Record of Revision. Sr.No Revision. Technical Guidelines for Grid Tied Distributed Generation (Solar). i

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2 Record of Revision Sr.No Revision Item/Clause No Nature of Change Approved By No 1 R1 D Table Addition DSP/AM 2 R1 E Addition DSP/AM 3 R1 I.VIII Added DSP/AM 4 R1 Anexxure1.1 to 1.8 Added and Edited DSP/AM 5 R1 Annexure 2.1 to 2.7 Added and Edited DSP/AM 6 R1 Annexure5.8 to 5.24 & Note Added and Edited DSP/AM 7 R1 Annexure6 Addition DSP/AM 8 R1 Annexure-3.1 To 3.5 Addition and Edited DSP/AM 9 R1 Annexure-4 (10 th Count) Deletion DSP/AM 10 R1 Annexure-7 Addition DSP/AM Technical Guidelines for Grid Tied Distributed Generation (Solar). i

3 Content: Sr. No. Description Page No A Introduction 1 B Salient Stipulations in MERC Reg C Codes and Standards 2 D E IEEE 519 Harmonic Standards and IEC Flicker Standards Technical requirement of the Grid Connected Roof Top Solar F Equipment Features 6 i Solar PV modules and array 6 ii Module mounting structure 7 iii Power Conditioning Unit/Inverter 7 iv ACDB (LT Panel) 8 v DC & AC Switches 8 vi Cables and installation accessories 8 vii Earthing and lightning protection 8 G Preliminary Site Visit Check List 9 H Pre Commissioning Check List 9 I Safety 9 Annexure 1: SLD for < 8 kw, single-phase 12 Annexure 2: SLD for > 8 kw but < 150 kw, 3-phase 13 Annexure 3: SLD for > 150 kw, 3-phase 15 Annexure 4: Preliminary Survey Check-Sheet 16 Annexure 5: Commissioning Check-Sheet 17 Annexure 6: Dimensions of equipment 17 Annexure---7: Sample Documents Technical Guidelines for Grid Tied Distributed Generation (Solar). ii

4 List of Tables Sr. No. Description Page No 1 Codes and Standards 2 2 Harmonic Voltage Distortion Limits in Percent of Nominal Fundamental Frequency Voltage ( IEEE Standard , table 11.1) 3 Basis for Harmonic Current Limits 2 4 Harmonic Current Distortion limits (I h ) in percent of I L 2 5 Flicker standard IEC Grid Connectivity technical requirement Technical Guidelines for Grid Tied Distributed Generation (Solar). iii

5 List of Figures Sr. No. Description Page No 1 Standard Shutdown Procedure Signage content 10 2 Specification on the Meter Cabin 11 3 Signage on/near the components in the meter cabin 11 4 Signage near Inverter 11 A.1 A.2 A.3 Typical SLD of grid Connected Roof Top PV with capacity below 8kW Typical SLD for grid Connected Roof Top PV with capacity above 8kW and below 150kW Typical SLD grid Connected Roof Top PV with capacity above 150kW Technical Guidelines for Grid Tied Distributed Generation (Solar). iv

6 A. Introduction The depleting sources of fossil fuels, sharp increase in power tariffs to industrialists due to heavy subsidies to Agriculture, very high T&D losses, decrease in reliability of power required, leads one to think of the alternative soco-economic, efficient, environment friendly and reliable sources of energies. The Power crises in Maharashtra is increasing day by day with a peak demand shortfall of 2000 MW. Maharashtra is having a total installed capacity of MW (including Central sector share) of centralized power plants and 623 MW of decentralized non-conventional power plants. Still there is a large potential in the non-conventional energy sources sector which can be tapped. This distributed potential can be harnessed to meet increasing power demand and to improve the techno-economic scenario. Setting up of large solar power projects requires huge land space whereas availability of land is a major constraint in Mumbai city limits. The prevailing scenario of declining trend in solar prices and increasing retail power tariff across most consumer categories like residential, commercial and industrial consumers would encourage consumers to install roof top solar systems.. Therefore, roof top solar is set to witness appreciable scaling of capacities in Mumbai. With the new regulation (Net Metering for Roof-top Solar PV Systems Regulations 2015) issued by MERC, RInfra has decided to issue Technical policy document for NET-metering and LT connectivity. B. Salient Stipulations in MERC (Net Metering for Roof-top Solar PV Systems) Regulations, 2015 at a Glance 1. Shall be permitted on first come first serve basis (Cl. 3.1) 2. Cumulative Capacity of all Roof-top Solar PV (RT-SPV) Systems under Net Metering connected to a particular DT of RInfra shall not exceed 40 % of its Capacity (Cl.4.1) 3. RInfra shall provide information on Website regarding Solar capacity available against each DT within 3 months of this notification (Cl. 4.2) 4. Roof-top Solar PV System Capacity shall not exceed the Consumer s Contract Demand (in kva) or Sanctioned Load (in kw) (Cl. 5.1) 5. AC Voltage level of Solar Injection shall be as below: (Cl. 5.2) a. 230 / 240 V (single-phase) for capacity less than 8 kw / 40 Amp b. 400 / 415 V (three-phase) for cap. less than 150 kw /187 kva c. 11 kv and above for cap. above 150 kw / 187 kva 6. HT (11 kv & above) Consumers may inject at LT Bus-bar, provided that Net Meter is installed on the HT side of Transformer.(Cl.5.4) Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 1 of 24

7 7. Consumer may install RT-SPV with or without Battery back-up provided that if battery is present, separate back-up wiring to prevent the battery Power from flowing into the RInfra Grid in absence of Grid supply. (Cl.6.2) 8. Consumer shall provide adequate protection for Islanding the RT-SPV from RInfra Network in the event of grid supply failure (Cl.6.4) 9. RInfra shall ensure that the inter-connection of the RT-SPV System with it s Network conforms to Specifications, Standards and other provisions specified in the CEA (Technical Standard for Connectivity of the Distributed Generation Resources) Regulations, 2013, the CEA (Measures Relating to Safety & Electric Supply) Regulations 2010 and the MERC (State Grid Code) Regulations 2006 or as may be specified in future.(cl. 6.1) 10. Metering arrangement shall have Net Meter (procured and installed by RInfra) and also Solar Generation Meter (procured & installed by Consumer or RInfra, who desires that such energy be counted towards meeting its RPO) (Cl. 7) C. Codes and Standards The installation shall meet the requirements of Indian Electricity rules, CEA and MERC Guidelines for grid connectivity. The materials, equipment and methods used in the installation shall conform to the latest edition of IS and IEC standards, and other national and international applicable standards including the following. If standard other than IS/IEC are used in design, manufacturing and testing, a copy of the same in English shall be submitted. IEEE IEC Part 1-2 IEEE 519 IEC IEC IEC Recommended Practice for Utility Interface of Photovoltaic (PV) Systems Requirements for construction & requirements for testing, for safety qualification Power Quality Standards Flicker Standard Photovoltaic systems - Power conditioners - Procedure for measuring efficiency Balance-of-system components for photovoltaic systems - Design qualification natural environments EMC EN , EN , EN , EN , EN IEC Safety of power converters for use in photovoltaic power systems - Part 2: Particular requirements for inverters IEC IEC / IS IS IEC IS 1554 IS 2551 Test procedure of islanding prevention measures for utility interconnected photovoltaic inverters Low voltage fuses Testing, Evaluation, Installation and Maintenance of ac Electricity Meters - Code of Practice. Low Voltage Switchgear and Control-gear PVC Insulated Cable for working voltages up to and including 1100V Signage Requirement Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 2 of 24

8 IS 3043 Earthing Standards IEC Lightning Protection IEC Operation, Maintenance and Documentation IS 732 Wiring Rules CEA Technical Standards for connection to grid 2007 ( amendment 2013) CEA-2013 Technical standard for Connectivity of the Distributed generation resources regulation 2013 MERC Maharashtra Electricity Regulatory Commission ( Net Metering for Roof Top Solar Phot0 Voltaic Systems) Regulation 2013 Table 1: Codes and Standards D. IEEE 519 Harmonic Standards and IEC Flicker Standards Bus Voltage at PCC Vn (kv) Individual Harmonic Voltage Total Voltage Distortion, THDVn Distortion (%) (%) Vn Vn Vn > Table 2: Harmonic Voltage Distortion Limits in Percent of Nominal Fundamental Frequency Voltage ( IEEE Standard , table 11.1) Short Circuit ratio at PCC Max individual frequency voltage harmonic (%) Related Assumption Dedicated system Large customer A few relatively large customer medium size customer Many small customer Table 3 Basis for Harmonic Current Limits Isc/I L h<11 11 h h h h TDD < > Table 4: Harmonic Current Distortion limits (I h ) in percent of I L Note: I L : is fundamental component of the maximum demand load current Isc: Short circuit current at PCC Ih: Magnitude of individual harmonic component (rms amps) Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 3 of 24

9 Value Observation Interval Limiting Value Pst (Short term flicker "perceptibility" value) 10 min 1.0 Plt (Long term flicker "perceptibility" value) 2 h 0.65 Table 5: Flicker standard IEC E. Technical requirement of the Grid Connected Roof Top Solar Sr.No Parameter Reference Requirement Overall State Distribution/Supply 1 conditions of Reference to State Distribution Code Code service Overall Grid 2 CEA Regulation 2010 Reference to regulations Standards 3 Equipment BIS / IEC / IEEE Reference to standards 4 Meters Central Electricity authority (Installation & operation of meters) Regulation Safety and supply Harmonic Requirements Harmonic Current 7 Synchronization 8 Voltage 9 Flicker 10 Frequency 11 DC injection Central Electricity authority (measure for safety and electricity supply) Regulation 2010 IEEE 519, CEA (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations 2013 CEA (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations 2013 CEA (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations 2013 CEA (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations 2013 CEA (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations 2013 CEA (Technical Standards for Connectivity of the Reference to regulations and additional conditions issued by the Commission. Reference to regulations Harmonic current Injections from a generating station shall not exceed the limits specified in IEEE 519 (indicated in Section D) Photovoltaic system must be equipped with a grid frequency synchronization device. Every time the generating station is synchronized to the electricity System, It shall not cause voltage fluctuation greater than +/- 5% at point of connection. The voltage-operating window should minimize nuisance tripping and should be lie in operating range 80% to 110% of the nominal connected voltage. Beyond a clearing time of 2 second, the photovoltaic system must isolate itself from the grid. Operation of Photovoltaic system should not cause voltage flicker in excess of the limits stated in IEC standards or other equivalent Indian standards, if any. (indicated In Section C) When the Distribution system frequency deviates outside the specified conditions (50.5 Hz on upper side and 47.5 Hz on Lower side), There should be Over and under frequency trip Functions with a clearing time of 0.2 seconds. Photovoltaic system should not inject DC current more than 0.5% of full rated output. Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 4 of 24

10 12 Power Factor Islanding and Disconnection Overload and Overheat Paralleling Device Capacity of Plant Connection Voltage Level 18 Reclosing 19 Manual Isolating Switch between grid and Distributed generation 20 Test Certificate 21 Schematic Diagrams Distributed Generation Resources) Regulations 2013 IEC 61727/ CEA (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations 2013 CEA (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations 2013 CEA (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations 2013 CEA (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations 2013 MERC regulation 2015 MERC Regulation 2015 clause 5.2 CEA (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations 2013 CEA (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations 2013 CEA (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations 2013 (clause 10) CEA (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations 2013 While the output of the inverter is greater than 50%,it should operate in the range of 0.9 lag and lead (IEC)./ The inverter should dynamically operate in the range of 0.95 lag- to lead(cea) The photovoltaic system in the event of fault, voltage or frequency variation must island/disconnect itself as per IEC standard in stipulated period. The inverter should have the facility to automatically switch off in case of overload or overheating and should restart when normal conditions are restored Paralleling device of photovoltaic system shall be capable of withstanding 220% Of the normal voltage at the interconnection point. The total capacity of Solar Power connected to the distribution Transformer should be below 40% of Utility transformer capacity. Moreover, individual Solar Plant capacity should not exceed its customers approved contract demand Solar Capacity below 8KW can be injected at single phase. Moreover above 8kW and below 150kW it should be at three Phase 415 Volt. However above 150kW and below 1MW it should be at 415 V, while net meter will be installed at 11kV. The Reconnection of the Distributed Generation to Grid in the event of disconnection prior, should happen only if frequency and voltage are stable for atleast 1 minute. Capable of being Locked in open position, May not be rated for Load Break nor may have feature of over current protection. It should be reached quickly and conveniently. Should be located at height of at least 2.44 meter above the ground level. Inspection, test, Calibration and Maintenance prior to connection shall be done by applicant in consultation with the appropriate licensee is required. The applicant shall prepare Single Line Schematic Diagram in respect of its system facility and make the same available to the appropriate licensee Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 5 of 24

11 22 Power Quality Measurement 23 Protection Solar meter Location Statutory Approval Certification of Equipments Voltage Standards (clause 9) CEA (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations 2013 (clause 8.2) CEA (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations 2013 (clause 7.a,b) MERC Regulation 2015 clause 7.8, Annexure and MERC Regulation 2015 clause Annexure -3.4 MERC Regulation 2015 clause Annexure-3.1 Maharashtra Electricity Regulation Committee Standards of Performance of Distribution Licensees. Table 6: Grid Connectivity technical requirement DC current injection, Flicker and harmonic shall be done with calibrated meters before commissioning of the project and once a year in presence of parties concerned and indicative date shall be communicated. Circuit Breakers or other interrupting equipment shall be suitable for their indented application with the capability of interrupting the maximum available fault current. The DG (distributed generation) and associated equipment shall be designed so that the failure of any single device or component shall not potentially compromise the safety and reliability of the system. The Net Meter and the Solar Generation Meter shall be installed at such locations in the premises of the Eligible Consumer as would enable easy access to the Distribution Licensee for meter reading. Annexure-3 The Licensee shall specify the interface/inter-connection point and metering point. The uni-directional and bidirectional or pair of meters shall be fixed in separate meter boxes in the same proximity. The Eligible Consumer shall obtain any statutory approvals and clearances that may be required, such as from the Electrical Inspector or the municipal or other authorities, before connecting the Roof-top Solar PV System to the distribution Network. The equipment connected to the Licensee s Distribution System shall be compliant with relevant International (IEEE/IEC) or Indian Standards (BIS), as the case may be, and the installation of electrical equipment shall comply with the requirements specified by the Central Electricity Authority regarding safety and electricity supply. The Grid voltage maximum limit is 250 Volt (i.e. 433 Volt) and ± 6% variation in voltage. Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 6 of 24

12 F. Equipment Features I. Solar PV modules and array 1. Crystalline PV modules type. 2. The mechanical structure to withstand gusts of wind / cyclonic wind up to 120km/hr. 3. The offered modules conform to the latest edition of any of the following IEC/ equivalent BIS Standards for PV module design qualification and type approval: - Crystalline Silicon Terrestrial PV Modules : IEC 61215/IS PV modules also qualify Salt Mist Corrosion Testing as per IEC61701/IS PV modules used in solar power plants warranted for output wattage, which should not be less than 90% at the end of 10 years and 80% at the end of 25 years. II. Module mounting structure The PV modules will be mounted on fixed metallic structures of adequate strength and appropriate design, which can withstand load of modules and high wind velocities up to 120 km per hour. The support structure used in the power plants will be hot dip Galvanized Iron (G.I). Note: Point F.I and F.II are guidelines for Applicant, it is not RInfra requirement III. Power Conditioning Unit/Inverter 1. The Inverter shall have internal protection arrangement against any sustained fault in the feeder line and against lightning in the feeder line 2. The inverter shall have the required protection arrangements against earth leakage faults 3. DC lines shall have suitably rated isolators to allow safe start up and shut down of the system 4. Circuit breakers used in the DC lines must be rated suitably 5. The inverter shall preferably have provision for galvanic isolation. 6. Each solid state electronic device shall have to be protected to ensure long life of the inverter as well as smooth functioning of the inverter 7. The inverter shall include appropriate self protective and self diagnostic feature to protect itself and the PV array from damage in the event of inverter component failure or from parameters beyond the inverter s safe operating range due to internal or external causes. 8. Maximum Power tracking facility should be present.. 9. Protection against I. Over current II. Sync loss III. Over temp. IV. DC bus over voltage. Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 7 of 24

13 V. Cooling Fan failure(if provided) VI. Grid Under/Over voltage and frequency 10. Dynamic Reactive Power Support to be present in inverter. 11. Integrated protection in the DC and three phase system. 12. Ground Fault and Arc protection should be there for DC (PV array). Moreover, insulation monitoring of PV array should be there. 13. AC and DC side disconnect switch / MCCB /ACB should be there for protection/isolation. 14. Power regulation in the event of thermal failure. 15. The Inverter should have functionally to limit the fault current contribution from the Distributed generation to its full load limit. The protection equipments should be designed to protect against system abnormality. IV. ACDB (LT Panel) 1. All outdoor devices/equipment to be IP65 as minimum V. DC & AC Switches 1. DC SIDE a. FUSE /MCB of suitable rating should be provided for array input b. The Input of the Inverter should have DC isolation switch. 2. AC SIDE a. MCB/MCCB /ACB of suitable rating shall be provided for connection and disconnection of Inverter & load. b. Isolating switches (No load Break) should be provided at incoming of the meter cabin. c. Isolating switches should be provided at the output of the inverter. d. The Phase and Earth fault protection embedded switches should be provided at output of the inverter and also in the meter cabins corresponding to solar circuit. VI. Cables and installation accessories The size of the cables between array interconnections, array to junction boxes, junction box to PCU, PCU to AC Distribution Box etc shall be so selected to keep the voltage drop and losses to the minimum. Permissible Wire Drop on DC side shall be <= 2% All cabling on the roof to be provided with suitable mechanical protection (i.e. cable trays with top cover or metal conduits). PVC conduits or pipes are not be used. To minimize the impact of the voltage rise variables such as inverter location, inverter output-circuit length and conductor size are to be selected accordingly. Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 8 of 24

14 VII. Earthing and lightning protection Earthing: The array structure of the PV yard shall be grounded properly using adequate number of earthing kits. All metal casing or shielding of the power plants shall be thoroughly grounded to ensure safety of the solar power plants. Lightning: The PV plants shall be provided with lightning & over voltage protection. Lightning protection to be as per Indian or relevant IEC standard. Surge Protection Device Type 1 and 2 to be provided for lightning and surge protection respectively. G. Preliminary Site Visit Check List As given in Annexure 4 H. Pre-Commissioning Check List As given in Annexure - 5 I. Safety I. The equipment connected to the Licensee s Distribution System shall be compliant with relevant International (IEEE/IEC) or Indian Standards (BIS), as the case may be, and the installation of electrical equipment shall comply with the requirements specified by the Central Electricity Authority regarding safety and electricity supply. II. The design, installation, maintenance and operation of the Roof-top Solar PV System shall be undertaken in a manner conducive to the safety of the Roof-top Solar PV System as well as the Licensee s Network. III. If, at any time, the Licensee determines that the Eligible Consumer s Roof-top Solar PV System is causing or may cause damage to and/or results in the Licensee s other consumers or its assets, the Eligible Consumer shall disconnect the Roof-top Solar PV System from the distribution Network upon direction from the Licensee, and shall undertake corrective measures at his own expense prior to re-connection. IV. The Licensee shall not be responsible for any accident resulting in injury to human beings or animals or damage to property that may occur due to back- feeding from the Roof-top Solar PV System when the grid supply is off. The Licensee may disconnect the installation at any time in the event of such exigencies to prevent such accident. Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 9 of 24

15 V. The Isolating switches should be provided at output and the input of the Inverter. Moreover, protection switches as indicated in Annexure should have Phase and earth Fault Protection. VI. The Meter cabin and corresponding switchgear should be easily accessible. VII. The Body Earthing of each and every equipment should be followed as per standards. (Atleast at two separate points for each equipment viz. solar panel, inverter etc should be done from two separate connected earth pits). VIII. Standard shutdown procedure to be located close to the inverter. Each circuit switches should be indicated by the red colored signage (Aluminum plate). Fig 1: Standard Shutdown Procedure Near Inverter (Laminated Paper fixed to Wall- Font size 16 Arial) Note: All Signage should be engraved (red color letter and height 7mm) on Aluminum plate with rivet for fitting at relevant locations. Points I-IV Refer MERC Regulation Annexure-3 clause Date Of Commissioning 2. Contact Number responsible for O&M of Plant 3. Peak Plant Capacity (KW) 4. No of Inverters with each rating 5. Inverter AC voltage and current 6. Inverter DC input Voltage and current 7. Short Circuit current fed by Inverter during fault 8. No of PV Panels 9. No of Strings 10. No of PV Panel in each Strings 11. Voc of a PV Panel 12. Isc of a PV panel Fig 2: Specification on the Meter Cabin (Laminated Paper and Fixed in meter cabin-font size 16 Arial) Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 10 of 24

16 CAUTION SOLAR ELECTRIC SYSTEM LOAD SWITCH SOLAR SWITCH NET SWITCH RINFRA SWITCH SOLAR METER NET METER Fig 3: Signage to be fitted near the components in the meter cabin INVERTER AC DISCONNECT SWITCH INVERTER DC DISCONNECT SWITCH Fig 4: Signage near Inverter Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 11 of 24

17 Annexure - 1 SLD are categorized accordingly to Generating capacity of PV(Photo Voltaic) plant and voltage level (Refer: MERC regulation clause 5.2). Case1:: Typical SLD of grid Connected Roof Top PV with capacity below 8kW single-phase DC Solar meter B A Rinfra MCB/Fuse Net Meter Grid Solar Inverter Surge protection Load Load Fig A.1: Typical SLD of grid Connected Roof Top PV with capacity below 8kW 1. The solar circuit switch B should have provision for Phase and earth fault protection. 2. On DC input side and AC output side of the Inverter, should have isolation switch. 3. Rinfra MCB will be of same rating as per existing policy guidelines. 4. The Inverter AC side (as indicated in SLD) and DC side (after DC connector box but input of inverter) should have isolation switch. 5. If applicant needs to operate in islanded mode during grid failure. The provision should be made by the customer to automatically trip switch A (shown in SLD) to avoid flow of power in to the grid/utility. Otherwise, customer should make provision for manual isolation switch A. 6. The separate meter boxes should be there to accommodate solar meter and bidirectional meter. Moreover, both meters should be in close proximity. The Net Meter and the Solar Generation Meter shall be installed at such locations in the premises of the Eligible Consumer as would enable easy access to the Distribution Licensee for meter reading. 7. Rating of all switches viz inverter, consumer and switch A will be selected based upon rating/ capacity of load and generation. It shall be procured by customers only. 8. In case of multiple injections from single-phase DG connected to the same upstream DT, RInfra shall ensure that they are on alternate phases to prevent undue Voltage imbalance. Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 12 of 24

18 Annexure 2 Case-2 :: Typical SLD for grid Connected Roof Top PV with capacity above 8kW and below 150kW for Three-phase Solar Panel Inverter Switch Solar Inverter ACDB (AC Distribution Board) Isolating Transformer Star /Delta Switch Solar Meter B A Rinfra Switch Net Meter DC fuse Inverter Surge protection Consumer ACDB Load Switch Load Fig A.2: Typical SLD for grid Connected Roof Top PV with capacity above 8kW and below 150kW 1. Rinfra Switch should be as per our existing policy: 2. The Inverter AC side (as indicated in SLD) and DC side (after DC connector box but input of inverter) should have isolation switch. 3. The isolating Transformer (Galvanic Isolation) is advisable in case of load above 8KW solar generation. 9. If applicant needs to operate in islanded mode during grid failure. The provision should be made by the customer to automatically trip switch A (shown in SLD) to avoid flow of power in to the grid/utility. Otherwise, customer should make provision for manual isolation switch A. Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 13 of 24

19 4. The size of the ACDB should be able to accommodate the switch A, and B (along with manual isolation switch, as per MERC Regulation). The ACDB should be provided by the applicant. 5. The Net Meter and the Solar Generation Meter shall be installed at such locations in the premises of the Eligible Consumer as would enable easy access to the Distribution Licensee for meter reading. Moreover they should be in separate boxes and in close proximity. 6. If Isolation transformer is not there, then corresponding solar side transformer switch may not be present. 7. Rating of all switches viz inverter, consumer and switch A will be selected based upon rating capacity of load and generation. Moreover, the inverter switch and switch A, B should have earth fault and phase protection i.e 50-50N and 51-51N relay. Note: N Instantaneous Phase and earth fault relay N Over current Phase and Earth fault relay. Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 14 of 24

20 Annexure 3 Case 3:: Typical SLD grid Connected Roof Top PV with capacity above 150kW Three-phase Solar Panel DC fuse Inverter ACB 50-50N and 51-51N Two winding Isolating 415/415 Volt Delta/Star ACB 50-50N and 51-51N Surge protection Solar meter ACDB ACB 50-50N and 51-51N ACB 50-50N and 51-51N 0.415/11kV Star/Delta Load A Net meter Consumer 11kV Breaker 50-50N and 51-51N RInfra RMU Fig A.3:; Typical SLD grid Connected Roof Top PV with capacity above 150kW 1. Rinfra 11kV Switchgear should be as per our existing policy: 2. The Inverter AC (as indicated in SLD) and DC side (after DC connector box but input of inverter) should have isolation switch. 3. Inverter Main SFU/MCCB (switch B) should be in accordance with total capacity of Solar generation (i.e. it may be 110% of the full load rating of the inverter). The ACB should have with 50-50N and 51-51N protection relay. Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 15 of 24

21 4. If applicant needs to operate in islanded mode during grid failure. The provision should be made by the customer to automatically trip switch A (shown in SLD) to avoid flow of power in to the grid/utility. 5. The Net Meter and the Solar Generation Meter shall be installed at such locations in the premises of the Eligible Consumer as would enable easy access to the Distribution Licensee for meter reading. Moreover they should be in separate boxes and in close proximity. Annexure 4 Preliminary Site Survey Check List (after Application) Sr.No Description Y/N/Value Remarks 1 Capacity of the proposed PV Plant 2 Contract Demand (Sanctioned Load) of Consumer 3 Existing Network SLD details up to the Consumers Point of Supply and Last mile connectivity. The SLD should Indicate existing protection equipment (Fuse Rating, Voltage, MCB/MCCB, ACB rating), cable size, transformer size and loading of equipments uptil Point of supply i.e. Upstream network 4 Existing protection (MCB/Fuse/Breaker) details and SLD after Meter of Consumer 5 AC Voltage Level at which connectivity is sought 6 Rated output AC Voltage of the proposed Solar Plant (230,415 Volt). 7 Available cumulative capacity of relevant DT and substation Name Space availability/feasibility to commission new 8 Meter cabin /Panel accommodating Net meter, Solar Meter and Isolating switches. Consumer advised to ensure readiness of the meter cabin of adequate size to accommodate 9 equipment as per relevant SLD along with work completion report (Plant Setup Intimation). Moreover, intimation to furnish the documents prior to commissioning test. Note: Preliminary Site Survey Activity to be done by Divisional Load remark and Business team Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 16 of 24

22 Commissioning Check List Annexure - 5 Sr. Description Y/N/Value Remarks No 1 New Meter Cabin of requisite dimensions ready 2 Automation-compliant motorized Islanding Switch (A as per concept SLD) is installed. (In case Anti-islanding is not there or for Island operation with Battery or Diesel Generator is planned by applicant). 3 Protection switch B (as per SLD) installed is having Phase & Earth Fault protection 4 The switches are there as per SLD shown in Annexure 1,2 and 3 5 Solar /Net Meter is installed 6 Danger Board/Signage as Shown in Section I are incorporated at suitable locations. 7 Voltage magnitude at point of connection with grid. 230V/420 V 8 Full Load output Power of Plant in KW 9 AC and DC side manual isolating switches located near inverter. 10 Surge Protection (Type-II) device is installed on AC/DC side of Inverter 11 Voltage magnitude at the output of inverter 230V/420V 12 The DC/AC Ground Fault monitoring Feature in Inverter 13 Is Isolation Transformer (if applicable) installed -- to avoid DC current injection, harmonic injection and protect inverter from grid disturbances. Under (80%) /Over (110%) Voltage and Under (47.5)/Over (50.5) frequency protection for 14 Islanding is inbuilt in Inverter with minimum clearing time 2 sec(for voltage) and 0.2 sec (for frequency) respectively (as per section C) Power Quality Norms viz. harmonic limits, flicker 15 and DC current (refer Section C). The customer should provide test report from the government/nabl accredited Labs. a TDD Harmonic level in (5%) b DC Injection (0.5 % of FLC) c Flicker Interval / Value (Plt/Pst) Inverter should be configured to provide Dynamic Reactive support. The settings should be Power factor (capacitive and inductive) (for 8KW to 150KW) and 0.90 power factor for (150 KW and above) according to grid voltage variation. 17 The reconnection time should be 1 minute The document indicating details of fault 18 contribution by inverter ( time, voltage and current magnitude in tabular form) 19 Anti-islanding feature available in inverter as tested Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 17 of 24

23 IEC62116 or IEE Is Earthing of Solar PV followed as per IS Is Lightning Protection provided 22 If PV is Single Phase, whether load balancing is required to be done by RInfra. Has Customer provided single document to indicate single line drawing with protection 21 details/ratings, Load Connectivity/Details, earthing details, Lightning protection, Inverter(protection features and make) and Solar PV panel details (ratings and connectivity). Undertaking by applicant for internal Power Quality 22 check every year for the PV output above 150kW and every 2 years for less than 150 kw to 8kW. 23 The Solar Installation approved by PWD Electrical Inspector. Responsibility matrix /ownership of Equipment 24 Maintenance Undertaking furnished by the applicant. Y/N Note: 1. Points 11 to 19 are the inverter features likely to be present /configured. The documents indicating its presence should be submitted to Business team and verified by Load remark team. Moreover, its need should be communicated /explained to consumer during application itself. Furthermore, the compliance of documents indicating the details of inverter from point 11 to 19 should be checked /confirmed prior to commissioning visit. 2. Point s 21, 22, 23 and 24 document compliance need to be checked/confirmed by Business team prior to commissioning visit. After Submission of Test report (harmonics, flicker, DC injection and reactive Support) by the Applicant to Businees team, RInfra Divisional Load remark team may check its validity by performing on site testing. 3. Commissioning Check Activity to be done by Divisional Load remark and Business team. 4. Applicant s Power factor degradation may occur due to lowering Active power import from grid. (it needs to communicated to consumer) Annexure - 6 Dimensions of Equipments Sr.No Description of Equipment Height Width Depth 1 Single phase meter Three Phase meter (in built CT) Single phase MCB Single Phase MCB with casing Neutral Link-63AMp Neutral Link-100AMp Single Phase with Neutral MCB Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 18 of 24

24 8 Three Phase MCB Three Phase Neutral MCB Amp Fuse unit Amp Fuse unit Amp Fuse unit On load sitch Disconnector-400A Amp SDF Amp SDF Amp SDF Amp SDF Amp SDF Amp SDF Amp MCCB Amp MCCB All dimensions in mm Note 1 Wire should be clipped at 50mm interval at regular interval 2 The Height of LT Incoming switchgear shall be 0.9 meters above the ground level. 3 Board wiring shall be carried out only on Fire retardant plywood of 19 mm thickness provided by the applicant. 4 Current capacity for 10sqmm wire is 51A and for 4sqmm is 29A as per IS: Safety operating clearance from the wall on which meters are installed shall be 1.5m 6 LT Switchgear earthing to main GI strip by means of 25X3 GI flat at diagonally opposite ear thing bolts to be provided on FU / SDF 7 Single phase ELCB is twice the width of Single Phase MCB 8 Three phase ELCB size is same for Three phase and Neutral MCB Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 19 of 24

25 Annexure 7 Sample Documents---- NEED NOT BE OF SAME FORMAT Documents 1, 2 and 3 should be Type test report or from NABL accredited lab report 1. Harmonics Report 2. Flicker 3. DC Current Injection 4. Fault current contribution Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 20 of 24

26 5. Voltage and Frequency protection The Routine test report available from inverter manufacturer indicating protection features present in inverter. However, it should be configured as per CEA Guidelines 6. Routine Test report indicating Reconnection time settings, it has to be configured as per CEA Guidelines. 7. Reactive Support routine test report, it should be reconfigured as per CEA guidelines. At 240 volt (Nominal Voltage) to 245 Volt it should operate at unity power factor. However, grid voltage reduces, inverter should operate in leading power factor with linearly increasing trend up to 230 Volt, and then it becomes fixed with 0.95 lead (i.e. 30% capacitive). Similarly, for voltage range from 245 to 255 Volt the Inverter should absorb reactive power gradually with maximum power factor 0.95 (i.e. Inductive 30%). Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 21 of 24

27 8. DC side ground fault monitoring feature in the inverter. It can confirm from datasheet of the inverter. Similar for AC side ground fault monitoring feature. 9. Sample Data Sheet of Inverter Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 22 of 24

28 10. Detail drawing of Plant Setup Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 23 of 24

29 1. Voc =36 Volt 2. Isc =8Amp 3. Vdc =600 Volt 4. Vac=415 volt 5. I= 20 Amp 6. Inverter output=20kw Manual Switch 100 Amp MCCB milliamp Technical Guidelines for Grid Tied Distributed Generation (Solar) Page 24 of 24