CURRENT TRANSFORMER. March 2018 WEST BENGAL STATE ELECTRICITY TRANSMISSION COMPANY LIMITED

Transcription

1 CURRENT TRANSFORMER March 2018 Engneerng Department WEST BENGAL STATE ELECTRICITY TRANSMISSION COMPANY LIMITED Regd. Offce: VdyutBhawan, Block DJ, Sector-II, Bdhannagar, Kolkata CIN: U40101WB2007SGC113474; Webste: Page 1 of 17

2 TECHNICAL SPECIFICATION FOR CURRENT TRANSFORMER 1. SCOPE : Ths specfcaton covers the desgn, manufacture, assembly, testng at the manufacturer s works of SF 6 flled current transformers of 400KVvoltage class & Ol flled s of400kv, 220KV, 132KV & 33KV voltage class. 2. STANDARD : The current transformers and accessores covered by ths specfcaton shall comply wth the requrement of the latest edton of the followng standards unless otherwse stated n ths specfcaton. IS:2705 (Part-I-IV) : Specfcaton for current Transformers. IS:4201 : Applcaton gude for current transformers. IS:5621/2099 : Specfcaton for Bushngs/hollow nsulators for alternatng voltages above 1000V. IS:335 : Specfcaton for nsulaton ol for transformers and swtchgears IEC: :. IEC: : Gude for selecton of Insulators n respect of polluted condton. IEC: IEC: : SF6 gas IEC: : Slcon Composte Insulator 3. DEVIATION : Normally the offer should be as per Techncal Specfcaton wthout any devaton. But any devaton felt necessary to mprove performance, effcency and utlty of equpment must be mentoned n the Devaton Schedule wth reasons duly supported by documentary evdence. Such devatons suggested may or may not be accepted by the Board. Devatons not mentoned n Devaton schedule wll not be consdered. 4. DESIGN & CONSTRUCTION OF SF6 FILLED CURRENT TRANSFORMERS: The desgn features and constructon detals of current transformer shall be n accordance wth the requrement stpulated n ths specfcaton and as per relevant IS. ) The CT s shall be sngle phase, Lve tank, SF6 flled, Hermetcally sealedoutdoor type wth slcon composte nsulator. ) The SF6 current transformers shall be complete n all respects and shall conform to the modern practce of desgn and manufacture. ) The SF6 current transformers shall be of low Reactance outdoor type, sngle phase, 50 Hz, wth Slcon composte Insulators sutable for operaton under the servce condtons and ste requrement as descrbed n ths techncal specfcaton. v) The maxmum permssble temperature rse of the SF6 current transformer wndng when carryng a prmary current equal to the rated contnuous current at rated frequency and wth rated burden over an ambent temperature (not exceedng 50 o C) and daly Page 2 of 17

3 average not exceedng 40 o C shall not exceed the lmts as specfed n case of Class E nsulaton. v) The SF6 current transformers shall be sutable for up rght mountng on steel structures. Necessary flanges, bolts, clamp fttngs etc. for base of SF6 CT shall also be suppled by the Manufacturer/Contractor. v) The metal tanks shall have bare mnmum no. of welded jonts so as to mnmze possble locatons of gas leakage. v) The head of the CT shall be made of Alumnum alloy. A steel rupture dsc wth sutable burstng pressure shall be provded on the top of the head to prevent any abnormal rse n the nternal pressure due to any nternal fault & avod an exploson of the CT. v) The SF6 CT shall be complete wth all accessores lke prmary & secondary termnals, weather proof termnal box for secondary connecton, lftng lugs, termnal connector, groundng termnals, name plate, SF6 fllng valve, Slcon composte nsulator, rupture dsc, SF6 Pressure Gauge wth two N/C contact for alarm purpose, Spacer, Head housng, outlet tube etc. Separate valve shall be provded on the equpment for connectng vacuum pump or gas fllng devce for toppng up or removal of gas nsde the equpment. Two nos. of complete gas fllng devce shall be wthn the scope of supply of the contractor for each substaton wthout any addtonal prce. Supply of termnal connectors x) shall be guded by the techncal specfcaton of Clamps & Connectors. The CT shall be provded wth class - E nsulaton. It shall be of hermetcally sealed type constructon to prevent ar & mosture from enterng the tank. The desgn and constructon of CTs shall be suffcent to wthstand the thermal and mechancal stresses resultng from the specfed short crcut currents and specfed duraton as mentoned n Specfc Techncal Parameters. x) The core of the SF6 CTs shall be hgh grade non-ageng, electrcal, CRGO slcon steel lamnated steel of low hysteress loss and hgh permeablty to ensure hgh accuracy at both normal and over current. x) x) x) xv) xv) xv) The exctng current shall be as low as possble and the SF6 CTs shall be capable of mantanng ts rated accuracy at dfferent burdens and wthn saturaton lmts. Ratng plate markng shall be provded as per relevant clause of IS:2705& relevant IEC. CT Characterstcs shall be such as to provde satsfactory performance as per IS:2705 for burdens rangng from at least 25% to 100% of rated burden over a range of 5% to 120% of rated current n case of meterng CT cores and upto knee pont voltage n case of protecton CT cores. The SF6 CT secondary termnals shall be brought out n a weather proof termnal box. The termnal box shall be provded wth glands sutable for 1.1 KV grade, steel armoured PVC nsulated, PVC sheathed multcore 4 Sq.mm stranded copper conductor cable Connecton between CT to CT Juncton Box s to be done wth 4 core copper control cable for ndvdual core Connecton between CT Juncton Box to C&R Panel s to be done wth 4 sq mm copper cable for ndvdual core.. The CT secondary to be used for meterng and nstruments shall be of accuracy class and ISF as specfed. The saturaton factor of ths core shall be low enough so as not to cause any damage to measurng nstruments n the event of maxmum short crcut current. The CT secondary to be used for protectve relayng purposes shall be of accuracy class and Knee Pont Voltage as specfed. The magnetsaton curve of the cores shall be furnshed wth tender. xv) The rato changng arrangement shall be provded on secondary sde of CT. Termnal markngs for connectons shall be marked on both prmary and secondary termnals of each CT. xv) Secondary wndng of 400kV CT shall be of copper only. However Prmary wndng of 400kV CT shall ether be Alumnum or Copper. xx) xx) xx) The CT shall be provded wth Gas Densty Montor wth separate potental free Alarm & Trp contact. Arrangement of remote montorng for alarm or trppng shall also be provded. Due to openng & closng of SF6 gas fllng & dranng valve hermetc sealng of CT shall not be dsturbed. Page 3 of 17

4 xx) Faclty shall be provded for short crcutng & groundng of the CT sec termnals nsde the termnal box. xx) The CT shall provde freedom from Capactance &tanδ measurement. xxv) If any auxlary CT s are to be used n the current transformer then all parameters specfed shall have to be met treatng auxlary C.T.s as an ntegral part of the current transformer. The auxlary C.T. shall preferably be of nbult constructon of the CTs or to be mounted nsde secondary termnal box of Man CT. 5. DESIGN & CONSTRUCTION OF OIL FILLED CURRENT TRANSFORMERS : The desgn features and constructon detals of current transformer shall be n accordance wth the requrement stpulated n ths specfcaton and as per relevant IS. ) The current transformers shall be complete n all respects and shall conform to the modern practce of desgn and manufacture. ) The current transformers shall be of low Reactance outdoor type, sngle phase, 50 Hz,self cooled ol flled wth shaded porcelan bushng/insulators sutable for operaton under the servce condtons as specfed n the general condton of ste sutable for outdoor operaton. ) The maxmum permssble temperature rse of the current transformer wndng when carryng a prmary current equal to the rated contnuous current at rated frequency and wth rated burden over an ambent temperature (not exceedng 50 o C) and daly average not exceedng 40 o C shall not exceed the lmts as specfed below : Class of nsulaton Maxmum Temperature Rse ( o C) a) All classes mmersed n ol : 55 o C (Measured by Resstance method) b) Ol at the top of the tank or housng (Measured by Thermometer) ) Wth Conservator/Inert Gas : 50 o C ) Wthout Conservator/Inert Gas : 45 o C v) The current transformers shall be sutable for up rght mountng on steel structures. Necessary flanges, bolts, clamps fttngs etc. for base of CT shall also be suppled by the Manufacturer/Contractor. v) The CT shall be complete wth all accessores lke prmary & secondary termnals, termnal connectors, weather proof termnal box for secondary connecton, lftng lugs, groundng termnals, ol sght glass, fllng and dranng valves and name plate. v) The CT shall be ol mmersed type provded wth class - A nsulaton. It shall be of hermetcally sealed type constructon to prevent ar & mosture from enterng the tank. The desgn and constructon of CTs shall be suffcent to wthstand the thermal and mechancal stresses resultng from the specfed short crcut currents and specfed duraton as mentoned n General Techncal Specfcaton. v) The core of the CTs shall be hgh grade non-ageng, electrcal, CRGO slcon steel lamnated steel of low hysteress loss and hgh permeablty to ensure hgh accuracy at both normal and over current. v) The exctng current shall be as low as possble and the CTs shall be capable of mantanng ts rated accuracy at dfferent burdens and wthn saturaton lmts. x) Ratng plate markng shall be provded as per relevant clause of IS:2705. x) CT Characterstcs shall be such as to provde satsfactory performance as per IS:2705 for burdens rangng from at least 25% to 100% of rated burden over a range of 5% to 120% of rated current n case of meterng CT cores and upto knee pont voltage n case of protecton CT cores. Page 4 of 17

5 x) The CT secondary termnals shall be brought out n a weather proof termnal box. The termnal box shall be provded wth glands sutable for 1.1 KV grade, steel armoured, PVC nsulated, PVC sheathed multcore 4 Sq. mm stranded copper conductor cable Connecton between CT to CT Juncton Box s to be done wth 4 core copper control cable for ndvdual core Connecton between CT Juncton Box to C&R Panel s to be done wth 4 sq mm copper cable for ndvdual core.. x) The CT shall be hermetcally sealed. Each CT shall be provded wth ol level gauge and a pressure releasng devce to just release the abnormal nternal pressure. x) The CT secondary to be used for meterng and nstruments shall be of accuracy class and ISF as specfed. The saturaton factor of ths core shall be low enough so as not to cause any damage to measurng nstruments n the event of maxmum short crcut current. xv) The CT secondary to be used for protectve relayng purposes shall be of accuracy class and Knee Pont Voltage as specfed. The magnetsaton curve of the cores shall be furnshed wth tender. xv) Upto 33 KV level the CTs must be Dead Tank type and from 132 KV onwards the CTs shall be of ether Lve Tank or Dead Tank type.for 132KV and onwards current transformer STUD arrangement should be n horzontal confguraton. xv) The rato changng arrangement shall be provded on secondary sde of CT. Termnal markngs for connectons shall be marked on both prmary and secondary termnals of each CT. xv) Prmary wndng shall be of copperfor 33KV, 132KV. For 220KV& 400KV current transformer prmary wndng may be Alumnum or copper consderng current densty for prmary wndng max 1.75 A/sq. mm for copper and 0.75 A/Sq.mm for alumnum. xv) Secondary wndng of all voltage class CT shall be made of Copper. xx) If any auxlary CT s are to be used n the current transformer then all parameters specfed shall have to be met treatng auxlary C.T.s as an ntegral part of the current transformer. The auxlary C.T. shall preferably be of nbult constructon of the CTs or to be mounted nsde secondary termnal box of Man CT. 6. INSULATOR HOUSING (FOR SF6 CT) : ) The Slcon Composte Insulator shall be of Manufacturer s make. ) Slcon composte nsulator s to be used for SF6 flled CT as per relevant IS & IEC. The nsulator housng shall be of shatter proof.. ) The nsulaton of slcon composte nsulator shall be co-ordnate wth that of the SF6 current transformer such that the flashover, f any wll occur only external to the CT. v) Each of the slcon composte nsulators shall have creepage dstance sutable for dfferent voltage class as per specfc techncal parameters. v) Cantlever strength of slcon composte nsulators of SF6 CT s to be furnshed. v) The nsulator housng shall be of Shatter proof hgh qualty Slcon Composte materal. The Slcon sheds shall exhbt hydrophobc property and also should be able to transfer the property of polluton layer. v) The nsulator housng shall be of a sngle pece constructon wthout any jonts or couplng. 7. BUSHING (FOR OIL FILLED CT): v) x) Ol flled condenser type porcelan bushng/insulator conformng to latest edton of IS:2099/IS:5621 shall be used for the CTs above 33KV class and up to 220KV class.the Slcon Composte Insulator shall be used for 400KV CT. Ol expanson chamber and bushng clamp shall be of hgh strength. They shall have smooth surface to prevent dscharge takng place between the metal parts and porcelanas a result of onsaton. Ferrous Parts only shall be hot dp galvansed. Page 5 of 17

6 x) The nsulaton of bushngs shall be co-ordnated wth that of the current transformer such that the flashover, f any wll occur only external to the CT. x) Each of the bushngs porcelan shall have creepage dstance sutable for dfferent voltage class as specfed n specfc techncal parameters. x) Cantlever strength of Bushng/nsulator shall be as per Cl. 5.5 of IS:2099 (latest edton) for all voltage classes. 8. GROUNDING TERMINALS : Two groundng termnals on dagonally opposte sdes sutable for connectng G.S. Flat of 50 10mm for all voltage classes shall be provded. 9. SECONDARY TERMINAL BOX : ) All secondary termnals shall be brought out n a compartment on one sde of each current transformer for easy access. CT sec. termnal box shall be made of sheet steel havng mnmum thckness of 3 mm. However, 2 mm. thckness havng power coated pantng s acceptable. ) The exteror of ths termnal box shall be hot-dp galvanzed or panted. ) Arrangement for shortng of CT secondary termnals shall be provded n the CT v) secondary termnal box wth supply of shortng lnk made of copper. The termnal box shall be provded wth removable cable gland plate wth provson of punchng at bottom for mountng requred number of cable glands of 1.1 KV grade steel wre armoured, PVC nsulated PVC sheathed 4 sq.mm multcore stranded copper conductor cables. The cable glands shall be ncluded wthn the scope of supply. v) The termnal box shall be provded wth a door n front so as to have easy access of secondary termnals. The door shall have a sealng/ lockng arrangement and shall be sutable to prevent penetraton of mosture and ran water. Degree of protecton shall not be less than IP 55 as per relevant IS. v) All termnals shall be clearly marked wth dentfcaton number to facltate connecton to external wrng wth suffcent space n between. 10. PAINTING : ) The tank and top metallc cover shall be hot-dp galvanzed or panted. All steel surfaces shall be cleaned by sand blastng or chemcal process as requred to produce a smooth surface, free of scale, grease and drt. However Alumnum castng CT tank wth PU pant s also acceptable. ) Steel surface n contact wth nsulatng ol shall be panted wth heat resstant ol nsoluble nsulatng varnsh. ) External surfaces shall be gven a coat of hgh qualty red or yellow chromate prmer and fnshed wth two coats of synthetc enamel pants (lght grey as per shade 631 of IS:5) v) Pants shall be carefully selected to wthstand tropcal heat, ran etc. The pants shall not scale off or crnkle or be removed by abrason due to normal handlng. 11. SF6 GAS: The SF6 gas shall comply wth IEC 60376; 60376A and 60376B and shall be sutable n all respect for use n the swtchgear under operatng condton. Page 6 of 17

7 12. INSULATING OIL: Insulatng ol to be used for current transformer shall be of EHV grade and shall confrm to IS:335 (requred for frst fllng). 13. TESTS AT FACTORY AND TEST CERTIFICATES : ) Each C.T. shall comply wth the requrements of routne test as specfed n IS:2705 Part (I to IV). ) All Routne test at manufacturer's works on all CTs shall be carred out and Test Reports are to be submtted to WBSETCL alongwth nspecton call letter. For 66KV & above voltage class CT s Delectrc Dsspaton Factor (tanδ) s to be measured at manufacturer s works for all CTs wherever applcable. The measured tanδ values ndcatng sl. of CTs are to be submtted alongwth submsson of nspecton offer.durng physcal nspecton of CTs at the manufacturer s works offcers of WBSETCL shall wtness Routne/Acceptance test.r.o 10% or more as per IS/IEC for all voltage class CTs (33KV to 400KV). However tanδ value s to be measured for all CTS of 132KV & above voltage class durng routne/acceptance test at the manufacturer s works n presence of representatve of WBSETCL.Maxmum allowable value for tanδ shall be 0.7% for 132KV and above voltage class. Bdder to assure that the tanδ value wll reman wthn 0.7% for one year perod. ) All Acceptance tests shall be carred out at the manufacturer s works on every lot offered for nspecton as per relevant IS. Selecton of samples for acceptance test as well as rejecton and retestng shall be guded by relevant IS& IEC. The entre cost of acceptance and routne tests that are to be carred out as per relevant IS shall be treated as ncluded n quoted prce of. Three (3) copes of test reports shall be submtted for approval and adequate extra copes for dstrbuton to ste. v) The contractor shall gve at least 15 (ffteen) days advance notce ntmatng the actual date of nspecton and detals of all tests that are to be carred out. 14. TEST REPORTS AND TYPE TESTS : Only type tested Current transformers from the maker s lst of WBSETCL are to be offered for 400KV, 220KV, 132KV and 33KV class CT s conformng to our techncal specfcaton, and relevant IS and IEC. offered should be smlar wth ones on whch type testng has been carred out as per relevant IS and IEC.Three sets of complete test report of all test (ncludng Type Test of CT as well as for Slcon composte nsulator),as stpulated n the relevant IS & IEC,carred out n Govt. recognzed Test House or Laboratory /NABL accredted laboratory shall have to be submtted by successful bdder postvely alongwth submsson of drawngs durng detaled Engneerng. Successful bdder may be requred to produce orgnal copes of type test reports at the tme of detal engneerng, f asked by WBSETCL. Each type test report shall comply wth the followng nformaton wth test result: - ) Complete dentfcaton, date and seral no. ) Relevant drawngs as documented wth test report. ) v) Method of applcaton, where appled, duraton and nterpretaton of each test. All Type tests report whch have been carred n accordance wth IEC:44-1/IS:2705 ncludng Fast Transent Test report to assess the CT performance havng 300KV or hgher voltage class n servce to wthstand hgh frequency over voltage generated due to closng &openng of solators & Breaker Page 7 of 17

8 15. GURANTEE : Electrcal characterstcs shall be guaranteed by the bdder. In case of falure of materals to meet the guarantee, WBSETCL shall have rght to reject the materal. Guaranteed Techncal Partculars are to be submtted by successful bdder durng detaled engneerng alongwth submtted drawngs/documents. However format for submssonof GTP shall be handed over to ntendng bdders at the tme of sale of tender documents. 16. CONTRACT DRAWINGS AND MANUALS : In the event of placement of order the followng drawngs and manuals shall be submtted n sx (6) copes for approval. a) General outlne dmenson drawng of current transformers furnshng front and sde elevaton, top and bottom plan, vews showng all accessores, mountng arrangement on steel structures, spacng and sze of the bolts, total creepage dstance of bushng, electrcal dagram for prmary and secondary connectons wth polarty mark, termnal arrangement for secondary termnal box, sze of prmary termnals, groundng termnals and lftng lugs, quantty of nsulatng ol, net and shppng weght, shppng dmenson etc. b) Name and ratng plate dagram of CT. c) Marked erecton pont dentfyng the component parts of SF6 CT d) Detal vew of core, wndng assembly, wndng connectons and tappngs. e) Guaranteed Techncal partculars After approval, four (4) sets of approved drawngs and operatng and mantenance manual ncludng the nstructon manual both n soft and hard format shall be submtted for our record and dstrbuton to ste. Instructon manual should contan : a) A bref descrpton of C.T. furnshng the constructonal features. b) Instructon for handlng, storng, erecton, commssonng and operaton and mantenance of C.Ts c) General outlne drawng of the C.Ts along wth all components and accessores. d) Marked erecton ponts dentfyng the component parts of C.T. e) Detaled dmensons of assembly and descrpton of all accessores. f) Detaled vews of, wndng assembly, wndng connectons and ts tappng. g) Lst of spares and other necessary nformaton for C.Ts. h) A set of approved test certfcate. ) All notes and legends of the drawngs shall be furnshed n Englsh and all dmensons shall be marked n metrc unts. Page 8 of 17

9 CORE DETAILS OF CURRENT TRANSFORMER Sl. Descrpton 1. a) 400 KV CT (Bay) Feeder, Transformer, Bus Reactor, Bus Coupler & Bus Transfer Bay No of 5 Applcaton 1 Protecton 2 Protecton 3 Meterng 4 Protecton 5 Protecton b) 400kV CT (One & a Half Breaker GIS) 4 Protecton cores Lne sde CT 6 2 Meterng cores Te & Bus sde 4 4 Protecton CT cores c) Bushng CT (Transformer) Current 1000/1A 1000/1A 1000/1A 1000/1A 1000/1A /1A /1A /1A Output Burden (VA) at Lower ISF (Max) Accuracy class as per IS 2705 Mn Knee pont Voltage (V) Max CT Secy Wndng Resstance (W) Max exctaton current (ma) at Knee pont Voltage PS Class 2000/ /5 30/60 PS Class 2000/ /5 30/60 PS Class 2000/ /5 30/60 PS Class 2000/ /5 30/60 PS Class 3000/ /10 30/45 PS Class 3000/ /10 30/45 400KV sde, 220kV sde & Neutral of 315 MVA, 400/220/33KV Transformer 1 1 Protecton 1000/1A PS Class 1000V at Vk/2 Page 9 of 17

10 Sl. Descrpton No of Applcaton Current Output Burden (VA) at Lower ISF (Max) Accuracy class as per IS 2705 Mn Knee pont Voltage (V) Max CT Secy Wndng Resstance (W) Max exctaton current (ma) at Knee pont Voltage d) Bushng CT (Bus Reactor) 400KV lne sde of 80MVAR Bus Reactor Neutral sde of 80MVAR Bus Reactor Protecton 200/1A PS Class 200V 1 40 at Vk/4 2 Protecton 200/1A PS Class 200V 1 40 at Vk/4 3 Protecton 200/1A PS Class 200V 1 40 at Vk/4 4 Meterng 200/1A Protecton 1000/1A PS Class 2000/1000V 10/5 30/60 2 Protecton 1000/1A PS Class 2000/1000V 10/5 30/60 3 Protecton 200/1A PS Class 200V 1 40 at Vk/4 4 WTI a) 220 KV CT (Bay) Feeder, Transformer & Bus Transfer Bay Bus Coupler Meterng 2 Protecton 3 Protecton 4 Protecton 5 Protecton 1 Meterng 2 Protecton 3 Protecton /1A 1600/1A 1600/1A PS Class PS Class PS Class PS Class 1500/1200/ 600V 1500/1200/ 600V 1500/1200/ 600V 1500/1200/ 600V 5/4/2 30/37.5/75 5/4/2 5/4/2 5/4/2 30/37.5/75 30/37.5/75 30/37.5/75 PS Class 2000/1600V 10/8 30/37.5 PS Class 2000/1600V 10/8 30/37.5 Page 10 of 17

11 Sl. Descrpton No of Applcaton Current Output Burden (VA) at Lower ISF (Max) Accuracy class as per IS 2705 Mn Knee pont Voltage (V) Max CT Secy Wndng Resstance (W) Max exctaton current (ma) at Knee pont Voltage b) Bushng CT (Transformer) 220KV sde, 132KV sde & Neutral of 160MVA Transformer 220KV sde & Neutral of 50MVA Transformer c) 33 KV CT for Tertary Loadng 1 1 Protecton 800/1A PS Class 1000V at Vk/2 1 1 Protecton PS Class 800V at Vk/2 1 Meterng /1A 220/132/33 KV Transformer Bay 3 2 Protecton /1A PS Class 1200/600V 4/ Protecton /1A PS Class 1200/600V 4/ a) 132KV CT (Bay) Feeder, Transformer & Bus Transfer Bay 5 1 Meterng Protecton Protecton Protecton Protecton PS Class 1500/1200/ 600V PS Class 1500/1200/ 600V PS Class 1500/1200/ 600V PS Class 1500/1200/ 600V 5/4/2 30/37.5/75 5/4/2 30/37.5/75 5/4/2 30/37.5/75 5/4/2 30/37.5/75 Page 11 of 17

12 Sl. Descrpton No of Bus Coupler Bay 3 Applcaton 1 Meterng 2 Protecton 3 Protecton Current 1600/1A 1600/1A 1600/1A Output Burden (VA) at Lower ISF (Max) Accuracy class as per IS 2705 Mn Knee pont Voltage (V) PS Class 2000/1600V PS Class 2000/1600V Max CT Secy Wndng Resstance (W) Max exctaton current (ma) at Knee pont Voltage 8/6.4 30/37.5 8/6.4 30/37.5 b) Bushng CT (Transformer) 132KV sde & Neutral of 50MVA Transformer 1 1 Protecton /1A PS Class V at Vk/2 v 33KV sde of 50MVA Transformer 132KV sde & Neutral of 31.5MVA Transformer 33KV sde of 31.5MVA Transformer 1 1 Protecton 1000/1A PS Class at Vk/2 1 1 Protecton 150/1A PS Class at Vk/2 1 1 Protecton 800/1A PS Class at Vk/2 c) 132KV CT for Ralway Tracton Sub-Statons& for Bulk(only for Meterng purpose) Feeder wthout Crcut Breaker Feeder as Specal 2 1 & 2 Meterng /1A S 2 1 & 2 Meterng 50-25/1A S Page 12 of 17

13 Sl. Descrpton No of Applcaton Current Output Burden (VA) at Lower ISF (Max) Accuracy class as per IS 2705 Mn Knee pont Voltage (V) Max CT Secy Wndng Resstance (W) Max exctaton current (ma) at Knee pont Voltage 4. a) 33KV CT (Bay) Feeder, Transformer, Capactor Bank & Bus Transfer Bay 3 1 Meterng Protecton Protecton PS Class 1000/800/400 4/3.2/1.6 30/37.5/75 PS Class 1000/800/400 4/3.2/1.6 30/37.5/75 b) 33KV CT (Indoor Swtchgear) 1 Meterng /1A Transformer (In comer) 3 2 Protecton /1A PS Class 250/200 4/3.2 30/ Protecton /1A PS Class 1000/800 4/3.2 30/ Meterng 800- Feeder, Capactor Bank & Bus Transfer Bay 2 Protecton 3 Protecton PS Class 200/ / /75 PS Class 800/ / /75 1 Meterng /1A Bus Coupler Bay 2 2 Protecton (O/C & E/F) /1A PS 250/200 4/ at Vk Page 13 of 17

14 Sl. Descrpton No of Applcaton Current Output Burden (VA) at Lower ISF (Max) Accuracy class as per IS 2705 Mn Knee pont Voltage (V) Max CT Secy Wndng Resstance (W) Max exctaton current (ma) at Knee pont Voltage 5a) 11KV CT (Bay) 1 Meterng / 1A Protecton / 1A PS Class 300 at hgher rato 4/2 at 75 C at hgher rato 30 at Vk/2 at lower rato Incomng Feeder 4 3 Protecton / 1A PS Class 300 at hgher rato 4/2 at 75 C at hgher rato 30 at Vk/2 at lower rato 4 Protecton / 1A PS Class 300 at hgher rato 4/2 at 75 C at hgher rato 30 at Vk/2 at lower rato 1 Meterng / 1A Outgong Feeder 2 2 Protecton / 1A PS Class 150at hgher rato 2 at 75 C at hgher rato 30 at Vk/2 at lower rato Page 14 of 17

15 SPECIFIC TECHNICAL PARTICULARS OF CURRENT TRANSFORMER Sl. NO DESCRIPTION 1. Rated system voltage KV(rms) 2. Hghest system voltagekv(rms) 3. Rated current(amp)/burden(va) TECHNICAL PARAMETERS 400 KV 220KV 132 KV 33 KV 400KV KV As per schedule of requrements 4. System frequency (Hz) System neutral earthng 6. Installaton Effectvely Earthed Outdoor Effectvely Earthed Earthed through groundng transformer for 220/132/33KV & 132/33KV substaton 7. Extended current ratng 120 % Max. 8. Rated short tme thermal current for 1 second/3 second (KArms) 50 for 1 sec. 40 (3 sec) 31.5 (3 sec) 25 (3 sec) 9. Rated Dynamc current KA (peak) (should be at least 2.5 tmes of above ratng Rated Insulaton level : a) 1.2/50 mcrosecond mpulse wthstand voltage (KVpeak) b) One mnute power frequency wthstand voltage (KVrms) on prmary wndng Power frequency over voltage wthstand requrements for secondary wndng for one mnute (KVrms) Over voltage nterturn test As per clause 9.5 of IS:2705 Part-I & relevant IEC 13. Creepage Dstance(Heavly polluted atmosphere) Total Lmt of temp. rse of wndngs O C at rated current 55 O C Page 15 of 17

16 15. Type of mountng Pedestal Type 16. Insulaton medum SF6 Gas / Ol (as per schedule) Ol 17. Type of Tank Lve Tank / Dead Tank Dead Tank 18. Insulator Slcon Composte Insulator Ol flled condenser type porcelan bushng/insulator 19. Instrument securty factor Less than 5 for meterng core 20. Type of connectors sutable for 4" Al. ppe/acsr Conductor. 21. Mnmum vsble Corona dscharge voltage (KVrms) RIV test rms. (mcro volts) Not exceedng 1000 (at 266 KV rms) 3" Al.Ppe/ ACSR conductor _ Not exceedng 500 (at 156 KV rms) 2.5" Al.Ppe/ ACSR conductor _ Not exceedng 500 (at 92 KV rms) 23. Partal dscharge level (PC) Not exceedng 10 PC excludng 33KV /2500 mcro Sec. Swtchng mpulse wthstand dry & wet (between lne termnals and ground) 1050 KVp 25. Class of nsulaton E or A (as per schedule) A 1.5" Al.Ppe/ACSR conductor _ - Page 16 of 17

17 GUARANTEED TECHNICAL PARTICULARS OF CURRENT TRANSFORMERS 1 CT : GENERAL a) Name of Manufacturer (To be flled n and sgned by the Bdder) b) Type & Model of the Manufacturer c) Conformng Standard d) Date of Last Type Test e) Dead Tank or Lve Tank Constructon f) Dameter of Hgh Voltage Stud (mm) x Length (mm) g) Total Heght of the CT h) Total Weght of the CT ) Materal Used n Prmary Wndng j) Materal Used n Secondary Wndng k) Rated voltage (KV) 2 CT INSULATION LEVEL a) 1.2/50 mcro second Impulse wthstand voltage (dry) on prmary wndng (KV peak) b) One mnute power frequency wthstand voltage(dry) on prmary wndng (KV rms) c) One mnute power frequency wthstand voltage(wet) on prmary wndng (KV rms) d) One mnute power frequency wthstand test voltage n secondary wndng (KV rms) 3 CT CURRENT a) Rated prmary current (Amp) b) Rated secondary current (Amp) c) Extended current ratng (Amp) d) Short tme thermal ratng of prmary current for e) 1 sec and 3 sec f) Rated dynamc current of prmary (KAp) g) Rated contnuous thermal current (KA rms) h) Temperature rse at rated contnuous thermal current over 50oC Ambent Temp. (oc) 4 CT Bushng a) Mnmum creepage dstance (mm) b) Whether CT bushng s hermetcally sealed or not c) Cantlever Strength (Kgf) 5 CT :Detals of s a) Current rato b) Accuracy Class/ALF/ISF c) Kn/Ie/RCT at hghest rato Page 17 of 17