Amendment to RFP & TSA: Transmission System for Transmission Scheme for Solar Energy Zone in Bidar (2500 MW), Karnataka) Page 1 of 40 Amendment –III dated 01.06.2020 on the Request for Proposal and Transmission Service Agreement issued for selection of bidder as Transmission Service Provider to establish “Transmission System for Transmission Scheme for Solar Energy Zone in Bidar (2500 MW), Karnataka” through tariff based competitive bidding process Amendment in Technical Specifications of Transmission System Sl. No. Existing Provision New / Revised Provision SPECIFIC TECHNICAL REQUIREMENTS FOR TRANSMISSION LINE 1. 2.1 Steel section of grade E 250 and/or grade E 350 as per IS 2062, are only permitted for use in towers, extensions, gantry structures and stub setting templates. For towers in snowbound areas, steel sections shall conform to Grade-C of IS-2062. 2.1 Steel section of grade E 250 and/or grade E 350 as per IS 2062, only are permitted for use in towers, extensions, gantry structures and stub setting templates. For towers in snowbound areas, steel sections shall conform to Grade-C of IS-2062. 2. 8.0 b) Minimum ground clearance: 15 m 8.0 b) Minimum ground clearance: 18 m 3. 11.0 In case of 765kV voltage class lines, at least one out of two earth wires shall be OPGW and second earth wire, if not OPGW, shall be either of galvanized standard steel (GSS) or AACSR or any other suitable conductor type depending upon span length and other technical consideration. Each tower shall be earthed such that tower footing impedance does not exceed 10 ohms. Pipe type or Counterpoise type earthing shall be provided in accordance with relevant IS. Additional earthing shall be provided on every 7 to 8 kms distance at tension tower for direct earthing of both shield 11.0 In case of 765kV voltage class lines, at least one out of two earth wires shall be OPGW and second earth wire, if not OPGW, shall be either of galvanized standard steel (GSS) or AACSR or any other suitable conductor type depending upon span length and other technical consideration.
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1. 2.1SteelsectionofgradeE250and/orgradeE350asperIS2062,areonlypermittedforuseintowers,extensions,gantrystructuresandstub setting templates. For towers in snowbound areas, steelsectionsshallconformtoGrade-CofIS-2062.
2.1Steel section of grade E 250 and/or grade E 350 as per IS 2062,onlyarepermittedforuseintowers,extensions,gantrystructuresand stub setting templates. For towers in snowbound areas, steelsectionsshallconformtoGrade-CofIS-2062.
2. 8.0b)Minimumgroundclearance:15m
8.0b)Minimumgroundclearance:18m
3. 11.0In case of 765kV voltage class lines, at least one out of two earthwires shallbeOPGWandsecondearthwire, ifnotOPGW, shallbeeither of galvanized standard steel (GSS) or AACSR or any othersuitable conductor type depending upon span length and othertechnicalconsideration.Eachtowershallbeearthedsuchthattowerfootingimpedancedoes not exceed 10 ohms. Pipe type or Counterpoise typeearthing shall be provided in accordance with relevant IS.Additional earthing shall be provided on every 7 to 8 kmsdistance at tension tower for direct earthing of both shield
11.0In case of 765kVvoltage class lines, at least one out of two earthwiresshallbeOPGWandsecondearthwire, ifnotOPGW,shallbeeither of galvanized standard steel (GSS) or AACSR or any othersuitable conductor type depending upon span length and othertechnicalconsideration.
Eachtowershallbeearthedsuchthattowerfootingimpedancedoes not exceed 10 ohms. Pipe type or Counterpoise typeearthing shall be provided in accordance with relevant IS.Additional earthing shall be provided on every 7 to 8 kmsdistance at tension tower for direct earthing of both shieldwires. If site condition demands, multiple earthing or use ofearthingenhancementcompoundshallbeused.
6. NewPointtobeinserted 14.0Transmission line route shall be finalized, in consultationwithappropriateauthoritiessoastoavoidthehabitantzonesofGreatIndian Bustard and other protected species. Bird diverters,whereverrequired,shallbeprovidedontheline.
SPECIFICTECHNICALREQUIREMENTSFORSUBSTATION
7. GeneralThe proposed new substation shall be conventional AIS typegenerally conforming to the requirements of CEA regulation forconstructionofsubstation.TheproposedaugmentationatMaheswaram(PG)shallbeGIS type
GeneralThe proposed new substation shall be conventional AIS typegenerally conforming to the requirements of CEA (TechnicalStandards for Construction of Electrical Plants and ElectricLines)Regulations2010,asamendedfromtimetotime.The proposed augmentation atMaheswaram (PG) shall be GIS type
generally conforming to the requirement of CEA regulation forconstructionofsubstation.
generally conforming to the requirement of CEA (TechnicalStandards for Construction of Electrical Plants and ElectricLines)Regulations2010,asamendedfromtimetotime.
The switchgear shall be designed and specified to withstandoperating conditions and duty requirements. The rated current ofequipmentshallbeasmentionedbelow:
The switchgear shall be designed and specified to withstandoperating conditions and duty requirements. The rated current ofequipmentshallbeasmentionedbelow:
Further, current rating of all equipment in one diameter shallbe the highest current rating required for connectedline/ICT/Reactorsothatthesystemcouldoperatewithoutanyconstraintincaseofoutageofanybusbar.At765kVMaheswaramGISsubstation,2nos.of765kVGIScompletediametersshall……………………..
11. 2.1 (765/Ö3) / (400/Ö3) / 33 kV Single PhaseAutotransformerTransformer shall conform to IEC-60076 in general. Thetransformer and all its accessories including bushing/ built in CTsetc.shallbedesignedtowithstandthermalandmechanicalstressescaused by symmetrical or asymmetrical faults on any terminals.Mechanical strength of the transformer shall be such that it canwithstand3-phaseand1-phasethroughfaultfortransformerratedvoltageappliedtoHVand/orIVterminalsoftransformer.TheshortcircuitshallalternativelybeconsideredtobeappliedtoeachoftheIV,HVandtertiary(LV)terminalsofthetransformer.Thetertiaryisnot considered to be connected to source. The maximum shortcircuitoutputcurrentat thetertiaryterminalsshallbe limitedtoasafevaluetomakethetransformershortcircuitproof.TheTertiarywinding shall be designed to withstand mechanical and thermalstresses due to dead short circuit on its terminals. However, thecoolingforcontinuousthermalratingofthetertiarywindingshallbeofatleast5MVAcapacity.Core shall be constructed from high grade, non-ageing cold rolledsuper grain oriented silicon steel laminations with requisite BIScertification (HI-B or better grade). The maximum flux density inany part of the core and yoke at the rated MVA, voltage andfrequencyshallnotexceed1.9Teslaatalltappositionsduring10%continuous over voltage condition. The Transformers shallwithstand without damage and over-heating due to over fluxingconditionsof105% for continuous, 125% for1minute and150%for5seconds.All the windings shall be capable of withstanding the dielectric,
2.1(765/Ö3)/(400/Ö3)/33kVSinglePhaseAutotransformerTransformershallconformtoIEC-60076ingeneral.Thetransformerand all its accessories including bushing/ built in CTs etc. shall bedesigned to withstand thermal and mechanical stresses caused bysymmetrical or asymmetrical faults on any terminals. Mechanicalstrength of the transformer shall be such that it can withstand 3-phase and 1- phase through fault for transformer rated voltageapplied toHVand/or IV terminalsof transformer.The short circuitshallalternativelybeconsideredtobeapplied toeachof the IV,HVandtertiary(LV)terminalsofthetransformer.Thetertiaryshallbeconsidered not connected to source. The maximum short circuitoutput current at the tertiary terminals shall be limited to a safevalue to make the transformer short circuit proof. The Tertiarywinding shall be designed to withstand mechanical and thermalstresses due to dead short circuit on its terminals. However, thecoolingforcontinuousthermalratingofthetertiarywindingshallbeofatleast5MVAcapacity.Core shall be constructed from high grade, non-ageing cold rolledsuper grain oriented silicon steel laminations with requisite BIScertification(HI-Borbettergrade).Themaximumfluxdensityinanypart of the core and yoke at the ratedMVA, voltage and frequencyshallnotexceed1.9Teslaatalltappositionsduring10%continuousover voltage condition. The Transformers shall withstand withoutdamageandover-heatingduetooverfluxingconditionsof110%forcontinuous,125%for1minuteand150%for5seconds.All the windings shall be capable of withstanding the dielectric,mechanicalandthermalstresseswhichmaybecausedbyswitching,deadshortcircuitonitsterminals.Transfersurgeattertiaryshallnot
mechanicalandthermalstresseswhichmaybecausedbyswitching,dead short circuit on its terminals. Transfer surge at tertiary shallnotexceed250kVpduringimpulsefromHV&IVTerminals.Theaircore reactance of the HV winding shall be not less than 25%.External or internal reactors shall not be used to achieve thespecifiedHV/IV,HV/LVandIV/LVimpedances.Transformershallbe fittedwith4x33.3%independentcoolerbanks, out of which 3x33.3% shall be capable of dissipatingtotal losses at continuous maximum rating and 1x33.3%radiator bank shall be used as stand by. Each cooler bank(1x33.3%) shall be capable of dissipating33.3per cent of theloss at continuous maximum rating independently. Coolingshallbesodesignedthatduringtotalfailureofpowersupplytocoolingfansandoilpumps(consideringonlythreecoolerbank(3x33%), the transformer shall be able to operate at full loadforatleasttwenty(20)minuteswithoutthecalculatedwindinghot spot temperature exceeding 140 deg C. Transformer shallbe designed so that tank hotspot shall not exceed 110 deg C,consideringmaximumambienttemperatureof50Deg.C.The transformer shall be complete with all required accessories,Bushing CTs, Neutral CT (outdoor type), cooler control cabinet,individualandcommonmarshallingbox,RTCC etc. as required forsatisfactory operations of transformer.The transformer shall beprovidedwith IEC 61850 compliant digital RTCC relay havingautomatic voltage regulating features using Bay control andprotectionunitusedforSAStooperateOLTCincludingparalleloperationof transformers.Neutralof the transformershallbesolidlygrounded.
exceed250kVpduringimpulsefromHV&IVTerminals.TheaircorereactanceoftheHVwindingshallbenotlessthan20%.Externalorinternal reactors shall not be used to achieve the specified HV/IV,HV/LVandIV/LVimpedances.Transformershallbefittedwithtwocoolerbanks,eachcapableof dissipating 50 per cent of the loss at continuous maximumrating.Transformershallbecapableofoperatingatfullloadfor20minutesintheeventoffailureoftheoilcirculatingpumporblowersassociatedwithonecoolerbankandforatleastten(10)minutes in theeventof total failureofpowersupply tocoolingfans and oil pumps, without winding hot spot temperatureexceeding140degC.Transformershallbedesignedsothattankhotspot shall not exceed 110 deg C, considering maximumambienttemperatureof50Deg.C.The transformer shall be complete with all required accessories,Bushing CTs, Neutral CT (outdoor type), cooler control cabinet,individual and common marshalling box, etc. as required forsatisfactoryoperationsoftransformer.Remotetapchangercontroland monitoring system including parallel operation oftransformers shall be carried out using Bay control unit ordigitalRTCCrelaythroughSubstationAutomationSystem.Sparetransformerunitshallbeplacedandconnectedinsuchawaythatincaseoffaultanyunitofanyofthetransformerbankscanbereplacedbyspareunitwithoutphysicallymovingit.
HV & IV bushings shall be porcelain / composite type andhermetically sealedoil filled condenser type. LVbushing shallbeofRIP(resinimpregnatedpapercondenser)withcompositeinsulator type. 36kV Neutral bushing shall be solid or oilcommunicatingtypewithporcelainhousing.The Technical Particulars / Parameters of Transformer are givenbelow:Sr.No. Description Unit Parameters1 RatedCapacity:
HV,andIVbushingshallbeRIP(ResinImpregnatedPaper)/RIS(ResinImpregnatedSynthetic)withcompositeinsulatortype.LVbushing shall be OIP/RIP/RIS. 36kV Neutral bushing shall besolidporcelainoroilcommunicatingtype.The Technical Particulars / Parameters of Transformer are givenbelow:S.No. Description Unit Parameters
12. 2.2765/Ö3kVSinglePhaseShuntReactor………….The shunt reactor shall be of either gapped core type ormagneticallyshieldedaircoretype(shelltype)construction.Theimpedance ratio (X0/X1) specified shall be achieved adopting byeither single phase construction in separate tanks or 3 limb coreconstruction.Incaseofcorelessconstruction,amagneticshieldshall be provided around the coreless coils and non-magneticmaterial sheet shall form the central core to minimize thevibrations. Core shall be constructed fromnon-ageing, cold rolledgrain oriented silicon steel laminations with requisite BIScertification.………………..Thereactorshallbecompletewithallrequiredaccessories,BushingCTs,NeutralCT(outdoortype)(ifrequired),individualandcommonmarshalling box etc. as required for satisfactory operations ofreactor. HV bushing shall be porcelain/composite type andhermetically sealedoil filled condenser type.NeutralBushing shallbe 145kV RIP (resin impregnated paper condenser) withcompositeinsulatortype.
2.2765/Ö3kVSinglePhaseShuntReactor…………The shunt reactor shall be of gapped core type construction. Theimpedance ratio (X0/X1) specified shall be achieved adopting byeither single phase construction in separate tanks or 3 limb coreconstruction.Coreshallbeconstructedfromnon-ageing,coldrolledgrain oriented silicon steel laminations with requisite BIScertification.……………………..Thereactorshallbecompletewithallrequiredaccessories,BushingCTs,NeutralCT(outdoortype)(ifrequired),individualandcommonmarshalling box etc. as required for satisfactory operations ofreactor. HV bushing shall be porcelain/composite type andhermeticallysealedoilfilledcondensertype.NeutralBushingshallbe145kVRIP(ResinImpregnatedPaper)/RIS(ResinImpregnatedSynthetic)withcompositeinsulatortype.
6 Crest value of ThirdHarmonic content inphase current atrated voltage withsinusoidalwaveform
% ≤ 3% of the crestvalueoffundamental
7 Range of constantcurrent
Upto1.25p.u.voltage
8 Toleranceoncurrent % (i) 0 to +5% for asinglephaseunit
±1% for betweenunits
Sparereactorunitshallbeplacedandconnectedinsuchawaythatincaseoffaultanyunitofanyofthelinereactorbanksorbus reactor banks can be replaced by spare unit withoutphysicallymovingit.The Technical Particulars / Parameters of 1-phase, 80 MVAr,765/√3kVShuntReactoraregivenbelow:S.No. Description Unit TechnicalParameters1. Ratedcapacityat
………………NeutralGroundingReactor(NGR)andSurgeArresterfor765kVlinereactorsTheneutral grounding reactors are required for groundingofthe neutral point of shunt reactors to limit the secondary arccurrentandtherecoveryvoltagetoaminimumvalue.TSPshallprovideNGRofsuitablevalue(Ohm)asperactual line length.NGRshallbedrytypeaircoreforoutdoorapplication.LineandgroundsideofNGRshallberatedfor145kVand36kVclassofinsulation respectively. NGR shall be rated for continuouscurrent of 20A and short time current of 240A r.m.s for 1minute. However, the NGR shall be designed for a short timecurrent of 600Amp r.m.s to ensuremechanical robustness. It
voltage&frequency
27. MaximumPermissibleLossesofReactor
i) Max. Total loss atrated current andfrequencyandat75OC
kW 98
ii) Max. I2RLoss at ratedcurrentandfrequencyandat75OC
…………………NeutralGroundingReactor(NGR)andSurgeArresterfor765kVlinereactorsTSPshallprovideNGRofsuitablevalue(Ohm)asperactuallinelength. NGR shall be oil filled or dry type air core for outdoorapplication. Line and ground side of NGR shall be rated for145kVand36kV classof insulation respectively.Oil filledNGRshall be rated for continuous current of 10A and short timecurrentof60Ar.m.sfor10secondswhileaircoreNGRshallberated for continuous current of 20A and short time current of240A r.m.s for 1 minute. However, the air core NGR shall bedesigned for a short time current of 600 Amp r.m.s to ensuremechanical robustness. The air coreNGR shall bemounted on
shallbesolidlyconnectedbetweenneutralofshuntreactorandearth. The NGR shall be mounted on support structure (non-magnetic material) high above ground level (2.55 meter) toallow free and safe access at ground level for personnel.Further, a suitable bypass switching arrangement should beprovided across NGR so that neutral of line reactor can besolidlygroundedbybypassingNGRandlinereactorcanbeusedasbusreactor,ifrequired.The surge arresters (rated voltage 132kV) shall be of heavyduty station class type. It shall be physically located betweenthe neutral of shunt reactor (brought out at 145kV classbushing) and neutral grounding reactor. The surge arrestersshall conform in general to IEC-60099-4. Surgearresters shallbe of gapless typewithout any series or shunt gap. Arrestersshall be hermetically sealed units, of self-supportingconstruction,suitableformountingonstructures.
support structure (non-magnetic material) high above groundlevel(2.55meter) toallowfreeandsafeaccessatgroundlevelforpersonnel.The surgearresters (ratedvoltage120kV) shallbeprovided&physicallylocatedbetweentheneutralofshuntreactor(broughtoutat145kVclassbushing)andneutralgroundingreactor.ThesurgearrestersshallbeofheavydutystationclassgaplessMetaloxide (ZnO) type conforming in general to IEC-60099-4.Arresters shall be hermetically sealed units, of self-supportingconstruction,suitableformountingonstructures.
13. 2.3400/220kV,3-PhaseTransformerTransformer shall conform to IEC60076 in general. The500MVAtransformers shall be designed based on design of dynamic shortcircuit tested315MVAor500MVAtransformers.Thetransformerand all its accessories including bushing/ built in CTs etc shall bedesigned towithstand thermal andmechanical stresses caused bysymmetrical or asymmetrical faults on any terminals. Mechanicalstrength of the transformer shall be such that it canwithstand 3-phase and 1- phase through fault for transformer rated voltageappliedtoHVand/orIVterminalsoftransformer.TheshortcircuitshallalternativelybeconsideredtobeappliedtoeachoftheHV,IVandtertiary(LV)transformerterminals.Tertiaryisnotconsideredtobeconnectedtosource.
2.3400/220kV,3-PhaseTransformerTransformer shall conform to IEC 60076 in general. The 500MVAtransformers shall be designed based on design of dynamic shortcircuit tested 315MVA or 500MVA transformers. The transformerand all its accessories including bushing/ built in CTs etc shall bedesigned to withstand thermal and mechanical stresses caused bysymmetrical or asymmetrical faults on any terminals. Mechanicalstrength of the transformer shall be such that it can withstand 3-phase and 1- phase through fault for transformer rated voltageappliedtoHVand/orIVterminalsoftransformer.Theshortcircuitshallalternativelybeconsideredtobeapplied toeachof theHV, IVandtertiary(LV)transformerterminals.Tertiaryshallbeconsiderednot connected to source. The maximum short circuit output
…………………The transformer shall be complete with all required accessories,Bushing CTs, cooler control cabinet, individual and commonmarshallingbox,RTCCetcasrequiredforsatisfactoryoperationsoftransformer.ThetransformershallbeprovidedwithIEC61850compliant digital RTCC relay having automatic voltageregulatingfeaturesusingBaycontrolandprotectionunitusedfor SAS, to operate OLTC including parallel operation oftransformers.
Neutralofthetransformershallbesolidlygrounded.HV, IV and LV bushing shall be RIP (resin impregnated papercondenser) with composite insulator type. 36kV Neutralbushingshallbesolidporcelainoroilcommunicatingtype.
currentatthetertiaryterminalsshallbelimitedtoasafevalueto make the transformer short circuit proof. The Tertiarywindingshallbedesignedtowithstandmechanicalandthermalstressesduetodeadshortcircuitonitsterminals.However,thecooling for continuous thermal rating of the tertiary windingshallbeforatleast5MVAcapacity.…………….The transformer shall be complete with all required accessories,Bushing CTs, cooler control cabinet, individual and commonmarshalling box, etc as required for satisfactory operations oftransformer.RemotetapchangercontrolandmonitoringsystemincludingparalleloperationoftransformersshallbecarriedoutusingBaycontrolunitordigitalRTCCrelaythroughSubstationAutomationSystem.Neutralofthetransformershallbesolidlygrounded.HV, IV and LV bushing shall be RIS (Resin ImpregnatedSynthetic)/ RIP (Resin Impregnated Paper) with compositeinsulator type. LV bushing shall be OIP/RIP/RIS. 36kV Neutralbushingshallbesolidporcelainoroilcommunicatingtype.
Themajortechnicalparticulars/parametersoftransformeraregivenbelow:TechnicalParticulars/Parametersof500MVA,400/220/33kV,3-PhaseAutotransformerSl. Description Unit TechnicalParameters1. RatedCapacity:
HV/IV/LV(Tertiary)MVA 500/500/166.67
2. …………. ………. …………….
3. …………. ………. …………….
….. …………. ………. …………….
15. InsulatingOil virgin high gradeinhibited, conforming toIEC-60296
The major technical particulars / parameters of transformer aregivenbelow:Technical Particulars/ Parameters of 500MVA, 400/220/33kV,3-PhaseAutotransformerSl. Description Unit TechnicalParameters1. RatedCapacity:
HV/IV/LV(Tertiary)MVA 500/500/166.67
Tertiary active loading: 5MVA
2. …………. ………. …………….
3. …………. ………. …………….
….. …………. ………. …………….
15. InsulatingOil Unused inhibited oruninhibited Transformeroil, conforming to IEC-60296-2012
14. 2.4420kV,3-Phase,ShuntReactor……………..The reactor shall be of either gapped core type ormagneticallyshielded air core type (shell type) construction. The impedanceratio (X0/X1) specified shall be achievedby adopting either singlephaseconstructioninseparatetanksorthreephasewith3limbor5limb core construction. In case of coreless construction, amagneticshieldshallbeprovidedaroundthecorelesscoilsandnon-magnetic material sheet shall form the central core tominimize the vibrations. Core shall be constructed from non-
2.4420kV,3-Phase,ShuntReactor……………….Thereactorshallbeofgappedcoretypeconstruction.Theimpedanceratio (X0/X1) specified shall be achieved by adopting either singlephaseconstructioninseparatetanksorthreephasewith3limbor5limb core construction. Core shall be constructed from non-ageing,coldrolledgrainorientedsiliconsteellaminationswithrequisiteBIScertification.
………………………Thereactorshallbecompletewithallrequiredaccessories,BushingCTs, marshalling box etc as required for satisfactory operations ofreactor.HVandNeutralbushingsshallbeRIP(ResinImpregnatedPaper)/ RIS (Resin Impregnated Synthetic) with compositeinsulatortype.TheTechnicalParticulars/Parametersof3-phase,125MVAr,420kVShuntReactoraregivenbelow:S.No Description Unit Technical
…………….NeutralGroundingReactor(NGR)andSurgeArresterfor400kVLineReactors(asapplicable)Theneutral grounding reactors are required for groundingofthe neutral point of shunt reactors to limit the secondary arccurrentandtherecoveryvoltagetoaminimumvalue.NGRshallbe oil filled type suitable for outdoor application. Line andgroundsideofNGRshallberatedfor145kVand36kVclassofinsulation respectively. NGR shall be rated for continuouscurrent of 10A and short time current of 60A r.m.s for 10seconds.Itshallbesolidlyconnectedbetweenneutralofshuntreactorandearth.
……………..Neutral Grounding Reactor (NGR) and Surge Arrester for LineReactorsTSPshallprovideNGRofsuitablevalue(Ohm)asperactuallinelength. NGR shall be oil filled or dry type air core suitable foroutdoorapplication.LineandgroundsideofNGRshallberatedfor 145kV and 36kV class of insulation respectively. Oil filledNGRshallberatedforcontinuouscurrentof10Aandshorttimecurrentof60Ar.m.sfor10secondswhileaircoreNGRshallberated for continuous current of 20A and short time current of240A r.m.s for 1 minute. However, the air core NGR shall bedesigned for a short time current of 600 Amp r.m.s to ensuremechanical robustness. The air coreNGR shall bemounted onsupport structure (non-magnetic material) high above groundlevel(2.55meter) toallowfreeandsafeaccessatground levelforpersonnel.
The surge arresters (rated voltage 120kV) shall be of heavyduty station class type. It shall be physically located betweenthe neutral of shunt reactor (brought out at 145kV classbushing) and neutral grounding reactor. The surge arrestersshall conform in general to IEC-60099-4. Surgearresters shallbe of gapless typewithout any series or shunt gap. Arrestersshall be hermetically sealed units, of self-supportingconstruction,suitableformountingonstructures.
The surgearresters (ratedvoltage120kV) shallbeprovided&physicallylocatedbetweentheneutralofshuntreactor(broughtoutat145kVclassbushing)andneutralgroundingreactor.ThesurgearrestersshallbeofheavydutystationclassgaplessMetaloxide (ZnO) type conforming in general to IEC-60099-4.Arresters shall be hermetically sealed units, of self-supportingconstruction,suitableformountingonstructures.
15. 2.5765kVGISSubstationequipmentGIS(GasInsulatedSwitchgear)shallbeIndoortypeinaccordancetoIEC:62271-203.Theswitchgearshallbedesignedandspecifiedtowithstand operating conditions and duty requirements. All theswitchgearsuchasCircuitBreaker, isolator, earthswitch includingCT, PT etc. shall be GIS type.OutdoorSurgeArrestor andVoltageTransformershallbeAISorGIStype.TheGIS assembly shall consist of separatemodular compartmentse.g.CircuitBreakercompartment,Busbarcompartment filledwithSF6Gasandseparatedbygastightpartitionssoastominimizerisktohumanlife,alloweaseofmaintenanceandlimittheeffectsofgasleaks failures & internal arcs etc. These compartments shall bedesigned tominimize the risk of damage to adjacent sections andprotectionofpersonnelintheeventofafailureoccurringwithinthecompartments.Rupturediaphragmswithsuitabledeflectorsshallbeprovided to prevent uncontrolled bursting pressures developingwithin the enclosures under worst operating conditions, thusproviding controlled pressure relief in the affected compartment.Thearrangementofgassectionsorcompartmentsshallbesuchas
2.5765kVGISSubstationequipmentGIS(GasInsulatedSwitchgear)shallbeIndoortypeinaccordancetoIEC:62271-203.The switchgear shall bedesignedand specified towithstand operating conditions and duty requirements. All theswitchgear such as Circuit Breaker, isolator, earth switch includingCT, PT etc. shall be GIS type. The Surge Arrestor and VoltageTransformershallbeeitherGISoroutdoorAIStype.The GIS assembly shall consist of separate modular compartmentse.g. Circuit Breaker compartment, Bus bar compartment filledwithSF6Gasandseparatedbygastightpartitionssoastominimizerisktohumanlife,alloweaseofmaintenanceandlimittheeffectsofgasleaks failures & internal arcs etc. These compartments shall bedesigned to minimize the risk of damage to adjacent sections andprotectionofpersonnelintheeventofafailureoccurringwithinthecompartments.Rupturediaphragmswithsuitabledeflectorsshallbeprovided to prevent uncontrolled bursting pressures developingwithin the enclosures under worst operating conditions, thusprovidingcontrolledpressurereliefintheaffectedcompartment.Thearrangement of gas sections or compartments shall be such as to
to facilitate future extension of any make without any drilling,cuttingorweldingontheexistingequipment.Toaddequipment, itshallnotbenecessarytomoveordislocatetheexistingswitchgearbays.The bus bar modules including auxiliary bus modules (whereverapplicable) shall be provided with suitable End Piece (Interface)module with the test link facility for future extension as perprovisions of future requirement. The end piece module shall bedesigned in such a way so that future GIS modulemay be testedwithout extending test voltage to existing bus and vice-versa byremovingthetestlink.………………………………………..
facilitatefutureextensionofanymakewithoutanydrilling,cuttingorweldingontheexistingequipment.Toaddequipment,itshallnotbenecessary to move or dislocate the existing switchgear bays. ThelayoutofGas InsulatedBusDucts shallbeproperlyplanned tooptimize the length of bus ducts and for easy accessibility formaintenance.Thelengthofbusbars,busducts,isolatorsectionsshall be optimized considering effects of fast transient voltageduetoisolatoroperations.The bus bar modules including auxiliary bus modules (whereverapplicable) shall be provided with suitable End Piece (Interface)module with the test link facility for future extension as perprovisions of future requirement. The end piece module shall bedesigned in such a way so that future GIS module can be testedwithout extending test voltage to existing bus and vice-versa byremovingthetestlink.………………………………………..
16. 2.5.1CircuitBreakersGISCircuitbreakersshallingeneralbeofC2-M2classandcomplytoIEC- 62271-100. The rated break time shall not exceed 40ms for765kV. Circuit breakers shall be provided with single phase andthreephaseauto reclosing.TheCircuitbreakers controlling765kVlines shall beprovidedwithpre insertion closing resistor of about450ohmswith9ms insertiontimeorControlledSwitchingDevice(CSD). The short line fault capacity shall be same as the ratedcapacityandthisisproposedtobeachievedwithoutuseofopeningresistors. Control switching device shall be provided in CircuitBreakerofswitchablelinereactorbayandinMain&Tiebaycircuit
2.5.1CircuitBreakersGISCircuitbreakersshallingeneralbeofC2-M2classandcomplytoIEC- 62271-100. The rated break time shall not exceed 40 ms for765kV.Circuitbreakersshallbeprovidedwithsinglephaseandthreephase auto reclosing. The Circuit breakers controlling 765kV linesshall be provided with pre insertion closing resistor of about 450ohmswith9msinsertiontimeorControlledSwitchingDevice(CSD).Theshort linefaultcapacityshallbesameastheratedcapacityandthis is proposed to be achieved without use of opening resistors.Control switching device shall be provided in Circuit Breaker ofswitchablelinereactorbayandinMain&Tiebaycircuitbreakersof
17. 2.5.2IsolatorsThe isolators shall comply to IEC 62271-102 in general. Isolatorsshall be motor (DC powered) operated. Earth switches areprovidedatvariouslocationstofacilitatemaintenance.Mainbladesandearthbladesshallbeinterlockedandinterlockshallbefailsafetype.Allearthswitchesshallbemotoroperatedtype.IsolatorshallbesuitableforBusTransferCurrentSwitchingdutyasper IEC standard. High speed earthing switches shall be providedfor grounding purpose at overhead line terminations & cableterminations & cable terminations and shall have fault makingcapability as specified. Earth switch for line isolator shall be ofearthing switch class E1 and shall be suitable for induced currentswitchingdutyasdefinedforClass-Basperrelevantstandard.
2.5.2IsolatorsThe isolators shall comply to IEC 62271-102 in general. Isolatorsshallbemotor(DCpowered)operated.Earthswitchesareprovidedatvariouslocationstofacilitatemaintenance.Mainbladesandearthblades shall be interlocked and interlock shall be fail safe type. Allisolatorsandearthswitchesshallbemotoroperatedtype.Isolatorshallbeofextendedmechanicalenduranceclass-M2andsuitableforBusTransferCurrentSwitchingdutyasperIECstandard.High speed earthing switches shall be provided for groundingpurposeatoverheadlineterminations&cableterminations&cableterminations and shall have fault making capability as specified.EarthswitchforlineisolatorshallbeofearthingswitchclassE1andshall be suitable for induced current switching duty as defined forClass-Basperrelevantstandard.
18. 2.5.3CurrentTransformersCurrent Transformers shall complywith IEC 61869 in general. Allratios shallbeobtainedby secondary tapsonly.Generally,CurrentTransformers(CT)shallhavefivecores(fourforprotectionandoneformetering)whereas;CTinTiebaysshallhavesixcores(fourforprotections&twoformetering)suitablydistributedonbothsidesofCB(for400kVandabovevoltageclass).Theburdenandkneepointvoltageshallbeinaccordancewiththerequirementsofthesystemincludingpossiblefeedsfortelemetry.Accuracyclassforprotectioncore shall be PX and formetering core it shall be 0.2S. The ratedburdenofcoresshallbeclosertothemaximumburdenrequirementofmetering&protectionsystemforbettersensitivityandaccuracy.
2.5.3CurrentTransformersCurrent Transformers shall comply with IEC 61869 in general. Allratios shall be obtained by secondary taps only. Generally, CurrentTransformers(CT)shallhavefivecores(fourforprotectionandoneformetering)whereas;CT inTiebaysshallhavesixcores (four forprotections&twoformetering)suitablydistributedonbothsidesofCB(for400kVandabovevoltageclass).Theburdenandkneepointvoltage shall be in accordancewith the requirementsof the systemincludingpossible feeds for telemetry.Accuracyclass forprotectioncore shall be PX and for metering core it shall be 0.2S. The ratedburdenofcoresshallbeclosertothemaximumburdenrequirementofmetering&protectionsystem(notmorethan20VAformetering
19. 2.5.4VoltageTransformers……………The ratedburdenof cores shall be closer to themaximumburdenrequirementofmetering&protection system forbetter sensitivityandaccuracy.
2.5.4VoltageTransformers…………….The rated burden of cores shall be closer to themaximum burdenrequirementofmetering&protectionsystem(notmorethan50VAformeteringcore)forbettersensitivityandaccuracy.
20. 2.6CircuitBreaker(AIS)The circuit breakers and accessories shall conform to IEC: 62271-100, IEC: 62271-1 and shall be of SF6Type. The rated break timeshallnotexceed40msfor765kV&400kVcircuitbreakersand60ms for 220kV circuit breakers. 765kV, 400kV and 220kV Circuitbreakersshallbeprovidedwithsinglephaseand threephaseautoreclosing. The Circuit breakers controlling 765kV lines shall beprovided with pre insertion closing resistor of about 450 ohmsmaximum with 9 ms minimum insertion time or ControlledSwitching Device. The Circuit breakers controlling 400kV lines ofmorethan200kmlengthshallbeprovidedwithpreinsertionclosingresistorofabout400ohmsmaximumwith8msminimuminsertiontime or Controlled Switching Device. The short line fault capacityshall be same as the rated capacity and this is proposed to beachievedwithoutuseofopeningresistors.Controlswitchingdeviceshall be provided in Circuit Breaker of switchable line reactor bayand inMain&Tiebaycircuitbreakersof linewithnon-switchablelinereactors,Busreactorsand765/400kVTransformers(wherever
2.6CircuitBreaker(AIS)The circuit breakers and accessories shall conform to IEC: 62271-100, IEC: 62271-1 and shall be of SF6 Type.The circuit breakersshall be of class C2-M2 (as per IEC) with regard to restrikeprobabilityduring capacitive currentbreakingandmechanicalendurance.Theratedbreaktimeshallnotexceed40msfor765kV&400kVcircuitbreakersand60msfor220kVcircuitbreakers.765kV,400kV and 220kV Circuit breakers shall be provided with singlephase and three phase auto reclosing. The Circuit breakerscontrolling765kV linesshallbeprovidedwithpre insertionclosingresistorofabout450ohmsmaximumwith9msminimuminsertiontimeorControlledSwitchingDevice.TheCircuitbreakerscontrolling400kV linesofmore than200km length shall beprovidedwithpreinsertion closing resistor of about 400 ohms maximum with 8 msminimum insertion time or Controlled Switching Device. The shortline fault capacity shall be same as the rated capacity and this isproposed to be achieved without use of opening resistors. Controlswitching device shall be provided in Circuit Breaker of switchable
applicable). line reactorbayand inMain&Tiebaycircuitbreakersof linewithnon-switchable line reactors, Bus reactors and 765/400kVTransformers.
21. 2.7Isolator(AIS)The isolators shall comply to IEC 62271-102 in general. 765kVIsolatordesignshallbedoublebreakorverticalbreakorknee-type.400kVand220kVIsolatorsshallbedoublebreaktype.AllIsolatorsandearthswitchesshallbemotoroperated.Earthswitchesshallbeprovided at various locations to facilitate maintenance. Isolatorratedfor765kV,400kVand220kVshallbeofextendedmechanicalenduranceclass-M2andallearthswitchesshallbeclassM0asperIEC-62271-102.Main blades and earth blades shall be interlockedandinterlockshallbefailsafetype.765kV,400kVand220kVearthswitch for line isolator shall be suitable for induced currentswitchingdutyasdefinedforClass-B.
2.7Isolator(AIS)The isolators shall comply to IEC 62271-102 in general. 765kVIsolatordesignshallbedoublebreakorverticalbreakorknee-type.400kVand220kVIsolatorsshallbedoublebreaktype.AllIsolatorsandearthswitchesshallbemotoroperated.Earthswitchesshallbeprovidedatvariouslocationstofacilitatemaintenance.Isolatorratedfor 765kV, 400kV and 220kV shall be of extended mechanicalendurance class-M2 and suitable for bus transfer currentswitchingdutyasperIEC-62271-102.Mainbladesandearthbladesshall be interlocked and interlock shall be fail safe type. 765kV,400kVand220kVearthswitch for line isolatorshallbesuitable forinducedcurrentswitchingdutyasdefinedforClass-B
22. 2.8CurrentTransformer(AIS)Current Transformers shall complywith IEC 61869 in general. Allratiosshallbeobtainedbysecondarytapsonly.Generally,CurrentTransformers(CT)for765kV&400kVshallhavesixcores(fourforprotectionandtwoformetering).220kVCurrentTransformersshallhave five cores (four for protection and one for metering). Theburden and knee point voltage shall be in accordance with therequirements of the system including possible feeds for telemetry.AccuracyclassforprotectioncoreshallbePXandformeteringcoreit shall be 0.2S. The rated burden of cores shall be closer to themaximumburdenrequirementofmetering&protectionsystemforbettersensitivityandaccuracy.
2.8CurrentTransformer(AIS)Current Transformers shall comply with IEC 61869 in general. Allratiosshallbeobtainedbysecondarytapsonly.Generally,CurrentTransformers(CT)for765kV&400kVshallhavesixcores(fourforprotectionandtwoformetering).220kVCurrentTransformersshallhave five cores (four for protection and one for metering). Theburden and knee point voltage shall be in accordance with therequirements of the system including possible feeds for telemetry.AccuracyclassforprotectioncoreshallbePXandformeteringcoreitshall be 0.2S. The rated burden of cores shall be closer to themaximumburdenrequirementofmetering&protectionsystem(notmore than 20VA for metering core) for better sensitivity andaccuracy.Theinstrumentsecurityfactorshallbelessthan5forCTsupto400kVvoltageclassandlessthan10forCTsof765kV
23. 2.9CapacitorVoltageTransformers(AIS)Capacitive Voltage transformers shall comply to IEC 61869 ingeneral.These shall have three secondariesoutofwhich two shallbe used for protection and one for metering. Accuracy class forprotectioncoresshallbe3Pandformeteringcoreitshallbe0.2.TheCapacitivevoltagetransformersonlinesshallbesuitableforCarrierCoupling.TheCapacitanceofCVT for765kVshallbe8800pF.TheCapacitanceofCVTfor400kVand220kVshallbeof4400/8800pFdependingonPLCCrequirements.Theratedburdenofcoresshallbecloser to the maximum burden requirement of metering &protectionsystemforbettersensitivityandaccuracy.
2.9CapacitorVoltageTransformers(AIS)Capacitive Voltage transformers shall comply to IEC 61869 ingeneral.Theseshallhavethreesecondariesoutofwhichtwoshallbeused for protection and one for metering. Accuracy class forprotectioncoresshallbe3Pandformeteringcoreitshallbe0.2.TheCapacitivevoltagetransformersonlinesshallbesuitableforCarrierCoupling. The Capacitance of CVT for 765kV shall be 8800 pF. TheCapacitanceofCVT for400kVand220kVshallbeof4400/8800pFdependingonPLCCrequirements.Theratedburdenofcoresshallbeclosertothemaximumburdenrequirementofmetering&protectionsystem (not more than 50VA for metering core) for bettersensitivityandaccuracy.
24. 2.10SurgeArresters(AIS)624kV,336kV&216kVStationclass,current limiting,heavydutygapless typeSurgearrestersconforming to IEC60099-4 ingeneralshallbeprovided for800kV,420kV&245kVsystemsrespectively.The rated voltage of Surge arrester and other characteristics arechosen in accordance with system requirements. Surge arrestersshallbeprovidednearlineentrances,transformers&Reactorsoasto achieveproper insulation coordination. SurgeArresters shall beprovided with porcelain/ polymer housing fitted with pressurereliefdevices.Aleakagecurrentmonitorwithsurgecountershallbeprovidedwitheachsurgearrester
2.10SurgeArresters(AIS)624kV,336kV&216kVStationclass,heavydutygaplesstypeSurgearrestersconformingtoIEC60099-4ingeneralshallbeprovidedfor800kV, 420kV & 245kV systems respectively. The rated voltage ofSurge arrester and other characteristics are chosen in accordancewith system requirements. Surge arresters shall be provided nearline entrances, transformers & Reactor so as to achieve properinsulation coordination. Surge Arresters shall be provided withporcelain/ polymer housing fitted with pressure relief devices. Aleakage currentmonitorwith surge counter shall be providedwitheachsurgearrester.
25. 2.11ProtectionRelaying&ControlSystemThe protective relaying system proposed to be provided fortransmission lines, auto-transformers, reactors and bus bars to
2.11ProtectionRelaying&ControlSystemThe protective relaying system proposed to be provided fortransmission lines, auto-transformers, reactors and bus bars to
minimize thedamage to the equipment in the events of faults andabnormal conditions, is dealt in this section. All main protectiverelays shall be numerical type with IEC 61850 communicationinterface. All numerical relays shall have built in disturbancerecordingfeature.
minimize the damage to the equipment in the events of faults andabnormal conditions, is dealt in this section. All main protectiverelays shall be numerical type with IEC 61850 communicationinterface. All numerical relays shall have built in disturbancerecordingfeature.The protection circuits and relays of transformer and reactorshall be electrically and physically segregated into two groupseachbeingindependentandcapableofprovidinguninterruptedprotection even in the event of one of the protection groupsfailing,toobtainredundancy,andtotakeprotectionsystemsoutformaintenancewhiletheequipmentremainsinservice.
26. 2.11(a)TransmissionLinesProtection765kV,400kVand220kV linesshallhaveMain-Inumerical threezonedistanceprotection schemewith carrier aided inter-trippingfeature. 765 kV, 400kV and 220kV lines shall also have Main-IInumerical distance protection scheme like Main-I but fromdifferent make that of Main-I. The Main-I and Main-II protectionrelaysofsamemakemaybeprovidedonlyiftheyareofdifferenthardware&manufacturingplatformLine Current Differential relay (with back up distance protectionfeature)asMain–IandMain-IIshallbeconsideredatbothendsforshort lines (line length below 30kM) having Fibre Opticcommunication link. Differential relay at remote end shall beprovided by the TSP. Associated power & control cabling andintegrationwithSASatremoteendshallbeprovidedbyrespective
2.11(a)TransmissionLinesProtection765 kV, 400kV and 220kV lines shall have Main-I numerical threezone distance protection scheme with carrier aided inter-trippingfeature. 765 kV, 400kV and 220kV lines shall also have Main-IInumericaldistanceprotectionscheme likeMain-Ibut fromdifferentmakethatofMain-I.TheMain-IandMain-IIprotectionrelaysofsamemake may be provided only if they are of different hardware,manufacturingplatformordifferentprincipleofoperation.However, Line Current Differential relay (with back up distanceprotectionfeature)asMain–IandMain-IIshallbeconsideredatbothends for short lines (line length below 30kM) having Fibre Opticcommunication link. Differential relay at remote end shall beprovided by the TSP. Associated power & control cabling andintegrationwithSASat remoteend shall beprovidedby respective
27. 2.11(b)AutoTransformerProtection………………….Suitablemonitoring,control(operationofassociatedcircuitbreaker&isolator)andprotectionforLTauxiliarytransformerconnectedtotertiary winding of auto- transformer for the purpose of auxiliarysupply shall be provided. The Over current and open deltaprotectionisrequiredtobeprovidedfortheauxiliarytransformer.These protection and control may be provided as built in featureeither in thebaycontroller tobeprovided for theauxiliarysystemor in the control & protection IEDs to be provided forautotransformer.
2.11(b)AutoTransformerProtection……………...Suitablemonitoring,control(operationofassociatedcircuitbreaker&isolator)andprotectionforLTauxiliarytransformerconnectedtotertiary winding of auto- transformer for the purpose of auxiliarysupply shall be provided. The Over current and other necessaryprotectionshallopendeltaprotectionisrequiredtobeprovidedforthe auxiliary transformer. These protection and control may beprovidedasbuiltinfeatureeitherinthebaycontrollertobeprovidedfor the auxiliary system or in the control & protection IEDs to beprovidedforautotransformer.
28. 2.12a)……………..The Automation System shall be provided with the facility ofcommunicationandcontrolforremoteendoperationsothatbyproviding remote HMI and suitable communication link, thesubstation can be controlled from a remote location.Mode ofcommunication shall be considered as optical fibre or leasedlinebasedonIEC-60870-5-104communicationprotocol.At new substations, the SubstationAutomation System (SAS) shallbesuitableforoperationandmonitoringofthecompletesubstation
2.12a).....................Atnewsubstations,theSubstationAutomationSystem(SAS)shallbesuitable for operation and monitoring of the complete substationincludingproposedfuturebays/elements.………………….
29. 3.1AC&DCpowersuppliesFor catering the requirements of three phase & single phase ACsupply and DC supply for various substation equipment, thefollowingarrangementisenvisaged:-i) ……………….
ii) …….iii) Suitable AC & DC distribution boards and associated LT
Switchgear shall be provided at new substation. For newsubstation,followingswitchboardswithminimumratingasspecified here under shall be considered with duplicatesupply:
3.1AC&DCpowersuppliesFor catering the requirements of three phase & single phase ACsupply and DC supply for various substation equipment, thefollowingarrangementisenvisaged:-i) ……………….
Additionally,ActiveEnergyMetersmaybeprovidedatthesamepoint in the33kV tertiaryofTransformerby local SEB/DISCOMforenergyaccounting.
ii) ……………iii) Suitable AC & DC distribution boards and associated LT
Switchgear shall be provided at new substation. Sizing of LTSwitchgearshallbesuitabletocatertherequirementforallpresent and future bays. AC&DC distribution boards shallhave modules for all the present and future feeders asspecified.
Fornewsubstation,followingswitchboardsshallbeconsideredwith duplicate supply with bus coupler/ sectionalizer andduplicate outgoing feeders except for Emergency lightingdistributionboardwhichshallhaveonlyoneincomingfeeder:(a) 415VMainSwitchboard–1nos.(b) ACdistributionboard–1nos.
Sizing of LT Switchgear shall be suitable to cater therequirement for all present and future bays. AC & DCdistribution boards shall have modules for all the feeders(includingfutureasspecified).
31. 3.8Visualmonitoringsystemforwatchandwardofsubstationpremises:Visual monitoring system for effective watch and ward ofsubstation premises covering the areas of entire switchyard,Control room building, other buildings/stores andmain gate,shall be provided. The Visual Monitoring System shall haveprovisionofWANconnectivityforremotemonitoring.Thenumberofcamerasandtheirlocationsshallbedecidedinsuchawaythatanylocationcoveredinthesubstationareacanbe scanned. The cameras shall be located in such a way tomonitoratleast:
1. The operation of each and every isolator pole of thecompleteyardincaseofAISSub-station.
3.8 Visual monitoring system (VMS) for watch and ward ofsubstationpremises:Visual monitoring system for effective watch and ward ofsubstation premises shall cover all the transformers andreactors, all othermajorAIS Equipment (such as CB, isolators,CT,CVT,SAetc.asapplicable),GISbays,panelroom,allthegatesof switchyard and all entry and exit points of control roombuilding and accordingly the location of cameras shall bedecided.ThecamerashallbehighdefinitioncolorCCDcamerawithnightvisionfeature.TheVMSdatapartly/completelyshallberecorded(minimumfor15days)atleast@25fps(orbetter)and stored on network video recorder. The system shall usevideo signals from various cameras installed at differentlocations, process them for viewing onworkstations/monitorsinthecontrolroomandsimultaneouslyrecordallthecameras.
of Control Room Building, GIS hall and any otherbuildingasapplicable.
4. Allthegatesofswitchyard.
5. MainentranceGate
6. AllothermajorAISEquipment(suchasCB,CT,CVT,SA
etc.asapplicable)
Mouse/keyboardcontrollersshallbeusedforpan,tilt,zoomandother functions of the desired camera. The Visual MonitoringSystem shall have provision of WAN connectivity for remotemonitoring.All camerarecordings shallhaveCamera ID& location/areaofrecording as well as date/time stamp. The equipment shouldgenerally conform to Electromagnetic compatibilityrequirementforoutdoorequipmentinEHVsubstation.Atexistingsubstations,thevisualmonitoringsystemifavailableshall be augmented as per existing or better specification asrequired.
4.0e)In765&400kVswitchyard,ifsparebayofhalfdiameterisidentifiedas future, all the equipment forTie&Future bay shall be designedconsideringthecurrentratingoflinebayi.e.3150A.
33. PLCC & PBAX: Power line carrier communication (PLCC)equipmentcomplete forspeech, teleprotectioncommandsanddatachannelsshallbeprovidedoneachtransmissionline.Theprotections for transmission line and the line compensatingequipmentshallhavehundredpercentbackupcommunicationchannelsi.e.twochannelsfortele-protectioninadditiontoonechannel for speech plus data for each direction. The PLCCequipmentshallinbriefincludethefollowing:-Coupling device, line traps, carrier terminals, protectioncouplers,HFcables,PABX(ifapplicable)andmaintenanceandtestinginstruments.
A telephone exchange (PABX) of 24 lines shall be provided atnew substations as means of effective communication amongvariousbuildingsofthesubstation,remoteendsubstationsandwithcontrolcenters(RLDC/SLDC)etc.Couplingdevices shallbesuitable forphase tophasecouplingfor 765kV & 400kV Transmission lines. The pass band ofcoupling devices shall have sufficient margin for addingcommunication channel in future if required. Necessaryprotectiondevicesforsafetyofpersonnelandlowvoltagepartagainst power frequency voltages and transient over voltageshallalsobeprovided.The linetrapsshallbebroadbandtunedsuitable forblockingthecompleterangeofcarrierfrequencies.LineTrapshallhavenecessaryprotectivedevicessuchaslightningarrestersfortheprotection of tuning device. Decoupling network consisting ofline traps and coupling capacitors may also be required atcertainsubstationincaseofextremefrequencycongestion.The carrier terminals shall be of single side-band (SSB)amplitude modulation (AM) type and shall have 4 kHz bandwidth.PLCCCarrierterminalsandProtectioncouplersshallbeconsideredforbothendsoftheline.PLCC equipment for all the transmission lines covered underthescheme(consistingofonesetofanalogPLCCchannelalongwithcircuitprotectioncouplerandonesetofDigitalprotectioncouplerforbothends)shallbeprovidedbyTSP.Further,PLCCequipment for both ends of transmission lines not coveredunder present scope shall be provided by developer of lines.
However,CVT&Wavetrap forall the linebaysunderpresentscopeshallbeprovidedbyTSP.TSP shall provide/undertake necessaryaddition/modification/shifting/re-commissioning etc. of PLCCequipment due to LILO of transmission lines (whereverapplicable).All other associated equipment like cabling, coupling deviceandHFcableshallalsobeprovidedbytheTSP.ThewavetrapandCVTrequiredforPLCCatremoteendshallbeprovidedbyrespectivebayowner.
SPECIFICTECHNICALREQUIREMENTSFORCOMMUNICATION
34. ……………..1. ForBidarPS-Maheshwaram(PG)765kVD/ClineOn Bidar PS – Maheshwaram (PG) 765kV D/C line one OPGWcontaining 24 Fibres is to be installed by the TSP in place ofconventional earth wire during the construction of line. Theinstallation of OPGW shall be done from gantry of Bidar PS up togantry of Maheshwaram (PG) 765kV and shall be terminated in aJoint Box to be provided by TSP at both the ends. In case ofrequirement of repeater to establish link between Bidar PS –Maheshwaram(PG), theOPGW(48F)connectivity frompower linecrossingpointuptorepeaterstationshallalsobeinthescopeofTSP.
……………..1. ForBidarPS-Maheshwaram(PG)765kVD/ClineOPGW:On Bidar PS –Maheshwaram (PG) 765kV D/C lineunder presentscopeoneOPGWcontaining24FibresistobeinstalledbytheTSPinplaceofconventionalearthwireduringtheconstructionofline.Theinstallation of OPGW shall be done from gantry of Bidar PS up togantry of Maheshwaram (PG) 765kV and shall be terminated in aJoint Box to be provided by TSP at both the ends. In case ofrequirement of repeater to establish link between Bidar PS –Maheshwaram (PG), the OPGW (48F) connectivity from power linecrossingpointuptorepeaterstationshallalsobeinthescopeofTSP.The protection system for 765kV and higher voltage
transmission line and the line compensating equipment shallhaveonehundredpercentbackupcommunicationchannelsi.e.twochannelsfortele-protectioninadditiontoonechannelforspeechplusdataforeachdirection.
35. NewPointtobeinserted PLCC&PBAX:Power line carrier communication (PLCC) equipment completeforspeech,tele-protectioncommandsanddatachannelsshallbeprovided on each transmission line. The protections fortransmission line and the line compensating equipment shallhavehundredpercentbackupcommunicationchannelsi.e.twochannels for tele- protection in addition to one channel forspeechplusdataforeachdirection.ThePLCCequipmentshallinbriefincludethefollowing:-• Coupling device, line traps, carrier terminals, protection
couplers, HF cables, PABX (if applicable) and maintenanceandtestinginstruments.
shall be provided at as means of effective communicationamong various buildings of the substation, remote endsubstationsandwithcontrolcentres(RLDC/SLDC)etc.
• Coupling devices shall be suitable for phase to phase
coupling for 765kV & 400kV Transmission lines. The passband of coupling devices shall have sufficient margin foradding communication channel in future if required.Necessaryprotectiondevicesforsafetyofpersonnelandlowvoltagepartagainstpowerfrequencyvoltagesandtransientovervoltageshallalsobeprovided.
• The line traps shall be broad band tuned suitable forblockingthecompleterangeofcarrierfrequencies.LineTrapshall have necessary protective devices such as lightningarresters for the protection of tuning device. Decouplingnetworkconsistingoflinetrapsandcouplingcapacitorsmayalso be required at certain substation in case of extremefrequencycongestion.
• The carrier terminals shall be of single side-band (SSB)
the scheme (consisting of one set of analog PLCC channelalongwith circuit protection coupler and one set of Digitalprotectioncoupler forbothends) shallbeprovidedbyTSP.CVT&Wave trap for all the line bays under present scopeshallbeprovidedbyTSP.
• TSP shall provide/undertake necessary
addition/modification/shifting/re-commissioning etc. ofPLCCequipmentduetoLILOoftransmissionlines(whereverapplicable).