to provide one more thermovision camera to Vizag division for use exclusively on 400 kv & 220 & 132 kv transmission lines emanating from Kalpaka, Gajuwaka, VSS, Pendurti and other adjoining substations of APTRANSCO. Telangana 61/III/5 Tripping of 400 kv Khammam - KTPS line-2 70/II/2 Tripping of 400kV Kurnool- Srisailam line at 10:52 hrs at 23:02 hrs at 21:57 hrs Line tripped on B-phase to earth fault. First fault was persistent for 380 ms. Auto-reclose was successful at Khammam end during 1st fault. 2nd fault occurred during re-claim time of breaker hence Khammam end Line tripped on operation of Over-Voltage protection at Srisailam and Direct Trip was received at Kurnool. Considerable voltage difference was observed between R, Y & B phases. 1. TSGENCO to implement the SRPC agreed philosophy for Power Swing Blocking in all distance relays on the feeders emanating from KTPS. TSGENCO to adopt stipulated OVR, Stage-I gradings for the 400 kv lines emanating from their 400 kv Srisailam LB RH, and furnish an action taken report w.r.t. mitigating observed voltage difference among R & Y & B phases TSGENCO TSGENCO mail dated : 1. According to SRPC phylosphy power swing block settings are changed to ALL ZONES BLOCK EXCEPT ZONE Completed TSGENCO Yet to be informed Pending Pending at 20:54 hrs at 21:19 hrs 70/II/3 Tripping of 400 kv Satenapalli- Srisailam line at 22:02 hrs at 23:09 hrs Line tripped on operation of over-voltage protection at Srisailam and Direct Trip was received at Sattenapalli. Considerable voltage difference was observed between R, Y & B phases at Srisailam end. TSGENCO to adopt stipulated OVR, Stage-I gradings for the 400 kv lines emanating from their 400 kv Srisailam LB RH, and furnish an action taken report w.r.t. mitigating observed voltage difference among R & Y & B phases. TSGENCO Yet to be informed Pending at 18:46 hrs 71/II/7 Tripping of 400 kv Narnoor Srisailam LB line at 18:49 hrs Line tripped due to operation of over voltage protection at Srisailam LB end. Considerable phase difference was observed between phases at Srisailam end 1. TSGENCO to take steps to replace the existing faulty CVT s at Srisalam end on 400 kv Srisailam Narnoor line at the earliest. TSGENCO Yet to be informed Pending 2. TSGENCO to adopt stipulated OVR, Stage-I gradings on all Page 14 of 38

83 2. TSGENCO to adopt stipulated OVR, Stage-I gradings on all 400 kv transmission lines emanating from Srisaliam LB. Annexure-III at 19:10 hrs 67/III/1 Tripping of 400 kv Gajwel - Bhoopalapalli line at 13:13 hrs Line tripped on B-ph to earth fault. Auto-reclose was successful at Bhoopalapally end and breaker tripped at Gajwel. 1. For the line under consideration, TSTRANSCO to sort-out A/R related issues at Gajwel end. 2. For the line under consideration, TSTRANSCO to configure EL at Gajwel such that PDR operation is also captured in it. 3. TSTRANSCO to configure DR s of protection relays at their Gajwel SS for a post-triggering period of 2 sec so as to capture complete A/R operation. TSTRANSCO Review Meeting dated : 1) & 2) & 3) TSTRANSCO informed that given reocmmendations would be complied with by TSTRANSCO MAIL DATED ON : Line Clearance could not be availed on as company engineer could not come as per Schedule. It is proposed to carry out End to end testing on by availing Line clearance. TSTRANSCO MAIL DATED ON : End to end testing is carried out on and checked the healthiness of PLCC system Pending TSTRANSCO MAIL DATED ON : 1) On , end to end testing was carried out and checked the healthiness of PLCC System. Along with that the A/R function was also checked at Gajwel end and is kept in service. After the testing, A/R has operated at Gajwel end for line to ground fault in the line. 2) Pending... 3) Pending... PAR/ PCSC-58 Provision of line differential protection for Jurala line 1 & 2 (line length-1.45 KM) feeders at 220 kv Jurala HPS [Carry-Over from Protection Audit Recommendations] TSGENCO/ TSTRANSCO The issue was discussed in PCSC-58 meeting held on , when PCSC forum agreed to de-link the implementation of the Item from the scope of Protection Audit Recommendations (PAR), and pursue it as part of PCSC Recommendations. TSGENCO mail dated Procurement of Differential Protection relays is under process and the work will be completed by the end of November Pending TSGENCO mail dated Procurement of Line Differential Protection Relays is under process and the work will be completed by the end of January Review Meeting dated : TSGENCO informed that they are in constant touch with TSTRANSCO in this regard, and hope to implement LDP by February, Page 15 of 38

84 Annexure-III Karnataka 41/I/1 GD-1 at 220kV Kadra power Station of KPCL at 12:56 hrs Triggering incident was B-phase to earth fault had occurred in 220kV Kadra-Kodasalli line. Line tripped from Kodasalli end only. 220kV Kaiga-Kadra tripped in Zone-3 from Kaiga end. Tripping of evacuating lines caused bus shut down at Kadra hydro station. 1. KPCL to make functional the Main2 (EPAC) relay with the help of KPTCL at the earliest. 2. KPCL to investigate the reason for DC fuse fail during transient fault in 220kV Kadra-Kodasalli line including the testing/ checking of DC supply cables, breaker control cables, and trip coils. 3. KPCL to ensure supply for Main-1& Main-2 protections, Trip Coils (TC1, TC2) from separate battery banks. KPCL Mail received on : 1. Main-2 relays already installed and commissioned. 2. DC fuses are intact. Till date no such incidence occurred. 3. Possibility of DC-1 & DC-2 arrangement and splitting of DC will be reviewed. Mail received on , and : Completed Completed. 3. Possibility of DC-1 & DC-2 arrangement and splitting of DC will be reviewed --- Pending Status received vide KPCL mail dated : 3. Providing 2 separate DC sources is under process --- Pending Status received vide KPCL mail dated : 3. Work under implementation stage --- Pending Pending Review Meeting dated : 3. KPCL informed that for providing 2 separate DC sources with new battery charger, LOA & Work order were placed on M/s Eltek Power system. The works would be completed in March, Pending 46/II/21 Trippings at 220kV Raichur TPS at 01:35 hrs 1. KPCL to check the operation of anti-pumping relay on 220 kv side and keep it in healthy condition. 2. KPCL to provide manual reset to the 220 kv side master trip relay. 3. KPCL to use both the 220 kv buses as main buses under normal operation, and should go for single bus operation only during emergencies. KPCL Mail received on : 1) Anti-pumping contactors of all the nine 220KV Lines are in circuit and tested periodically during AOH works of lines along with other protections. 2) Completed. 3) Possibility to use both the 220kV buses as main bus under normal operation is under review. Mail recieved on : 1) Completed 3) Two bus operation for 220kV buses : In place of existing CT switching relays, High speed manual heavy duty change over switch of sufficient current capacity will be retrofitted to all feeders at 220kV station and same will be operated manually during changeover of feeder by one bus to the other and this arrangement may facilitate to put both buses in service. Time Status received vide KPCL mail dated : 3) DPR for implementation of Two Bus operation for 220kV bus system has been prepared and proposal is placed for funds from PSDF. After the approval of the DPR, the work is proposed to be taken up. Pending Review Meeting dated : 3) KPCL informed that DPR for implementation of Two Bus operation for 220kV bus system has been prepared and proposal is placed for funds from PSDF. After the approval of the DPR, the work is proposed to be taken up. Time frame requested for is 2 yrs. Page 16 of 38

85 Annexure-III 54/II/4 Tripping of 400 kv Raichur TPS- Mahboobnagar line at 10:23 hrs Line tripped on operation of Backup impedance protection of line reactor. Direct trip was received at Mahboobnagar end. KPCL to keep the functioning of the concerned electromechanical back-up impedance protection relay under observation, and replace it with a spare at the earliest. KPCL Status received vide KPCL mail dated : The electro-mechanical back-up impedance protection relay is in service. However, Budgetary offer obtained for the retrofitting of Line reactor protection with Numerical relay and is under process Pending Status received vide KPCL mail dated : Tendering under process Review Meeting dated : KPCL informed that the new numerical relay for backup impedance protection of Line Reactor would be provided by June, KPCL Mail dated : E-tender for the retrofitting work of Line Reactor protections will be invited shortly. 54/II/9 Tripping of 400kV Raichur TPS Bus at 21:12 hrs Y-ph Pole of Tie-breaker of Unit-4 at RTPS failed. Unit-4 got tripped on operation of Generator Differential, Reverse power & LBB protection. Operation of LBB protection led to tripping of BUS-2 at RTPS 1.KPCL to undertake the following remedial measures to avoid breaker flashovers: (i) Replacing all porcelain insulators with composite insulators (ii) Carrying out hot-line water washing of all insulators on regular basis. (iii) Applying Room Temperature Vulcanizing (RTV) Silicone high voltage insulator coatings to all bus-connected ceramic insulators of equipment like CT, PT, CB, Isolators etc. 2.KPCL to take steps to provide dedicated breaker flashover protection to all breakers at Raichur TPS at the earliest. KPCL Status received vide KPCL mail dated : 1. (ii) Hot line water washing stopped and off line water washing is carried out whenever the 400 KV Unit or line is under tripped condition / Shutdown condition. --- Completed 1. (iii) Silicon coating for Unit#8 main & tie breakers carried out in Sep'16 and same is under observation. Till today in order and good condition. For remaining breakers, since it is big order, approval for the same is under process. --- Pending 2. Static / Electromechanical relays are existing in all 1 to 7 units. Breaker flash over protection feature will be enabled (if available) in the numerical relays which will be retrofitted in phased manner during R&M works. Status received vide KPCL mail dated : 1.(i) --- Pending Review Meeting dated : 1 (iii) As upgradation of 400kV switchyard equip's to be taken under PSDF funds, Silicon rubber coating for breakers is deffered till then. --- Pending Pending 2. Replacement by Num relay for Units - 5,6 & 7 completed in the month of Oct Main-I is Seimens make and Main-II is ABB make. --- Pending KPCL mail dated : 2. Replacement of Numerical relays for Units-5, 6 & 7 have been completed. Referred to OEM for providing the Breaker flashover protection for all the breakers. 54/II/13 Tripping of Units at 220 kv Raichur TPS at 15:36 hrs During testing of retrofitted distance protection in 400kV Raichur-2 feeder, LBB protection trip DC got extended to Bus trip. This resulted in tripping of 220kV bus at RTPS and all connected 220 kv elements. Unit-4 which is connected to 400 kv Bus got tripped due to tripping of Station Utility Transformer that is connected 220 kv bus In view of the availability of two buses along with healthy buscoupler at 220 kv RTPS, KPCL is recommended to put in Two Bus operation for 220kV bus is being carried out whenever required. However scheme KPCL Status received vide KPCL mail dated & : service the double-bus operation at 220 kv RTPS by suitably for tripping of one bus during LBB/fault and maintaining the other bus intact by tripping B/C distributing loads within 15 days. breaker will be taken up in R&M works. Review Meeting dated : 3) KPCL informed that DPR for implementation of Two Bus operation for 220kV bus system has been prepared and proposal is placed for funds from PSDF. After the approval of the DPR, the work is proposed to be taken up. Time frame requested is 2 yrs. Pending Page 17 of 38

86 Annexure-III 58/I/3 (GD) Complete outage of 220 kv Kadra power station of KPCL at 14:40 hrs LBB of 220kV Kodasalli breaker at Kadra end got operated which resulted in tripping of Bus at Kadra and in turn led to tripping of all elements 1) KPCL to check settings of LBB protection in all relays from which it was implemented, and ensure that their configuration, logic, and timing are in order at their 220 kv Kadra PH. 2) KPCL to furnish details regarding the existing LT auxiliary supply arrangement at their 220 kv Kadra PH, and take steps to provide a suitable Auto-Main-Fail (AMF) panel for DG set to effect its auto-starting in case of failure of LT supply. 3) KPCL to ensure time-sync of all relays (DR s & EL s) with GPS at their 220 kv Kadra PH. 4) KPCL to provide stand-alone Event Logger at their 220 kv Nagjheri PH. KPCL Status received vide KPCL mail dated : 1. All logics checked and found normal. LBB timing checked and found 200msec as per KPTCL MRT recommendation. - Completed 2. Work Under Progress ---- Pending 3. New GPS System commissioned along with new numerical and synchronised with GPS system - Complied 4. Work Under Progress ---- Pending Status received vide mail dated : 1),3),4) Completed 2. Auto Start of DG set is taken up --- Pending Review Meeting dated : 2. KPCL informed that for AMF of DG, Scheme prepared & material procurement under process. The AMF scheme will be implemented in January Pending 3. The GPS system commissioned on Nov 2016 & all the numarical relay time synchronised with GPS ---- Completed Pending 62/I/1 Complete outage of 220 kv Nagjheri substation of KPCL at 00:38 hrs Triggering event was the fault on 220 kv Nagjheri Kodasalli line-2. Both buses of 220 kv Nagjeri power station of KPCL got de-energized. 1. KPCL to adopt the following VT fuse-fail logic for all 220 kv lines emanating from NPH: Under VT fuse fail condition, distance protection shall normally be kept blocked. However, upon detection of a fault (sensed by negative sequence component), blocking of distance protection shall give rise to operation of its inherent Over-Current protection set with a definite time delay of 500 msec. 2. KPTCL/ KPCL to revise Zone-2, Zone-3 and Zone-4 (reverse) timings of DPR of all 220 kv lines emanating from Nagjheri PH in line with Ramakrishna Committee guidelines. KPCL Status received vide mail dated : 1. Already settings are discussed with EE(RT), Hubli and soon relays will be tested for VT fuse fail condition. 2. Timings of Zones were set as per the recommendations of CE(RT) & R&D, KPTCL, Bangalore & EE(RT), KPTCL, Hubli.Regarding revision of timings will be carried out in co- ordination with EE(RT), KPTCL, Hubli. Status received vide mail dated : 1. As per the recommendations of SRPC and SRLDC, in the event of VT fuse fail, non directional over current and earth fault feature is enabled in the distance relay with a definite time lag of 600msec on pick up and the same is tested by KPTCL Hubli(RT) and KPCL jointly on Completed Pending Pending Review Meeting dated : 2. KPCL informed that Zone settings of distance relays of all 220 kv lines emanating from Magjheri SS had been revised in line with Ramakrishna Committee guidelines Completed. 69/II/8 Tripping of 220 kv Kaiga- Kadra line at 22:22 hrs While de-synchronising of Unit-2, B-phase pole of GCB did not open and pole descrepancy relay operated. Hence all 220KV lines CB hand tripped. KPCL to take steps to replace the existing static protection relays for Generator Units and Generating Transformers (GT s) with suitable Numerical relays at their 220 kv Kadra PH. KPCL Yet to be informed Pending 72/I/4 Complete outage of 220kV Sedam, Shahapur, Shahabad, Kapanoor, Humnabad and Halabarga Stations of KPTCL at 17:46 hrs High resistance fault occurred in 110kV Sedam-Chittapur KPCL to disable GFC protection on all lines emanating from line near Sedam end. Line DEF operated and backup OC their generating stations. protection of 100MVA transformer operated at Sedam end. But line breaker and transformer HV breaker didn t open due to problem in trip circuit. This resulted in cascade tripping of upstream feeders and power supply was lost to six 220kV stations of KPTCL. KPCL Yet to be informed Pending 73/I/5 Complete outage of 220kV Varahi power station at 22:36 hrs There was Y-phase to ground fault on 220 kv Varahi - Shimoga line-2. Consequent to persisting fault in Y phase, the breaker failure protection operated resulting in operation of 220KV bus bar protection at Varahi, tripping all the connected lines and Varahi running units. KPCL to take steps to put double-bus operation into service at KPCL Yet to be informed Pending their 220 kv Varahi PH. Page 18 of 38

87 Annexure-III 73/II/6 Multiple trippings at 220 kv Sharavathy Power station at 22:05 hrs The incident happened during shifting of Unit-8 from 220 kv North West bus to 220 kv South West Bus. The 220 kv buses got tied together without synchronizing which resulted in operation of bus bar protection. KPCL to take steps to using full-fledged Double Main-Bus KPCL Yet to be informed Pending system with four sections instead of the present Single Main- Bus with two sections at their 220 kv Sharavathy GS. 40/I/1 GD-1 at 220kV Ambewadi Station of KPTCL at 21:22 hrs Triggering incident was B-phase to earth fault in 220kV Ambewadi- Nagzari line-1. B-pole of breaker did not open at Ambewadi end. LBB protection not available at Ambewadi end. All elements tripped on Zone-2 from remote ends. 1. Till the completion of R&M works for bus bar and LBB protection, KPTCL shall explore the possibility of having split bus operation at Ambewadi and submit the details of the same to PCSC forum. 2. KPTCL shall provide the details of the tripping of Supa hydro station connected downstream from 110 kv bus. KPTCL Mail received on : 1. In view of operating 220kV Ambewadi SS in split bus mode, action is being taken up by KPTCL. Problem in the 220kV bus coupler breaker is attended and isolator overhauling work is under progress. Spilt bus operation at Ambewadi will be made possible at the earliest. --- Pending 2. ICT Protection system at Ambewadi and trippings occured at Supa GS during the instance is checked up and remedial measures already furnished in this regard Completed Mail recieved on : 1. Action is being taken by KPTCL for operating Ambewadi in split bus mode. Problem in bus coupler breaker is attended.isolator overhaulling work is completed.pts are already provided to 220kV Bus-II. After commissioning of Bus-II PTs, Ambewadi can be operated in split bus KPTCL Mail dated & Review Meeting dated : 1. Recommended works at Ambewadi have not been taken up due to various problems faced due to poor response from the turn key agency M/s ERL. A site meeting is planned during this month to discuss about further plan of action for attending SRPC recommendations pertaining to the Sub station. Pending The issue was discussed in the review meeting. Considering the importance of the substation and delay in executing the works, it was decided to escalate all pending issues relating to Ambewadi SS to KPTCL top Management for early completion. Page 19 of 38

88 Annexure-III 40/IV/1 220kV Sedam Line tripped on Yphase to earth fault from both the ends KPTCL was requested to explore the possibility of providing KPTCL Mail recieved on : Tandur line at 22:20 hrs A/R feature to this line and submit the remedial measures to the PCSC forum. Carrier protection is being restored for 220kV Sedam-Tandoor line at Sedam end. After restoring the carrier protection, AR will be enabled. KPTCL mail recieved on : Carrier protection is being restored for 220kV Sedam-Tandoor line at Sedam end. After restoring the carrier protection, AR will be enabled. KPTCL mail recieved on : SEE,SCADA to update the latest status KPTCL mail recieved on : Action is being taken to restore carrier protection.ar will be enabled once carrier signal is restored. Pending KPTCL Mail Recieved dated : The Wave traps required are supplied under R&U project and the same is to be commisioned at Sedam end for restoration of PLCC. Also,M-II distance relays have already been supplied by GE Ltd. KPTCL Mail dated : Carrier protection is to be restored. B/U OC and EF relay is to be replaced by M-II distance relay. Required materials like wave trap, M-II distance relay are already supplied. The work will be taken up on top priority through GE Ltd. Review Meeting dated : KPTCL informed that the works relating to put A/R in service are going on at their Sedam SS, and assured that it would be put into service by February, /I/4 Complete outage at 220kV at 8.00 Sedam Substation of KPTCL (GD- hrs 1) R-Phase to ground fault occurred on 220kV Sedam- Shahpur line. Fault not cleared from Sedam end due to stuck-breaker condition. While the Sedam- Sahapur line tripped from Shahapur end in Zone-1, the other 220 kv lines from Sedam tripped at remote ends in Zone-2. This caused complete outage of 220kV Sedam substation. 1. KPTCL to provide Bus bar and LBB protections for 220 kv bus at Sedam S/s. 2. KPTCL to implement A/R feature on 220 kv Sedam- Tandur inter-state line. KPTCL Mail received on : Procurement of Bus bar and LBB protection is in the final tendering stage. 2. Action is being taken to restore the carrier protection for 220kV Sedam-Tandoor line. AR will be enabled. Mail received on : 1. Procurement of Bus bar and LBB protection is in the final tendering stage. 2. Action is being taken to restore the carrier protection for 220kV Sedam-Tandoor line. AR will be enabled after restoration of PLCC. KPTCL mail received on : 1. Bus bar protection panels pocured and erected at Sedam. Wiring, testing,commissioning is being taken up.planned to complete by April Action is being taken to restore the carrier protection for 220kV Sedam-Tandoor line. AR KPTCL Mail dated : 1 & 2) Replacement of Bus Bar Protection is included under R&U project. Awarded to M/s GE Ltd. Panels have alredy been supplied by the Agency. The work will be taken up on top priority. Pending Review Meeting dated : KPTCL informed that the works relating to put A/R in service are going on at their Sedam SS, and assured that it would be put into service by February, Page 20 of 38

89 Annexure-III 42/I/1 Complete outage of 220kV Sedam substation of KPTCL at 14:24 hrs Fault occurred in 220kV Sedam-Shahpur line 1. KPTCL to provide Bus Bar protection and LBB protection at Sedam S/s and furnish the status of their implementation to PCSC forum. 2. KPTCL to implement A/R feature on 220 kv Sedam-Tandur inter-state line. KPTCL Mail received on : 1. Bus Bar protection will be provded under R&U. 2. A/R yet to be enabled. Mail received on : 1. Procurement of Bus bar and LBB protection is in the final tendering stage. 2. Action is being taken to restore the carrier protection for 220kV Sedam-Tandoor line. AR will be enabled after restoration of PLCC. KPTCL Mail Recieved dated : Bus Bar Protection panel and required Wave traps are supplied under R&U. Wave trap to be commisioned in Tandoor line and PLCC to be restored.once PLCC is restored AR will be enabled. Pending KPTCL Mail dated : 1. Replacement of Bus Bar Protection is included under R&U project. Awarded to M/s GE Ltd. Panels have alredy been supplied by the Agency. The work will be taken up on top priority. 2. AR feature will be enabled during retrofitting of Main-2 relays. Review Meeting dated : 1 & 2) KPTCL informed that the works are under progress and are targeted to be completed by February, /I/2 (GD) Complete outage of 220 kv Ambewadi substation of KPTCL at 7:51 hrs Fault in 220kV Ambewadi-Nagjheri line-2 1. KPTCL shall provide A/R feature on Ambewadi Ponda 220 kv D/C inter-state line. 2. Till the completion of R&M works for bus bar and LBB protection, KPTCL shall explore the possibility of having split bus operation at Ambewadi and submit the details of the same to PCSC forum. KPTCL Mail received on : 1. Procurement of Bus bar and LBB protection is in the final tendering stage. 2. Action is being taken to restore the carrier protection for 220kV Sedam-Tandoor line. AR will be enabled after restoration of PLCC. KPTCL Mail Recieved dated & : 1.Enabling the AR feature was discussed during PCSC meetings and since Ambewadi-Ponda and Ambewadi-Xeldom lines are radial lines, it was decided that enabling AR is not required. To clear the faults in the abovelines early, the timings of the Zone 2 was reduced to 150mS and the Back Up EFR timings have been reducedto 150mS. --- Completed Pending 2.The planned works as per R&M could not be taken up due to the problem with the vendor and could not be taken up under R&U project due to administrative reasons Pending Review Meeting dated : 2. The issue was discussed. Considering the importance of the substation and delay in executing the works, it was decided to escalate all pending issues relating to Ambewadi SS to KPTCL top Management for early completion. 48/I/2 Complete outage of 220kV Peenya Substation in Karnataka at 4:23:17 hrs All connected 220kV lines and transformers were taken on 220kV North bus as South bus was under shut down for conversion of strung bus to rigid bus and isolator replacement under R&M works. Failure of HV side Y phase CT of 150MVA Transformer-3 occurred at Peenya Substation which resulted in operation of Differential and HV REF protection. The failure of CT also resulted in a 220kV bus fault in North Bus. KPTCL to revise distance relay settings at Nelamangala end for 220 kv Nelamangala Hebbal - Peenya line 1 for the effective line length of 17 km. These new settings can be appropriately reviewed as and when the tie-arrangement at Hebbal is done away with. KPTCL KPTCL mail received on : Presentl 220kV Nelamangala -Hoody (i.e. nelamangala-peenya-hebbal -Hoody line is made LIILO at Yelahanka sub station and breaker at Peenya is kept open, necessary modification in distance relay settings adopted for new configuration. KPTCL Mail Recieved dated : Since usage of this line as an Incoming line at Peenya is required for emrgency purposes, the settings of this line at Nelamangala end will be reduced to 17KMs and as a special case, to cover the rest of the length of the line, Zone 2 timing will be reduced to 150 ms. Pending KPTCL Mail dated : The revised settings to be adpopted for this line considering reduced protected line length( 17KMs) is issued as a special case which will be implemened and tested during scheduled outage. Review Meeting dated : KPTCL informed that the revised setting would be implemented by December, Page 21 of 38

90 Annexure-III 48/I/3 Outage of 220kV Ambewadi station in Karnataka at 10:41 hrs 220kV Ambewadi-Nagjheri line-2 tripped on B-phase to earth fault. This resulted in loss of supply to 220kV Ambewadi bus. 220kV Ambewadi-Ponda line-1&2 were hand tripped after deenergization of bus at Ambewadi. KPTCL to fast-track providing A/R on all 220 kv lines emanating from Ambewadi SS to prevent Station shut-down on temporary faults. KPTCL KPTCL mail received on : Will be complied in a months time. KPTCL Mail Recieved dated : Enabling the AR feature was discussed during PCSC meetings and since Ambewadi-Ponda and Ambewadi-Xeldom lines are radial lines, it was decided that enabling AR is not required. To clear the faults in the abovelines early, the timings of the Zone 2 was reduced to 150mS and the Back Up EFR timings have been reducedto 150mS. KPTCL Mail dated : Enabling the AR feature was discussed during PCSC meetings and since Ambewadi-Ponda and Ambewadi-Xeldom lines are radial lines, it was decided that enabling AR is not required. To clear the faults in the abovelines early, the timings of the Zone 2 was reduced to 150mS and the Back Up EFR timings have been reduced to 150mS. In view of the above, it is requested to drop the issue from this list. Review Meeting dated : KPTCL informed that AR would be enabled at Ambewadi end for lines other than Ponda and Xeldom lines during retrofitting of Back Up protection by Distance protection relay at Ambewadi. Pending Considering the importance of the substation and delay in executing various works, it was decided to escalate all pending issues relating to Ambewadi SS to KPTCL top Management for early completion. 51/II/21 Multiple tripping at 400kV Guttur SS at 18:53 hrs Failure of Lightning Arrestor of Y-phase Line Reactor of 400kV Guttur-Hiriyur line-1 and line tripped on distance protection Zone-1. Bus-bar protection of 400kV Bus-2 at Guttur substation also got operated during the event sensing this through fault. 400/220 kv ICT-1 & 2 at Guttur, 400kV Kaiga-Guttur-2, 400kV Guttur-Narendra-2, 400kV Guttur-Hiriyur-2 and 400kV Guttur-Munirabad which are on 400kV Bus-2 got tripped during the incident. 400kV Guttur-Narendra-1 which was on Bus-1 also tripped at the same time. 1. KPTCL to configure all DR s and EL s at 400 kv Guttur SS so that they will also get triggered for BBP operation. 2. KPTCL to ensure time-synchronization of all DR s and EL s with GPS at their 400 kv Guttur SS. KPTCL KPTCL Mail received dated : SEE, RTC, Bangalore to update the status KPTCL Mail received dated : Providing numerical bus bar protection to 400kV buses and GPS time synchronising equipment at Guttur is considered under R&U. Work is awarded to M/s Alstom, execution will be taken up shortly. KPTCL Mail received dated : GPS and accessories will be supplied during May 2017, expected to complete the work within a month after supply of materials. Pending 1. Time-frame? 2. Time-frame? KPTCL Mail dated : 1). The work of replacing static type 400kV Bus Bar Protection scheme by numerical BBP is under progress at Guttur. --- Pending 2). GPS time syncronising device is expected to be supplied before end of December Pending Review Meeting dated : 1) & 2) KPTCL informed that the works are under progress, and are targeted to br completed by February, Page 22 of 38

91 Annexure-III 52/I/3 Complete outage of 220 kv Shimoga substation at 15:03 hrs 220kV Bus Bar protection operated during failure of R phase CT in DVG-2 line bay. KPTCL to operate 220 kv Shimoga on multi-bus operation under normal conditions, and put it on single-bus operation only under emergency conditions. KPTCL KPTCL Mail received dated : Replacement of existing BBP by new BBP with 4 zone protection is being taken up under R&U. KPTCL Mail Recieved dated : GE Ltd has already supplied the necessary Bus Bar protection panels for replacement of the existing static type BBP by new numerical BBP with 4 zone protection under R&U project. The work of commissioning the same will be taken up shortly. Pending KPTCL Mail dated : Due to operational constraints two/ multi bus operation is not being implemented. Review Meeting dated : It was noted that Shimoga SS is having required configuration for providing double-bus operation. However, due to large no. of feeders (15 in no) with variable gneration at certain remote ends like Varahi, the flows on these lines are bound to vary. As such it is necessary to zero in on appropriate arrangement of feeders on different buses so that bus-isolators of the feeders are not overloaded. 53/I/1 Complete outage of 220kV Peenya Substation of KPTCL at 11:39 Hrs 220kV Peenya-Nelamangala-3 tripped on B-E fault at both ends. At the same time, 220kV Peenya- Nelamangala-4 tripped on R-Y fault only at Nelamangala end, and was in service from Peenya end. Due to tripping of these two lines, 220kV Peenya-Nelamangala- 2 tripped on overcurrent protection. KPTCL to furnish a report on the tripping of 220 kv Peenya- Nelamangala line-4 Nelamangala detailing the remedial measures taken including the settings adopted for Z1B (Zone extension) and Power Swing Block. The issue was discussed. KPTCL was asked to try out multi-bus operation on trial basis to arrive at suitable arrangement of feeders. KPTCL KPTCL Mail received dated : SEE, RTC, Bangalore to update the status KPTCL Mail Recieved dated : Since usage of this line as an Incoming line at Peenya is required for emrgency purposes, the settings of this line at Nelamangala end will be reduced to 17KMs and as a special case, to cover the rest of the length of the line, Zone 2 timing will be reduced to 150 ms. Pending KPTCL Mail dated : Considering it as special case, revised settings to be adpopted for this line considering reduced protected line length( 17KMs) is issued which will be implemened and tested during next scheduled outage. Review Meeting dated : KPTCL informed that the revised settings would be implemented by December, /II/1 Tripping of 220 kv Chikkodi at 03:03 Mudshingi and 220 kv Chikkodi- hrs Talandage lines Triggering incident was failure of B-ph PT of 220kV Bus-2 (western bus) at 220KV Chikkodi substation. 220KV Chikodi- Belgaum-I line tripped on DEFR (Inst), 220KV Chikkodi-Kudachi line tripped on Distance protection and also 100MVA transformer-2 tripped on E/F protection. 1.KPTCL to take steps to provide busbar protection at their 220 kv Chikkodi inter-regional substation, and furnish a timeline for the same. 2.KPTCL to review distance protection settings for 220 kv Chikkodi Kudachi line. 3.KPTCL to furnish equipment failure report of the current incident to PSE&TD Division of CEA with a copy marked to SRPC. KPTCL KPTCL Mail Recieved dated : 1. The necessary Bus Bar protection panels are already supplied to Chikkodi under R&U project. Presently R&U works at sub stations subjected to audit are taken up. After completion of PAR works, the baove works are planned. --- Pending Pending Pending KPTCL mail dated : 1.The necessary Bus Bar protection panels are already supplied to Chikkodi under R&U project. Control cables have to be supplied. Presently R&U works at sub stations subjected to audit are taken up. After completion of PAR works at 26 Sub stations, remaining works will be taken up through M/s GE. --- Pending Pending Pending Pending Review Meeting dated : 1. KPTCL informed that BBP would be provided by April, Pending 2. KPTCL informed that DPR settings had been reviewed Completed 3. EFR on failure of B-ph PT of 220 kv Bus-2 had been furnished to CEA Completed Page 23 of 38

92 Annexure-III 62/II/3 Tripping of 220 kv Bus 2 and connected elements (220kV HAL at 23:06 hrs #1 and 2, 400/220 kv ICT- 1, 2 and 220/66 kv ICT-2) at 400/220 kv Hoody substation of KPTCL (Load loss : 590 MW) Failure of R-phase CT of 220/ 66 kv transformer-2 at 220kV Hoody end resulted in a bus fault in 220kV Bus-2. Fault was cleared by backup protection of ICT's (220kV lines were being radially operated) due to absence of busbar protection 1. KPTCL to provide Busbar protection at their 220 kv Hoody SS at the earliest. 2. KPTCL to furnish an Equipment Failure Report on CT failure to CEA with a copy marked to SRPC. KPTCL KPTCL mail received dated : Numerical BBP is being provided under R&M works. KPTCL Mail Recieved dated : 1. Numerical Bus Bar protection panels have already been supplied as a part of R&M works awarded to GE Ltd. Due to issue regarding the sectionaliser CTs, the work had stopped. Now the same is resolved and the the above work will be taken up after supply of sectionaliser CTs. --- Pending Pending Pending 62/II/5 69/III/5 Tripping of 220 kv South Bus and at 14:34 connected elements (220kV HSR, hrs 220kV Nagnathpura, 220 kv Harohalli, 220 kv Subramanyapura, 220 kv Tataguni, 220 kv Mallur and 400/220kV ICT-2 and 3) at 400/220kV Somanhalli substation of KPTCL Tripping of 220 kv Sedam- Tandur line at 00:50 hrs & at 17:27 hrs Triggering incident was fault in 66 kv Somanahalli - Bannerghatta line and fault was cleared by operation of Back-up OCR at Somanahalli end. Tripped on Y-Phase to ground fault due to distance protection operation. Auto reclosure could not be validated from the submitted DR/EL. KPTCL to provide numerical Busbar Protection at their 220 kv Somanahalli SS at the earliest. KPTCL to enable and put A/R into service from Sedam end on 220 kv Sedam Tandur S/C line. KPTCL Mail dated : 1. Numerical Bus Bar protection panels have already been supplied as a part of R&M works awarded to GE Ltd. Due to issue regarding the sectionaliser CTs, the work had stopped. Now the same is resolved and the the above work will be taken up after supply of sectionaliser CTs. --- Pending KPTCL KPTCL mail received dated : Numerical BBP is being provided under R&M works KPTCL Mail Recieved dated : Tesing & Commissioning of numerical BBP at Somanahalli is under progress. There was some technical issue wth BBP scheme supplied to Somanahally which is being finalised in consultation with OEM SIFANG. Numerical BBP will be commissioned at Somanahally within a month's time. KPTCL Mail dated : KPTCL Review Meeting dated : KPTCL informed that the works relating to put A/R in service are going on at their Sedam SS, and assured that it would be put into service by February, Pending Pending 72/I/3 Complete outage of 220kV TK Halli, Kadakola, Chamarajanagara and Maduvinahally substation of KPTCL at 12:41 hrs Snapping of B-phase Jumper in 220 kv Bastipura - Kadakola line-1 resulted in tripping of the line. 220kV Bastipura-Kadakola line-2 also got tripped during fault in line-1. Due to tripping of above lines bus shutdown occurred at TK Halli, Madhuvanahally, Chamarajanagara and Kadakola stations due to overloading of connected lines. 1. KPTCL to provide the detailed logics of SPS proposed in Hotagally Bastipura Kadakola area, and take steps to implement the same at the earliest. 2. KPTCL to take steps to put A/R into service on 220 kv Bastipura Kadakola lines at the earliest. KPTCL Yet to be informed Pending Page 24 of 38

93 Annexure-III 49/I/3 Complete outage of 220kV Ambewadi Substation of KPTCL at 14:34 hrs 220kV Nagjheri-Ambewadi line-1 tripped at 13:33 hrs due to B phase to earth fault. Ambewadi was radially fed from Nagjheri power station through 220kV Nagjheri- Ambewadi line-2. Tripping of this line caused 220kV Bus shut down at Ambewadi and remaining lines and transformers were hand tripped 1. KPCL to provide A/R on all 220 kv lines emanating from Nagjheri PH. 2. KPTCL to provide A/R on all 220 kv lines emanating from Ambewadi SS. KPCL/ KPTCL KPTCL Mail Recieved dated : 1. coordination of KPCL has been requested for enabling AR lines terminated to Nagajari. 2. AR will be enabled at Ambewadi end for lines other than Ponda and Xeldom lines during retrofitting of Back Up protection by Distance protection relay at Ambewadi. KPTCL Mail dadted & Review Meeting dated : 1. KPTCL informed that Coordination of KPCL has been requested for enabling AR lines terminated to Nagajari. --- Pending 2. KPTCL informed that AR would be enabled at Ambewadi end for lines other than Ponda and Xeldom lines during retrofitting of Back Up protection by Distance protection relay at Ambewadi. -- Pending Pending 51/I/3 Complete outage of 220 kv Nagjheri power station and 220 kv Ambewadi substation of KPTCL at 12:36 220kV lines from Nagjheri power house started tripping hrs from 11:00 hrs due to fault in lines. The sequence of tripping is shown in SOE list. At 12:33 hrs, 220kV Narendra-Ambewadi lines-1&2 got tripped which resulted in loss of evacuation path to Nagjheri station resulting in tripping of running Units and complete outage at Nagjhheri power station. 220kV Ambewadi station also got de-energized due to tripping of source feeders i.e. 220kV Narendra-Ambewadi-1&2 and 220kV Nagjheri-Ambewadi-1&2. 1. To avoid tripping of transmission lines on transient faults, KPCL/ KPTCL is recommended to carry out periodic patrolling of lines, and ensure their proper maintenance by carrying out jungle/ bushing clearance and trimming of tree branches within the RoW of transmission lines as per the SRPC transmission line patrolling guidelines (available under the menu item "All Uploads/ Operation/ Miscellaneous/ Transmission Line Patrolling Protocol / Guidelines for Southern Region" on SRPC website). 2. KPCL/ KPTCL to review operation of SPS at NPH for functionality (reduction of generation with tripping of evacuating lines) and healthiness. 3. KPCL to put 220 kv Kodasalli - Nagjheri D/C lines into service if more than 200 MW generation from Kali Complex (with Nagheri Contribution not less than 50 MW) is ensured on sustained basis. KPCL/ KPTCL Status informed during Special Meeting held on : Pending 1. KPTCL informed that the matter had been taken up with concerned Line Operation and Maintenance wing to carry out corridor clearance and maintenance as per schedule to avoid frequent line faults in this corridor. A letter had also been addressed to Chief Engineer, Bhagalkot zone, to ensure lines in & around Kali complex are maintained in healthy condition Completed 2. KPTCL assurd that the final modified SPS would be implemented at Nagjheri PH at the earliest Pending 3. KPCL informed that Nagjhari- Kodasalli Lines 1 & 2 had been kept in service since 08.06hrs. --- Completed KPTCL Mail received dated : KPTCL Mail dated : 1) & 3). --- Completed. 2). Proposed revision in existing SPS scheme is already submitted to SRLDC/SRPC., yet to be discussed and approved by the SRPC forum --- Pending Review Meeting dated : 2. The SPS proposed by KPTCL was discussed and the PCSC forum suggested certain changes for suitable incorporation. KPTCL agreed to look into the same and assured that the modified SPS would be furnished by January, Page 25 of 38

94 Annexure-III 53/I/3 Complete outage of 220kV at 14:40 Ambewadi Narendra line-2 tripped on fault and 220kV 1. KPCL to furnish a report on the reasons for Unit-6 tripping KPCL/ KPTCL KPTCL Mail received dated : Ambewadi station of KPTCL and hrs 220kV Nagjheri of KPCL ambewadi Narendra line-1 tripped due to over-loading. Running Units at Nagjheri also tripped during the event due to tripping of evacuating lines at Nagjheri PH. 2. KPCL/ KPTCL to modify suitably the SPS at Nagjheri Power House such that it would also factor in the over loading of Ambewadi-Narendra lines. 3. KPCL to put 220 kv Kodasalli - Nagjheri D/C lines into service if more than 200 MW generation from Kali Complex (with Nagheri Contribution not less than 50 MW) is ensured on sustained basis. Modifications to be carried in Nagzari SPS logic is submitted to SRLDC/SRPC for verification and approval Status received vide KPCL mail dated : 1. Tripped since there was evacuation problem and there were only two lines NA-1 and NA Completed 2. Will be reviewed in consultation with EE(RT), KPTCL, Hubli. --- Pending 3. Both the lines are in charged condition. --- Completed. KPTCL Mail Recieved dated : 2. Proposed revision in existing SPS scheme is already submitted to SRLDC/SRPC., yet to be discussed and approved by the SRPC forum. --- Pending Pending 62/II/7 Tripping of running Units & 230kV feeders at Tuticorin TPS of TANGEDCO (Gen Loss: 640 MW) at 22:36 hrs Failure of Bus Section-I Y-ph CT resulted in operation of bus-bar protection for Bus Sections -I & II. Running Units#1, 4 and 5, 230 kv Kayathar, 230kV Kudankulam, 230kV Sterlite, Station Transformer-1, 2 & 3 got tripped during the incident. Unit 2 & 3 were not in service. Tamil Nadu 1. TANGEDCO to replace existing Check-Zone relay with a new TANGEDCO one possessing required performance. 2. TANGEDCO to take steps to provide numerical busbar protection at their 220 kv Tuticorin TPS. TANGEDCO may also explore providing dual CT s (on either side) for all B/S breaakers at the time of commissioning of numerical BBP, if there were no space constraints. 3. TANGEDCO to take steps to provide for standalone Event Logger (EL) and standalone Disturbance Recorder (DR) with automatic downloading facility to a centralized server. KPTCL Mail dated : TANGEDCO mail dated : 1) New Relay is tested and ready for replacement.now all 5 units are in service.the relay will be replaced when lesser units are in service. --- Pending 2.a)Steps are taken to renovate & mordernization of all the control panel into Numerical based control panels. --- Pending 2.b) Since 230 KV indoor switchyard has no spare space providing dual CT`s is not fessible. -- Completed 3) Procurement of EL & DR is under progress. --- Pending TANGEDCO mail dated : 1) Check zone New Relay is replaced on Completed Pending Pending TANGEDCO mail dated : 2).P & C wing gives clearance to TTPS to procure the Bus bar protection relays and protection relays and SER / DR system vide Lr.CE/P&C/SE/D/EEPC4/AEE3/F.TECH/D.27/17 Dated: To get administrative approval budgetary offer has bar protection relay from various companies ----Pending Pending 3). SRPC vide Lr: SRPC/SE- III/CEA/2017/6450/DT: gives features of SER/DR. Budgetary offer will be called for SER / DR having above features. ---Penidng Review Meeting dated : 2) & 3) The issue was discussed and TANGEDCO was asked to provide time-line for implementing the recommendations. Mail dated : Procurement work is under progress and will be completed by December /II/5 Tripping of 400kV Alamathy- SVChatram line-1&2 and 400/230kV ICT at S.V.Chatram at 15:29 hrs Line-2 tripped on R-phase to earth fault. Line autoreclosed at SVChatram end and failed to reclose at Alamathy end. Bphase to earth fault in line-1. Line tried for A/r but due to permanent fault line did not reclose. ICT tripped on operation of over flux protection. TANTRANSCO was requested to swap the relays between two TANTRANSCO stations, so that Main-1 and Main-2 will be of different make at each station. TANTRANSCO vide their mail dated informed that different relays in Main-I & Main-II would be ensured at the earliest. Mail recieved on , and : Different relays in Main-I & Main-II will be ensured. Mail received on : TANTRANSCO: Not feasible in the existing SAS sub stations. Hence, exemption may be given for these sub stations. Mail received on , , & : As discussed in the 52nd PCSC meeting, Swapping of Relays between two stations is not feasible in the existing SAS sub stations. Hence, exemption may be given for these sub stations. Status received vide mails received on & & & Pending Page 26 of 38

95 Annexure-III TANTRANSCO Mail dated : Different make Relays will be ensured for Main-I & II relays at Alamathy end. Tender floated for relay procurement. Review Meeting dated : TANTRANSCO informed that the recommendation would be complied with by June, TANTRANSCO Mail dated : Different make Relays will be ensured for Main-I & II relays at Alamathy end. Tender floated for relay procurement. Timeline: June /I/1 Disturbance in 220kV Tamilnadu system at 14:04 Complete outage of 230kV Palladam, 230 kv hrs Othakalmandapam S/s, 230 kv Coimbatore S/s, 230 kv Thudialur and 230 kv Sadayapalayam S/s TANTRANSCO to take suitable measures like installing more stub-towers along 230 kv OK Mandapam Myvady line to avoid excessive sag due to over-loading. TANTRANSCO TANTRANSCO Mail received on , and : 230kV Othakalmandapam - Myvadi feeder will be made LILO at Kongal Nagar. Line restringing will be carried out along with the above proposal. Mail Received on , , & : 230kV Othakalmandapam - Myvadi feeder will be made LILO at Kongal Nagar. Line restringing will be carried out along with the above proposal. Status received vide mails received on & & & & & : 230kV Othakalmandapam - Myvadi feeder will be made LILO at Kongal Nagar. Line restringing will be carried out along with the above proposal. TANTRANSCO mail dated & : Othakalmandapam - Myvadi feeder will be made LILO at Kongal Nagar. Line restringing will be carried out along with the above proposal. Pending Status received vid dated : Othakalmandapam - Myvadi feeder replacement of kundha conductor with Zebra and tower replacement work has been sanctioned. Work will be taken up. Review Meeting dated : TANTRANSCO informed that 230 kv OK Mandapam - Myvady feeer was LILOed at Anaikadavu on Further replacement of the existing Kundah condductor with Zebra has also been taken up, and is targeted to be completed by June, TANTRANSCO mail dated : 230kV Othakalmandapam - Myvadi feeder replacement of kundha conductor with Zebra and tower replacement work has been sanctioned. Work will be taken up. Timeline: June /I/3 Complete outage of 230kV at 6:28 Mywadi station of TANTRANSCO hrs Busbar protection got operated for a fault in 230kV Mywadi-Anaikadavu line TANTRANSCO to examine the feasibility of providing two main-zone operation for bus bar protection by exploring various alternatives like replacing existing bus-coupler CB with a hybrid bus-coupler CB that comes with inbuilt CT, replacing existing BBP relay with another suitable relay that supports two main-zone operation, and implement the same. TANTRANSCO TANTRANSCO Mail received on and : Revision of Bus Bar Protection setting was carried out. The stabilizing voltage setting was raised from 410 to 450 volts. After completing the necessary test, the bus bar protection put in to service on Mail Received on , , & : Revision of Bus Bar Protection setting was carried out. After completing the necessary test, the bus bar protection put in to service on Mail received on & : Provision of Bus Coupler bay arrangement was included in the Upgradation works proposed and the same was sanctioned by MoP through PSDF. Numerical relay allotted and being commissioned. Mail received on : Numerical BBP relay was commissioned on Status received vide mail dated & & : Numerical BBP relay was commissioned on Provision of Bus Coupler bay arrangement was included in the Upgradation works proposed and the same was sanctioned by MoP through PSDF. Status received vide mail dated : Pending Time-frame? Page 27 of 38

96 Annexure-III Status received vide mail dated & : Numerical BBP relay was commissioned on Provision of CT in Bus Coupler bay is arranged and zone segregation will be provided. Status received vid dated : Numerical BBP relay was commissioned on Provision of CT in Bus Coupler bay has been allotted. Zone segregation will be provided after commissioning of CT. Review Meeting dated : TANTRANSCO informed that the recommendation would be complied with by March, TANTRANSCO Mail received on : Provision of CT in Bus Coupler bay is arranged and zone segregation will be provided. Timeline: March Page 28 of 38

97 Annexure-III 51/I/1 (GD) Complete outage of 230kV Madurai S/s (Chekanaurani) of TANTRANSCO at 11:56 hrs Fault had occurred in 230kV Madurai-Sembatty line. Trip 1. TANTRANSCO to provide split-bus operation with bus from distance relay was not extended to breaker due to sectionalizer CB for their 230 kv Madurai (Chekanurani) SS. protection DC fail. LBB protection got operated resulting in a busbar trip at 230kV Madurai substation. All 2. TANTRANSCO to provide two main-zone operation for the elements got tripped as there is a single bus operation at numerical BBP that is being commissioned. 230kV Madurai S/s 3. TANTRANSCO to examine the feasibility of providing Re- Trip feature for the LBB protection, and accordingly take steps for implementing the same. TANTRANSCO TANTRANSCO mail received on : CMR relay for extending LBB protection was released and LBB extended from Distance Protection relay directly. CT is not available in the Bus Coupler bay for zone segregation. However, during commissioning of third ICT, Bus section Breaker will be provided for zone segregation. Numerical BBP relay will be provided. Status received vide mails recieved on and , , , , & & & & : 1 & 2) CT is not available in the Bus Coupler bay for zone segregation. However, during commissioning of third ICT, Bus section Breaker will be provided for zone segregation. Numerical BBP relay will be provided. Status received vide mail dated : 1 & 2) Contract awarded for providing third ICT & Bus modification works to accomodate bus coupler bay. Numerical BBP relay has been provided and tesing under progress. Status received vide mail dated : 1 & 2) Contract awarded for providing third ICT & Bus modification works to accomodate bus coupler bay. Numerical BBP relay has been provided and tesing under progress. Status received vide mail dated : 1 & 2) Contract awarded for providing third ICT & Bus modification works to accomodate bus coupler bay. TANTRANSCO mail received on : 1) Commissioning of Bus Coupler CT, Extended Bus with Additional Bus Coupler is under progress. Timeline: June ) Numerical BBP commissioned on to enable Bus seggregation. 3) Providing Re-Trip feature for LBB will be studied. Pending 55/I/1 (GD) Complete outage of 230 kv Gummidipoondi Station of TANTRANSCO at 12:15 hrs Flashover of Auto Transformer- 2 HV B-phase Isolator supporting insulator of 230kV Southern Bus occurred at Gummidipoondi station. At the time of fault, Bus bar protection relay was not in service for precommissioning testing of Auto Transformer-2. All feeders got tripped due to operation of zone-2 protection from remote ends. TANTRANSCO to take steps to provide double-bus operation at their 230 kv Gummidipoondi SS. TANTRANSCO Mail recieved on & : TANTRANSCO: Auto Transformer-2 HV side Bus isolator 'C'-phase support insulator of 230kV Southern Bus was replaced and Bus Bar Protection scheme was restored on Status received vide mails received on & & & & & & : CT is not available in the Bus Coupler bay for zone segregation. CT latch relay is to be provided for all bays for zone segregation. Status received vide mails received on & : Numerical Bus bar protection panel allotted and will be commissioned with zone segregation.. Pending Review Meeting dated : TANTRANSCO informed that Numerical BBP would be commissioned by March, TANTRANSCO mail received on : Commissioning of Numerical Bus bar protection is under progress. Zone segregation will be ensured. Timeline: March Page 29 of 38

98 Annexure-III 58 Different type and Make of distance protection relays to be provided for Main-I & Main-II protection for 230kV feeders at 400 kv Sunguvarchathiram & 230 kv TANTRANSCO The issue was discussed in PCSC-58 meeting held on , when PCSC forum agreed to Pending Sunguvarchathiram Substation [Carry-Over from Protection Audit Recommendations] de-link the implementation of the Item from the scope of Protection Audit Recommendations (PAR), and pursue it as part of PCSC Recommendations. Status received vide mails dated & & & & & & & : Different make Relays will be provided for Main-I & II relays at Sunguvarchatram end in a phased manner. 58/II/17 Multiple tripping at 230 kv Alamathy Station at 11:13Hrs Bus Bar Protection (Zone-2) of 230 kv Bus-B got operated at Alamathy Station during fault in 230 kv Alamathy-Korattur feeder. 1. TANTRANSCO to check the healthiness of BBP relay by conducting stability test, and take appropriate remedial action like increasing voltage settings, ensuring the healthiness of CT s, using CT s with similar characteristics (equal saturation effects & equal winding resistances) etc. at their 230 kv Alamathy SS. 2. TANTRANSCO to replace the existing high-impedance BBP relay with its low-impedance/ numerical variant so as to accommodate variation in CT characteristics at their 230 kv Alamathy SS. TANTRANSCO Review Meeting dated : TANTRANSCO informed that the recommended works of providing different make Relays for Main-I & Main-II are targeted to be completed by September, Mail received on & : Pending 1. The Bus Bar Protection scheme will be tested for healthiness including the CT circuits. 2. High impedance BBP relay will be replaced by Numerical relay. Status received vide mails dated & & & : 1. The Bus Bar Protection scheme was tested for healthiness including the CT circuits. AREVA make CTs in Alamathy SS are having different kneepoint voltage for the cores. CT cores of higher knee point voltage has been choosen for BBP in 230kV Korattur, 230kV OPG-1 & 230kV OPG-2 feeders on Completed. 2. High impedance BBP relay will be replaced by Numerical relay. --- Pending, Status received vide mails dated & & & Completed 2. High impedance BBP relay will be replaced by Numerical relay. --- Pending at 22:14 hrs Bus Bar Protection (Zone1) of 230kV Bus-A got operated at Alamathy Station during fault in 230 kv Alamathy-OPG- 1 feeder. Review Meeting dated : 2) TANTRANSCO informed that Numerical BBP would be provided by April, Pending TANTRANSCO mail received on : Complied. 2. High impedance BBP relay will be replaced by Numerical relay. Timeline: April Page 30 of 38

99 Annexure-III 64/1/4 Complete outage of North Chennai TPS STG at 23:14hrs Tripping of evacuating lines due to fault led to tripping of running Unit at NCTPS Stg-1 1. TANTRANSCO to take steps to complete insulator replacement works on the 230 kv lines owned by them in NCTPS area within 6 months. 2. TANTRANSCO to take steps to implement A/R on all 230 kv lines emanating from NCTPS-I at the earliest. TANTRANSCO Status received vide mails dated & & : 1. All the Porcelain insulators were replaced with Polymer insulators in 230kV NCTPS-I - Tondiarpet feeders - 1 & Completed 2. AR will be implemented on all 230kV lines emanating from NCTPS-I. --- Pending Status received vid dated : 1. Completed 2. The scheme needs modification to enable AR, since AR was not envisaged for this station during commissioning. AR will be implemented on all 230kV lines emanating from NCTPS-I within six months. --- Pending Pending 73/I/6 Complete outage of 400 kv Sriperumbudur station at 18:01 hrs There was HV side Y-phase CT failure of 400/ 230 kv ICT- 2 at Sriperumbudur. This resulted in tripping of all connected feeders and ICTs. 1) TANTRANSCO to ensure healthiness of 400 kv side CB of ICT-3 (CB-1752) and integrity of its LBB protection. 2) TANTRANSCO to furnish equipment failure report of the current incident (CT blast) to PSE&TD Division of CEA with a copy marked to SRPC. TANTRANSCO Yet to be informed Pending 3) TANTRANSCO to refer the instant case of PRV operation of ICT-1 to its OEM, and take appropriate action based on their advice. Page 31 of 38

100 Annexure-III Kerala 44/I/1 Complete outage of Idukki Hydro Power Station (GD-1) at 12:30 Hrs 220 kv breaker of unit-3 at Idukki Power house flashed and bus differential protection acted. All Generators (6Nos.) along with all 220 kv feeders tripped during the incident. 1. KSEB to reduce sensitivity of REF protection appropriately at Idukki PH. 2. KSEB to replace/ repair the faulty breaker. 3. KSEB to check the PLCC equipment at New Pallom and inform the remedial measures taken to PCSC forum. KSEB Mail received on : 1. Reducing the sensitivity of REF protection of Unit # 4, 5, 6 at Idukki PH: - Generation wing is planning to purchase new transformer management relays with low impedance REF protection. Purchase procedures initiated Pending 2. The replacement/ repair of faulty breakers are under the consideration of Generation wing. Breakers will be replaced / repaired in a phased manner. Unit #3 breaker was replaced with available breaker from the 220kV IDMD feeder. The 220kV CBs of unit #2 and unit #3 will be replaced with in two months. --- Pending 3. No abnormalities were noticed in the PLCC equipment at New Pallom station. It is kept under observation. --- Pending Mail recieved on : 1. Purchase procedures is still in progress --- Pending 2. Replaced. --- Completed. KSEB Mail dated : 1.Generation wing is planning ti provide low impedance REF protection by retrofitting numerical ABB make transformer management relay in the existing panel. --- Pending Pending KSEB Mail dated : 1. On consultation with OEM, it was understood that the retrofitting of numerical ABB make transformer management relay in the existing panel is not possible. Generation wing is planning to change the panels as part of RMU and is scheduled to start from January'18 beginning. --- Pending Page 32 of 38

101 Annexure-III 58/I/1 (GD) Complete outage of 220 kv Kalamassery Substation at 11:20 hrs Triggering incident was conductor snapping in 110 kv Kalamassery- Kaloor feeder KSEB to take steps to provide the following at their 220/ 110 kv Kalamassery SS: 1. Busbar protection at 110 kv level 2. Connecting 220 kv and 110 kv sides on to a common earthmat 3. Redundant DC supply for both protection (220 V) and communication (48 V) applications 4. Stand-alone Event Logger KSEB PGCIL (SR-I) & PGCIL (SR-II) KSEB Mail received vide dated : kv bus bar protection progressing ----Pending 2. Connection of 220kV earth mat and 110 kv plate earthing system completed.---- Completed 3. Redundancy of 110V DC system in progress. Complete independent redundancy is not practical for the time being. 48 V DC redundancy was already there. ----Pending 4. Instead of stand alone event logger, SCADA system of 110 kv feeder is expected to be completed by the end of SCADA system of 220kV side will be taken up after that ---- Pending KSEB Mail received vide dated : Status received vide mail dated : 1. Detailed engineering of the scheme has been completed. Material procurement is in progress. ---Pending 2., Completed Pending 1. Time-frame? 55/II/9 Tripping of HVDC Gazuwaka pole at 11:41 Pole tripped on operation of differential current 2 hrs protection of east side of Pole-2 PGCIL (SR-I) to take up the issue of differential protection operation of converter transformer on low voltage fluctuations with their OEM, and submit a detailed report on it. PGCIL (SR-I) PGCIL-SR1 Mail dated & Review Meeting dated : Issue taken up with OEM and still under study. Till now the OEM could not explain the reason for the said operation of protection. All data has been shared with OEM and further perused to identify the cause of the same and remedial action. Pending 56/II/11 Tripping of HVDC GazuwakaPole at 5:20 2 Hrs HVDC Pole-2 got tripped on operation of Bus differential protection PGCIL (SR-I) to get the tripping of HVDC Pole-2 tripping on Win-Bus differential protection thoroughly investigated for correctness of operation, and submit a report thereon. PGCIL (SR-I) PGCIL-SR1 Mail dated & Review Meeting dated : Issue taken up with OEM and still under study. Till now the OEM could not explain the reason for the said operation of protection. All data has been shared with OEM and further perused to identify the cause of the same and remedial action. Pending 65/II/15 Tripping of HVDC Gazuwaka Pole at 09:45 HVDC pole-1 got tripped due to operation of South filter 1&2 hrs inter zone protection and HVDC pole-2 got tripped due to operation of differential protection PGCIL (SR-I) to furnish detailed report on the events that led to tripping of HVDC Poles 1 & 2 including remedial measures taken to PCSC forum. Further, the OEM report w.r.t. tripping of HVDC Pole-2 shall also be furnished. PGCIL (SR-I) PGCIL (SR-I) Mail dated & Review Meeting dated : Issue taken up with OEM and still under study. Till now the OEM could not explain the reason for the said operation of protection for Pole 2. All data has been shared with OEM and further perused to identify the cause of the same and remedial action thereof if any. Pending 67/II/5 Tripping of HVDC Bhadravati Pole at 10:59 hrs Pole-1 tripped due to PC1 INTERNAL MINOR ALARM WEST - ALARM. Pole protection extended trip without any protection operation PGCIL (SR-I) in coordination with PGCIL (WR-I) to take up the issue with its OEM, and furnish the reasons for Pole-1 tripping along with remedial measures taken. PGCIL (SR-I) Review Meeting dated : Pending PGCIL (SR-I) was asked to take up the sissue with PGCIL (WR-I) and furnish action taken report by Page 33 of 38

102 Annexure-III 67/II/6 Tripping of HVDC Bhadravati Pole at 14:43 hrs Pole-1 tripped due to PC1 INTERNAL MINOR ALARM WEST - ALARM. Pole protection extended trip without any protection operation PGCIL (SR-I) in coordination with PGCIL (WR-I) to take up the issue with its OEM, and furnish the reasons for Pole-1 tripping along with remedial measures taken. PGCIL (SR-I) Review Meeting dated : Pending PGCIL (SR-I) was asked to take up the sissue with PGCIL (WR-I) and furnish action taken report by /II/8 Tripping of HVDC Gazuwaka Pole at 17:30 HVDC Poles 1 & 2 got tripped due to Auxilliary supply 1 & Pole-2 hrs failure PGCIL (SR-I) to study the solution proposed by ABB in their paper on Mitigation of Ferro-resonance in Line Commutated HVDC Converter Interconnected with Series Compensated Overhead Line Transmission System presented in 2016 IEEE Electrical Power and Energy Conference (EPEC) for implementation feasibility, and furnish an Action Taken Report w.r.t. the same. PGCIL (SR-I) PGCIL-SR1 Mail dated : Ferro resonance is being observed at GWK for any disturbance at Jepore end. ABB have suggested to keep FSC in service at Jeypore end when powerflow is more than 250MW per line. At low powers FSC is generating resonanting frequencies & causing ferro resonance. If SRPC advises, the FSC shall be kept out for powerflow below 500 MW as a mitigation measure to avoid ferro-resonance. Review Meeting dated : PGCIL (SR-I) was requested to refer the solution propsoed to their Corporate for implementation feasibility. It was also made clear to PGCIL (SR-I) that any issue relating to revision of FSC settings can be directly taken up with NLDC. Pending 68/II/12 Tripping of 400 kv NPS Nellore PG D/C line at 18:58 hrs 70/II/6 Tripping of 400 kv Nellore-PG - NPS line at 13:06 hrs Lines tripped during a fault on 400 kv Nellore-PG Vijayawada line-2 Line tripped due to mal-operation of differential relay at NPS end and was in service from Nellore. 1. For the 400 kv Nellore-PG Vijayawada line, PGCIL (SR-I) to investigate the reasons for 3-ph tripping of Main-CB upon detection of the fault without trying for A/R and operation of Stub/ Tee protection at the time of Tie-CB A/R attempt at Vijayawada end during instant trippings, and furnish remedial measures taken to address the issues involved. For the subject line, PGCIL (SR-I) to configure DR s & EL s of Line Differential Relays for recording all requisite protection operations at their Nellore PS. PGCIL (SR-I) PGCIL-SR1 Mail dated & Review Meeting dated : Pending. 2. Due to CSD contractor problem CB Y-pole reclosed & defective contactors replaced & wiring problem in CSD rectified on next day --- Completed. Pending 3. NPS end DR & EL configured as suggested. --- Completed. PGCIL (SR-I) Yet to be Informed Pending at 14:26 hrs 70/III/4 Tripping of 400 kv Ramagundam at 13:17 R-phase to earth fault had occurred in line. line autoreclosed at Ramagundam Chandrapur line-2 hrs end PGCIL (SR-I) to furnish an action taken report on the reasons for A/R non-operation at Chandrapur end including remedial measures taken to PCSC forum. PGCIL (SR-I) Yet to be Informed Pending 71/II/3 Tripping of HVDC Gazuwaka Pole at 19:29 Pole-2 got tripped due to failure of Valve Cooling system PGCIL (SR-I) to furnish reasons for VFD-1 failure in the 2 hrs VFD (Variable Freq Drive control) instant tripping, and share OEM s observations w.r.t. the same, along with remedial measures proposed. PGCIL(SR-I) Yet to be Informed Pending 72/II/9 Tripping of HVDC Gazuwaka pole at 06:38 hrs Due to fault in 220kV line, ICT-1 at Gazuwaka got tripped PGCIL (SR-I) to furnish a compliance report on the measures due to directional OC high set. Since tertiary of ICT-1 was suggested in the special meeting on HVDC Gajuwaka Pole feeding the auxiliary supply to Pole-1, tripping of ICT-1 trippings held on led to the tripping of Pole-1 due to loss of auxiliary supply PGCIL(SR-I) Yet to be informed Pending Page 34 of 38

103 Annexure-III Pole 2 tripped due to the activation of WA2 Ferro at 00:23 Resonance Detected" in hrs East side 72/II/10 Tripping of HVDC Gazuwaka Pole at 01:38 hrs Pole 2 tripped due to the activation of WA2 Ferro Resonance Detected" in East side PGCIL (SR-I) to furnish a compliance report on the measures suggested in the special meeting on HVDC Gajuwaka Pole trippings held on PGCIL(SR-I) Yet to be informed Pending at 01:31 hrs Pole 2 tripped due to the activation of WA2 Protective Y- Block Executed" due to external AC side disturbance 72/II/12 Tripping at 400 kv Raichur PG - Raichur TPS line - 1 & at 17:15 hrs While carrying out bus bar scheme checking, RTPS- Raichur PG 1 and RTPS-Raichur PG 2 lines tripped at Raichur PG end. Direct Trip (DT) was received at RTPS end. Bus-1 was under shutdown. PGCIL (SR-I) to furnish single line diagram of 765/ 400 kv Raichur-PG substation showing details such as (a) busbararrangement, and (b) the type of protection operated on the CB's involved. Further, a report detailing the reasons for tripping of both Raichur (PG) RTPS lines 1 & 2 along with remedial measures taken shall also be furnished. PGCIL (SR-I) Yet to be informed Pending 72/II/14 73/II/8 Tripping of 400 kv Gooty NPS line-2 Tripping of 400 kv Pavagada- Tumkur line-1, 400/ 220 kv ICT- 1&2 at 400 kv Pavagada SS at 16:30 hrs at 14:18 Hrs Line tripped due to Tie-CB LBB relay mal-operation at Gooty. Multiple trippings occurred during charging of 400 kv Pavagada-Tumkur line-2. PGCIL (SR-I) to furnish single line diagram of 400/ 220 Gooty substation showing details such as (a) busbar-arrangement, and (b) the type of protection operated on the CB's involved. PGCIL (SR-I) Further, a report detailing the reasons for tripping of NPS line- Yet to be informed Pending 2 at Gooty end along with remedial measures taken shall also be furnished. 1) PGCIL (SR-II) to review SOTF settings at Tumkur end on PGCIL (SR-II) Yet to be Informed Pending Tumkur Pavagada lines considering the least expected fault current levels. 73/II/9 Tripping of HVDC Talcher-Kolar Pole at 15:12 hrs Talcher Kolar Pole-1 tripped due to mal operation of DC protection system at Talcher end and Emergency Switch OFF (ESOF) signal received at Kolar end. PGCIL (SR-II) to furnish a detailed report on the instant tripping explaining clearly the reasons for repeated voltage recovery sequences, reasons for Pole-2 going into ground return mode while attempting Pole-1 de-block around 20:28 hrs, and non-operation of SPS PGCIL (SR-II) Yet to be Informed Pending (i) at around 15:12 hrs when the Pole-1 was blocked, and (ii) at around 20:28 hrs when Pole-2 went into ground return mode. 73/III/4 Tripping of 400 kv ILFS- Nagapattinam PS line at 10:32 Hrs R-phase to earth fault had occurred in line. Auto-reclose attempt could not be validated with submitted DR of Nagapattinam end. PGCIL (SR-II) to furnish a report on the reasons for A/R nonoperation, PGCIL (SR-II) Yet to be Informed Pending and the remedial action taken to rectify the same. Page 35 of 38

104 Annexure-III 54/I/1 Complete outage of 230 kv at 17:08 B-phase CT failure occurred in 230 kv S.P.Koil - MAPS 1.MAPS to furnish a detailed report on the tripping of SP Koil NPCIL (MAPS) S.P.Koil Station of TANTRANSCO hrs line-1. Busbar protection got operated at SP.Koil station. MAPS lines 1 & 2 at MAPS end with focus on the All elements except 230kV Oragadam and 230kV Kalivandapattu got tripped at 230kV S.P.Koil station. Y correctness of the settings of Main-I & Main-II relays (for primary & back-up protections) on both the lines. phase CT and support insulators also got damaged. 2.MAPS to take steps to provide down-loading facility for DR & EL from Main-I & Main-II relays on all 230 kv lines emanating from MAPS. 62/III/2 Tripping of 400 kv Kaiga-Guttur line at 05:01 hrs B-phase to earth fault. Line did not auto-reclose at Kaiga end. 1. KGS to properly configure all relays DR s time scale for a post-triggering period of 2 sec to capture events such as complete A/R operation. Others 3.MAPS, in co-ordination with SP Koil, to carry out PLCC endto-end testing, on SP Koil MAPS lines 1 & 2, and ensure healthiness of PLCC communication & carrier-aided protection. 4.MAPS to put in service Auto-Reclosure feature on all four 230 kv lines emanating from MAPS by June, KGS to ensure time-synchronization of all protection relays with GPS in their 400 kv switchyard. Status revided vide MAPS mail dated ; 1. The settings given by M/s TANTRANSCO were adopted for Main I & Main- II relays for both the lines. The same settings were verified to be same. Subsequently calibrated was done and no drift was observed. --- Completed 2. From May 2016 onwards, the DR, EL and trip report are being sent by mail to SRLDC, Bengaluru by MAPS. --- Completed 3. Monthly maintenance of PLCC equipments is being done by M/s TANTRANSCO. At present PLCC telephone is not working, it is being followed up. --- Completed 4. CVTs are planned to be procured from M/s TANTRANSCO by the end of February 2017 and A/R will be implemented for all the lines emanating from MAPS by July-2017 as discussed in the current SRPC meeting on 25/11/ Pending Status received vide MAPS mail dated & Review Meeting dated ; The CVTs procurement is in progress and the scheme (A/R) would be implemented before NPCIL (KGS) Status received vide mail dated & Review Meeting dated : 1. All 400kv transmisisonlines relays DR time scale for a post-triggering period of 2 sec is implemented. ----Completed 2.Time-synchronization for all lines protection relays (M1 &M2) with GPS in their 400 kv switchyard is being implemeneted. Scheme design is in process. ECD-April Pending Pending Pending 67/II/7 Tripping of 400kV JSWEL - Guttur at 18:02 line hrs & at 02:05 hrs Line tripped on operation of Over Voltage, Stage-1 protection at Guttur end and Direct Trip was received at JSWEL. JSWEL to configure their end DR s and EL s for DT receipt/ JSWEL Status received vide mail dated send event for 400 kv JSWEL Guttur line. JSWEL will configure DR s & event lists for DT send/ Receipt for 400kV JSWEL-Guttur Line during next opportunity / outage in concurrence with Guttur end. Review Meeting dated : It was noted that no JSWEL representative had come to the meeting. The issue was discussed, and it was decided that JSWEL would complete the recommended work by the end of December, Pending Status received vide mail dated JSWEL will configure DR s & event lists for DT send/ Receipt for 400kV JSWEL-Guttur Line during next opportunity / outage in concurrence with Guttur end. 68/II/11 Tripping of 400 kv K V KOTA - HNPCL lines 1 & at 22:36 hrs Line-1 tripped on R-E Zone-1 fault, and the Line-2 tripped on Direct Trip receipt at KV Kota end 1. HNPCL to ensure time sync of all of their protection relays with GPS, and to configure corresponding DR s for post triggering time of 2 sec.hnpcl to configure DEF operation only when Distance relay does not sense the fault. HNPCL HNPCL Mail dated : 1. Time synchronization of protection relays and BCU's with GPS completed. As per APTRANSCO recommendations DEF has been switched off in line protection relays. --- Pending Pending 2.HNPCL to ensure healthiness of A/R scheme implemented on all 400 kv lines at their station. 3.HNPCL to provide priority A/R scheme for 400 kv Tie-CB s with s suitable dead-time of say 2 sec Pending 3. Line Tie CBs Priority closing has been implemented for all the lines. --- Pending Pending Page 36 of 38

105 Annexure-III 69/I/1 Complete outage of 400kV TPCIL station at 19:33 hrs 400 kv TPCIL-Nellore PS line-1 got tripped from TPCIL end during fault in 400kV Nellore-Nellore PS line-2. Running units at TPCIL got tripped due to loss of evacuating line. 400kV Nellore PG - Nellore PS line-2 and 400kV TPCIL - Nellore PS line-1 were under shutdown. TPCIL to configure DEF protection such that it remains in TPCIL Yet to be informed Pending blocked condition as long as Distance Protection is active, and becomes active only when distance protection does not pickup. 69/II/9 Tripping of 400 kv Neyvelli TS2 Pugalur and 400 kv Neyvelli TS2 (exp) Pugalur line at 23:54 hrs Protection at NLCTS-2 & NLCTS-2 Exp has sensed as R-Y-E fault and given a 3 phase trip. At Pugalur end protection has sensed fault as Y-N and B-N fault in 400kV Neyveli TS2-Pugalur line & 400kV Neyveli TS2 EXP-Pugalur line respectively. Breaker at Pugalur got tripped due to Direct Trip receipt. 1.For the tripping of 400 kv NLC TS2 Pugalur line, NLCIL to NLCIL investigate the reasons for sending of DT to Pugalur end, and furnish an action taken report including remedial action taken and setting right various LEGEND issues in DR & EL of protection relays to PCSC forum. 2. For the tripping of 400 kv NLC TS2Exp Pugalur line, NLCIL to investigate the reasons for 3-ph tripping (detection of the fault as Y-B-E) of the line from NLC TS2Exp end including verifying pertinent settings of P437 relay (reference may be made to explanation given by TPCIL in GD - I.1/ GD - I.2), and furnish an action taken report including remedial action taken and setting right various LEGEND issues in DR & EL of protection relays to PCSC forum. NLCIL Mail dated : Pending 1. Shut down was taken on 400kV Neyveli TS-II to Pugalur feeder on to check the endto-end communication for DT/ permissive & other signals by testing at both the ends and to check the healthiness of the PLCC system components. The system was thoroughly checked and the missing loops in the relay circuit (Carrier send in Main1 relay and Carrier receive in Main2 relay) were provided. NLCIL Mail dated : 1. Completed. 2. The tripping of Pugalur feeder on at 23:54 hrs as per PCSC recommendation, the Defective relay P437 was replaced with spare P437 relay and the settings were checked.the spare relay replacement work carried out on 26& 27th March at the time shut down of Pugalur feeder. 71/III/1 Tripping of 400 kv HNPCL- KV Kota line at 12:34 hrs R-phase to earth fault had occurred in line. Breakers at HNPCL got tripped due to auto-reclose lockout and autoreclose was successful at KV Kota end. HNPCL to furnish a report detailing the reasons for A/R nonoperation HNPCL Yet to be informed Pending in the instant tripping, and remedial measures taken to set right them. 73/I/3 Complete outage of following at 10:01 220kV stations of KPTCL hrs Narendra (KPTCL), Bidnal, SRS Hubballi, Ambewadi Haveri, Karwar, Belgaum, Chikkodi, Soudatti, ML Pura, Athani, Kudachi, Ghataprabha, MK Hubli, NPH, Kodasalli and Kadra 220kV Kaiga-kadra and 220kV Kadra-Kodasalli lines tripped on backup over-rcurrent protection. 400/220kV Narendra ICT tripped on over load protection. Running units at Nagjhari and Kodasalli tripped due to nonavailability of evacuation lines. Cascaded tripping occurred due to overloading of 220 kv network and there was complete outage of several stations of KPTCL. 1). NPCIL (KGS) to use stipulated formats for furnishing FIR and TR. 2). NPCIL (KGS) to configure DR s & EL s of all protection relays at their 400 kv & 220 kv Kaiga GS for recording all mandated protections. NPTCIL (KGS) Yet to be informed Pending Page 37 of 38

106 Annexure-III 73/I/4 Complete outage of 220kV Kemar, MSEZ Bajpe, Kavoor, Netlamandur (Puttur) and 400/ 220 kv ICT-2 at UPCL at 18:45 hrs Fault in 220 kv Kemar Bajpe line-2 led to tripping of 220kV UPCL-Kemar Line-2 due to faulty LBB operation. Subsequently, lnie faults on 220 kv Varahi Kemar lines and UPCL Kemar line-1 led to complete outage of 220kV Kemar, MSEZ Bajpe, Kavoor, Netlamandur (Puttur). UPCL to provide re-trip feature for LBB protection of all UPCL Yet to be informed Pending breakers at their 220 kv Udupi power plant. 73/III/3 Tripping of 400kV Kaiga- Narendra line at 13:25 hrs Narendra end auto reclose could not be attempted due to direct trip receive from Kaiga. From EL of Kaiga, R- phase Zone-1 trip and A/R lock out were observed. NPCIL (KGS) to take steps to disable sending of DT to remote NPCIL (KGS) Yet to be Informed Pending ends upon 86X operation for any line protection operation at its 400 kv KGS. Page 38 of 38

107 Annexure-IV Pending Remedial Measures/ Actions taken for the Critical Tripping Incidents (as on ) Sl.No. Element Name Outage date/time Revival date/time Reason for outage Sender/ Receiver Remedial Measures/ Actions taken 1 400kV VTPS -MALKARAM /10:45: /11:51:00 DT RECEIVED APGENCO/ TSTRANSCO TSTRANSCO: Tripped at Both ends. Tripped on Direct Trip received indications at Malkaram end. Other end tripped on Over Voltage KV-MALKARAM-VTPS_IV /14:39: /15:42:00 MAL-OPERATION TSTRANSCO/ APGENCO APGENCO: TSTRANSCO: Line is in service at Malkaram end. APGENCO: 3 220KV-AMBEWADI-PONDA-2220KV /10:41: /11:07:00 TRIPPED ON A PHASE TO GND KPTCL/GED FAULT To-be-discussed 4 400KV-KOCHI-TRICHUR /18:01: /18:33:00 TRIPPED ON B-N FAULT PGCIL(SR-II) To-be-discussed 5 400KV-NELAMANGALA-HASSAN /16:02:00 TRIPPED ON R-N FAULT KPTCL/ PGCIL (SR-II) To-be-discussed 6 400KV/220KV PAVAGADA-ICT /15:09: /18:06:00 HAND TRIPPED AFTER IDLE CHARGE PGCIL (SR-II) To-be-discussed 7 400KV-NELAMANGALA-TALGUPPA /16:04: /18:16:00 TRIPPED ON R-N FAULT KPTCL To-be-discussed 8 220KV-AMBEWADI-PONDA /13:51: /14:12:00 DISTANCE PROTECTION KPTCL/ GED To-be-discussed 9 220KV-SEDAM-TANDUR /20:11:00 R-N FAULT KPTCL/TSTRANSCO KV/220KV TALGUPPA-ICT /16:47:00 TRIPPED ON LA BLAST KPTCL To-be-discussed TSTRANSCO: Tripped at Tandur end only. Tripped on R- Phase to ground, Zone-3 indications. Sparks in the bus was reported at Sedam end. KPTCL: KV-GAJWEL-RAMAGUNDAM /13:44: /14:30:00 Tripped due to fault in B phase TSTRANSCO/NTPC TSTRANSCO: Tripped at both ends. Tripped on B-Phase to ground indications at Gajwel end. A/R acted and unsuccessful. Test charged the line and stood OK. No fault found. NTPC: Page 1 of 8

108 Annexure-IV KV-THIRUVALAM-CHITTOOR /13:38: /15:15:00 TRIPPED ON B PHASE FAULT PGCIL (SR-II)/APTRANSCO APTRANSCO: Entire Line belongs to PGCIL. PGCIL (SR-II): KV-THIRUVALAM-CHITTOOR /13:38:00 TRIPPED ON B PHASE FAULT PGCIL (SR-II)/APTRANSCO APTRANSCO: Entire Line belongs to PGCIL. PGCIL (SR-II): KV-BIDADI-TUMKUR /12:19: /12:40:00 TRIPPED ON R-N FAULT PGCIL (SR-II) To-be-discussed KV-CHITTOOR-RAYALSEEMA TPP /10:57: /14:33:00 RELAY MALOPERATION APTRANSCO/APGENCO APTRANSCO: Feeder tripped on DT receive,from RTPP stage 1. APGENCO: KV-AMBEWADI-PONDA /06:01: /17:18:00 DISTANCE PROTECTION KPTCL/GED To-be-discussed KV-TALGUPPA-HASSAN /07:01: /15:41:00 TRIPPED ON Y-N FAULT KPTCL/PGCIL(SR-II) To-be-discussed KV-AMBEWADI-PONDA /06:21: /17:20:00 DISTANCE PROTECTION KPTCL/GED To-be-discussed KV-UPCL-HASSAN /12:43: /13:17:00 TRIPPED DUE TO R-N FAULT UPCL/PGCIL(SR-II) To-be-discussed KV-UPCL-HASSAN /19:38:00 Tripped on Y-B Fault UPCL/PGCIL(SR-II) To-be-discussed KV-UPCL-HASSAN /19:43:00 Tripped on R-B Fault UPCL/PGCIL(SR-II) To-be-discussed KV-AMBEWADI-PONDA /06:45: /09:05:00 BUS BAR PROTECTION OPERATED KPTCL/GED To-be-discussed KV-AMBEWADI-PONDA /06:45: /09:25:00 BUS BAR PROTECTION OPERATED KPTCL/GED To-be-discussed KV-BIDADI-TUMKUR /15:27: /17:15:00 TRIPPED ON R-Y FAULT PGCIL (SR-II) To-be-discussed KV/220KV UPCL-ICT /18:34: /19:42:00 TRIPPED DUE TO LIGHTNING UPCIL To-be-discussed KV-ILFS-NAGAPATTNAM_PS /11:09: /13:37:00 R-N FAULT ILFS/ PGCIL (SR-II) To-be-discussed KV-PAVAGADA-TUMKUR /19:52:00 TRIPPED ON SINGLE PHASE TO GND FAULT PGCIL (SR-II) KV-REGULAPADU-ALIPUR /09:35: /10:20:00 Transient fault APTRANSCO/ KPTCL To-be-discussed APTRANSCO: A/R successful at Regulapadu end. KPTCL: KV-NARNOOR-SRISAILAM_LEFT_BANK /17:53: /20:31:00 Y-PH DIFFERENTIAL PROTECTION OPERATED APTRANSCO/TSGENCO APTRANSCO: Direct trip not generated at Narnoor end.planned for testing on KV-MYSORE-KOZHIKODE /17:58: /18:10:00 TRIPPED DUE TO B-N LINE FAULT PGCIL (SR-II) TSGENCO: To-be-discussed Page 2 of 8

109 Annexure-IV KV-NELLORE_PG-SRIPERUMBADUR /18:02: /18:37:00 BUS BAR PROTECTION OPERATED PGCIL (SR-I)/PGCIL (SR-II) PGCIL (SR-I): Line tripped on Y-N,Z2 fault due to the uncleared fault at SVCM SS,TNEB. Dist 260KM,1.9KA from NLR end. PGCIL (SR-II): KV-SRIPERUMBADUR-THIRUVALAM /18:02: /18:15:00 BUS BAR PROTECTION OPERATED PGCIL (SR-II) To-be-discussed KV-SRIPERUMBADUR-SUNGAVARACHA /18:02: /18:52:00 BUS BAR PROTECTION OPERATED PGCIL (SR-II)/ TANTRANSCO TANTRANSCO: SVChatram end Z2 time 350msec. SPDR bus fault sensed in reverse zone time delay 500msec. APTRANSCO: Feeder tripped in Zone-2. No carrier signal received. PGCIL (SR-II): KV/230KV PALAVADI-ICT /01:50: KV-SRIPERUMBADUR-CHITTOOR /18:02: /18:29:00 TRANSFORMER CLOSED INDICATION BUS BAR PROTECTION OPERATED PGCIL (SR-II) PGCIL (SR-II)/ APTRANSCO To-be-discussed To-be-discussed KV/110KV SRIPERUMBADUR_TN-ICT /18:02: /19:25:00 BUS BAR PROTECTION OPERATED TANTRANSCO TANTRANSCO: BBP operated on 400kVBus.2. ICT 4 connected to Bus.1 hence holding KV-NELLORE_PG-SRIPERUMBADUR /18:02: /18:21:00 BUS BAR PROTECTION OPERATED PGCIL (SR-I)/ PGCIL (SR-II) PGCIL (SR-I): Line tripped on Y-N,Z2 fault due to the uncleared fault at SVCM SS,TNEB. Dist 256.3KM,1.9KA from NLR end. PGCIL (SR-II): KV-KAIGA-GUTTUR /19:55: /21:18:00 PMU RECTIFICATION NPCIL (KGS)/KPTCL To-be-discussed KV-GUTTUR-HIRIYUR /11:33: /11:54:00 MAL-OPERATION KPTCL/ PGCIL (SR-II) To-be-discussed KV-PAVAGADA-BPS /17:33:00 H /T TO CONTAIN OVER VOLTAGR PGCIL (SR-II)/KPTCL To-be-discussed KV-NELAMANGALA-HASSAN /20:45:00 R-N FAULT KPTCL / PGCIL (SR-II) To-be-discussed Page 3 of 8

110 Annexure-IV KV-SEDAM-TANDUR /14:50: /16:40:00 EARTH FAULT RELAY OPERATED KPTCL/TSTRANSCO TSTRANSCO: Line is in service at Tandur end. KPTCL: KV-NELAMANGALA-HASSAN /16:10:00 HEAVY WIND AND LIGHTETING KPTCL/PGCIL (SR-II) To-be-discussed KV-RAICHUR_PG-SHOLAPUR /12:58: /14:24:00 TRIPPED ON R-N FAULT PGCIL (SR-I)/PGCIL (WR-I) PGCIL (SR-I): Line tripped on R-N fault. A/R successful & tripped due to persisting fault. Line belongs to M/s RSTCL KV/220KV KOZHIKODE-ICT /14:02: /23:49:00 HEALTHINESS CHECKING PGCIL (SR-II) To-be-discussed KV-KARAIKUDI-TRICHY /15:55: /16:05:00 TRIPPED ON R-N FAULT PGCIL (SR-II) To-be-discussed KV-GAZUWAKA-JEYPORE /22:40: /23:49:00 TRIPPED ON B PHASE FAULT PGCIL (SR-I)/PGCIL (ER-I) PGCIL (SR-I): Tripped on B-N fault. DT receieved within dead time caused 3-ph tripping from Jeypore end, From Gajuwaka end: Distance- 175KM,Fc-1.47 KA; From Jeypore end: Distance-25.0 KM,FC-4.01 KA. Jeypore end O/V stg-2 optd during the dead time of A/R KV-SHOLINGANALLUR-KALVENDAPATT /06:03: /16:04:00 DT Received from Kalvanipattu end TANTRANSCO TANTRANSCO: DT received due to coupler problem at Kalevendupattu end KV-SHOLINGANALLUR-KALVENDAPATT /06:03: /16:15:00 DT Received from Kalvanipattu end TANTRANSCO TANTRANSCO: DT received due to coupler problem at Kalevendupattu end KV/220KV KOZHIKODE-ICT /10:46: /14:18:00 DIFFERENTIAL PROTECTION ACTED PGCIL (SR-II) To-be-discussed KV-AMBEWADI-PONDA /13:51:00 Tripped due to Ambewadi bus dead KPTCL/GED To-be-discussed KV-HINDUJA-KV_KOTA /01:59:00 DISTANCE PROTECTION HNPCL/APTRANSCO APTRANSCO: Patrolling was done.no Visible fault found. HNPCL: KV-NELAMANGALA-TALGUPPA /01:32: /01:52:00 DISTANCE PROTECTION KPTCL To-be-discussed KV-GOOTY-NPS /16:36: /17:43:00 phase to phase fault KPTCL/APTRANSCO To-be-discussed KV-NELLORE_AP-VTPS_IV /15:49: /20:21:00 Tripped due to PRV Relay operated APTRANSCO/APGENCO To-be-discussed KV-HINDUJA-KV_KOTA /19:34:00 TRIPPED ON Y PHASE FAULT HNPCL/APTRANSCO To-be-discussed Page 4 of 8

111 Annexure-IV KV-RAICHUR_PG-SHOLAPUR /16:29: /17:27:00 TRIPPED ON Y PHASE FAULT PGCIL (SR-I)/ PGCIL (WR-I) To-be-discussed KV-MARADAM-KALPAKKA /19:33:00 R-N FAULT APTRANSCO To-be-discussed KV-GHANAPUR-RAMAGUNDAM /05:16:00 Y-N FAULT PGCIL (SR-I)/NTPC To-be-discussed KV-GOOTY-NARNOOR /08:02: /10:32:00 DISTANCE PROTECTION PGCIL (SR-I)/ APTRANSCO To-be-discussed KV-SEDAM-TANDUR /01:16: /01:45:00 TRIPPED DUE TO B-N LINE FAULT KPTCL / TSTRANSCO KV/220KV MARADAM-ICT /10:10:00 MAL-OPERATION APTRANSCO To-be-discussed KV/220KV GUTTUR-ICT /13:02: /13:29:00 DIFFERENTIAL PROTECTION ACTED KPTCL To-be-discussed KV-NARNOOR-GHANI /13:52: /14:11:00 RELAY MALOPERATION APTRANSCO To-be-discussed KV/220KV GUTTUR-ICT /20:23:00 BUS BAR PROTECTION OPERATED AT LV SIDE KPTCL To-be-discussed KV-YERRAANDAHALLI-HOSUR_TN /11:51: /12:30:00 TRIPPED ON B-N FAULT KPTCL/ TANTRANSCO TSTRANSCO: A/R operated and successful at Tandur end. KPTCL: TANTRANSCO: passing fault KV-EDAMON-KUNDARA /20:01: /22:00:00 TRIPPED ON FAULT AT 110 KV KSEB BUS To-be-discussed KV-KUNDARA-KAYAMKULAM /20:01: /23:02:00 TRIPPED ON FAULT AT 110 KV KSEBL/ NTPC BUS To-be-discussed KV-HINDUJA-KV_KOTA /16:27: /17:15:00 DISTANCE PROTECTION HNPCL/ APTRANSCO To-be-discussed KV-JINDAL-BPS /16:25: /18:04:00 MAL OPERATION JSWEL/ KPTCL To-be-discussed KV-KAIGA-GUTTUR /11:45: /12:29:00 DC FAIL NPCIL (KGS)/ KPTCL To-be-discussed KV-HINDUJA-KV_KOTA /20:20: /22:01:00 DISTANCE PROTECTION HNPCL/ APTRANSCO To-be-discussed KV-KALPAKKA-KHAMMAM /10:25: /10:40:00 MAL-OPERATION APTRANSCO/ PGCIL (SR-I) To-be-discussed KV-YERRAANDAHALLI-HOSUR_TN /13:15: /15:40:00 DC EARTH FAULT KPTCL/ TANTRASNCO KPTCL: TANTRANSCO: Line patrol carried out and there is no visible fault KPTCL: KV-YERRAANDAHALLI-HOSUR_TN /12:45: /12:57:00 TRIPPED DUE TO B-N LINE FAULT KPTCL/ TANTRASNCO TANTRANSCO: No visible fault KPTCL: KV/220KV GUTTUR-ICT /12:53: /13:07: KV/220KV GUTTUR-ICT /12:53: /13:07:00 BUS BAR PROTECTION OPERATED AT LV SIDE BUS BAR PROTECTION RELAY OPERATED AT LV SIDE KPTCL KPTCL To-be-discussed To-be-discussed KV/220KV SOMANAHALLI-ICT /08:29: /09:08:00 BUS -1 R-pH CVT FAILURE PGCIL (SR-II) To-be-discussed Page 5 of 8

112 Annexure-IV KV/220KV SOMANAHALLI-ICT /08:30: /09:29:00 BUS -1 R-pH CVT FAILURE PGCIL (SR-II) To-be-discussed KV/220KV GUTTUR-ICT /12:50: /13:47:00 BUS BAR PROTECTION OPERATED KPTCL To-be-discussed KV/220KV NELAMANGALA-ICT /12:55: /14:12:00 BUS BAR PROTECTION OPERATED KPTCL To-be-discussed KV/220KV GUTTUR-ICT /12:50: /13:47:00 BUS BAR PROTECTION OPERATED KPTCL To-be-discussed KV-GHANAPUR-MAHESHWARAM_PG /13:00: /13:45:00 Tripped on R-Phase to groung PGCIL (SR-I) fault To-be-discussed KV-BIDADI-NELAMANGALA /13:33: /14:50:00 TRIPPED WHILE CHARGING NLMGLA ICT 3 PGCIL (SR-II)/KPTCL To-be-discussed KV-BIDADI-NELAMANGALA /12:55: /13:26:00 BUS BAR PROTECTION OPERATED PGCIL (SR-II)/KPTCL To-be-discussed KV-GOOTY-NELAMANGALA /14:33: /14:40:00 B PHASE TO GROUND FAULT KPTCL To-be-discussed KV-BIDADI-NELAMANGALA /13:33: /14:38:00 TRIPPED WHILE CHARGING NLMGLA ICT 3 PGCIL (SR-II)/KPTCL To-be-discussed KV-AMBEWADI-XELDEM /14:15: /17:43:00 B PHASE TO GROUND FAULT KPTCL/ GED To-be-discussed KV-BIDADI-NELAMANGALA /12:55: /13:20:00 BUS BAR PROTECTION OPERATED PGCIL (SR-II)/KPTCL To-be-discussed KV/220KV NELAMANGALA-ICT /14:33: /14:55:00 TRIPPED DUE TO TRIPPING OF KPTCL GOOTY-NLMGALA To-be-discussed KV-DICHPALLY-RAMAGUNDAM /11:45: /12:16:00 Tripped on R-Phase to groung fault TSTRANSCO/ NTPC TSTRANSCO: Test charged the line after tripping and the line stood OK. NTPC: KV/220KV HOODY-ICT /17:18: /18:50:00 H/T DUE TO HEAVY SPARK KPTCL To-be-discussed KV-MARADAM-KALPAKKA /11:53: /12:34:00 DISTANCE PROTECTION APTRANSCO To-be-discussed KV/220KV JAMMALAMADUGU-ICT /13:48: /14:48:00 DISTANCE PROTECTION APTRANSCO To-be-discussed KV-MARADAM-KALPAKKA /11:53: /12:10:00 DISTANCE PROTECTION APTRANSCO To-be-discussed KV-NARNOOR-MAHESHWARAM_PG /16:50: /17:06:00 MAL-OPERATION APTRANSCO/PGCIL (SR-I) To-be-discussed KV-YERRAANDAHALLI-HOSUR_TN /13:10: /13:25:00 tripped at hosur end only KPTCL/ TANTRANSCO TANTRANSCO: No visible fault KV/220KV SOMANAHALLI-ICT /15:23: /15:29:00 MAL-OPERATION PGCIL (SR-II) To-be-discussed KV/220KV TALGUPPA-ICT /16:30: /17:30:00 TRIPPED ON OCR OPERATED KPTCL To-be-discussed KPTCL: Page 6 of 8

113 Annexure-IV KV-NELAMANGALA-HASSAN /18:16:00 TRIPPED ON B-N FAULT KPTCL/PGCIL (SR-II) To-be-discussed / 220 kv Maradam ICT /16: /16:46:00 Relay Maloperation APTRANSCO To-be-discussed KV-CHITTOOR_AP-THIRUVALAM_TN /13:20: /13:40:00 TRIPPED ON B PHASE FAULT APTRANSCO/ TANTRANSCO To-be-discussed KV-WANAPARTHY-BRAMHANA_KOTKUR /13:32: /14:37:00 TRIPPED ON Y-N FAULT APTRASNCO To-be-discussed KV-HINDUJA-KV_KOTA /13:01: /13:46:00 TRIPPED ON Y-N FAULT HNPCL/ APTRANSCO To-be-discussed KV-VALLUR-ALAMATHY /19:58: /20:33:00 TRIPPED ON R-N FAULT NTECL/ TANTRANSCO To-be-discussed KV-SRIKAKULAM-ANGUL /06:36: /06:55:00 TRIPPED ON B PHASE FAULT PGCIL (SR-I)/ PGCIL (ER-I) To-be-discussed KV/220KV HOODY-ICT /07:13: /09:16:00 PRESSURE RELIEF DEVICE OPERATED KPTCL To-be-discussed KV-THENI-MOOZIYAR /15:13: /15:38:00 TRIPPED ON Y-N FAULT TANTRANSCO/ KSEBL To-be-discussed KV-VTPS_IV-SURYAPET /15:40:00 DISTANCE PROTECTION APGENCO/ TSTRANSCO To-be-discussed KV-NELLORE_PG-VIJAYAWADA /16:09: /16:36:00 TRIPPED ON B-N FAULT PGCIL (SR-I) To-be-discussed KV-HINDUJA-KV_KOTA /10:12:00 TRIPPED ON B-N FAULT HNPCL/ APTRANSCO To-be-discussed KV-CHITTOOR-KRISHNAPATNAM /10:16: /18:53:00 TRIPPED ON Y-N FAULT APTRANSCO/ APGENCO To-be-discussed KV-HINDUJA-KV_KOTA /10:12: /11:24:00 TRIPPED ON B-N FAULT HNPCL/ APTRANSCO To-be-discussed KV-NELLORE_PG-VIJAYAWADA /16:49: /19:23:00 TRIPPED ON B-N FAULT PGCIL (SR-I) To-be-discussed KV-SURYAPET-SHANKARAPALLY /00:01:00 H /T TO CONTAIN OVER VOLTAGE TSTRANSCO To-be-discussed KV-SRIKAKULAM-ANGUL /23:35: /00:19:00 R-PHASE FAULT PGCIL (SR-I)/PGCIL(ER-I) To-be-discussed KV-KURNOOL_PG-RAICHUR_PG /17:17: /21:45:00 TRIPPED ON B-N FAULT PGCIL (SR-I) To-be-discussed KV-KHAMMAM-NAGARJUNASAGAR_PG- H /T TO CONTAIN OVER /23:42:00 3 VOLTAGR PGCIL (SR-I) To-be-discussed KV-NAGARJUNASAGAR_PG-MEHBOOBN /17:00:00.. LINE TO GROUND FAULT PGCIL (SR-I)/ TSTRANSCO To-be-discussed KV-SRISAILAM_LEFT_BANK-DINDI /13:17: /19:48:00 TRIPPED ON Y-N FAULT TSGENCO/ TSTRANSCO To-be-discussed KV-PAVAGADA-TUMKUR /19:56:00 TRIPPED DUE TO B-N LINE FAULT PGCIL (SR-II) To-be-discussed KV-KURNOOL_PG-RAICHUR_PG /22:14:00 H /T TO CONTAIN OVER VOLTAGE PGCIL (SR-I)/PGCIL(SR-II) To-be-discussed KV-TALGUPPA-HASSAN /22:53:00 TRIPPED ON B-N FAULT KPTCL/ PGCIL (SR-II) To-be-discussed 124 HVDC500KV-TALCHER-KOLAR_DC /19:34: /20:08:00 ESOF PGCIL (SR-II) To-be-discussed KV/220KV URAVAKONDA-ICT /17:57: /18:55:00 MAL-OPERATION APTRANSCO To-be-discussed KV-NEYVELI_TS_II-PUGALUR /05:49:00 TRIPPED ON B PHASE FAULT NLCIL/ PGCIL (SR-II) To-be-discussed KV-PAVAGADA-TUMKUR /22:02:00 H /T TO CONTAIN OVER VOLTAGR PGCIL (SR-II) To-be-discussed KV-GOOTY-NPS /20:29:00 MAL-OPERATION PGCIL (SR-I) To-be-discussed KV-NELAMANGALA-TALGUPPA /16:20:00 TRIPPED ON B-N FAULT KPTCL To-be-discussed KV-JINDAL-BPS /19:56: /21:53:00 BREAKER AIR LOCK OUT JSWEL/ KPCL To-be-discussed KV-NARNOOR-JAMMALAMADUGU /17:29:00 LINE TO GROUND FAULT APTRANSCO To-be-discussed KV-SRIKAKULAM-VEMAGIRI_PG /05:51:00 Y-N FAULT PGCIL (SR-I) To-be-discussed KV-RAICHUR_PG-RTPS /18:03: /03:30:00 LINE TO GROUND FAULT PGCIL (SR-I)/KPCL To-be-discussed KV-BHOOPALAPALLY-WARANGAL /13:56: /21:52:00 TRIPPED ON B-N FAULT TSGENCO/ PGCIL (SR-I) To-be-discussed KV/220KV MYSORE-ICT /02:31:00 VOLTAGE REGULATION PGCIL (SR-II) To-be-discussed KV/220KV MYSORE-ICT /02:11:00 VOLTAGE REGULATION PGCIL (SR-II) To-be-discussed Page 7 of 8

114 Annexure-IV KV-RASIPALYAM-ANAIKADAVU /03:06:00 H /T TO CONTAIN OVER VOLTAGR TANTRANSCO To-be-discussed KV-SRISAILAM_LEFT_BANK-DINDI /02:57:00 H /T TO CONTAIN OVER VOLTAGE TSGENCO/ TSTRANSCO To-be-discussed KV-MAMIDAPALLI-DINDI /02:54:00 H /T TO CONTAIN OVER VOLTAGE TSTRANSCO To-be-discussed KV-RTPS-BTPS /14:14: /19:26:00 TRIPPED ON B-N FAULT KPCL To-be-discussed KV-NELAMANGALA-HASSAN /01:28:00 TRIPPED ON Y-N FAULT KPTCL/PGCIL (SR-II) To-be-discussed KV-RTPS-BTPS /12:54: /17:57:00 TRIPPED DUE TO B-N LINE FAULT KPCL To-be-discussed Page 8 of 8

115 Page 1 of 3 Annexure-V

116 Page 2 of 3 Annexure-V

117 Page 3 of 3 Annexure-V

118 Annexure-VI SOUTHERN REGIONAL POWER COMMITTEE BENGALURU Over Voltage Relay (OVR) Grading for 400 kv & 765 kv Transmission Lines of Southern Region (SR) I. Introduction Over Voltage Line Protection is a protection used for preventing the transmission line from experiencing sustained over voltages. The over voltage level and the time duration which the transmission line can be subjected to are generally dictated by parameters like its Voltage-Time curves, Power Frequency Withstand Voltage, etc. Since the rate at which the Voltage varies (from slowly increasing ramp to extremely fast changing ramp) is contingent upon system conditions, it is necessary to provide Two-Stage Over Voltage Protection (OVR, Stage-I & OVR, Stage-II) to take care of both extremities. Before going into the nitty-gritties of OVR grading, the following may be noted: 1. It may be appreciated that in order for OVR grading to be effective, the Network under consideration should be a reasonably developed one meaning it should contain sufficient no. of transmission lines. Because, when only a few lines are present, it is very much possible that over voltage conditions which those lines are subjected to may not vanish/subside/come down even after controlled tripping of these lines by OVR grading them. Similarly, when the network is fully developed [i.e., where from each Node (Bus) emanate a good no. of lines], the chances for over voltage conditions may get drastically reduced. 2. Since OVR, Stage-II protection is an instantaneous protection, OVR grading of transmission lines essentially refers to grading them for OVR, Stage-I protection only. 3. It may be noted that OVR, Stage-I protection is very well suited for Indian electric-grid at 400 kv & 765 kv voltage levels since it is characterized by slowly varying Voltage-ramp, and sufficient time-window exists for the Node (Bus) Voltage to reach from one significant level (say 108% of Nominal Voltage) to next higher significant level (say 109% of Nominal Voltage). II. Guidelines & Regulations Over Voltage Relay grading elucidated in the following Sections is based on the following guidelines/ regulations: 1. Ramakrishna Committee Guidelines for Line Over Voltage Protection (These in turn are based on CBIP and CIGRE guidelines): FOR 400kV LINES: Low set stage (Stage-I) may be set in the range of 110% - 112% (typically 110%) with a time delay of 5 seconds. High set stage (Stage-II) may be set in the range 140% - 150% with a time delay of 100 milliseconds. OVR Grading for 400 kv and 765 kv Transmission Lines of Southern Region Page 1 of 6

119 Annexure-VI FOR 765kV LINES: Low set stage (Stage-I) may be set in the range of 106% - 109% (typically 108%) with a time delay of 5 seconds. High set stage (Stage-II) may be set in the range 140% - 150% with a time delay of 100 milliseconds. However, for Over Voltage Stage-I protection, a time grading of 1 to 3 seconds may be provided between overvoltage relays of double circuit lines. Grading on overvoltage tripping for various lines emanating from a station may be considered and same can be achieved using voltage as well as time grading. Longest timed delay should be checked with expected operating time of Over-fluxing relay of the transformer to ensure disconnection of line before tripping of transformer. It is desirable to have Drop-off to pick-up ratio of overvoltage relay better than 97%. 2. CEA (Technical Standards for Construction of Electrical Plants and Electric Lines) Regulations: Regulation 43(1)(a): Salient Technical Particulars and Requirements of Substations and Switchyards Power Frequency withstand Voltage under dry conditions for 400 kv SS (kvrms) = 680 Power Frequency withstand Voltage under dry conditions for 765 kv SS (kvrms) = 830 Regulation 89(1)(a)(i): Salient Technical Particulars and Requirements of Transmission lines Power Frequency withstand Voltage under dry conditions for 400 kv Transmission lines (kvrms) = 680 Power Frequency withstand Voltage under dry conditions for 765 kv Transmission lines (kvrms) = 830 II. General Philosophy 1. General Logic: We know that a basic transmission line can be represented by its equivalent π-model as shown below: Here, the parameters, Series Resistance (R), Series Inductive Reactance (X), and Parallel Capacitive Susceptance (B), define the transmission line under consideration. Since Over Voltage phenomenon at a particular Node (Bus) is basically due to the Net Capacitive Vars (Q) contributed by the transmission lines at that Node (Bus), the fundamental logic to be followed to contain Over Voltage is to: Trip the transmission lines in the descending order of their respective Net Capacitive Vars (Q) contribution OVR Grading for 400 kv and 765 kv Transmission Lines of Southern Region Page 2 of 6

120 Annexure-VI The same logic holds good even when the transmission line contains Line (Shunt) Reactors (shown as X1 and X2 in the below figure) since their effect essentially will be in reducing net Capacitive (Q) Vars. It is pertinent to note at this juncture that Bus Reactors at a Node (Bus) will not have any effect on OVR grading employed for transmission lines emanating from that Node (Bus), even though the same are installed for improving the general voltage profile at that particular Node (Bus). 2. Qualified Logic: Since the reality invariably differs from the theory, the above theoretically apt logic has to be qualified by factoring in other significant factors like the typical power flow, and the criticality or the relative importance of that line, etc. to render OVR grading applicable/ suitable/ workable under real-time grid operation as illustrated below: In case of a generator connected to grid by two lines of equal length [hence contributing equal capacitive (Q) Vars], even though it is theoretically correct to trip both the lines simultaneously, in order to ensure that the generator clings on to the grid for longer duration, it is essential that its evacuating lines are given different gradings. Similarly, a line carrying less power and contributing less Capacitive (Q) Vars may have to be tripped prior to another line carrying more power and contributing more Capacitive (Q) Vars due to criticality of the latter line in real-time grid operation. Further, while OVR grading different lines at a node, due consideration also needs to be given to avoid possible simultaneous tripping and possible voltage recovery on tripping of a line. Finally, any undue qualification (discretion) that may have stealthily crept in while applying above logic should be taken care of/ brought down to the minimum by circulating the to-be-adopted OVR gradings to all stakeholders for suggestions, and incorporating their comments/ observations appropriately. OVR Grading for 400 kv and 765 kv Transmission Lines of Southern Region Page 3 of 6

121 Annexure-VI III. OVR Grading for 400 kv Transmission Lines of Southern Region In line with Ramakrishna Committee guidelines, CBIP guidelines, and CEA Standards, the following Voltage Time grading matrix has been adopted for OVR grading 400 kv transmission lines of SR: 1. Voltage-Time (OVR) Grading Matrix: Voltage Setting (% of Nominal Voltage) Time Setting (Sec) OVR Grading Order of Tripping A B C D E F G H I 1 Here, Nominal Voltage = 400 kv; Order of tripping = Order in which the lines at a Node (Bus) will be tripped based on their Voltage and Time settings. 2. OVR Grading Order Details: In the 400 kv Southern Grid, the no. of transmission lines emanating from a particular Node (Bus) are found to be varying from a minimum of one (1) to a maximum of fourteen (14) lines, which also means grading has to be given to so many lines at that particular Node. In this regard, the following Table containing the Grading Order details has been made use of: No. of 400 kv Transmission Lines to be OVR graded at a particular Node 4 [GDBA/ FDBA] 5 [GEDBA] 6 [HGEDBA] 7 [HGEDCBA] 8 [HGEDCBAA] 9 [HGFEDCBAA] 10 [IHGFEDCBAA] 11 [IHGFEDDCBAA] 12 [IHGFEDDCBBAA] 13 [IHGFEEDDCBBAA] 14 [IHGFEEDDCBBAAA] 15 [IHGFEEDDCBBAAAA] 16 [IHGFEEDDCBBBAAAA] Specific Order being followed for OVR grading the 400 kv Transmission Lines (from Left to Right) at a particular Node OVR Grading for 400 kv and 765 kv Transmission Lines of Southern Region Page 4 of 6

122 Annexure-VI For example, when the total no. of lines to be graded at a Node (Bus) are 10, the Grading Order to be followed is [IHGFEDCBAA]. Here the first three are given grading at 109% level, then the next four are given grading at 110% level, and the last three are given grading at 111% level. Since only nine (9) grading levels are employed, it is but obvious that some of the lines will have to be given the same grading. 3. Study Results: After finalizing the Voltage-Time gradings to be adopted, and the Order in which these are to be applied to the transmission lines emanating from 400 kv Nodes (Buses), the final and the most important step of assigning/ correlating above gradings to actual transmission lines emanating from various Nodes (Buses) has been carried out using the general and qualified logics already illustrated. The study results, thus obtained, for 400 kv SR-grid are enclosed at Annexure-I (OVR-400) for kind reference. IV. OVR Grading for 765 kv Transmission Lines of Southern Region In line with Ramakrishna Committee guidelines, CBIP guidelines, and CEA Standards, the following Voltage Time grading matrix has been adopted for OVR grading 765 kv transmission lines of SR: 1. Voltage - Time (OVR) Grading Matrix: Voltage Setting (% of Nominal Voltage) Time Setting (Sec) OVR Grading Order of Tripping A B C D E F G H 1 Here, Nominal Voltage = 765 kv; Order of tripping = Order in which the lines at a Node (Bus) will be tripped based on their Voltage and Time settings. 2. OVR Grading Order Details: In the 765 kv Southern Grid, the no. of transmission lines emanating from a particular Node (Bus) are found to be varying from a minimum of two (2) to a maximum of six (6) lines. In this regard, the following Table containing the Grading Order details has been made use of: OVR Grading for 400 kv and 765 kv Transmission Lines of Southern Region Page 5 of 6

123 Annexure-VI No. of 400 kv Transmission Lines to be OVR graded at a particular Node 2 [EA] 4 [ECBA] 6 [HGECBA] Specific Order being followed for OVR grading the 400 kv Transmission Lines (from Left to Right) at a particular Node For example, when the total no. of lines to be graded at a Node (Bus) are 6, the Grading Order to be followed is [HGECBA]. Here the first two are given grading at 107% level, then the next one is given grading at 108% level, and the last three are given grading at 109% level. 3. OVR-graded 765 kv Network of Southern Region: 4. Study Results: After finalizing the Voltage-Time gradings to be adopted, and the Order in which these are to be applied to the transmission lines emanating from 765 kv Nodes (Buses), the final and the most important step of assigning/ correlating above gradings to actual transmission lines emanating from various Nodes (Buses) has been carried out using the general and qualified logics already illustrated. The study results, thus obtained, for 765 kv SR-grid are enclosed at Annexure-II (OVR-765) for kind reference. ***** OVR Grading for 400 kv and 765 kv Transmission Lines of Southern Region Page 6 of 6

124 OVR Grading for 400 kv Transmission Lines of Southern Region Annexure-VI Annexure-I (OVR-400) 1. Voltage - Time (OVR) Grading Matrix: 2. Circuit ID/ Branch ID Legend: Page 1 of 24

125 3. Study Results: Annexure-VI Annexure-I (OVR-400) From Bus Number From Bus Name To Bus Number To Bus Name Ckt Id Length, km Charging 'B' (pu) Q' from Line (B/2) [= Q1] Q' from Line Reactor [= Q2] Net 'Q' from Line [= Q1 + Q2] Power Flow, MW Order as per Criticality JP_GZW_HVDC JP_GZW_FSC T A JP_GZW_HVDC JP_GZW_FSC T D GOOTY KURNOOL T B GOOTY NELLORE-PS Q D GOOTY NELLORE-PS Q H GOOTY KURNOOL-PG T A GOOTY GTYNLM-FSC C ** ** GOOTY GTYSMN-FSC C ** ** GOOTY RAICHUR-PG Q A GOOTY RAICHUR-PG Q G GOOTY PAVAGADA T C GOOTY PAVAGADA T E CHITTOOR CHINAKMPALLI T H CHITTOOR SDSTPS Q B CHITTOOR SDSTPS Q G CHITTOOR KALIKILI T A CHITTOOR KALIKILI T E CHITTOOR SRIPERUMBDUR T D CHITTOOR TIRUVALAM-PG Q A CHITTOOR TIRUVALAM-PG Q C NELLORE-PG NUNNA T D NELLORE-PG NUNNA T H NELLORE-PG NELLORE-PS Q A NELLORE-PG NELLORE-PS Q B NELLORE-PG SRIPERUMBDUR T C NELLORE-PG SRIPERUMBDUR T G NELLORE-PG TIRUVALAM-PG Q A NELLORE-PG TIRUVALAM-PG Q E New OVR Grading (at FROM BUS end) Page 2 of 24

126 Annexure-VI Annexure-I (OVR-400) CHINAKMPALLI CHITTOOR T D CHINAKMPALLI CNP-FSC C ** ** CHINAKMPALLI CNP-FSC C ** ** CHINAKMPALLI NP KUNTA T A CNP-FSC CHINAKMPALLI C ** ** CNP-FSC TALLAPALLI T A CNP-FSC CHINAKMPALLI C ** ** CNP-FSC TALLAPALLI T B TALLAPALLI CNP-FSC T C TALLAPALLI CNP-FSC T G TALLAPALLI KURNOOL-PG T E TALLAPALLI VELTOOR T A TALLAPALLI RSTPS NTPC T A TALLAPALLI RSTPS NTPC T D TALLAPALLI GHANAPUR T I TALLAPALLI KHAMMAM T B TALLAPALLI KHAMMAM T F TALLAPALLI KHAMMAM T H NUNNA NELLORE-PG T D NUNNA NELLORE-PG T H NUNNA VTS-IV T A NUNNA VEMAGIRI T C NUNNA LANCO T B NUNNA LANCO T D NUNNA SATTENAPALLI T E NUNNA NELLORE-AP T I NUNNA VEMAGIRI_PG T A NUNNA VEMAGIRI_PG T B NUNNA VEMAGIRI_PG T G NUNNA KHAMMAM T F Page 3 of 24

127 Annexure-VI Annexure-I (OVR-400) GAZUWAKA KALPAKKA T B GAZUWAKA KALPAKKA T G GAZUWAKA SIMHADRI-II T A GAZUWAKA SIMHADRI-II T D GAZUWAKA VEMAGIRI_PG T E KURNOOL GOOTY T C KURNOOL KURNOOL-PG Q A KURNOOL KURNOOL-PG Q D KURNOOL JAMALAMADUGU Q B KURNOOL JAMALAMADUGU Q G KURNOOL GHANI Q A KURNOOL GHANI Q F KURNOOL SRISAILAMLB T E KURNOOL MHSWRM-PG T H KALPAKKA GAZUWAKA T A KALPAKKA GAZUWAKA T F KALPAKKA SIMHADRI-I T A KALPAKKA SIMHADRI-I T B KALPAKKA SIMHADRI-I T D KALPAKKA VEMAGIRI T G KALPAKKA HINDUJA T B KALPAKKA HINDUJA T E KALPAKKA MARADAM Q D KALPAKKA MARADAM Q H KALPAKKA KHAMMAM T I KALPAKKA ASUPAKA T C SIMHADRI-I KALPAKKA T A SIMHADRI-I KALPAKKA T D SIMHADRI-I KALPAKKA T F Page 4 of 24

128 Annexure-VI Annexure-I (OVR-400) VTS-IV NUNNA T A VTS-IV SATTENAPALLI T B VTS-IV SATTENAPALLI T E VTS-IV NELLORE-AP T H VTS-IV SURYAPET T D VTS-IV SURYAPET T G VEMAGIRI NUNNA T H VEMAGIRI KALPAKKA T D VEMAGIRI GMR T C VEMAGIRI GMR T F VEMAGIRI GAUTHAMI T B VEMAGIRI GAUTHAMI T E VEMAGIRI KONASEEMA T A VEMAGIRI KONASEEMA T E VEMAGIRI GVK-II T A VEMAGIRI GVK-II T D VEMAGIRI SIMHADRI-II T G VEMAGIRI SATTENAPALLI T I VEMAGIRI VEMAGIRI_PG T A VEMAGIRI VEMAGIRI_PG T B GMR VEMAGIRI T A GMR VEMAGIRI T D GAUTHAMI VEMAGIRI T B GAUTHAMI VEMAGIRI T E KONASEEMA VEMAGIRI T B KONASEEMA VEMAGIRI T E GVK-II VEMAGIRI T A GVK-II VEMAGIRI T D LANCO NUNNA T B LANCO NUNNA T E Page 5 of 24

129 Annexure-VI Annexure-I (OVR-400) SIMHADRI-II GAZUWAKA T A SIMHADRI-II GAZUWAKA T D SIMHADRI-II VEMAGIRI T E SIMHADRI-II VEMAGIRI_PG T B SIMHADRI-II VEMAGIRI_PG T G SATTENAPALLI NUNNA T E SATTENAPALLI VTS-IV T A SATTENAPALLI VTS-IV T D SATTENAPALLI VEMAGIRI T G SATTENAPALLI SRISAILAMLB T B SATTENAPALLI SRISAILAMLB T H SIMHAPURI NELLORE-PS Q B SIMHAPURI MEENAKSHI Q E NELLORE-PS GOOTY Q G NELLORE-PS GOOTY Q I NELLORE-PS NELLORE-PG Q B NELLORE-PS NELLORE-PG Q E NELLORE-PS SIMHAPURI Q C NELLORE-PS MEENAKSHI Q D NELLORE-PS TPCIL Q A NELLORE-PS TPCIL Q F NELLORE-PS NCC Q A NELLORE-PS NCC Q H MEENAKSHI SIMHAPURI Q D MEENAKSHI NELLORE-PS Q A HINDUJA KALPAKKA T A HINDUJA KALPAKKA T D HINDUJA K V KOTA T B HINDUJA K V KOTA T G NELLORE-AP NUNNA T F NELLORE-AP VTS-IV T B NELLORE-AP SDSTPS Q A NELLORE-AP SDSTPS Q D Page 6 of 24

130 Annexure-VI Annexure-I (OVR-400) SDSTPS CHITTOOR Q B SDSTPS CHITTOOR Q F SDSTPS NELLORE-AP Q A SDSTPS NELLORE-AP Q D KURNOOL-PG GOOTY T B KURNOOL-PG TALLAPALLI T G KURNOOL-PG KURNOOL Q A KURNOOL-PG KURNOOL Q D GTYNLM-FSC GOOTY C ** ** GTYNLM-FSC NELAMANGALA T A GTYSMN-FSC GOOTY C ** ** GTYSMN-FSC SOMANAHALLI T B TPCIL NELLORE-PS Q A TPCIL NELLORE-PS Q D NCC NELLORE-PS Q B NCC NELLORE-PS Q E JAMALAMADUGU KURNOOL Q A JAMALAMADUGU KURNOOL Q D JAMALAMADUGU URAVAKONDA Q B JAMALAMADUGU URAVAKONDA Q G NP KUNTA CHINAKMPALLI T A NP KUNTA KOLAR T D URAVAKONDA JAMALAMADUGU Q A URAVAKONDA JAMALAMADUGU Q D URAVAKONDA VELTOOR Q B URAVAKONDA VELTOOR Q G Page 7 of 24

131 Annexure-VI Annexure-I (OVR-400) VEMAGIRI_PG NUNNA T B VEMAGIRI_PG NUNNA T G VEMAGIRI_PG NUNNA T A VEMAGIRI_PG GAZUWAKA T E VEMAGIRI_PG VEMAGIRI T A VEMAGIRI_PG VEMAGIRI T D VEMAGIRI_PG SIMHADRI-II T C VEMAGIRI_PG SIMHADRI-II T H GHANI KURNOOL Q B GHANI KURNOOL Q E K V KOTA HINDUJA T A K V KOTA HINDUJA T D K V KOTA SURYAPET T B K V KOTA SURYAPET T D RYTPS STG V KALIKIRI T A RYTPS STG V KALIKIRI T D MARADAM KALPAKKA Q B MARADAM KALPAKKA Q E KALIKIRI CHITTOOR T B KALIKIRI CHITTOOR T F KALIKIRI RYTPS STG V T A KALIKIRI RYTPS STG V T D VELTOOR TALLAPALLI T H VELTOOR URAVAKONDA Q D VELTOOR URAVAKONDA Q G VELTOOR MHSWRM-PG T B VELTOOR MHSWRM-PG T E VELTOOR RAICHUR TPS T A Page 8 of 24

132 Annexure-VI Annexure-I (OVR-400) RSTPS NTPC TALLAPALLI T A RSTPS NTPC TALLAPALLI T D RSTPS NTPC GHANAPUR T C RSTPS NTPC GHANAPUR T H RSTPS NTPC DICHIPALLI T E RSTPS NTPC GAJWEL T G RSTPS NTPC WARANGAL T B RSTPS NTPC MALKARAM T I RSTPS NTPC BHADRAWATHI T A RSTPS NTPC BHADRAWATHI T F GHANAPUR TALLAPALLI T H GHANAPUR RSTPS NTPC T C GHANAPUR RSTPS NTPC T G GHANAPUR MAMIDIPALLI T D GHANAPUR GAJWEL T A GHANAPUR MALKARAM T B GHANAPUR MHSWRM-PG T E KHAMMAM TALLAPALLI T D KHAMMAM TALLAPALLI T F KHAMMAM TALLAPALLI T H KHAMMAM NUNNA T E KHAMMAM KALPAKKA T G KHAMMAM MAMIDIPALLI T D KHAMMAM MAMIDIPALLI T I KHAMMAM WARANGAL T A KHAMMAM KTPS-VI T A KHAMMAM ASUPAKA T B KHAMMAM KTPS-VII T C SRISAILAMLB KURNOOL T E SRISAILAMLB SATTENAPALLI T B SRISAILAMLB SATTENAPALLI T G SRISAILAMLB DINDI T A SRISAILAMLB DINDI T D Page 9 of 24

133 Annexure-VI Annexure-I (OVR-400) MAMIDIPALLI GHANAPUR T D MAMIDIPALLI KHAMMAM T A MAMIDIPALLI KHAMMAM T G MAMIDIPALLI DINDI T B MAMIDIPALLI DINDI T E DICHIPALLI RSTPS NTPC T F DICHIPALLI NIZAMABAD I D DICHIPALLI NIZAMABAD I A GAJWEL RSTPS NTPC T E GAJWEL GHANAPUR T B GAJWEL KAKATIYA TPS T A GAJWEL KAKATIYA TPS T G GAJWEL SHANKARPALLI T D GAJWEL SINGARENI Q C GAJWEL SINGARENI Q H GAJWEL NARSARPUR T A KAKATIYA TPS GAJWEL T B KAKATIYA TPS GAJWEL T F KAKATIYA TPS WARANGAL T A KAKATIYA TPS WARANGAL T D WARANGAL RSTPS NTPC T B WARANGAL KHAMMAM T F WARANGAL KAKATIYA TPS T A WARANGAL KAKATIYA TPS T D MALKARAM RSTPS NTPC T A MALKARAM GHANAPUR T D MALKARAM SURYAPET T B MALKARAM SURYAPET T G KTPS-VI KHAMMAM T D KTPS-VI KTPS-VII T A Page 10 of 24

134 Annexure-VI Annexure-I (OVR-400) SHANKARPALLI GAJWEL T C SHANKARPALLI SURYAPET Q D SHANKARPALLI SURYAPET Q H SHANKARPALLI NARSARPUR T A SHANKARPALLI NIZAMABAD T B SHANKARPALLI NIZAMABAD T G SHANKARPALLI MAHES-TS T A SHANKARPALLI MAHES-TS T E BHADRAWATHI RSTPS NTPC T A BHADRAWATHI RSTPS NTPC T D SINGARENI GAJWEL Q A SINGARENI GAJWEL Q D SURYAPET VTS-IV T A SURYAPET VTS-IV T D SURYAPET K V KOTA T C SURYAPET K V KOTA T H SURYAPET MALKARAM T A SURYAPET MALKARAM T F SURYAPET SHANKARPALLI Q E SURYAPET SHANKARPALLI Q I SURYAPET JULURPADU Q B SURYAPET JULURPADU Q G NARSARPUR GAJWEL T A NARSARPUR SHANKARPALLI T D NIZAMABAD DICHIPALLI I A NIZAMABAD DICHIPALLI I D NIZAMABAD SHANKARPALLI T B NIZAMABAD SHANKARPALLI T G DINDI SRISAILAMLB T A DINDI SRISAILAMLB T D DINDI MAMIDIPALLI T B DINDI MAMIDIPALLI T F Page 11 of 24

135 Annexure-VI Annexure-I (OVR-400) ASUPAKA KALPAKKA T D ASUPAKA KHAMMAM T A MHSWRM-PG KURNOOL T H MHSWRM-PG VELTOOR T B MHSWRM-PG VELTOOR T G MHSWRM-PG GHANAPUR T E MHSWRM-PG MAHES-TS Q A MHSWRM-PG MAHES-TS Q D MAHES-TS SHANKARPALLI T B MAHES-TS SHANKARPALLI T G MAHES-TS MHSWRM-PG Q A MAHES-TS MHSWRM-PG Q D JULURPADU SURYAPET Q B JULURPADU SURYAPET Q E KTPS-VII KHAMMAM T D KTPS-VII KTPS-VI T A HOODY NELAMANGALA T G HOODY KOLAR B A HOODY KOLAR B D HOODY YELAHANKA T B NELAMANGALA GTYNLM-FSC T D NELAMANGALA HOODY T D NELAMANGALA BIDADI T A NELAMANGALA BIDADI T C NELAMANGALA HASSAN T F NELAMANGALA TALAGUPPA T I NELAMANGALA HIRIYUR T A NELAMANGALA HIRIYUR T H NELAMANGALA MYSORE T E NELAMANGALA MYSORE T G NELAMANGALA YELAHANKA T B Page 12 of 24

136 Annexure-VI Annexure-I (OVR-400) SOMANAHALLI GTYSMN-FSC T E SOMANAHALLI BIDADI T C SOMANAHALLI BIDADI T G SOMANAHALLI KOLAR T A SOMANAHALLI HOSUR T H SOMANAHALLI DHARAMAPURI Q B SOMANAHALLI DHARAMAPURI Q D RAICHUR TPS VELTOOR T B RAICHUR TPS RAICHUR-PG Q A RAICHUR TPS RAICHUR-PG Q D RAICHUR TPS BELLARY TPS T E RAICHUR TPS MUNIRABAD T G BIDADI NELAMANGALA T A BIDADI NELAMANGALA T G BIDADI SOMANAHALLI T B BIDADI SOMANAHALLI T E BIDADI TUMKUR T D BIDADI TUMKUR T H TUMKUR BIDADI T A TUMKUR BIDADI T D TUMKUR KUDUGI-PG Q C TUMKUR KUDUGI-PG Q H TUMKUR PAVAGADA T A TUMKUR PAVAGADA T E TUMKUR PAVAGADA Q B TUMKUR PAVAGADA Q G RAICHUR-PG GOOTY Q B RAICHUR-PG GOOTY Q F RAICHUR-PG RAICHUR TPS Q A RAICHUR-PG RAICHUR TPS Q D Page 13 of 24

137 Annexure-VI Annexure-I (OVR-400) KOLAR NP KUNTA T G KOLAR HOODY B A KOLAR HOODY B C KOLAR SOMANAHALLI T E KOLAR HOSUR T B KOLAR HOSUR T D KOLAR TIRUVALAM-PG T H BELLARY TPS RAICHUR TPS T D BELLARY TPS JINDAL TPS T A BELLARY TPS HIRIYUR T B BELLARY TPS HIRIYUR T F GUTTUR JINDAL TPS T C GUTTUR KAIGA APS T A GUTTUR KAIGA APS T G GUTTUR MUNIRABAD T E GUTTUR NARENDRA T D GUTTUR NARENDRA T H GUTTUR HIRIYUR T A GUTTUR HIRIYUR T B HASSAN NELAMANGALA T H HASSAN TALAGUPPA T G HASSAN MYSORE T B HASSAN MYSORE T E HASSAN UDUPI PCL Q A HASSAN UDUPI PCL Q D JINDAL TPS BELLARY TPS T B JINDAL TPS GUTTUR T F JINDAL TPS BPS Q A JINDAL TPS BPS Q D KAIGA APS GUTTUR T B KAIGA APS GUTTUR T F KAIGA APS NARENDRA A A KAIGA APS NARENDRA A D Page 14 of 24

138 Annexure-VI Annexure-I (OVR-400) MUNIRABAD RAICHUR TPS T A MUNIRABAD GUTTUR T D NARENDRA GUTTUR T B NARENDRA GUTTUR T G NARENDRA KAIGA APS A A NARENDRA KAIGA APS A E NARENDRA KUDUGI-PG Q D NARENDRA KUDUGI-PG Q H TALAGUPPA NELAMANGALA T E TALAGUPPA HASSAN T B HIRIYUR NELAMANGALA T D HIRIYUR NELAMANGALA T H HIRIYUR BELLARY TPS T B HIRIYUR BELLARY TPS T G HIRIYUR GUTTUR T A HIRIYUR GUTTUR T E MYSORE NELAMANGALA T B MYSORE NELAMANGALA T G MYSORE HASSAN T A MYSORE HASSAN T E MYSORE KOZHIKODE T D MYSORE KOZHIKODE T H UDUPI PCL HASSAN Q A UDUPI PCL HASSAN Q D YELAHANKA HOODY T E YELAHANKA NELAMANGALA T B Page 15 of 24

139 Annexure-VI Annexure-I (OVR-400) KUDUGI-PG KOLHAPUR-PG H D KUDUGI-PG KOLHAPUR-PG H H KUDUGI-PG TUMKUR Q E KUDUGI-PG TUMKUR Q I KUDUGI-PG NARENDRA Q B KUDUGI-PG NARENDRA Q G KUDUGI-PG KUDGI-NTPC Q A KUDUGI-PG KUDGI-NTPC Q A KUDUGI-PG KUDGI-NTPC Q C KUDUGI-PG KUDGI-NTPC Q F KUDGI-NTPC KUDUGI-PG Q A KUDGI-NTPC KUDUGI-PG Q B KUDGI-NTPC KUDUGI-PG Q D KUDGI-NTPC KUDUGI-PG Q G YERMARUS TPS BPS Q A YERMARUS TPS BPS Q D PAVAGADA GOOTY T A PAVAGADA GOOTY T E PAVAGADA TUMKUR T A PAVAGADA TUMKUR T D PAVAGADA TUMKUR Q B PAVAGADA TUMKUR Q G PAVAGADA BPS Q C PAVAGADA BPS Q H BPS JINDAL TPS Q A BPS JINDAL TPS Q E BPS YERMARUS TPS Q B BPS YERMARUS TPS Q G BPS PAVAGADA Q D BPS PAVAGADA Q H Page 16 of 24

140 Annexure-VI Annexure-I (OVR-400) SRIPERUMBDUR CHITTOOR T D SRIPERUMBDUR NELLORE-PG T B SRIPERUMBDUR NELLORE-PG T G SRIPERUMBDUR S V CHATHRAM T A SRIPERUMBDUR TIRUVALAM-PG T E ALAMATTY S V CHATHRAM T B ALAMATTY S V CHATHRAM T G ALAMATTY NTECL-VALLUR T A ALAMATTY NTECL-VALLUR T C ALAMATTY NCTPS-II T A ALAMATTY TIRUVALAM-TN T D ALAMATTY TIRUVALAM-TN T H ALAMATTY MANALI T E SALEM-PG MYWADI T D SALEM-PG MYWADI T H SALEM-PG HOSUR T B SALEM-PG HOSUR T G SALEM-PG NEYVELI-II T A SALEM-PG NEYVELI-II T C SALEM-PG DHARAMAPURI Q E SALEM-PG DHARAMAPURI Q A MYWADI SALEM-PG T A MYWADI SALEM-PG T D MYWADI TIRUNELVELLI T A MYWADI TIRUNELVELLI T E MYWADI CHIKKANURANI T H MYWADI ARASUR T C MYWADI ARASUR T G MYWADI PALAKKAD T B MYWADI PALAKKAD T F Page 17 of 24

141 Annexure-VI Annexure-I (OVR-400) TIRUNELVELLI MYWADI T A TIRUNELVELLI MYWADI T F TIRUNELVELLI CHIKKANURANI T D TIRUNELVELLI CHIKKANURANI T H TIRUNELVELLI KKNPP Q A TIRUNELVELLI KKNPP Q E TIRUNELVELLI KANARPATY Q B TIRUNELVELLI TRIVENDRUM T C TIRUNELVELLI TRIVENDRUM T G HOSUR SOMANAHALLI T E HOSUR KOLAR T A HOSUR KOLAR T D HOSUR SALEM-PG T B HOSUR SALEM-PG T G KALIVNDPATTU PUGALUR T C KALIVNDPATTU PUGALUR T H KALIVNDPATTU NTECL-VALLUR T B KALIVNDPATTU NTECL-VALLUR T G KALIVNDPATTU TIRUVALAM-PG T A KALIVNDPATTU TIRUVALAM-PG T E KALIVNDPATTU SHOLINGNLLUR T A KALIVNDPATTU SHOLINGNLLUR T D ALUNDUR CHIKKANURANI T G ALUNDUR KARAIKUDI T D ALUNDUR NAGAPTNAM PS T A ALUNDUR NAGAPTNAM PS T B Page 18 of 24

142 Annexure-VI Annexure-I (OVR-400) CHIKKANURANI MYWADI T F CHIKKANURANI TIRUNELVELLI T D CHIKKANURANI TIRUNELVELLI T H CHIKKANURANI ALUNDUR T A CHIKKANURANI KARAIKUDI T B CHIKKANURANI PUGALUR T C CHIKKANURANI PUGALUR T G CHIKKANURANI TUTICORINPS Q A CHIKKANURANI TUTICORINPS Q E ARASUR MYWADI T B ARASUR MYWADI T G ARASUR KARAMADAI T A ARASUR KARAMADAI T D KARAIKUDI ALUNDUR T A KARAIKUDI CHIKKANURANI T D KARAIKUDI PUGALUR Q B KARAIKUDI PUGALUR Q G KARAIKUDI KAYATHAR Q C KARAIKUDI KAYATHAR Q H KARAIKUDI KAMUTHI Q A KARAIKUDI KAMUTHI Q E NEYVELI1EXP NEYVELI-II T A NEYVELI1EXP NAGAPTNAM PS T D NEYVELI-II SALEM-PG T D NEYVELI-II SALEM-PG T G NEYVELI-II NEYVELI1EXP T B NEYVELI-II PUGALUR T H NEYVELI-II NEYVELI2EXP T A NEYVELI-II NAGAPTNAM PS T E NEYVELI-II PONDY T C Page 19 of 24

143 Annexure-VI Annexure-I (OVR-400) PUGALUR KALIVNDPATTU T D PUGALUR KALIVNDPATTU T H PUGALUR CHIKKANURANI T B PUGALUR CHIKKANURANI T E PUGALUR KARAIKUDI Q C PUGALUR KARAIKUDI Q G PUGALUR NEYVELI-II T A PUGALUR NEYVELI2EXP T A NEYVELI2EXP NEYVELI-II T A NEYVELI2EXP PUGALUR T D KKNPP TIRUNELVELLI Q A KKNPP TIRUNELVELLI Q D KKNPP TUTICORINPS Q B KKNPP TUTICORINPS Q F S V CHATHRAM SRIPERUMBDUR T A S V CHATHRAM ALAMATTY T B S V CHATHRAM ALAMATTY T E S V CHATHRAM NCTPS-II T D S V CHATHRAM NCTPS-II T H S V CHATHRAM PONDY T G NTECL-VALLUR ALAMATTY T B NTECL-VALLUR ALAMATTY T G NTECL-VALLUR KALIVNDPATTU T D NTECL-VALLUR KALIVNDPATTU T H NTECL-VALLUR NCTPS-II T A NTECL-VALLUR NCTPS-II T E METTUR-III KARAMADAI T B METTUR-III KARAMADAI T G METTUR-III PALAVADI Q A METTUR-III PALAVADI Q D TUTICORINJV TUTICORINPS Q B TUTICORINJV TUTICORINPS Q E Page 20 of 24

144 Annexure-VI Annexure-I (OVR-400) NCTPS-II ALAMATTY T E NCTPS-II S V CHATHRAM T B NCTPS-II S V CHATHRAM T H NCTPS-II NTECL-VALLUR T A NCTPS-II NTECL-VALLUR T D NCTPS-II MANALI T G COASTAL ENER TUTICORINPS Q A COASTAL ENER TUTICORINPS Q D TIRUVALAM-PG CHITTOOR Q A TIRUVALAM-PG CHITTOOR Q B TIRUVALAM-PG NELLORE-PG Q A TIRUVALAM-PG NELLORE-PG Q D TIRUVALAM-PG KOLAR T H TIRUVALAM-PG SRIPERUMBDUR T E TIRUVALAM-PG KALIVNDPATTU T C TIRUVALAM-PG KALIVNDPATTU T G SHOLINGNLLUR KALIVNDPATTU T A SHOLINGNLLUR KALIVNDPATTU T D DHARAMAPURI SOMANAHALLI Q B DHARAMAPURI SOMANAHALLI Q G DHARAMAPURI SALEM-PG Q A DHARAMAPURI SALEM-PG Q E DHARAMAPURI TUTICORINPS H C DHARAMAPURI TUTICORINPS H H DHARAMAPURI NAGAPTNAM PS H A DHARAMAPURI NAGAPTNAM PS H D Page 21 of 24

145 Annexure-VI Annexure-I (OVR-400) TUTICORINPS CHIKKANURANI Q A TUTICORINPS CHIKKANURANI Q G TUTICORINPS KKNPP Q D TUTICORINPS KKNPP Q H TUTICORINPS TUTICORINJV Q B TUTICORINPS TUTICORINJV Q E TUTICORINPS COASTAL ENER Q A TUTICORINPS COASTAL ENER Q E TUTICORINPS DHARAMAPURI H F TUTICORINPS DHARAMAPURI H I TUTICORINPS TUTICORN-GIS Q A TUTICORINPS TUTICORN-GIS Q B TUTICORINPS TUTICORN-GIS Q C TUTICORINPS TUTICORN-GIS Q D KAYATHAR KARAIKUDI Q B KAYATHAR KARAIKUDI Q G KAYATHAR KANARPATY T A KAYATHAR KANARPATY T D TIRUVALAM-TN ALAMATTY T A TIRUVALAM-TN ALAMATTY T D TIRUVALAM-TN PALAVADI Q B TIRUVALAM-TN PALAVADI Q G ILFS NAGAPTNAM PS Q A ILFS NAGAPTNAM PS Q D NAGAPTNAM PS ALUNDUR T C NAGAPTNAM PS ALUNDUR T H NAGAPTNAM PS NEYVELI1EXP T D NAGAPTNAM PS NEYVELI-II T A NAGAPTNAM PS DHARAMAPURI H A NAGAPTNAM PS DHARAMAPURI H G NAGAPTNAM PS ILFS Q B NAGAPTNAM PS ILFS Q E Page 22 of 24

146 Annexure-VI Annexure-I (OVR-400) KAMUTHI KARAIKUDI Q A KAMUTHI KARAIKUDI Q D KARAMADAI ARASUR T A KARAMADAI ARASUR T D KARAMADAI METTUR-III T B KARAMADAI METTUR-III T G KANARPATY TIRUNELVELLI Q D KANARPATY KAYATHAR T A KANARPATY KAYATHAR T G PALAVADI METTUR-III Q A PALAVADI METTUR-III Q E PALAVADI TIRUVALAM-TN Q D PALAVADI TIRUVALAM-TN Q H PALAVADI RASIPALYAM Q B PALAVADI RASIPALYAM Q G MANALI ALAMATTY T B MANALI NCTPS-II T E RASIPALYAM PALAVADI Q B RASIPALYAM PALAVADI Q G RASIPALYAM ANIKADV T A RASIPALYAM ANIKADV T D ANIKADV RASIPALYAM T A ANIKADV RASIPALYAM T D TUTICORN-GIS TUTICORINPS Q A TUTICORN-GIS TUTICORINPS Q B TUTICORN-GIS TUTICORINPS Q D TUTICORN-GIS TUTICORINPS Q G TRICHUR COCHIN Q B TRICHUR COCHIN Q G TRICHUR PALAKKAD T A TRICHUR PALAKKAD T D TRIVENDRUM TIRUNELVELLI T B TRIVENDRUM TIRUNELVELLI T E Page 23 of 24

147 Annexure-VI Annexure-I (OVR-400) COCHIN TRICHUR Q B COCHIN TRICHUR Q E PALAKKAD MYWADI T A PALAKKAD MYWADI T D PALAKKAD TRICHUR T B PALAKKAD TRICHUR T F KOZHIKODE MYSORE T A KOZHIKODE MYSORE T D PONDY NEYVELI-II T A PONDY S V CHATHRAM T D Page 24 of 24

148 Annexure-VI Annexure-II (OVR-765) 1. Voltage - Time (OVR) Grading Matrix: OVR Grading for 765 kv Transmission Lines of Southern Region 2. Circuit ID/ Branch ID Legend: Page 1 of 2

149 Annexure-VI Annexure-II (OVR-765) 3. Study Results: From Bus Number From Bus Name To Bus Number To Bus Name Ckt Id Length, km Charging 'B' (pu) Q' from Line (B/2) [= Q1] Q' from Line Reactor [= Q2] Net 'Q' from Line [= Q1 + Q2] Power Flow, MW Order as per Criticality KURNOOL-PG NELLORE-PS H B KURNOOL-PG NELLORE-PS H G KURNOOL-PG RAICHUR-PG B A KURNOOL-PG RAICHUR-PG B E KURNOOL-PG TIRUVALAM H C KURNOOL-PG TIRUVALAM H H NELLORE-PS KURNOOL-PG H A NELLORE-PS KURNOOL-PG H E SRIKAKULAM ANGUL H A SRIKAKULAM ANGUL H C SRIKAKULAM VEMAGIRI_PG H B SRIKAKULAM VEMAGIRI_PG H E VEMAGIRI_PG SRIKAKULAM H A VEMAGIRI_PG SRIKAKULAM H E NIZAMABAD WARDHA-PG H B NIZAMABAD WARDHA-PG H E NIZAMABAD MAHESWARAM H A NIZAMABAD MAHESWARAM H C MAHESWARAM NIZAMABAD H A MAHESWARAM NIZAMABAD H E RAICHUR-PG SOLAPUR-PG B A RAICHUR-PG SOLAPUR-PG B C RAICHUR-PG KURNOOL-PG B B RAICHUR-PG KURNOOL-PG B E TIRUVALAM KURNOOL-PG H A TIRUVALAM KURNOOL-PG H E New OVR Grading (at FROM BUS end) Page 2 of 2

150 Page 1 of 32 Annexure-VII

151 Page 2 of 32 Annexure-VII

152 पत स च / Address List Annexure-VII 1. म ख य अ भय त (एचप स व जल प8रय जन ) एप ज नक, 4व म जल, ग णदल, वजयव ड आ / Chief Engineer (Generation), APGENCO, 4 th Floor, Vidyut Soudha, Eluru Road, Gunadala, Vijayawada, AP म ख य अ भय त (प8रय जन ), एप ज नक, 4व म जल, ग णदल, वजयव ड आ / Chief Engineer (Projects), APGENCO, 4 th Floor, Vidyut Soudha, Eluru Road, Gunadala, Vijayawada, AP म ख य अ भय त (आईप स व वय त ण ल), एप R न स क,3र म जल, ग णदल, वजयव ड आ / Chief Engineer (IPC & Power Systems), APTRANSCO, 3 rd Floor, Vidyut Soudha, Eluru Road, Gunadala, Vijayawada, AP म ख य अ भय त ( उत प दन), टएसज नक, ह दर ब द/ Chief Engineer (Generation), TSGENCO, Hyderabad 5. म ख य अ भय त (प8रय जन ), टएसज नक, ह दर ब द/ Chief Engineer (Projects), TSGENCO, Hyderabad 6. म ख य अ भय त (वय त ण ल), टएसR न स क, ह दर ब द/ Chief Engineer (Power System), TSTRANSCO, Hyderabad 7. म ख य अ भय त (इल.Vडज़ ईन), क प स एल, बगल र/ Chief Engineer (Ele. Designs), KPCL, Bangalore 8. म ख य अ भय त ( आर ट और आर & ड ), क प टस एल, बगल र/ Chief Engineer (RT and R&D), KPTCL, Bangalore 9. म ख य अ भय त, एसएलड स, क प टस एल, बगल र/ Chief Engineer, SLDC, KPTCL, Bangalore 10. म ख य अ भय त (एम.ट.एस), ट नज डक, च न न / Chief Engineer (MTS), TANGEDCO, Chennai (Fax No: ) 11. म ख य अ भय त (जल वय त), ट नज डक, च न न / Chief Engineer (Hydro),TANGEDCO, Chennai (Fax No: ) 12. म ख य अ भय त (स रण एव स च र), ट एन ई ब, च न न / Chief Engineer (Protection & Communication), TANTRANSCO, Chennai 13. म ख य अ भय त (प र षण), ण ल च लन, एचएमट क ल न, क एसईब, कलमस स र / Chief Engineer (Transmission) System Operation, HMT Colony, KSEB, Kalamassery अध क अ भय त -, वय त वभ ग, 137, एनएसस ब स स ल, प द च र / Superintending Engineer I, Electricity Department, 137, NSC Bose Salai, Puducherry (Fax No: ) 15. ज एम ( च व अन ) द -, प वर_ड, सक दर ब द/ GM (O&M), SR-I, PGCIL, Secunderabad 16. ज एम ( च व अन ) द -, प वर_ड, बगल र/ GM (O&M), SR-II, PGCIL, Bengaluru 17. मह ब धक (ओ एस), एनटप स, दण य म ख य लय, सक दर ब द/ General Manager (OS), NTPC SRHQ, Secunderabad 18. म ख य मह ब धक,टप एस- वस त र,एनएलस आईएल,न व ल / Chief General Manager, TPS-I Expn. NLCIL, Neyveli (Fax No: ) 19. म ख य अ भय त (प र षण) एनप स आईएल, म बई/ Chief Engineer (Transmission), NPCIL, Mumbai. 20. क "नद शक, क ज एस, क ग, कन #टक/ Station Director, KGS, Kaiga, Karnataka 21. क "नद शक, एमएप एस, कल पक कम/ Station Director, MAPS, Kalpakkam 22. क "नद शक, क क एनप प, "तbनल व ल जल, त मलन ड / Station Director, KKNPP, Thirunelveli Dist, TamilNadu Page 3 of 32

153 Annexure-VII 23. c प प ज स टन, एज एम (ईएम), एनटईस एल, च न न -103/ Shri P.P. Gestine, AGM (EM), NTECL, Chennai c एम भ कर, मह ब धक ( व अ), एनटप एल, ह ब#र ए ट ट, त त क ड / Sh. M. Prabhakar, GM (O&M), NTPL, Harbour Estate, Tuticorin (Fax No: ) 25. c स य# क श, उप e य (च लन व अन रण), ज एसडf g य एनजh ल. त रणगg ल, बg ल र / Shri Surya Prakash, Vice President (Operations & Maintenance), M/s JSW Energy Ltd, Toranagallu, Bellary c श त र म प, सह उप e य (वय त एव प8रय जन ), ज एसडf g य एनजh ल. त रणगg ल, बg ल र / Shri Shantharam Pai, Associate Vice President (Electrical & Projects), M/s JSW Energy Ltd, Toranagallu, Bellary c आर व भjए, उप ध य ( च लन) य प स एल, बगल र/ Shri R.V.Bhat, Vice President (Operations), UPCL, Bangalore 28. सह उप e य ( स रण व म ट8र ग), अद न प वर ल, 8-ए, 'स भव' जज भवन क स मन, ब दकद व, अहमद ब द , ग जर त / Associate Vice President (Protection & Metering), Adani Power Ltd, 8-A, Sambhav, Opp. Judge s Bungalow, Bodakdev, Ahmedabad , Gujarat, India 29. c lबय त च$बतh (ध न वय त एव स आई अन रण) टप स आईएल, m य नप रम / न लn त b _ म, म त क र म डल, एसप एसआर न g ल र / Sh. Bidyut Chakraborty (Head Electrical and C&I Maintenance), TPCIL, Pyanampuram/ Nelaturu Village, Muthukur Mandal, SPSR Nellore (Fax No: ) 30. c आर एस क म र व म, सल ह र(वय त), स ईप एल, म लमरड र _ म, ओ+jपदरम त g ल क, त त क ड , त मलन ड / Sh. R.S. Kumaraswamy, Advisor (Electrical), CEPL, Melamarudur Village, Ottipidaram Taluk, Tuticorin , Tamil Nadu (Fax No: ) 31. c oकश र आक# ट, व8र. उप e य ( व अ), आईएल व एफएस, टप स एल, स प द प j ड क, परनग प j, भ वनग8र त g ल क, क डल र जल, त मलन ड / Sh. Kishore Arcot, Sr. Vice President (O&M), IL&FS Tamilnadu Power Company Ltd., C.Pudhupettai (post), Parnagipettai, Bhuvanagiri Taluk, Cuddalore Dist, Tamilnadu (Fax No: ) 32. c सf यस च म खजh, व8र. उप e य ( एव अ) +ह द ज एनप स एल, प टग pयड म डल, वश खपpनम, आ / Sh. Sabyasachi Mukherjee, Sr. Vice President (O&M), Hinduja NPCL, Pedagantyada Mandal, Visakhapatnam, AP c एस स दरम "त#, उप e य ( च लन), ल नक कqडपg ल प वर ल मट ड, आईड ए कqडपg ल, इr +हमपpनम म डल, क t ण जg ल, आ u द श / Sh. S. Sundaramoorthy-Vice President (operations), Lanco Kondapalli Power Limited, IDA Kondapalli, Ibrahimpatnam Mandal, Krishna district, Andhra Pradesh , (Fax No: ) ***** Page 4 of 32

154 Annexure-VII OVR (Stage-I) Grading for 400 kv Transmission Lines of Southern Region 1. Voltage - Time (OVR) Grading Matrix: 2. Circuit ID/ Branch ID Legend: Page 5 of 32

155 Annexure-VII 3. Over Voltage Relay (Stage-I) Gradings: From Bus Number From Bus Name To Bus Number To Bus Name Ckt Id Length, km Line Reactor VARs at FROM BUS end (pu) New OVR Grading (at FROM BUS end) JP_GZW_HVDC JP_GZW_FSC T A JP_GZW_HVDC JP_GZW_FSC T D GOOTY KURNOOL T B GOOTY NELLORE-PS Q D GOOTY NELLORE-PS Q H GOOTY KURNOOL-PG T A GOOTY GTYNLM-FSC C 0 0 ** GOOTY GTYSMN-FSC C ** GOOTY RAICHUR-PG Q A GOOTY RAICHUR-PG Q G GOOTY PAVAGADA T C GOOTY PAVAGADA T E CHITTOOR CHINAKMPALLI T H CHITTOOR SDSTPS Q B CHITTOOR SDSTPS Q G CHITTOOR KALIKILI T A CHITTOOR KALIKILI T E CHITTOOR SRIPERUMBDUR T D CHITTOOR TIRUVALAM-PG Q A CHITTOOR TIRUVALAM-PG Q C Page 6 of 32

156 Annexure-VII NELLORE-PG NUNNA T D NELLORE-PG NUNNA T H NELLORE-PG NELLORE-PS Q A NELLORE-PG NELLORE-PS Q B NELLORE-PG SRIPERUMBDUR T C NELLORE-PG SRIPERUMBDUR T G NELLORE-PG TIRUVALAM-PG Q A NELLORE-PG TIRUVALAM-PG Q E CHINAKMPALLI CHITTOOR T D CHINAKMPALLI CNP-FSC C ** CHINAKMPALLI CNP-FSC C ** CHINAKMPALLI NP KUNTA T A CNP-FSC CHINAKMPALLI C 0 0 ** CNP-FSC TALLAPALLI T A CNP-FSC CHINAKMPALLI C 0 0 ** CNP-FSC TALLAPALLI T B TALLAPALLI CNP-FSC T C TALLAPALLI CNP-FSC T G TALLAPALLI KURNOOL-PG T E TALLAPALLI VELTOOR T A TALLAPALLI RSTPS NTPC T A TALLAPALLI RSTPS NTPC T D TALLAPALLI GHANAPUR T I TALLAPALLI KHAMMAM T B TALLAPALLI KHAMMAM T F TALLAPALLI KHAMMAM T H Page 7 of 32

157 Annexure-VII NUNNA NELLORE-PG T D NUNNA NELLORE-PG T H NUNNA VTS-IV T A NUNNA VEMAGIRI T C NUNNA LANCO T B NUNNA LANCO T D NUNNA SATTENAPALLI T E NUNNA NELLORE-AP T I NUNNA VEMAGIRI_PG T A NUNNA VEMAGIRI_PG T B NUNNA VEMAGIRI_PG T G NUNNA KHAMMAM T F GAZUWAKA KALPAKKA T B GAZUWAKA KALPAKKA T G GAZUWAKA SIMHADRI-II T A GAZUWAKA SIMHADRI-II T D GAZUWAKA VEMAGIRI_PG T E KURNOOL GOOTY T C KURNOOL KURNOOL-PG Q A KURNOOL KURNOOL-PG Q D KURNOOL JAMALAMADUGU Q B KURNOOL JAMALAMADUGU Q G KURNOOL GHANI Q A KURNOOL GHANI Q F KURNOOL SRISAILAMLB T E KURNOOL MHSWRM-PG T H Page 8 of 32

158 Annexure-VII KALPAKKA GAZUWAKA T A KALPAKKA GAZUWAKA T F KALPAKKA SIMHADRI-I T A KALPAKKA SIMHADRI-I T B KALPAKKA SIMHADRI-I T D KALPAKKA VEMAGIRI T G KALPAKKA HINDUJA T B KALPAKKA HINDUJA T E KALPAKKA MARADAM Q D KALPAKKA MARADAM Q H KALPAKKA KHAMMAM T I KALPAKKA ASUPAKA T C SIMHADRI-I KALPAKKA T A SIMHADRI-I KALPAKKA T D SIMHADRI-I KALPAKKA T F VTS-IV NUNNA T A VTS-IV SATTENAPALLI T B VTS-IV SATTENAPALLI T E VTS-IV NELLORE-AP T H VTS-IV SURYAPET T D VTS-IV SURYAPET T G VEMAGIRI NUNNA T H VEMAGIRI KALPAKKA T D VEMAGIRI GMR T C VEMAGIRI GMR T F VEMAGIRI GAUTHAMI T B VEMAGIRI GAUTHAMI T E VEMAGIRI KONASEEMA T A Page 9 of 32

159 Annexure-VII VEMAGIRI KONASEEMA T E VEMAGIRI GVK-II T A VEMAGIRI GVK-II T D VEMAGIRI SIMHADRI-II T G VEMAGIRI SATTENAPALLI T I VEMAGIRI VEMAGIRI_PG T A VEMAGIRI VEMAGIRI_PG T B GMR VEMAGIRI T A GMR VEMAGIRI T D GAUTHAMI VEMAGIRI T B GAUTHAMI VEMAGIRI T E KONASEEMA VEMAGIRI T B KONASEEMA VEMAGIRI T E GVK-II VEMAGIRI T A GVK-II VEMAGIRI T D LANCO NUNNA T B LANCO NUNNA T E SIMHADRI-II GAZUWAKA T A SIMHADRI-II GAZUWAKA T D SIMHADRI-II VEMAGIRI T E SIMHADRI-II VEMAGIRI_PG T B SIMHADRI-II VEMAGIRI_PG T G SATTENAPALLI NUNNA T E SATTENAPALLI VTS-IV T A SATTENAPALLI VTS-IV T D SATTENAPALLI VEMAGIRI T G SATTENAPALLI SRISAILAMLB T B SATTENAPALLI SRISAILAMLB T H Page 10 of 32

160 Annexure-VII SIMHAPURI NELLORE-PS Q B SIMHAPURI MEENAKSHI Q1 5 0 E NELLORE-PS GOOTY Q G NELLORE-PS GOOTY Q I NELLORE-PS NELLORE-PG Q B NELLORE-PS NELLORE-PG Q E NELLORE-PS SIMHAPURI Q C NELLORE-PS MEENAKSHI Q D NELLORE-PS TPCIL Q A NELLORE-PS TPCIL Q F NELLORE-PS NCC Q A NELLORE-PS NCC Q H MEENAKSHI SIMHAPURI Q1 5 0 D MEENAKSHI NELLORE-PS Q A HINDUJA KALPAKKA T A HINDUJA KALPAKKA T D HINDUJA K V KOTA T B HINDUJA K V KOTA T G NELLORE-AP NUNNA T F NELLORE-AP VTS-IV T B NELLORE-AP SDSTPS Q A NELLORE-AP SDSTPS Q D SDSTPS CHITTOOR Q B SDSTPS CHITTOOR Q F SDSTPS NELLORE-AP Q A SDSTPS NELLORE-AP Q D Page 11 of 32

161 Annexure-VII KURNOOL-PG GOOTY T B KURNOOL-PG TALLAPALLI T G KURNOOL-PG KURNOOL Q A KURNOOL-PG KURNOOL Q D GTYNLM-FSC GOOTY C 0 0 ** GTYNLM-FSC NELAMANGALA T A GTYSMN-FSC GOOTY C 0 0 ** GTYSMN-FSC SOMANAHALLI T B TPCIL NELLORE-PS Q A TPCIL NELLORE-PS Q D NCC NELLORE-PS Q B NCC NELLORE-PS Q E JAMALAMADUGU KURNOOL Q A JAMALAMADUGU KURNOOL Q D JAMALAMADUGU URAVAKONDA Q B JAMALAMADUGU URAVAKONDA Q G NP KUNTA CHINAKMPALLI T A NP KUNTA KOLAR T D URAVAKONDA JAMALAMADUGU Q A URAVAKONDA JAMALAMADUGU Q D URAVAKONDA VELTOOR Q B URAVAKONDA VELTOOR Q G VEMAGIRI_PG NUNNA T B VEMAGIRI_PG NUNNA T G VEMAGIRI_PG NUNNA T A VEMAGIRI_PG GAZUWAKA T E VEMAGIRI_PG VEMAGIRI T A VEMAGIRI_PG VEMAGIRI T D Page 12 of 32

162 Annexure-VII VEMAGIRI_PG SIMHADRI-II T C VEMAGIRI_PG SIMHADRI-II T H GHANI KURNOOL Q B GHANI KURNOOL Q E K V KOTA HINDUJA T A K V KOTA HINDUJA T D K V KOTA SURYAPET T B K V KOTA SURYAPET T D RYTPS STG V KALIKIRI T A RYTPS STG V KALIKIRI T D MARADAM KALPAKKA Q B MARADAM KALPAKKA Q E KALIKIRI CHITTOOR T B KALIKIRI CHITTOOR T F KALIKIRI RYTPS STG V T A KALIKIRI RYTPS STG V T D VELTOOR TALLAPALLI T H VELTOOR URAVAKONDA Q D VELTOOR URAVAKONDA Q G VELTOOR MHSWRM-PG T B VELTOOR MHSWRM-PG T E VELTOOR RAICHUR TPS T A RSTPS NTPC TALLAPALLI T A RSTPS NTPC TALLAPALLI T D RSTPS NTPC GHANAPUR T C RSTPS NTPC GHANAPUR T H RSTPS NTPC DICHIPALLI T E RSTPS NTPC GAJWEL T G Page 13 of 32

163 Annexure-VII RSTPS NTPC WARANGAL T B RSTPS NTPC MALKARAM T I RSTPS NTPC BHADRAWATHI T A RSTPS NTPC BHADRAWATHI T F GHANAPUR TALLAPALLI T H GHANAPUR RSTPS NTPC T C GHANAPUR RSTPS NTPC T G GHANAPUR MAMIDIPALLI T D GHANAPUR GAJWEL T A GHANAPUR MALKARAM T B GHANAPUR MHSWRM-PG T E KHAMMAM TALLAPALLI T D KHAMMAM TALLAPALLI T F KHAMMAM TALLAPALLI T H KHAMMAM NUNNA T E KHAMMAM KALPAKKA T G KHAMMAM MAMIDIPALLI T D KHAMMAM MAMIDIPALLI T I KHAMMAM WARANGAL T A KHAMMAM KTPS-VI T A KHAMMAM ASUPAKA T B KHAMMAM KTPS-VII T C SRISAILAMLB KURNOOL T E SRISAILAMLB SATTENAPALLI T B SRISAILAMLB SATTENAPALLI T G SRISAILAMLB DINDI T A SRISAILAMLB DINDI T D Page 14 of 32

164 Annexure-VII MAMIDIPALLI GHANAPUR T D MAMIDIPALLI KHAMMAM T A MAMIDIPALLI KHAMMAM T G MAMIDIPALLI DINDI T B MAMIDIPALLI DINDI T E DICHIPALLI RSTPS NTPC T F DICHIPALLI NIZAMABAD I D DICHIPALLI NIZAMABAD I A GAJWEL RSTPS NTPC T E GAJWEL GHANAPUR T B GAJWEL KAKATIYA TPS T A GAJWEL KAKATIYA TPS T G GAJWEL SHANKARPALLI T D GAJWEL SINGARENI Q C GAJWEL SINGARENI Q H GAJWEL NARSARPUR T A KAKATIYA TPS GAJWEL T B KAKATIYA TPS GAJWEL T F KAKATIYA TPS WARANGAL T A KAKATIYA TPS WARANGAL T D WARANGAL RSTPS NTPC T B WARANGAL KHAMMAM T F WARANGAL KAKATIYA TPS T A WARANGAL KAKATIYA TPS T D MALKARAM RSTPS NTPC T A MALKARAM GHANAPUR T D MALKARAM SURYAPET T B MALKARAM SURYAPET T G Page 15 of 32

165 Annexure-VII KTPS-VI KHAMMAM T D KTPS-VI KTPS-VII T A SHANKARPALLI GAJWEL T C SHANKARPALLI SURYAPET Q D SHANKARPALLI SURYAPET Q H SHANKARPALLI NARSARPUR T A SHANKARPALLI NIZAMABAD T B SHANKARPALLI NIZAMABAD T G SHANKARPALLI MAHES-TS T A SHANKARPALLI MAHES-TS T E BHADRAWATHI RSTPS NTPC T A BHADRAWATHI RSTPS NTPC T D SINGARENI GAJWEL Q A SINGARENI GAJWEL Q D SURYAPET VTS-IV T A SURYAPET VTS-IV T D SURYAPET K V KOTA T C SURYAPET K V KOTA T H SURYAPET MALKARAM T A SURYAPET MALKARAM T2 0 0 F SURYAPET SHANKARPALLI Q E SURYAPET SHANKARPALLI Q I SURYAPET JULURPADU Q B SURYAPET JULURPADU Q G NARSARPUR GAJWEL T A NARSARPUR SHANKARPALLI T D Page 16 of 32

166 Annexure-VII NIZAMABAD DICHIPALLI I A NIZAMABAD DICHIPALLI I D NIZAMABAD SHANKARPALLI T B NIZAMABAD SHANKARPALLI T G DINDI SRISAILAMLB T A DINDI SRISAILAMLB T D DINDI MAMIDIPALLI T B DINDI MAMIDIPALLI T F ASUPAKA KALPAKKA T D ASUPAKA KHAMMAM T A MHSWRM-PG KURNOOL T H MHSWRM-PG VELTOOR T B MHSWRM-PG VELTOOR T G MHSWRM-PG GHANAPUR T E MHSWRM-PG MAHES-TS Q A MHSWRM-PG MAHES-TS Q D MAHES-TS SHANKARPALLI T B MAHES-TS SHANKARPALLI T G MAHES-TS MHSWRM-PG Q A MAHES-TS MHSWRM-PG Q D JULURPADU SURYAPET Q B JULURPADU SURYAPET Q E KTPS-VII KHAMMAM T D KTPS-VII KTPS-VI T A HOODY NELAMANGALA T G HOODY KOLAR B A HOODY KOLAR B D HOODY YELAHANKA T B Page 17 of 32

167 Annexure-VII NELAMANGALA GTYNLM-FSC T D NELAMANGALA HOODY T D NELAMANGALA BIDADI T A NELAMANGALA BIDADI T C NELAMANGALA HASSAN T F NELAMANGALA TALAGUPPA T I NELAMANGALA HIRIYUR T A NELAMANGALA HIRIYUR T H NELAMANGALA MYSORE T E NELAMANGALA MYSORE T G NELAMANGALA YELAHANKA T B SOMANAHALLI GTYSMN-FSC T E SOMANAHALLI BIDADI T C SOMANAHALLI BIDADI T G SOMANAHALLI KOLAR T A SOMANAHALLI HOSUR T H SOMANAHALLI DHARAMAPURI Q B SOMANAHALLI DHARAMAPURI Q D RAICHUR TPS VELTOOR T B RAICHUR TPS RAICHUR-PG Q A RAICHUR TPS RAICHUR-PG Q D RAICHUR TPS BELLARY TPS T E RAICHUR TPS MUNIRABAD T G Page 18 of 32

168 Annexure-VII BIDADI NELAMANGALA T A BIDADI NELAMANGALA T G BIDADI SOMANAHALLI T B BIDADI SOMANAHALLI T E BIDADI TUMKUR T D BIDADI TUMKUR T H TUMKUR BIDADI T A TUMKUR BIDADI T D TUMKUR KUDUGI-PG Q C TUMKUR KUDUGI-PG Q H TUMKUR PAVAGADA T A TUMKUR PAVAGADA T E TUMKUR PAVAGADA Q B TUMKUR PAVAGADA Q G RAICHUR-PG GOOTY Q B RAICHUR-PG GOOTY Q F RAICHUR-PG RAICHUR TPS Q A RAICHUR-PG RAICHUR TPS Q D KOLAR NP KUNTA T G KOLAR HOODY B A KOLAR HOODY B C KOLAR SOMANAHALLI T E KOLAR HOSUR T B KOLAR HOSUR T D KOLAR TIRUVALAM-PG T H Page 19 of 32

169 Annexure-VII BELLARY TPS RAICHUR TPS T D BELLARY TPS JINDAL TPS T1 8 0 A BELLARY TPS HIRIYUR T B BELLARY TPS HIRIYUR T F GUTTUR JINDAL TPS T C GUTTUR KAIGA APS T A GUTTUR KAIGA APS T G GUTTUR MUNIRABAD T E GUTTUR NARENDRA T D GUTTUR NARENDRA T H GUTTUR HIRIYUR T A GUTTUR HIRIYUR T B HASSAN NELAMANGALA T H HASSAN TALAGUPPA T G HASSAN MYSORE T B HASSAN MYSORE T E HASSAN UDUPI PCL Q A HASSAN UDUPI PCL Q D JINDAL TPS BELLARY TPS T1 8 0 B JINDAL TPS GUTTUR T F JINDAL TPS BPS Q A JINDAL TPS BPS Q D KAIGA APS GUTTUR T B KAIGA APS GUTTUR T F KAIGA APS NARENDRA A A KAIGA APS NARENDRA A D MUNIRABAD RAICHUR TPS T A MUNIRABAD GUTTUR T D Page 20 of 32

170 Annexure-VII NARENDRA GUTTUR T B NARENDRA GUTTUR T G NARENDRA KAIGA APS A A NARENDRA KAIGA APS A E NARENDRA KUDUGI-PG Q D NARENDRA KUDUGI-PG Q H TALAGUPPA NELAMANGALA T E TALAGUPPA HASSAN T B HIRIYUR NELAMANGALA T D HIRIYUR NELAMANGALA T H HIRIYUR BELLARY TPS T B HIRIYUR BELLARY TPS T G HIRIYUR GUTTUR T A HIRIYUR GUTTUR T E MYSORE NELAMANGALA T B MYSORE NELAMANGALA T G MYSORE HASSAN T A MYSORE HASSAN T E MYSORE KOZHIKODE T D MYSORE KOZHIKODE T H UDUPI PCL HASSAN Q A UDUPI PCL HASSAN Q D YELAHANKA HOODY T E YELAHANKA NELAMANGALA T B KUDUGI-PG KOLHAPUR-PG H D KUDUGI-PG KOLHAPUR-PG H H KUDUGI-PG TUMKUR Q E KUDUGI-PG TUMKUR Q I Page 21 of 32

171 Annexure-VII KUDUGI-PG NARENDRA Q B KUDUGI-PG NARENDRA Q G KUDUGI-PG KUDGI-NTPC Q A KUDUGI-PG KUDGI-NTPC Q A KUDUGI-PG KUDGI-NTPC Q C KUDUGI-PG KUDGI-NTPC Q F KUDGI-NTPC KUDUGI-PG Q A KUDGI-NTPC KUDUGI-PG Q B KUDGI-NTPC KUDUGI-PG Q D KUDGI-NTPC KUDUGI-PG Q G YERMARUS TPS BPS Q A YERMARUS TPS BPS Q D PAVAGADA GOOTY T A PAVAGADA GOOTY T E PAVAGADA TUMKUR T A PAVAGADA TUMKUR T D PAVAGADA TUMKUR Q B PAVAGADA TUMKUR Q G PAVAGADA BPS Q C PAVAGADA BPS Q H BPS JINDAL TPS Q A BPS JINDAL TPS Q E BPS YERMARUS TPS Q B BPS YERMARUS TPS Q G BPS PAVAGADA Q D BPS PAVAGADA Q H Page 22 of 32

172 Annexure-VII SRIPERUMBDUR CHITTOOR T D SRIPERUMBDUR NELLORE-PG T B SRIPERUMBDUR NELLORE-PG T G SRIPERUMBDUR S V CHATHRAM T A SRIPERUMBDUR TIRUVALAM-PG T E ALAMATTY S V CHATHRAM T B ALAMATTY S V CHATHRAM T G ALAMATTY NTECL-VALLUR T A ALAMATTY NTECL-VALLUR T C ALAMATTY NCTPS-II T A ALAMATTY TIRUVALAM-TN T D ALAMATTY TIRUVALAM-TN T H ALAMATTY MANALI T E SALEM-PG MYWADI T D SALEM-PG MYWADI T H SALEM-PG HOSUR T B SALEM-PG HOSUR T G SALEM-PG NEYVELI-II T A SALEM-PG NEYVELI-II T C SALEM-PG DHARAMAPURI Q E SALEM-PG DHARAMAPURI Q A MYWADI SALEM-PG T A MYWADI SALEM-PG T D MYWADI TIRUNELVELLI T A MYWADI TIRUNELVELLI T E MYWADI CHIKKANURANI T H MYWADI ARASUR T C MYWADI ARASUR T G Page 23 of 32

173 Annexure-VII MYWADI PALAKKAD T B MYWADI PALAKKAD T F TIRUNELVELLI MYWADI T A TIRUNELVELLI MYWADI T F TIRUNELVELLI CHIKKANURANI T D TIRUNELVELLI CHIKKANURANI T H TIRUNELVELLI KKNPP Q A TIRUNELVELLI KKNPP Q E TIRUNELVELLI KANARPATY Q B TIRUNELVELLI TRIVENDRUM T C TIRUNELVELLI TRIVENDRUM T G HOSUR SOMANAHALLI T E HOSUR KOLAR T A HOSUR KOLAR T D HOSUR SALEM-PG T B HOSUR SALEM-PG T G KALIVNDPATTU PUGALUR T C KALIVNDPATTU PUGALUR T H KALIVNDPATTU NTECL-VALLUR T B KALIVNDPATTU NTECL-VALLUR T G KALIVNDPATTU TIRUVALAM-PG T A KALIVNDPATTU TIRUVALAM-PG T E KALIVNDPATTU SHOLINGNLLUR T A KALIVNDPATTU SHOLINGNLLUR T D ALUNDUR CHIKKANURANI T G ALUNDUR KARAIKUDI T D ALUNDUR NAGAPTNAM PS T A ALUNDUR NAGAPTNAM PS T B Page 24 of 32

174 Annexure-VII CHIKKANURANI MYWADI T F CHIKKANURANI TIRUNELVELLI T D CHIKKANURANI TIRUNELVELLI T H CHIKKANURANI ALUNDUR T A CHIKKANURANI KARAIKUDI T B CHIKKANURANI PUGALUR T C CHIKKANURANI PUGALUR T G CHIKKANURANI TUTICORINPS Q A CHIKKANURANI TUTICORINPS Q E ARASUR MYWADI T B ARASUR MYWADI T G ARASUR KARAMADAI T A ARASUR KARAMADAI T D KARAIKUDI ALUNDUR T A KARAIKUDI CHIKKANURANI T D KARAIKUDI PUGALUR Q B KARAIKUDI PUGALUR Q G KARAIKUDI KAYATHAR Q C KARAIKUDI KAYATHAR Q H KARAIKUDI KAMUTHI Q A KARAIKUDI KAMUTHI Q E NEYVELI1EXP NEYVELI-II T A NEYVELI1EXP NAGAPTNAM PS T D NEYVELI-II SALEM-PG T D NEYVELI-II SALEM-PG T G NEYVELI-II NEYVELI1EXP T B NEYVELI-II PUGALUR T H NEYVELI-II NEYVELI2EXP T A Page 25 of 32

175 Annexure-VII NEYVELI-II NAGAPTNAM PS T E NEYVELI-II PONDY T C PUGALUR KALIVNDPATTU T D PUGALUR KALIVNDPATTU T H PUGALUR CHIKKANURANI T B PUGALUR CHIKKANURANI T E PUGALUR KARAIKUDI Q C PUGALUR KARAIKUDI Q G PUGALUR NEYVELI-II T A PUGALUR NEYVELI2EXP T A NEYVELI2EXP NEYVELI-II T A NEYVELI2EXP PUGALUR T D KKNPP TIRUNELVELLI Q A KKNPP TIRUNELVELLI Q D KKNPP TUTICORINPS Q B KKNPP TUTICORINPS Q F S V CHATHRAM SRIPERUMBDUR T A S V CHATHRAM ALAMATTY T B S V CHATHRAM ALAMATTY T E S V CHATHRAM NCTPS-II T D S V CHATHRAM NCTPS-II T H S V CHATHRAM PONDY T G NTECL-VALLUR ALAMATTY T B NTECL-VALLUR ALAMATTY T G NTECL-VALLUR KALIVNDPATTU T D NTECL-VALLUR KALIVNDPATTU T H NTECL-VALLUR NCTPS-II T A NTECL-VALLUR NCTPS-II T E Page 26 of 32

176 Annexure-VII METTUR-III KARAMADAI T B METTUR-III KARAMADAI T G METTUR-III PALAVADI Q A METTUR-III PALAVADI Q D TUTICORINJV TUTICORINPS Q B TUTICORINJV TUTICORINPS Q E NCTPS-II ALAMATTY T E NCTPS-II S V CHATHRAM T B NCTPS-II S V CHATHRAM T H NCTPS-II NTECL-VALLUR T A NCTPS-II NTECL-VALLUR T D NCTPS-II MANALI T G COASTAL ENER TUTICORINPS Q A COASTAL ENER TUTICORINPS Q D TIRUVALAM-PG CHITTOOR Q A TIRUVALAM-PG CHITTOOR Q B TIRUVALAM-PG NELLORE-PG Q A TIRUVALAM-PG NELLORE-PG Q D TIRUVALAM-PG KOLAR T H TIRUVALAM-PG SRIPERUMBDUR T E TIRUVALAM-PG KALIVNDPATTU T C TIRUVALAM-PG KALIVNDPATTU T G SHOLINGNLLUR KALIVNDPATTU T A SHOLINGNLLUR KALIVNDPATTU T D DHARAMAPURI SOMANAHALLI Q B DHARAMAPURI SOMANAHALLI Q G DHARAMAPURI SALEM-PG Q A DHARAMAPURI SALEM-PG Q E Page 27 of 32

177 Annexure-VII DHARAMAPURI TUTICORINPS H C DHARAMAPURI TUTICORINPS H H DHARAMAPURI NAGAPTNAM PS H A DHARAMAPURI NAGAPTNAM PS H D TUTICORINPS CHIKKANURANI Q A TUTICORINPS CHIKKANURANI Q G TUTICORINPS KKNPP Q D TUTICORINPS KKNPP Q H TUTICORINPS TUTICORINJV Q B TUTICORINPS TUTICORINJV Q E TUTICORINPS COASTAL ENER Q A TUTICORINPS COASTAL ENER Q E TUTICORINPS DHARAMAPURI H F TUTICORINPS DHARAMAPURI H I TUTICORINPS TUTICORN-GIS Q A TUTICORINPS TUTICORN-GIS Q B TUTICORINPS TUTICORN-GIS Q C TUTICORINPS TUTICORN-GIS Q D KAYATHAR KARAIKUDI Q B KAYATHAR KARAIKUDI Q G KAYATHAR KANARPATY T A KAYATHAR KANARPATY T D TIRUVALAM-TN ALAMATTY T A TIRUVALAM-TN ALAMATTY T D TIRUVALAM-TN PALAVADI Q B TIRUVALAM-TN PALAVADI Q G ILFS NAGAPTNAM PS Q A ILFS NAGAPTNAM PS Q D Page 28 of 32

178 Annexure-VII NAGAPTNAM PS ALUNDUR T C NAGAPTNAM PS ALUNDUR T H NAGAPTNAM PS NEYVELI1EXP T D NAGAPTNAM PS NEYVELI-II T A NAGAPTNAM PS DHARAMAPURI H A NAGAPTNAM PS DHARAMAPURI H G NAGAPTNAM PS ILFS Q B NAGAPTNAM PS ILFS Q E KAMUTHI KARAIKUDI Q A KAMUTHI KARAIKUDI Q D KARAMADAI ARASUR T A KARAMADAI ARASUR T D KARAMADAI METTUR-III T B KARAMADAI METTUR-III T G KANARPATY TIRUNELVELLI Q D KANARPATY KAYATHAR T A KANARPATY KAYATHAR T G PALAVADI METTUR-III Q A PALAVADI METTUR-III Q E PALAVADI TIRUVALAM-TN Q D PALAVADI TIRUVALAM-TN Q H PALAVADI RASIPALYAM Q B PALAVADI RASIPALYAM Q G MANALI ALAMATTY T B MANALI NCTPS-II T E Page 29 of 32

179 Annexure-VII RASIPALYAM PALAVADI Q B RASIPALYAM PALAVADI Q G RASIPALYAM ANIKADV T A RASIPALYAM ANIKADV T D ANIKADV RASIPALYAM T A ANIKADV RASIPALYAM T D TUTICORN-GIS TUTICORINPS Q A TUTICORN-GIS TUTICORINPS Q B TUTICORN-GIS TUTICORINPS Q D TUTICORN-GIS TUTICORINPS Q G TRICHUR COCHIN Q B TRICHUR COCHIN Q G TRICHUR PALAKKAD T A TRICHUR PALAKKAD T D TRIVENDRUM TIRUNELVELLI T B TRIVENDRUM TIRUNELVELLI T E COCHIN TRICHUR Q B COCHIN TRICHUR Q E PALAKKAD MYWADI T A PALAKKAD MYWADI T D PALAKKAD TRICHUR T B PALAKKAD TRICHUR T F KOZHIKODE MYSORE T A KOZHIKODE MYSORE T D PONDY NEYVELI-II T A PONDY S V CHATHRAM T D Page 30 of 32

180 Annexure-VII OVR (Stage-I) Grading for 765 kv Transmission Lines of Southern Region 1. Voltage - Time (OVR) Grading Matrix: 2. Circuit ID/ Branch ID Legend: Page 31 of 32

181 Annexure-VII 3. Over Voltage Relay (Stage-I) Gradings: From Bus Number From Bus Name To Bus Number To Bus Name Ckt Id Length, km Line Reactor VARs at FROM BUS end (pu) New OVR Grading (at FROM BUS end) KURNOOL-PG NELLORE-PS H B KURNOOL-PG NELLORE-PS H G KURNOOL-PG RAICHUR-PG B A KURNOOL-PG RAICHUR-PG B E KURNOOL-PG TIRUVALAM H C KURNOOL-PG TIRUVALAM H H NELLORE-PS KURNOOL-PG H A NELLORE-PS KURNOOL-PG H E SRIKAKULAM ANGUL H A SRIKAKULAM ANGUL H C SRIKAKULAM VEMAGIRI_PG H B SRIKAKULAM VEMAGIRI_PG H E VEMAGIRI_PG SRIKAKULAM H A VEMAGIRI_PG SRIKAKULAM H E NIZAMABAD WARDHA-PG H B NIZAMABAD WARDHA-PG H E NIZAMABAD MAHESWARAM H A NIZAMABAD MAHESWARAM H C MAHESWARAM NIZAMABAD H A MAHESWARAM NIZAMABAD H E RAICHUR-PG SOLAPUR-PG B A RAICHUR-PG SOLAPUR-PG B C RAICHUR-PG KURNOOL-PG B B RAICHUR-PG KURNOOL-PG B E TIRUVALAM KURNOOL-PG H A TIRUVALAM KURNOOL-PG H E Page 32 of 32

182 Annexure-VIII 73 rd PCSC meeting 26 th April 2018 Page 1 of 52

183 1. Complete outage of 220kV Hubli, Ambewadi and Nagjhari substations of KPTCL at 06:45 Hrs on Annexure-VIII List of 220kV lines out in antecedent condition: -220kV Hubli-Sirsi line-1&2 idle charged from Hubli end -220kV Naghjeri-Kodasalli line-1 &2 were kept open at Naghjeri -220kV Ambewadi-Narendra line-2 idle charged from Narendra -220kV Ambewadi Narendra line-1 out due to fault Page 2 of 52

184 Annexure-VIII List of 220kV lines tripped on fault : 220kV Bidnal-Savadatti at 6:14 hrs Bidnal : DPR, Z1, R-N, 7.34Km, Ir-8964A Savadatti : DPR, Zone-1 fault 220kV Bidnal-Hubli line-1 at 6:18 hrs Bidnal - DPR, Z2, RN, 3.3Km, Ir-4802A, Hubballi - DPR, R-N, Z2, 2.188Km, Ir-9.248KA 220kV Hubli-Narendra line-2 at 6:44 hrs Hubli : DPR Z1, R-N, 1 Km Narendra : DPR 220kV Hubli-Narendra-2 Hand tripped 220kV Hubli-Bidnal line-2 & Nagjheri-Bidnal-2 at 6:45 hrs Hubli : DOCR 1.13 A, 1.24 A, 1.18 A Running units at Nagjheri tripped due to loss of evacuating lines. 220kV Nagjheri station outage resulted in loss of supply to 220kV Hubli and Ambewadi. Total Load Loss / Generation loss Reported: 136MW / 643 MW. Page 3 of 52

185 2. Complete outage of 220kV Narendra (KPTCL), Belgaum, Chikkodi, Gataprabha, MKHubli, Mahalingapura, Soudatti, Athani & Kudachi at 09:13 hrs on Annexure-VIII Antecedent condition : 315MVA 400KV/220KV Narendra ICT-2 was under shutdown due to construction works. 220kV lines out due to fault: - 220kV Narendra Ambewadi line-1-220kv Narendra Huballi line-2-220kv Narendra Haveri line-1 and 2-220kV Bidnal Soudatti line - 220kV Bidnal Huballi line-1 and 2 220kV lines under idle charged condition - 220kV Ambewadi Narendra -2, 220kV Nagjheri Kodasalli lines, 220kV Hubli-Sirsi lines, Page 4 of 52 Antecedent Generation Sharavathy 350 MW Nagjheri 100 MW Kodasalli 80 MW Kadra 96 MW

186 Annexure-VIII Triggering Incident: 220kV ML Pura-Vajramatti line-1&2 tripped on OCR at Vajramatti 400/220kV ICT-1 due to overload (105% MW) Loss of supply : Belgaum, Chikkodi, Gataprabha, MKHubli, Mahalingapura, Soudatti, Athani & Kudachi Load Loss as reported: 460 MW Extract from Ramakrishna committee guidelines Page 5 of 52

187 Annexure-VIII 3. Complete outage of 220kV Narendra(KPTCL), Bidnal, SRS Hubballi, Ambewadi, Haveri, Karwar, Belgaum,Chikkodi, Soudatti, ML Pura, Athani, Kudachi, Gataprabha,MK Hubli, NPH, Kodasalli and Kadra at 10:01 hrs on Antecedent condition 315MVA 400KV/220KV Narendra ICT-2 was under shutdown due to construction works. 400kV and 220kV lines out of service: - 400kV Guttur Kaiga line-1 and kV Bidnal Harthi line-1 and 2-220kV Bidnal Soudatti line - 220kV Ambewadi Narendra line-1-220kv Haveri Guttur line -1 and 2-220kV Haveri Narendra line-1-220kv Kadra Karwar line kV Hubli Sirsi line-1 and 2 were in idle charged condition at Hubli end (As per KA SLDC instruction) Page 6 of 52

188 Narendra ICT-1 Annexure-VIII 220kV Kaiga-Kadra tripped at Kaiga end on backup over-current at Kaiga 220kV Kadra-Kodasalli and 220kV Kaiga-Kodasalli lines tripped on operation of backup over-current at Kodasalli end. 400/220kV Narendra (PG) ICT-1 tripped on backup over-current protection Page 7 of 52

189 Annexure-VIII Running Units 2 & 4 of 220kV Naghjeri tripped on under impedance stage-2 (21G stage-2 overcurrent interlock) and under excitation (40G) respectively due to system disturbance Due to non-availability of evacuating lines, running units at Kodasalli also tripped. Loss of supply - 220kV Narendra(KPTCL), Bidnal, SRS Hubballi, Ambewadi, Haveri, Karwar, Belgaum,Chikkodi, Soudatti, ML Pura, Athani, Kudachi, Gataprabha,MK Hubli, NPH, Kodasalli and Kadra Page 8 of 52

190 Annexure-VIII 4. Complete outage of 220kV Kemar, MSEZ Bajpe and Kavoor and tripping of 400/220kV ICT-2 at UPCL at 18:33 Hrs on Triggering incident Fault in 220kV Kemar-MSEJ line-2 220kV Kemar-UPCL tripped on zone-2 LBB operation at UPCL 220kV lines Varahi-Kemar lines tripped on transient faults Loss of supply Kemar, Puttur, MSEJ & Kavoor Load Loss: 500 MW Page 9 of 52

191 Annexure-VIII Sequence of tripping of lines 220kV Kemar-Bajape line -2 Over current relay operation (B phase) at Kemar end Delayed clearance observed from PMU data plots 220kV UPCL-Kemar line -2 Zone-2 operation at tripped at UPCL end (45.39 Kms, Ib=2.63 KA). LBB enabled in MICOM P442 relay operated and tripped the elements connected to the bus-2 at UPCL. Remaining 220kV lines tripped at Kemar : Varahi line-1 : Tripped on DPR ABC Trip, Zone-1, ABN Loop, Fault location= km Varahi line-2 : Tripped on DPR ABC Trip, Zone-1, ABN Loop, fault location L= km Varahi line-3 : Tripped on DPR, Zone-1 fault. Page 10 of 52

192 PMU Data Plots: 18:33:44 Annexure-VIII 400 ms 18:43:41 18:45:35 Page 11 of 52

193 5. Complete Outage of 220kV Varahi station at 22:36 Hrs on Annexure-VIII Shimoga Varahi Kemar UPCL Kavoor Puttur Triggering incident : Y-phase to ground fault on 220kV Varahi-Shimoga line-2 Varahi DR trigger 22:36: hrs DPR, Zone-1, Y-N LBB optd. Shimoga DR trigger 22:40: hrs DPR, Zone-1, Y-N A/r attempt unsuccessful LBB operated resulting in operation of 220kV bus bar protection at Varahi and all the connected elements and Varahi running units tripped. Generation Loss: 459 MW Page 12 of 52

194 Page 13 of 52 Annexure-VIII

195 Annexure-VIII 6. Multiple Tripping at 400kV Sriperumbudur Station at 18:02hrs on Source PG report Triggering incident: Failure of Y-phase CT of 400/230kV ICT-2 at 400kV Sriperambadur S/s (400kV TANTRANSCO switchyard). 400kV lines and ICT s at Sriperambadur tripped on operation of backup protections. Page 14 of 52

196 Annexure-VIII 520ms Tripping of 400/230kV ICT-2 Differential protection for ICT-2 operated. LBB protection operation also reported for ICT-2 HV side breaker indicating a possible lockout/ non-tripping of ICT-2 HV side breaker. 400kV lines connected to Sriperambadur(PG) Tripped on operation of reverse zone at Sriperumbudur and zone-2 at remote ends. Inter-bus tie CB 1152 tripped at 18:01: hrs i.e 500ms after occurrence of fault. LBB operated for ICT-5 (400/110kV 200MVA) LV breaker - 110kV breakers got tripped resulting in 110kV supply failure at Sriperampudur. 230kV LV breaker of ICT -3 (400/230kV 315MVA) got tripped on LV overcurrent (persistent for 2.2 seconds) Page 15 of 52

197 Observations from DR: Annexure-VIII 400kV Nellore-Sriperambadur line-1 Nellore FIR Zone-1, Y-N, Carried Send Sriperambadur DR trigger 18:01: hrs Distance zone-4 trip Ir-1A, Iy-2 A, Ib-0.5 A, In-0.9 A Fault current observed to be persistent for 500ms. Sriperumbudur tripped on Distance reverse zone. DR of Nellore end not furnished. Time synchronization of Sriperumbudur end DR needs to be checked. 400kV Nellore-Sriperambadur line-2 Nellore DR trigger 18: 01: hrs Sriperambadur DR trigger 18:01: hrs Zone-2, Y-N Distance zone-4 trip Ir-1kA, Iy-2 ka, Ib-0.4 ka, In-0.8 ka Fault current observed to be persistent for 500ms. Nellore end tripped on Distance Zone-2 and Sriperambadur on Distance reverse zone. Page 16 of 52

198 Annexure-VIII 400kV Thiruvelam-Sriperambadur line Thiruvelam Sriperambadur DR trigger 18:01:51.990hrs DR trigger 18:01: hrs Zone-2, Y-N, Grp-A/B optd. Distance zone-4 trip Fault current observed to be persistent for 500ms. Thiruvelam end tripped on Distance Zone-2 and Sriperambadur on Distance reverse zone. 400kV Chitoor-Sriperambadur line Chitoor FIR - Y phase, Z2 Sriperambadur DR trigger 18:01: hrs Distance zone-4 trip Fault current observed to be persistent for 500ms. Sriperambadur end tripped on Distance Zone-4. DR and EL of Chitoor end not furnished. Page 17 of 52

199 Annexure-VIII 400kV S.V.Chatram-Sriperambadur line S.V.Chatram DR trigger 18:01: hrs Distance zone-2 trip Sriperambadur Distance zone-4 pickup Fault current observed to be persistent for 500ms. S.V.Chatram end tripped on Distance Zone-2 ICT-3 at Sriperambadur S/s In DR the LV current was observed to be persistent for 2.2 seconds Page 18 of 52

200 Annexure-VIII Points for further discussion : 1. It was mentioned in TANTRANSCO FIR that upon failure of CT of ICT-2 had triggered busbar protection and differential protection of ICT-2. Also there was delayed operation of BBP. It could not be established whether the CT failure resulted into a Bus fault or whether it was LBB protection of ICT-2 HV CB which triggered bus bar trip. The reason for delayed busbar/ LBB protection needs review. 2. Reason for operation of LBB protection of ICT-2 HV CB LBB. Whether Main CB of ICT-2 was in stuck condition. 3. Reason for LBB operation in ICT-5 LV CB and the relay which triggered LV CB LBB 4. ICT-3 & 400kV Nellore-Sriperambadur line-1 (Sriperambadur end) DR were observed to be not time-synchronized with GPS. Page 19 of 52

201 Annexure-VIII 7. Complete outage of 220kV Vizag switching station (VSS) at 16:14 hrs on Triggering Incident: Failure of Bus coupler R-phase Current Transformer towards Bus-1 Bus bar protection operated resulting in tripping of all the connected elements. 220kV Kalpakka Dairy Farm feeders 1&2 tripped on jumper snapped due to overloading. Load Loss as reported : 700 MW Page 20 of 52

202 Page 21 of 52 Annexure-VIII

203 PMU Data Plots: Annexure-VIII Dip in R-phase voltage of 400kV Gazuwaka observed from PMU plots due to R-phase CT blast at 220kV Vizag switching station Page 22 of 52

204 Annexure-VIII After tripping of 400/220kV Gazuwaka ICTs, load shifted to 400/220kvVKalpakka ICTs and loading increased from 570MW to 860MW. 220kV Kalpakka Dairy Farm feeders 1&2 tripped on jumper snapped due to overloading. 220kV Kalpakka Dairy Farm feeder-1 tripped at 16:14 hrs due to B-phase jumper cut Page 23 of kV Kalpakka Dairy Farm feeder-2 also tripped at 16:26 Hrs due to B-phase jumper cut

205 8. Complete outage of 330kV Sedam Station of KPTCL at 17:59 hrs on Annexure-VIII Triggering Incident: R-Y-E phase fault in 220kV Sedam-Shahpur line. Antecedent condition All lines and ICT s at 220kV Sedam station were on 220kV Bus-2 of due to Bus-1 selector jumper snap in Bus Coupler Bay. 220kV Sedam-RTPS lines and 220kV Sedam tandur lines tripped on distance protection. Load loss as reported : 44 MW. Page 24 of 52

206 Annexure-VIII Zone-2 220kV Sedam Shahpur tripped from Shahpur end and did not trip from Sedam due to PT fuse fail At RTPS, Sedam line-1 - DPR, Zone-2,RY fault, 2.6kA, 2.2KA Sedam line-2 DPR, Zone-3, RYBN fault, 2.3kA At Tandoor Sedam line tripped on DPR, Zone-3. Remedial measures taken: R phase PT found burn at PT terminal and the same was replaced on Action has been taken to enable non directional OC/EF protection to get activated automatically in the event of PT fuse fail condition. Page 25 of 52

207 PMU Data Plots: Annexure-VIII Fault clearing time ms Page 26 of 52

208 9. Complete Outage of North Kerala and Tripping of 400/220kV Kozhikode ICTs at 17:15hrs on Annexure-VIII ICT-3 Idle charged from 220kV side Antecedent condition Bus-1 under shutdown for bus stability test for integration of new ICT /220kV ICT-2 (315MVA+315MVA) tripped due to LBB operation while carrying out stability checks and current injection in bus bay of 452 CB and trip extended to 552 CB. 400/220kV ICT-1 tripped on HV directional overcurrent. Page 27 of 52

209 Annexure-VIII Tripping of three ICTs resulted in loss of 600MW from 400kV Kozhikode substation. 220kV Madakkathara-Areakode and 220kV Madakkathara- Shornur lines and they both tripped on backup over current protection. Tripping of these 220kV resulted in the complete outage of Northern Kerala. 400kv Mysore-Kozhikode line-2 tripped on overvoltage stg-1 Page 28 of 52

210 Annexure-VIII Fault was not observed during the event Overvoltage was observed in the 400kV Kozhikode Mysore line-1 and 2 after the tripping of ICT#1. Page 29 of 52

211 1. Tripping of HVDC Talcher-Kolar Pole-1 in March 2018 Annexure-VIII Date & time of tripping at 16:15 Hrs at 09:38 Hrs at 15:12 hrs at 13:31 hrs Talcher Kolar Antecedent flow on Bipole Clogging of the mechanical filter of Pole-1 valve cooling system External protection operation trip mal operation of DC protection system DC protection system trip Details Emergency switch off 1500 MW Pole 2 went into metallic return mode. SPS operated. load relief MW Bipolar power Emergency switch off 2300 MW Pole 2 went into metallic return mode. SPS operated. load relief MW Emergency switch off 1400 MW Pole 2 went into metallic return mode. No SPS operation, At 20:28 hrs Pole-2 went to ground return mode due to sequence failure with a power flow ~ 140MW Emergency switch off 1500 MW Pole 2 went into metallic return mode. No SPS operation Page 30 of 52

212 Annexure-VIII Page 31 of 52

213 Annexure-VIII 2. Tripping of 400/220kV ICT-1 at N Sagar at 16:43 hrs on As reported, 400/220kV ICT-1 at N sagar got tripped due operation of Pressure Relief Device. Findings and remedial measures taken may be apprised at the forum. Page 32 of 52

214 Annexure-VIII 3. Tripping of 765kV KURNOOL-THIRUVALAM line-1 at 11:08 hrs on As reported, Direct trip received at Kurnool due to 705 CB gas compartment lockout at Tiruvalam end. Findings and remedial measures taken may be furnished. Page 33 of 52

215 Annexure-VIII 4. Bus Shutdown at 220kV Guttur substation at 06:41 hrs on NARENDRA HAVERI GUTTUR JOGIHALLI W NEELAGUNDA ITTAGI SHIMOGA DAVANAGERE HONNALI CHITRADURGA THALAK SHIRALAKOPPA RANEBENNUR Antecedent conditions : 220kV Guttur-Haveri Line-2 was under LC due to line fault. 220kV Haveri-Narendra line-1 &2 were under LC due to line fault. Haveri Sub station was radially fed through 220kV Guttur Haveri Line-1. Single bus operation at Guttur - Problem with 220kV side breaker of ICT-1 & Bus-II CVT. Page 34 of 52

216 Annexure-VIII NARENDRA HAVERI DPR; RN; Z1 GUTTUR JOGIHALLI NEELAGUNDA W ITTAGI SHIMOGA DAVANAGERE HONNALI CHITRADURGA THALAK SHIRALAKOPPA RANEBENNUR Details from KPTCL report : 220kV Guttur Haveri Line-1 tripped at Guttur end on DPR,Zone-1, RN Fault, km suspected due to fault Busbar protection got operated at Guttur during fault in 220kV Guttur-Haveri line-1 - Dead zone protection Operation of Bus Bar Protection caused complete outage of Guttur Sub Station on 220kV side. Remedial measures : Modification to be done in PSL logic of Bus bar relay. Feedback of OEM M/s GE is sought for making necessary modification in the PSL logic, till such time Dead zone protection has been disabled temporarily in the newly commissioned 220kV bus bar Protection scheme at Guttur. Page 35 of 52

217 Page 36 of 52 Annexure-VIII

218 5. Multiple Tripping at 220kV Sharavathy Station of KPCL at 22:05hrs on Annexure-VIII Antecedent conditions: 220 KV South bus : unit nos 1, 2, 3, 4, 5, 6, 7 and 220 KV lines Shimoga 1,3 &4 Talaguppa 1,2 and 3 and Belligavi(Shiralakoppa) lines 220 KV North bus : Unit Nos 8, 9,10 and 220 KV Sirsi 1 &2 lines 220kV Sharavathy- Sirsi -1 was under LC due to line fault. Page 37 of 52

219 Annexure-VIII Unit no-8 was being shifted from Northwest to 220 KV South West section of south bus Breaker of unit no-8 was opened and without opening the 220 KV North West bus isolator the 220 KV South West bus isolator was closed 220 KV buses were tied together without synchronizing resulting in operation of bus bar protection. Generation Loss: 234 MW Page 38 of 52

220 Annexure-VIII Operation of bus bar protection has resulted in tripping of 220KV SS1, SS2, S3, S4 & ST2 and unit are 6, 7, 8, 9 & 10 connected to faulty North West and South West buses. 220 KV Sharavathy-Talaguppa line-1&3 tripped at Talaguppa end on DPR in Zone-1 Generation Loss: 234 MW Page 39 of 52

221 Annexure-VIII Voltage dip was observed in R and Y phases of 400kV Kolar bus during the event. Page 40 of 52

222 6. Multiple Tripping at 400kV Guttur Substation at 08:24 Hrs on Annexure-VIII Circuit breaker of 400kV Kaiga - Guttur ckt-1 was in lockout condition due to low oil pressure. DT signal was received continuously due to mal operation of PLCC channel and initiated LBB operation resulting in tripping of elements connected to 400kV Bus kV Guttur-Narendra-1-400kV Guttur Hiriyur-2-400kV Guttur- JSW - 400kV Guttur Munirabad - 400/220kV ICT-2 at Guttur Page 41 of 52

223 PMU Data Plots: Annexure-VIII Page 42 of 52

224 7. Multiple tripping at 400kV Pavagada substation at 14:18 hrs on Annexure-VIII Antecedent condition : Pavagada station : Tumkur Pavagada Line-1 was charged from Tumkur end at 12:41Hrs and synchronized at Pavagada end at 12:44Hrs. Tumkur station Kudgi line-2, Bidadi D/C Lines, Tumkur 3&4 DC lines were in service. Kudgi-1 line was out of service due to system condition Page 43 of 52

225 Annexure-VIII Zone-2, Y-N OV Stg-2 DEF LV E/F Triggering incident: Y- phase to earth fault during charging of 400kV Pavagada- Tumkur line-2 from Tumkur end. Distance protection, SOTF or DEF protection did not operate for 400kV Pavagada-Tumkur line-2 at Tumkur end. Distance zone-2 and DEF not operated for 400kV Pavagada-Tumkur line-3&4 Fault was cleared in zone-2, DEF at remote ends and Pavagada ICT s backup earth fault protection. Over-voltage protection stage-2 operated for 400kV Pavagada-Tumkur line-2 at Tumkur end (2.145sec after occurrence of fault ). Page 44 of 52

226 Annexure-VIII PMU Data Plots: 2.12 sec Dip in Y-phase voltage was observed for 2.12 sec indicating a delayed clearance of fault. Page 45 of 52

227 Observation from DR 400kV Pavagada-Tumkur line-1 Pavagada Zone-2 Y-G Start 14:18: hrs Zone-2 Y-G trip 14:18: hrs Grp- A/B optd Tumkur No tripping Annexure-VIII Pavagada Tumkur Line-1 Tripped from Pavagada end on Zone 2 Y-G 400kV Kudgi-Tumkur line-1 Kudgi Tumkur DEF Start 14:18: hrs DT receive 14:18: A/B optd 14:18: hrs Grp A/B optd 400kV Pavagada Tumkur Line-1 tripped on operation of DEF protection at Kudgi and direct trip receive was received at Tumkur end Tripping of ICT 1 at Pavagada : ICT-1 67N pickup - 14:18: hrs 67N trip - 14:18: hrs Tripped on LV side Earth Fault Protection (1.964s) ICT-2 67N pickup - 14:18: hrs 67N trip - 14:18: hrs LV side Earth Fault Protection (1.175s) Page 46 of 52

228 Annexure-VIII Points for discussion : Non-operation of SOTF and DEF protection at Tumkur end for 400kV Pavagada-Tumkur line-2 : Main-1 & Main-2 relays the SOTF setting is 2A with CB manual close. However there was only 3.7 ka current during the fault. Non-operation of distance and DEF protection at Pavagada end for 400kV Pavagada-Tumkur line-3&4 Main-1 and Main-2 distance protection relays were not getting the neutral current for proper detection of zone fault. Discrepancy in the mutual compensation circuit which was not terminated as per scheme. Zone Settings of Line-1&2 (Pavagada end) Line length KM Z1 : Ohms, Z2 : 50 Ohms, td:500ms Z3 : 84.2 Ohms, Td:1.5s Zone Settings of Line-3&4 (Pavagada end) Line length KM Z1 : 14.8 Ohms Z2 : Ohms, Td:500 ms Z3 : 84.2 Ohms, Td:1.5s Page 47 of 52

229 Annexure-VIII 8. Multiple tripping at 220kV Trichur (Madakathara) substation at 21:26 Hrs on Triggering Incident: CT flashover of Y-phase of the bus sectionalizer CT. Bus bar protection operated and all the elements connected to Bus-1A and Bus-1B tripped. 220kV side of 400/220kV ICT-2 and ICT-3 also tripped. Load Loss as reported: 250MW Page 48 of 52