Sub station Sub station ►Function of sub station is to receive Function of sub station is to receive

electric power from generators or lines electric power from generators or lines and to deliver to other lines with or and to deliver to other lines with or without transformation.without transformation.

►Substation capacity is the total MVA Substation capacity is the total MVA capacity of transformers installed in capacity of transformers installed in the s/s. the s/s.

400 KV Bus

220 KV Bus

500 MVA400/220 KV Transformer

Incoming line Out going line

Out going line Incoming line

Simple schematic of sub-station lay-out

Sub-stationsSub-stations►400 KV Sub stations400 KV Sub stations

►220 KV Sub stations220 KV Sub stations

►132 KV Sub stations132 KV Sub stations

► 66 KV Sub stations 66 KV Sub stations

Sub-station equipmentsSub-station equipments►1.1. Switch yard equipmentsSwitch yard equipments

►2. Control Room Building 2. Control Room Building equipmentsequipments

Substation equipmentsSubstation equipments► Switch-yard equip.Switch-yard equip.

L.A.L.A. C.V.T./P.T./C.C.C.V.T./P.T./C.C. Wave TrapWave Trap BreakerBreaker IsolatorIsolator Earthing switchEarthing switch Power TransformerPower Transformer ReactorReactor Capacitor bankCapacitor bank C.T.C.T.

► Control Room bldg. Control Room bldg. equip.equip. Control panelControl panel Relay panelRelay panel Metering panelMetering panel PLCC panelPLCC panel RTU panelRTU panel Battery setsBattery sets DCDB & ChargerDCDB & Charger L.T.Panel boardL.T.Panel board Compressor panelCompressor panel C/R desk equips: PCs, C/R desk equips: PCs,

Telephones…etcTelephones…etc

L.A.L.A.

CVTCVT

CC VT / PT

Only for PLCC.Allows to pass PLCC Signals through HF point.

Secondary voltage of PT is usedFor Line Voltage measurement,line protection relays ,Synch. etc.

CVT Construction Details

Wave-TrapsWave-Traps►Line traps are either suspended from Line traps are either suspended from

gantry or placed on pedestal insulators.gantry or placed on pedestal insulators.►For 400 KV, 220 KV, 132 KV & 66 KV.For 400 KV, 220 KV, 132 KV & 66 KV.►Allows to pass 50 Hz power frequency Allows to pass 50 Hz power frequency

signal in to the switch-yard. Low signal in to the switch-yard. Low impedance to LF.impedance to LF.

►Blocks HF (50 kHz – 500 kHz) signals to Blocks HF (50 kHz – 500 kHz) signals to enter into S/Y. High impedance to HF.enter into S/Y. High impedance to HF.

►Normal blocking band is 150 – 500 kHz. Normal blocking band is 150 – 500 kHz.

Switch-yard equipmentsSwitch-yard equipments

Wave Trap

Current Transformer (C.T.)Current Transformer (C.T.)►C.Ts. Transforms current from say C.Ts. Transforms current from say

1000 A to 1 A.1000 A to 1 A.►Metering and ProtectionMetering and Protection►1000/1 A, 600/1 A, 300/1 A, 150/1 A 1000/1 A, 600/1 A, 300/1 A, 150/1 A

C.T.

Live Tank CTsLive Tank CTs

Dead tank PTsDead tank PTs

Hairpin design and Eye Bolt design

Circuit BreakersCircuit Breakers On load switchOn load switch

VCBVCB BOCBBOCB MOCBMOCB ABCBABCB SF6SF6

LIVE TANK TYPE

CLASIFICATION OF AIS BREAKERS

Classification of BreakersClassification of Breakers

Indoor Switchgear (GIS) Outdoor breakers (AIS)

Isolator Isolator ►Off load switchOff load switch

Center BreakCenter Break Double breakDouble break PentographPentograph Tandem Tandem

Power TransformerPower Transformer►400 / 220 KV Transformer400 / 220 KV Transformer

MVA Capacity & KVMVA Capacity & KV Changes voltage levels.Changes voltage levels. Step-up & Step-down transformers.Step-up & Step-down transformers.

Transformer PartsTransformer Parts► Main TankMain Tank► HV & LV & NEUTRAL HV & LV & NEUTRAL

bushingsbushings► OLTCOLTC► RadiatorRadiator► BreatherBreather► MOGMOG► Explosion ventExplosion vent

► Oil Circulating pumpOil Circulating pump► Buchcholz relay .Buchcholz relay .► PRVPRV► OSROSR► OTI & ITS POCKET OTI & ITS POCKET

AT TOP PLATE.AT TOP PLATE.► WTI * ITS POCKET WTI * ITS POCKET

AT TOP PLATE.AT TOP PLATE.► Cooling fanCooling fan

Power Transformer

Reactor

Capacitor BankCapacitor Bank

Bus bar ArrangementBus bar Arrangement►Single bus barSingle bus bar►Single section bus-barSingle section bus-bar►Main and Transfer bus barMain and Transfer bus bar►Double bus and Transfer bus barDouble bus and Transfer bus bar

Control PanelControl Panel► SemaphoresSemaphores► Annunciation schemesAnnunciation schemes► TNC SwitchTNC Switch► Isolator TNC switchesIsolator TNC switches► Indications for SF6 pr., ON/OFF breakerIndications for SF6 pr., ON/OFF breaker► Meters for MW,Amp,KV…with phase Meters for MW,Amp,KV…with phase

selection switch ...etcselection switch ...etc► DAS meterDAS meter► Annunciation RelayAnnunciation Relay

Relay PanelRelay Panel►Relays for:Relays for:

Distance relay for lines Distance relay for lines Main-1/Main- Main-1/Main-2..Micromho,numerical…etc.2..Micromho,numerical…etc.

Differential relay… TransformersDifferential relay… Transformers Auxiliary relays.. Under frequency, Under Auxiliary relays.. Under frequency, Under

voltage, O/V, Master Trip, …etc.voltage, O/V, Master Trip, …etc.

Relay PanelRelay Panel►Relays:Relays:

Electro magnetic Attraction typeElectro magnetic Attraction type Induction typeInduction type Static typeStatic type Thermal typeThermal type Numerical typeNumerical type

Metering PanelMetering Panel►ABT Metering of Inter-state and Intra-ABT Metering of Inter-state and Intra-

state lines.state lines.►Data……weekly mail for billingData……weekly mail for billing

PLCC PanelPLCC Panel►PLCC connects---Co-axial cable-- Yard PLCC connects---Co-axial cable-- Yard

LMULMU

►PLCC panel for:PLCC panel for: PLCC SpeechPLCC Speech Protection CouplerProtection Coupler

RTU PanelRTU Panel►RTU data flow to SLDC Gotri.RTU data flow to SLDC Gotri.►Connection to PLCC panelConnection to PLCC panel►DATA…. Parameters, position of brkr, DATA…. Parameters, position of brkr,

isolator…etc.isolator…etc.

Batteries Batteries Large lead acid Large lead acid

batteries for batteries for substationssubstations

Battery SetBattery Set► Battery is considered as the heart of sub-Battery is considered as the heart of sub-

station.station.

► Sub-station battery sets:Sub-station battery sets: 220 V DC220 V DC

► Single or double Single or double

110 V DC110 V DC► Single or double Single or double

48 V DC48 V DC► Single or double Single or double

Battery specificationsBattery specifications► Generally .. Telecom DC source .. 48 V dc.Generally .. Telecom DC source .. 48 V dc.► PLCC.. 1 extra cell to compensate cable PLCC.. 1 extra cell to compensate cable

drop.drop.► 50 V - 200 AH means Battery set is having 50 V - 200 AH means Battery set is having

25 nos.of 2-Volts cells that can deliver…25 nos.of 2-Volts cells that can deliver…► 10 Amps for 20 Hrs. 10 A10 Amps for 20 Hrs. 10 A××20 H = 200 AH 20 H = 200 AH

OROR► 20 Amps for 10 Hrs 20A20 Amps for 10 Hrs 20A××10 H= 200 AH 10 H= 200 AH

considering 100 % efficiency.considering 100 % efficiency.

Battery structureBattery structure►Hard rubber containerHard rubber container►Positive terminal post.. Lead peroxidePositive terminal post.. Lead peroxide►Negative terminal post.. Sponge LeadNegative terminal post.. Sponge Lead►Vent plugVent plug►Float level indicatorFloat level indicator► Inter-cell connector stripsInter-cell connector strips►Electrolyte…HElectrolyte…H22SOSO44

Chemical ReactionChemical Reaction► Pb + PbOPb + PbO22 + H + H22SOSO44

►DischargeDischarge ChargeCharge

► 2 PbSO2 PbSO44 + 2 H + 2 H22O O

Battery ChargerBattery Charger

Float charger Boost Float charger Boost chargercharger

Main Parts

Functions of Float chargerFunctions of Float charger► Converts 3-Ph AC into 48 V DC. (Rectifier)Converts 3-Ph AC into 48 V DC. (Rectifier)► Normally it delivers load & give trickle Normally it delivers load & give trickle

charging to Battery bank.charging to Battery bank.► Works on ‘Auto’ or ‘Manual’ mode.Works on ‘Auto’ or ‘Manual’ mode.► In ‘Auto’ mode, o/p DC voltage is In ‘Auto’ mode, o/p DC voltage is

controlled by ECU card to predefine value controlled by ECU card to predefine value irrespective of amplitude of AC voltage.irrespective of amplitude of AC voltage.

► In ‘Manual’ mode, o/p DC voltage is to be In ‘Manual’ mode, o/p DC voltage is to be controlled manually by external control.controlled manually by external control.

Functions of Boost chargerFunctions of Boost charger►Converts 3-Ph AC into 48 V DC.Converts 3-Ph AC into 48 V DC.

(Rectifier)(Rectifier)►Normally ,it is made OFF.Normally ,it is made OFF.►Works on ‘CC’ or ‘CV’ mode.Works on ‘CC’ or ‘CV’ mode.► In ‘CC’ mode, battery can be charged In ‘CC’ mode, battery can be charged

at constant current.at constant current.► In ‘CV’ mode, battery can be charged In ‘CV’ mode, battery can be charged

at constant voltage.at constant voltage.

►Boost charging is required only if whole Boost charging is required only if whole battery bank is drained considerably. At battery bank is drained considerably. At that time ,Float charger will deliver the that time ,Float charger will deliver the load.load.

►Boost charger is made on when Float Boost charger is made on when Float charger is out of order. In this case, charger is out of order. In this case, Boost section will charge battery bank Boost section will charge battery bank and battery bank output from tap-cell and battery bank output from tap-cell will deliver load.will deliver load.

Need for Boost chargerNeed for Boost charger

L.T.Panel BoardL.T.Panel Board►3-Phase and 1-Phase dist. Board3-Phase and 1-Phase dist. Board►For supply of s/y lighting, water pump, For supply of s/y lighting, water pump,

charger supply, aviation lighting, charger supply, aviation lighting, colony lighting, ….etccolony lighting, ….etc

Emulsifier, Hydrant and Helon Fire protection system