HARYANA VIDYUT PRASARAN NIGAM LTD. TECHNICAL SPECIFICATION SSD/S-03/R-1/DGM-605 TECHNICAL SPECIFICATION FOR 33 KV CAPACITOR BANKS CHIEF ENGINEER/MM HVPNL, PANCHKULA TELEPHONE & FAX: 0172-2583724 MARCH-2017-0 -
33kV CAPACITOR WITH ALLIED EQUIPMENT 1. GENERAL: This specification covers the basic requirements in respect of Capacitor Banks with internal/external fuse, mounting racks, supporting structures complete in all respect along with series reactors wherever required for installation at various 220/132/66kV S/Stn. 2. STANDARDS The shunt capacitor bank and associated equipment shall conform to the latest additions of the following standards except to the extent explicitly modified in the specification. a) Capacitor IEC/871-1/87/ IS:13925(Part-1) 1998 b) Series Reactor IS:5553 c) Internal fuse IEC593 d) External fuse IEC549/IS 9402 3. SERVICE CONDITIONS: The equipment is required to operate satisfactorily under the following site conditions: 3.1 Max. temperature 50 0 C 3.2 Min. Temperature -2.5 0 C 3.3 Max. relative humidity 100% 3.4 Min. relative humidity 26% 3.5 Average number of rainy days per Nearly 120 days annum. 3.6 Average annual rainfall 900mm 3.7 Average number of dust storm days 35 per annum. 3.8 Isoceraunic level 45 3.9 Max. wind pressure 195 kg/sq.mt. 3.10 Altitude above mean sea level Less than 1000 mts. 4. GENERAL ARRANGEMENT OF CAPACITOR BANKS a) The Capacitor banks shall be of outdoor type suitable for operation in the climatic conditions as given in this specification and mounted on steel racks and structure with suitable insulators as required to be supplied by the bidder. b) The bidder shall furnish details of connections between the Capacitor units and groups together with layout diagram showing the basic arrangement of banks complete with dimensions. 5. DESIGN CRITERIA REQUIREMENTS AND CONSTRUCTIONAL DETAILS OF CAPACITORS. i) 33kV rating Capacitor Bank shall be made up either by two groups of star connected or single groups star connected banks un-earthed, - 1 -
with a floating neutral but connected by a neutral protective current transformer (NCT) of suitable ratio to operate Protective relays. ii) The protective scheme shall be by a two step relay one step current arranged as follows: If the failure of one or more units causes an over-voltage of less than 10% tolerable on the other remaining healthy units, then the unbalance current shall cause in the first step to sound an alarm. But if more than the above number of units fail causing a voltage rise of more than 10% then the unbalance current shall cause to trip and isolate the capacitor bank instantaneously. iii) The per phase and individual star group rating shall be built by series parallel combination of individual unit so as to achieve the desired bank rating. The individual capacity rating shall be as per IS:13925 Part-I. iv) All parallel units in one series group shall preferably be arranged in different tiers, that is, one series group shall be duly insulated from one another by post insulators adequate to withstand the voltage that may be impressed and shall be sufficient to withstand even in case of total failure be duly insulated from the earth potential by supporting post insulators. v) Although the tolerances in the output rating of each individual units shall be as per IS:13925. Yet it shall be ensured that in a completely assembled bank, the departures from the nominal rating and within the specified tolerances values shall not cause nuisance alarm or tripping since such alarm or tripping shall be to meet only with the protective requirements specified. vi) The tolerance in the output ratings shall not cause departures in the line currents by that value specified in IS: 13925. Besides it shall also be ensured that these unsymmetrical current shall not cause unsymmetrical voltage rise, whether for a short period or during prolonged operation. vii) Individual units shall be designed to meet with the requirements of the permissible overloads as specified as per IS: 13925. Each unit shall also be provided with internal discharging devices complying with the requirements of IS. viii) The voltage rating of the NCT shall be decided by the Contractor by taking into consideration the voltage impressed on the NCT due to: a) Failure of one or more parallel units in a series bank. b) Voltage impressed on the NCT when all the parallel units in one series bank fail simultaneously. The bidders shall furnish along with the bid design calculations for the same. 6. CAPACITOR UNITS: a) Each capacitor unit in the Bank shall be self contained outdoor type having 2 bushing suitably rated for series/parallel connections with other units to form the capacitor bank of rated capacity at 50Hz. The bushing shall be of porcelain and shall be joined to case preferably by welding. - 2 -
b) The capacitor unit shall be manufactured using imported and of best quality obtainable in the international market, non-pcb impermanent and polypropylene as di-electric. Vendor s technical specification and test certificate shall be furnished alongwith the bid. The impregnation shall be carried out under high degree of vacuum and the unit shall be of totally sealed type. c) Each capacitor unit shall be provided with a internal discharge resistor designed to drain the phase voltage of the bank to 50 V or less within 5 minute after disconnection from the supply. d) Each capacitor unit shall be suitable for continuous operation at least 1.3 times the rated current at rated voltage of the bank and frequency. This over current factor shall include the combined effect of presence of harmonics and over voltage upto 1.1 times rated voltage. e) The container of capacitor unit shall be of stainless steel or CRCA steel painted with suitable anti rust primer and two finishing coats of paint as per manufacturers standard practice. The container shall be made from contraction due to all ambient and loading conditions expected during the life of the unit. f) The design of internally fused capacitor units shall be such that it shall permit upto 40% element failure in series group without passing more than 10% over voltage on other healthy units. g) Each capacitors units shall be mounted so that it can be easily removed from the racks and replaced without removing other units, de-assembling any portion of the rack. 7. PROTECTIVE FUSES: The capacitor unit shall be provided with either internal or external fuses as per standard practice of the manufacturer. a. CAPACITOR UNITS WITH INTERNAL FUSES: The internal fuses shall conform to IEC: 593/IS:12762 and the Bidder shall furnish type test certificates for compliance with IEC/IS a) The design of the internal fuse shall be same that residues from fuse operation(s) shall not cause deterioration of the impregnating fluid. The fuse assembly shall be distinct and separate from element packs and so constructed that operation of fuse indoor worst condition does not affect the other healthy elements. b) The fuses shall not melt or deteriorate when subjected to inrush currents, which occur during the life of the bank. c) The design of the fuse shall be such that it shall isolate only the faulty element and the operation of the fuse shall not affect the other healthy element. b. CAPACITOR UNIT WITH EXTERNAL FUSES: a) The external fuses shall be of current limiting (HRC) type. The fuse system shall in any event be designed to ensure that the energy released into faulty capacitor units is less than the value that will cause rupture or bursting of the container. The fuses shall conform to - 3 -
IEC:549/IS:9402 and Bidder shall furnish type test certificate for compliance with IEC/IS. b) The characteristics of the fuse shall be such that it shall isolate the faulty unit only and prevent it from mechanical destruction due to internal faults. The capacitor unit together with external fuses shall be arranged in the bank by providing adequate clearance between the body of the capacitor units of a phase and the line terminal or the common bus for the units of the other phases to obviate the possibility of occurrence of bird faults. The fuse shall isolate the faulty capacitor unit only and the healthy capacitor units shall not be affected in anyway be the isolation of faulty unit. c) The fuses shall not melt or deteriorate when subjected to inrush currents, which occur during the life of the bank. d) The external distance between two metal ends of the fuse shall comply with specified creepage distance (i.e., the length of the insulating part of the fuse shall be such that the specified creepage distance is achieved). e) The selection of fuse to be done in such a manner that characteristic of fuse shall match suitably with over current withstand characteristic of associated capacitor unit. f) The capacitor bank and protection shall be such that failure of one unit (i.e one external fuse operation) does not cause tripping of the bank. he bidder shall furnish detailed calculations in evidence of above along with the Bid. 8. MOUNTING RACKS a) The mounting racks shall be hot dip galvanised steel sections. Each end of the rack shall have provision to receive incoming line connection. b) The racks shall be complete with rack insulators, foundation bolts or any other hardware etc. for assembly into complete bank. c) The height of the racks of capacitor banks shall be such that for making electrical connections with other equipment, proper electrical clearances are maintained. d) The capacitor bank along with its mounting racks and series reactor and null CT shall be suitable for installation on the plinth and the enclosure shall be suitably fenced. 9. TESTS a) Type Test: The equipment offered should be type tested. Type test report should not be more than seven years old, reckoned from the date of bid opening in respect of the following tests, carried out in accordance Govt./Govt. approved test house, shall be submitted along with bid: i) Thermal stability test. ii) Impulse withstand tests between terminal container. iii) Endurance test as special test. - 4 -
The remaining type test report as per clause 12.2 of ISS:13925 (Part-I):98 shall be submitted by the successful bidder within three months from the date of placement of order. These type test reports shall be from Govt./Govt. approved test house and will not be more than 7 years old reckoned from the date of bid opening. b) Acceptance & Routine Test: The equipment shall comply with all routine and acceptance tests as per IS: 13925(Part-I). Sampling to be done as per Appendix-E, IS: 13925. 10. SERIES REACTORS: a. The series reactor of small size is required for limiting the inrush current. The series reactor shall be outdoor type, 50Hz, air cooled, air core type and suitable for operation in climatic conditions specified. b. Series reactors shall be capable of withstanding the specified short circuit currents. c. The percentage series reactance shall preferably be 0.2%. d. The series reactors shall conform to type tests and shall be subjected to routine tests as per IS. 11. TECHNICAL PARAMETERS OF CAPACITORS, SERIES REACTORS & NCT. 11.1(a) CAPACITOR for S/Stn. where 2 No. bays are available. Sr. ITEM SPECIFICATION No a. Nominal system voltage (kv) 33 b. MVAR Capacitor required at nominal system voltage (MVAR) 5.43+5.43 (separated by Isolators as per arrangement shown in drg.) c. Rated voltage of the (kv) 38 Capacitor Bank d. Rated output of Cap. Bank (KVAR) 7200+7200 at rated voltage e. Protection of capacitor units f. Type of connection g. Rating of Cap. Units with internal fuse h. Power loss (tan delta) including loss in the fuse External/ Internal fuse KVAR 7.3 KV 200 Not to exceed 0.2 W per KVAR subject to tolerance as per applicable standards. - 5 -
i. Permissible overloads Max. permissible overloads with reference to voltage current and reactive output shall conform to applicable standards. j. Type of grounding Un-grounded k. Capacity to receive inrush current Not less than 100 times rated current. l. Temperature category The capacitors shall be suitable for maximum ambient temperature of 50 deg. C. Adequate care should be taken to protect the capacitors from direct sun radiation on account of outdoor installations. Note: The capacitor bank shall be capable of running either half unit or full unit based on requirement of load. These shall be controlled by single breaker but two isolators. Series reactors shall be arranged accordingly. The maximum bay space available for two part capacitor bank shall be equivalent to 11400 mm (indicative sketch attached at Annexure-1). Special requirement of protection, if any, for two part operation of capacitor bank shall be brought out by the bidder. For single part capacitor unit the bay space available is 5700mm. 11.1(b) CAPACITOR for S/Stn. where 1 No. bay is available. Sr. ITEM SPECIFICATION No a. Nominal system voltage (kv) 33 b. MVAR Capacitor (MVAR) 10.872 required at nominal system voltage c. Rated voltage of the (kv) 38 Capacitor Bank d. Rated output of Cap. Bank at rated voltage (KVAR) 14400 e. Protection of capacitor units f. Type of connection g. Rating of Cap. Units with internal fuse External/ Internal Fuse KVAR 7.3 KV 400 h. Power loss (tan delta) Not to exceed 0.2 W per including loss in the fuse KVAR subject to tolerance as per applicable standards. - 6 -
i. Permissible overloads Max. permissible overloads with reference to voltage current and reactive output shall conform to applicable standards. j. Type of grounding Un-grounded k. Capacity to receive Not less than 100 times rated inrush current current. l. Temperature category The capacitors shall be suitable for maximum ambient temperature of 50 deg. C. Adequate care should be taken to protect the capacitors from direct sun radiation on account of outdoor installations. 11.2 SERIES REACTORS Sr. Item Specification No. a. Rated voltage 36 b. Type Air core c. Rating of series reactors 0.2% of capacitor bank rating to be connected on neutral end d. Insulation levels Impulse withstand 170 voltage /power frequency with 70 stand voltage e. Short-time withstand capacity and duration 16 times of 130% rated current of capacitor bank for 3 seconds. f. Linear characteristic Upto 1.5 pu. g. Continuous rating 130% of rated current of capacitor bank. Note: For 100 MVA, 220/33kV T/F Capacitor bank of capacity 2x10.872 MVAR to be installed per bay. 11.3 NEUTRAL CURRENT T/F a. Highest system voltage 36 kv b. Rated voltage 33 kv c. Reference standard IS-2705 d. Ratio To be suitably designed by the bidder as per actual requirement e. Rated VA Burden Core-I Core-II 15 15-7 -
f. Accuracy class Core-I Core-II g. i)accuracy limit factor Core-I ii) Instrument security factor Core-II 5P 1 Not less than 10 Not exceeding 5 h. Creepage distance 900 i. Minimum insulation voltage 15 kv 12. CAPACITOR LOSSES (WITHOUT CAPITALIZATION): The capacitor shall be of low loss type. The losses in watts for each capacitor unit including losses in fuses and discharge resistors forming integral part of the capacitors along with losses for series reactor shall be guaranteed. If the test figures of capacitor losses exceed 0.2 Watt/kVAR, the capacitors will be liable for rejection. 13. DRAWINGS The bidder shall furnish one set of following drgs. along with their bid to check the stability of their equipment: - 1. Out line general arrangement drg. of capacitor bank with detailed dimension of Capacitor Bank/Unit and structure with complete bill of material. 2. Electrical Layout drg. of Capacitor Bank showing spacing of each equipment. 3. Outline arrangement drawing of Capacitor Unit with detail dimensions. 4. Outline general arrangement drawing of 33kV NCT, Series Reactor & CT. 5. Terminal connector drawings for Capacitor Bank, NCT, Series Reactor & CT. The bidder shall submit four sets of final versions of complete and correct equipment drawings for purchaser s approval along with bid in a sealed envelope. The purchaser shall communicate his comments/approval on the drawings to the supplier within 21 days from the date of issue of LOI. The submission of complete and correct readable drawings for approval is the responsibility of the bidder/supplier. The supplier shall, if so required by the purchaser, modify the drawings and resubmit four copies of the modified drawings for purchaser s approval within two weeks from the date of purchaser s comments. Then, the purchaser shall approve the revised drawings within two weeks from the date of its receipt. The successful bidder shall also supply one set of instruction manual containing handling, installation, testing and commissioning of equipment at the time of despatch of material to the consignee with - 8 -
each equipment for our field staff. In addition, 5 sets of such bound manuals and final approved drawings shall be supplied for reference & record in our design office. One set of all the approved drawings and manual of instructions will be supplied along with each equipment without which the supply will not be considered as complete supply. 13.1 The manufacturing of the equipments shall be strictly in accordance with the approved drawings and no deviation shall be permitted without written approval of the purchaser. 13.2 Approval of drawings by purchaser shall not relieve the supplier of any of his responsibility and liability for ensuring correctness and correct interpretation of the drawings for meeting the requirement of the latest version of applicable standard of engineering, design and workmanship and latest revision of relevant standards at the time of supply an purchaser shall have the power to reject any work or material which in his judgment is not in accordance there-with. - 9 -
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GUARANTEED TECHNICAL PARTICULARS FOR CAPACITOR BANK Sr.No. DESCRIPTION PARTICULARS A. SHUNT CAPACITORS 1. Name of manufacturer and country 2. Applicable standard 3. CAPACITOR UNIT i) Rated Voltage KV ii) Maximum permissible continuous over voltage as of percentage of rated voltage. iii) Short time over voltage for 30 minutes for 1 minute for 1 second for 3 cycles % iv) a) Nominal capacitance at 25 o C, 50 o C. b) Manufacturing tolerance on capacitance values. v) a) Rated output at rated voltage and 50 Hz (KVAR) b) Maximum output (KVAR) vi) vii) viii) Type of impregnant used Type of fuse used Temperature category as per IS. ix) Discharge resistor value (ohm) x) Discharge time for 50 volts xi) BUSHING a) Number of bushings per unit & type. b) Rated voltage c) Rated Insulation level kv d) Total creepage distance. - 11 -
Sr.No. DESCRIPTION PARTICULARS xii) a) Type of dielectric used b) Voltage stress for dielectric (V/ Micron) c) Thickness of dielectric (Micron) xiii) a) 10 seconds test voltage (kv) b) Lightning impulse test voltage (kv peak) xiv) xv) a) Capacitor unit material b) Finish/ paint details c) Type of welding FUSES: a) Type (Internal/ External) b) Number per unit c) Maximum energy which fuse carrier can withstand without bursting. d) Max. Continuous rating of fuse without deterioration as a percentage of capacitor unit nominal current. e) Maximum recovery voltage at which fuse can operate. xvi) Overall dimensions (mm x mm x mm) xvii) Weight per unit (kg.) xviii) Losses under stabilized condition (after 40 hrs. of energisation.) Watts 4. CAPACITORS i) Rated Voltage ii) Maximum continuous over voltage rating as percentage of rated voltage. iii) Nominal capacitance at 25 o C (microfarad) iv) Manufacturing tolerance on nominal capacitance value. (+%) v) Variation of capacitance due to ambient temperature and load. (+%) - 12 -
Sr.No. DESCRIPTION PARTICULARS vi) vii) viii) ix) Variation of capacitance due to loss of units/ elements. (+%) a) At alarm stage. b) At trip stage. Number of unit in parallel per phase per series section. Number of series sections per phase. Connection symbol. x) Rated output (KVAR) xi) Rated current per phase (Amp.) xii) Withstand voltage of capacitor bank while switching ON/ OFF. (kv peak) xiii) Power frequency withstand voltage (kv rms) xiv) Creepage distance (mm) 5 Whether interstack and base insulators and terminal connectors for bank shall be included in the scope of supply? 6 Whether bus bar material for the capacitor bank included in the scope of supply. 7 Whether galvanized support structure and stack rack for the capacitor bank shall be included in the scope of 8 Overall dimensions of capacitor bank 9 Total weight of capacitor unit & bank B) Series Reactor I) Name of manufacturer and country II) Ref. Standard III) IV) V) Rated KVAR Inductance Rated Voltage VI) VII) VIII) Rated frequency Number of Phases Power Frequency withstand voltage - 13 -
Sr. No. IX) X) XI) XII) XIII) XIV) C 1 2 3 DESCRIPTION Lighting impulse withstand voltage Type of cooling Total losses corrected at 70 deg.c Creepage Distance Short time current rating Overall dimension NCT Make Rated Voltage Transformation ratio PARTICULARS 4 Accuracy 5 6 7. 8. Rated Burden Power frequency withstand voltage Lighting impulse withstand voltage Overall dimensions - 14 -