amendment –iii dated 01.06.2020 on the request for

AmendmenttoRFP&TSA:TransmissionSystemforTransmissionSchemeforSolarEnergyZoneinBidar(2500MW),Karnataka)Page1of40

Amendment–IIIdated01.06.2020ontheRequestforProposalandTransmissionServiceAgreementissuedforselectionofbidderasTransmissionServiceProvidertoestablish“TransmissionSystemforTransmissionSchemeforSolarEnergy

ZoneinBidar(2500MW),Karnataka”throughtariffbasedcompetitivebiddingprocess

AmendmentinTechnicalSpecificationsofTransmissionSystem

Sl.No.

ExistingProvision New/RevisedProvision

SPECIFICTECHNICALREQUIREMENTSFORTRANSMISSIONLINE

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.


Sl.No.


wires.4. NewPointtobeinserted 12.0

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.

5. NewPointtobeinserted 13.0Pilefoundationshallbeusedfortowerslocatedintheriverbed,oronriverbanksorinareaswhereriverfloworrivercourseisanticipatedtochangebasedonpreviousyears’hydrologydata.

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


Sl.No.


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.

8. 1.1InsulationCoordination

Thesystemdesignparametersforsubstations/switchyardsshallbeasgivenbelow:SlNo

Descriptionof

parameters

765/400/220kVBidarPS

765kVMaheswaram(PG)GISExtn.

765kVSystem

400kVSystem

220kVSystem

765kVSystem

10. Max. faultcurrent

50kA 63kA 50kA 40kA

1.1InsulationCoordination

The systemdesign parameters for substations/switchyards shall beasgivenbelow:SlNo

Descriptionof

parameters

765/400/220kVBidarPS

765kVMaheswaram(PG)GISExtn.

765kVSystem

400kVSystem

220kVSystem

765kVSystem

10. Max. faultcurrent

50kA 63kA 50kA 50kA

9. 1.2ii)Transformers of same HV rating shall be placed in differentdiameters.

1.2ii)TransformersandbusreactorsofsameHVratingshallbeplacedindifferentdiameters.

10. 2.0SubstationEquipmentandFacilities:

The switchgear shall be designed and specified to withstandoperating conditions and duty requirements. The rated current ofequipmentshallbeasmentionedbelow:

SlNo

Descriptionofbay

765/400/220kVBidarPS 765kVMaheswaram

(PG)GISS/SExtn.

765kV 400kV 200kV 400kV

1. BusBar 4000A 4000A 4000A 4000A2. LineBar 3000A 3000A 1600A 3000A

2.0SubstationEquipmentandFacilities:

The switchgear shall be designed and specified to withstandoperating conditions and duty requirements. The rated current ofequipmentshallbeasmentionedbelow:

SlNo

Descriptionofbay

765/400/220kVBidarPS 765kVMaheswaram

(PG)GISS/SExtn.

765kV 400kV 200kV 400kV

1. BusBar 4000A 4000A 4000A Sameasexisting2. LineBar 3150A 3150A 1600A 3150A


Sl.No.


3. ICTBay 3000A 3000A 1600A -4. Bus

Reactorbay

3000A 3000A - -

5. LineReactor

3000A - - -

6. GISAuxiliaryBusModuleforSwitching ofTransformer

- - - 3000A

7. BusCouplerbay

- - 4000A -

TransferBuscouplerbay

- - 1600A -

Bussectionalizerbay

- - 4000A -

Further, current rating of all equipment in one diameter shallbe the highest current rating required for connectedline/ICT/Reactorsothatthesystemcouldoperatewithoutanyconstraintincaseofoutageofanybusbar.At765kVMaheswaramGISsubstation,2nos.of765kVGIScompletediametersshall……………………..

3. ICTBay 3150A 3150A 1600A -4. Bus

Reactorbay

3150A 3150A - -

5. LineReactor

3150A - - -

6. GISAuxiliaryBusModuleforSwitching ofTransformer

- - - 3150A

7. BusCouplerbay

- - 3150A -

8. TransferBuscouplerbay

- - 1600A -

9. Bussectionalizerbay

- - 3150A -

At765kVMaheswaramGISsubstation,2nos.of765kVGIScompletediametersshall……………….


Sl.No.


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


Sl.No.


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.


Sl.No.


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/IVMVA 500MVA,1-phase

2 Voltageratio(PhaseVoltage)

kV (765/Ö3)/(400/Ö3)/33kV

3 VectorGroup (3–ph)

YNaOd114 Cooling ONAN/ONAF/(OFAFor

ODAF)OR

ONAN/ONAF1/ONAF2

5 Ratingatdifferentcooling

% 60/80/100

6 Frequency Hz 50

7 Impedanceat75DegC

TolerancesasperIEC

HV–IV % AtMax./Principal/Min.Voltagetap:12.8/14.0/

16.3 HV-LV % AtMax./Principal/Min.

Voltagetap:160/195/240

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

1. Voltageratio(Linetoground) kV (𝟕𝟔𝟓/√𝟑)/(𝟒𝟎𝟎/√𝟑)/

𝟑𝟑kV2. RatedCapacity

HV MVA 500IV MVA 500LV(Tertiary) MVA 5MVAactiveloading

3. Noofphases 1(Single)

4. VectorGroup YNaOd11(in3-phasebank)

5. TypeofTransformer Autotransformer6. ApplicableStandard IEC-60076/IS2026

7. Cooling

ONAN/ONAF/OFAF(or)

ONAN/ONAF/ODAF(or)

ONAN/ONAF1/ONAF2

8. Ratingatdifferentcooling % 60/80/100

9. CoolerBank 2X50%


Sl.No.


IV-LV % AtMax./Principal/Min.Voltagetap:150/180/220

8 Temp.riseover50degCAmbientTemp

Deg.C

Topoil:40,Winding:45,Hotspot:59

9 Losses a) MaximumNo-

LoadLossatratedvoltageandfrequency

kW 70

b) MaximumLoadLossatratedcurrentand750C

kW 450

c) MaximumAuxiliaryLossatratedvoltageandfrequency

kW 10

10 Windings i) InsulationLevel

(LI/SI/PF) kVp/kVp/kVrms

HV 1950/1550/- IV 1300/1050/570 LV 250/-/95 Neutral 170/-/70ii) Tandeltaof

windings% <0.5

11 TapChangeron

theneutralsideofthewinding&Tappingdetails

OLTCwithrange±5.5%forHVvariationinstepof0.5%,

22steps

12 Partialdischarge(PD)levelat1.58x765kV/√3

pC <100

Arrangement10. Frequency Hz 5011.

12. Impedanceat75DegCathighestMVAbase

i) HV–IV % 14.0ii) HV–LV % 195.0iii) IV–LV % 180.0

13. ToleranceonImpedance

% AsperIEC

14. Service Outdoor15. Duty Continuous16. OverloadCapacity IEC-60076-7

17. Max.temperatureriseover50degCambienttemperature

OC

i) TopoilmeasuredbythermometerOC 45

ii) Averagewindingmeasuredbyresistancemethod

OC 50

18. Windinghotspotriseoveryearlyweightedtemperatureof32OC

OC 61

19. TankHotspotTemperature

OC 110

20. Max.designAmbienttemp

OC 50

21. Windings

i) LightningImpulseWithstandVoltage

HV kVp 1950 IV kVp 1300


Sl.No.


13 Noiselevelatratedvoltageandatprincipaltapatfullloadandallcoolingactive

dB <80

14 Insulatingoil virginhighgradeinhibited,conformingtoIEC-60296

15 Bushing

A RatedvoltageHV/IV/LV/Neutral

kV 800/420/52/36

B Ratedcurrent(Min.):HV/IV/LV/Neutral

A 2500/2500/3150/3150

C InsulationLevel(LI/SI/PF)

kVp/kVp/kVrms

HV 2100/1550/970 IV 1425/1050/695 LV 250/-/105 Neutral 170/-/77D Tandeltaof

bushings% <0.5

E PDLevelofBushingatUm

pC <10

LV kVp 250 Neutral kVp 170

ii) ChoppedWaveLightningImpulseWithstandVoltage

HV kVp 2140 IV kVp 1430 LV kVp 275

iii) SwitchingImpulsewithstandVoltage

HV kVp 1550 IV kVp 1050

iv) OneMinutePowerFrequencyWithstandVoltage

HV kVrms - IV kVrms 570 LV kVrms 95 Neutral kVrms 70

v) Neutral SolidlyEarthedvi) Insulation

HV Graded IV Graded LV Uniform

vii) TertiaryConnection UngroundedDelta

viii) TandeltaofwindingsatambientTemperature

% ≤0.5

22. Bushing i) Ratedvoltage

HV kV 800 IV kV 420 LV kV 52


Sl.No.


Neutral kV 36ii) Ratedcurrent

HV A 2500 IV A 2500 LV A 3150 Neutral A 3150

iii) LightningImpulsewithstandVoltage

HV kVp 2100 IV kVp 1425 LV kVp 250 Neutral kVp 170

iv) SwitchingImpulsewithstandVoltage

(Specific creepagedistance: 25mm/kVcorresponding to theline to line highestsystemvoltage)

HV kVp 1550 IV kVp 1050 LV kVp - Neutral kVp -

v) OneMinutePowerFrequencywithstandVoltage

HV kVrms 970 IV kVrms 695 LV kVrms 105 Neutral kVrms 77

vi) Minimumtotalcreepagedistances

HV mm 20000 IV mm 10500 LV mm 1300


Sl.No.


Neutral mm 900

vii) MaxPartialdischargelevelatUm

HV pC 10 IV pC 10 LV pC 10 Neutral pC -

23. MaxPartialdischargelevelat1.58*Ur/√3

pC 100

24.

MaxNoiselevelatratedvoltage,principaltap&noloadandallcoolingactive

80

25. MaximumPermissibleLossesofTransformers

i) Max.NoLoadLossatratedvoltageandfrequency

kW 80

ii)

Max.LoadLossatratedcurrentandfrequencyandat75OCforHVandIVwindings,atprincipaltapposition

kW 450

iii)

Max I2R loss at ratedcurrentandfrequencyand at 75O C for HVand IV windings, atprincipaltapposition

kW 335

iv) Max.AuxiliaryLossatratedvoltageand kW 10


Sl.No.


frequency

26. Insulatingoil

UnusedinhibitedoruninhibitedtransformeroilconformingtoIEC-60296:2012.

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.


Sl.No.


TheTechnicalParticulars/ParametersofReactoraregivenbelow:Sr.No. Description Unit Parameters

1 Rated Capacity at765/√3kV

MVAR 80,1-phase

2 RatedVoltage(Ur) kV 765/√33 Maximumcontinuous

operating voltage(Um)

kV 800/√3

4 CoolingSystem ONAN

5 Permissible currentunbalance amongdifferentphases

±1%

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

765/√3kVMVAr 80

2. RatedVoltage(Ur) kV 765/√3

3. Maximumcontinuousoperatingvoltage(Um)(1p.u.)

kV 800/√3

4. Windingconnection Starwithneutral(in3PhaseBank)

5. Coolingtype ONAN

6. Frequency Hz 50

7. NoofPhases 1(Single)

8. Referencestandard IEC60076-6

9. Service Outdoor

10. Duty Continuousat800/√3kV

11. Permissibleunbalancecurrentamongphases

±1%

12. Crestvalueofthirdharmoniccontentinphasecurrentatrated

≤3%ofthecrestvalueoffundamental


Sl.No.


9 Ratio of zerosequence reactanceto positive reactance(X0/X1)

Range 0.9-1.0

10 Max.Temp. rise over50 deg C AmbientTemp and Voltage at800/√3KV

Topoil/Winding/Hotspot:40/45/59

11. Losses a) Maximum

PermissibleLossesatrated Voltage,Frequency and at750C(kW)

kW 98

12 Windings i) Insulation level

(LI/SI/PF) kVp/kVp/kVrms

HV 1950/1550/830(Ph-Earth)for5min.

Neutral 550/-/230ii) Tandeltaofwindings % <0.513 Vibration at 800/√3

kV and ratedfrequency

micron ≤200micronspeaktopeak

14 Noise level at at800/√3kVandratedfrequency

dB <80dBA

15 InsulatingOil virgin high gradeinhibited, conformingtoIEC-60296

16 Partial discharge(PD)levelat 1.58Ur/√3

pC <100

voltagewithsinusoidalwaveform

13. Rangeofconstantimpedance

Upto1.25p.u.(However,complete

saturationcharacteristicsoftheReactorsupto1.5p.u.

Voltageshallbefurnished)

14. Toleranceoncurrent (i)0to+5%forasingle-phaseunit(ii)±1%forbetweenunits

15. Ratioof zero sequencereactance to positivereactance(X0/X1)

Between0.9&1.0.

16. Temperature rise over50 °C Ambient Temp.andat800/√3kV

i) Top oil measured bythermometer

°C 40

ii) Average windingmeasured byresistancemethod

°C 45

17. Winding hot spottemperature rise overyearly weightedaverage temperatureof32°C

°C 61

18. Max. tank surfacetemperature

°C 110

19. Max design ambienttemperature

°C 50


Sl.No.


17 Bushing i) Rated voltage: HV /

NeutralkV 800/145

ii) Ratedcurrent (Min.):HV/Neutral

A 2500/1250

iii) Insulation level(LI/SI/PF)

kVp/kVp/kVrms

HV 2100/1550/970 Neutral 650/-/305iv) Tan delta of

bushings:HV/Neutral

% <0.5

v) PDofBushingatUm:HV/Neutral

pC <10

20. Windings

i) LightningImpulsewithstandVoltage

Lineend kVp 1950

Neutral kVp 550


Lineend kVp 2145iii) Switching Impulse

withstand Voltage atLineend

kVp 1550

iv) Power FrequencywithstandVoltage

Lineend kVrms 830kVrms(PhtoEarth)for5min

(tobetested) Neutral kVrms 230(foroneminute)

21. Neutralearthing SolidlyEarthed

22. Whether neutral is tobebroughtout

Yes(through145kVclassbushing)

23. Tan-deltaofwindingsatambientTemperature

<0.005

24. Bushing

i) Ratedvoltage Linebushing kV 800 Neutralbushing kV 145

ii) Ratedcurrent

Linebushing A 2500

Neutralbushing A 1250


Sl.No.


iii)

LightningImpulsewithstandVoltage

Linebushing kVp 2100 Neutralbushing kVp 650iv)

SwitchingImpulsewithstandVoltageofLinebushing

kVp 1550

v) Oneminutepowerfrequencywithstandofbushings(dry)

Linebushing kVrms 970

Neutralbushing kVrms 305

v) Minimumcreepagedistance

(Specific CreepageDistance: of 25mm/kVcorresponding tohighest line to linevoltage)

Linebushing mm 20000

Neutralbushing mm 3625

vi)

PartialdischargeofbushingsatUm(lineendandneutral)

pC <10

25. VibrationandtankstressatUm

Max≤200micronspeaktopeakAverage≤60micronspeaktopeakTankstress:≤2.0kg/sq.mmatanypointoftank

26. Maximumnoisepressurelevelatrated

dB 80


Sl.No.


………………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

kW 52

28. Insulatingoil UnusedinhibitedoruninhibitedtransformeroilconformingtoIEC-60296:2012

…………………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


Sl.No.


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


Sl.No.


…………………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.


Sl.No.


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.


Sl.No.


ageing, cold rolled grain oriented silicon steel laminations withrequisiteBIScertification.………………Thereactorshallbecompletewithallrequiredaccessories,BushingCTs,marshalling box etc as required for satisfactory operations ofreactor.HVandNeutralbushingsshallbeRIP(resinimpregnatedpapercondenser)withcompositeinsulatortype.TheTechnicalParticulars /Parametersof ShuntReactor aregivenbelow:Sl.No. Description Unit Parameters1.1 RatedVoltage,Ur(1p.u) kV 420

1.2 RatedCapacityat420kV MVAR 1251.3 CoolingSystem ONAN1.4 Permissiblecurrent

unbalanceamongdifferentphases

%±2

1.5 CrestvalueofThirdHarmoniccontentinphasecurrentatratedvoltagewithsinusoidalwaveform

% ≤3%ofthecrestvalueoffundamental

1.6 RangeofconstantImpedance

Upto1.5p.u.voltage

1.7 Toleranceoncurrent % 0to+5%

1.8 Ratioofzerosequence Range 0.9-1.0

………………………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

Parameters1. RatedCapacityat420kV MVAr 125

2. RatedVoltage(Ur)(1.0pu)

kV 420

3. Numberofphases 3(three)

4. Connection Star

5. Coolingtype ONAN

6. Frequency Hz 50

7. Referencestandard IEC60076-6

8. Service Outdoor

9. Permissibleunbalancecurrentamongphases

% ±2%

10. Crestvalueofthirdharmoniccontentin

% ≤3%ofthecrestvalueof


Sl.No.


reactancetopositivereactance(X0/X1)

1.9 Max.Temperatureriseover50degCAmbientTempatratedvoltage

Deg.C Topoil:40&Winding:45

1.10 (a) MaximumPermissibleloadLossesatratedVoltage,Frequencyandat75°C(kW)for420kV,125MVAR,3-PhaseReactor

kW 160

(b) MaximumPermissibleI2RLossesofReactoratratedVoltage,Frequencyandat75°C

kW 90

1.11 Windings

a) Insulationlevel(LI/SI/PF) kVp/kVp/kVrms

HV 1300/1050/- Neutral 550/-/230

b) Tandeltaofwindings % <0.51.11 Partialdischarge(PD)level

at1.58Ur/√3 pC <100

1.12 Vibration&Tankstresslevelatratedvoltageandfrequency

≤200micronspeaktopeak;Average:≤60micronspeaktopeak.Stress:≤2.0kg/sq.mm

phasecurrentatratedvoltagewithsinusoidalwaveform

fundamental

11. Rangeofconstantimpedance

Upto1.5p.uvoltage

(However,completesaturation

characteristicsoftheReactorsupto2.5p.u.Voltage

shallbefurnished)12. Toleranceoncurrent % 0to+5%

13. Ratio of zero sequencereactance to positivereactance(X0/X1)

Between0.9&1.0.

14. Temperatureriseover50°CAmbientTemp.at420kV

i) Topoilmeasuredbythermometer

°C 40

ii) Averagewindingmeasuredbyresistancemethod

°C 45

15. Windinghotspottemperatureriseoveryearlyweightedaveragetemperatureof32°C

°C 61

16. Max.tanksurfacetemperature

°C 110

17. Maxdesignambienttemperature

°C 50


Sl.No.


atanypointontank.

1.13 Noiselevelatratedvoltageandfrequency dB <80

1.14 Bushing a) Ratedvoltage:HV/Neutral kV 420/145

b) Ratedcurrent(Min.)HV/Neutral

A 800/800

c) Insulationlevel(LI/SI/PF) kVp/kVp/kVrms

HV 1425/1050/695

Neutral 650/-/305d) Tandeltaofbushings:HV/

Neutral% <0.5

e) PDofbushingsatlevelUm pC <101.15 InsulatingOil virginhigh

gradeinhibited,conformingtoIEC-60296

18. Windings

i) LightningImpulsewithstandVoltage

Lineend kVp 1300

Neutral kVp 550


Lineend kVp 1430iii) Switching Impulse

withstand Voltage atLineend

kVp 1050

iv) OneMinutePowerFrequencywithstandVoltage

Neutral kVrms 230

19. Tan-deltaofwindings <0.005

20. Neutralearthing SolidlyEarthed

21. Whetherneutralbroughtout

Yes(through145kVclassbushing)

22. Bushing

i) Ratedvoltage Linebushing kV 420 Neutralbushing kV 145ii) Ratedcurrent Linebushing A 800

Neutralbushing A 800

iii) LightningImpulsewithstandVoltage

Linebushing kVp 1425


Sl.No.


Neutralbushing kVp 650iv) SwitchingImpulse

withstandVoltageofLinebushing

kVp 1050

v) 1minutepowerfrequencywithstandofbushings(dry)

Linebushing kVrms 695 Neutralbushing kVrms 305vi) Minimumcreepage

distance (Specific Creepage

Distance: of25mm/kVcorresponding tohighest line to linevoltage)

Linebushing mm 10500

Neutralbushing mm 3625

vii) PartialdischargeofbushingsatUr(lineendandneutral)

pC <10

23. Maximumpartialdischargelevelat1.58Ur/√3

pC 100

24. Vibrationandtankstressatratedvoltage

Max≤200micronspeaktopeakAverage≤60micronspeaktopeakTankstress:≤2.0kg/sq.mmatanypointoftank


Sl.No.


…………….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.

25. Maximumnoisepressurelevelatratedvoltage&frequency

dB 80

26. Maximum PermissibleLosses of Reactor atrated current andfrequencyandat75°C

Totalloss

I2RLoss

i) 125MVAr420kV kW 160 90

27. Insulatingoil UnusedinhibitedoruninhibitedtransformeroilconformingtoIEC-60296:2012

……………..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.


Sl.No.


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


Sl.No.


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


Sl.No.


breakersoflinewithnon-switchablelinereactors,Busreactorsand765/400kVTransformers(whereverapplicable).

linewithnon-switchable linereactors,Busreactorsand765/400kVTransformers.

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


Sl.No.


core)forbettersensitivityandaccuracy.Theinstrumentsecurityfactorshallbelessthan5forCTsupto400kVvoltageclassandlessthan10forCTsof765kVvoltageclass.

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


Sl.No.


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


Sl.No.


voltageclass.

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


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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


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bayowner.…………………………..

bayowner.…………………………..

27. 2.11(b)AutoTransformerProtection………………….Suitablemonitoring,control(operationofassociatedcircuitbreaker&isolator)andprotectionforLTauxiliarytransformerconnectedtotertiary winding of autotransformer 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 autotransformer 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.………………….


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includingproposedfuturebays/elements.…………………

29. 3.1AC&DCpowersuppliesFor catering the requirements of three phase & single phase ACsupply and DC supply for various substation equipment, thefollowingarrangementisenvisaged:-i) ……………….

Additionally,ActiveEnergyMetersmaybeprovidedatthesamepointinthe33kVtertiaryofTransformerbylocalSEB/DISCOMforenergy

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:

(a) 415VMainSwitchboard–2nos.(twosectionsseparatedbyonebuscoupler)(b) ACdistributionboard–2nos.(twosectionsseparatedbyonebuscoupler)(c) Mainlightingdistributionboard–1no.(d) Emergencylightingdistributionboard–1no.(e) 220VoltDCdistributionboard–2nos.(f) 48VoltDCdistributionboard–2nos.

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.


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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).

………….

(c) Mainlightingdistributionboard–1no.(d) Emergencylightingdistributionboard–1no.(e) 220VoltDCdistributionboard–2nos.(f) 48VoltDCdistributionboard–2nos.…………………..

30. 3.2FireFightingSystem…………….BeamtypeheatdetectionforGIShallfireprotectionsystemshallbeprovidedforalltheGIShalls.Atexistingsubstations,thefire-fightingsystemsasavailableshallbeextendedtomeettheadditionalrequirements.

3.2FireFightingSystem……………….OpticalbeamtypeheatdetectionforGIShallfireprotectionsystemshallbeprovidedforalltheGIShalls.Atexistingsubstations,thefire-fightingsystemsasavailableshallbeextendedtomeettheadditionalrequirements.

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.


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2. TheOperationofeachbaybaysofGISHallasapplicable.

3. AlltheTransformerandReactors,alltheEntrancedoors

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.

32. 4.0e)In765&400kVswitchyard,ifsparebayofhalfdiameterisidentifiedas future,all theequipment forTie&Futurebayshallbedesignedconsideringthecurrentratingoflinebayi.e.3000A.

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.

Deleted.


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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.


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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


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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.

• Atnewsubstation,a telephoneexchange (PABX)of24 lines

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.


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• 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)

amplitudemodulation(AM)typeandshallhave4kHzbandwidth.PLCCCarrier terminalsandProtectioncouplers shallbeconsideredforbothendsoftheline.

• PLCCequipmentforallthetransmissionlinescoveredunder

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).

• Allotherassociatedequipment likecabling,couplingdevice

andHFcableshallalsobeprovidedbytheTSP.

amendment –iii dated 01.06.2020 on the request for

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