Date:02/02/2018

Report on Ichchhapore substation Substation:

SubstationEquipment:

1] PowerTransformer:

A staticelectricalmachineusedfortransformingpowerfromonecircuittoanother

circuitwithoutchangingfrequencyistermedasPowertransformer. Thetransformers

aregenerallyusedtostepdownorstepupthevoltagelevelsofa systemfor

transmissionandgenerationpurpose. Thesetransformersareclassifiedintodifferent types

basedon their design,utilization purpose,installation methods,and so on.

2] InstrumentTransformer

The current and voltage transformers are together called as the

Instrument transformers. Current transformer is usedfor themeasurement of the

alternatingcurrentbytakingsamplesofthehighercurrentsofthesystem. These

reducedsamplesarein accurateproportionswiththe actualhigh currentsofthe system.

Theseareusedforinstallationandmaintenanceofthecurrentrelaysin

substationsforprotectionpurposewhich are normally havelow-current ratingsfor

theiroperation.Potentialtransformeris quitesimilartothecurrenttransformer,butit isused

fortakingsamplesofhighvoltagesofasystemforprovidinglow-voltage to the relays of

protection system and also to the low-rating meters for voltage

measurement. Fromthis low-voltage measurement,the actualsystem’s high voltage

canbecalculatedwithoutmeasuringhighvoltages directlytoavoidthecostofthe

measurement system.

3] Conductors

The materialorobject thatobeystheelectrical propertyconductance(mostlymade of

metalssuchas aluminumandcopper)andthatallowstheflowofelectricchargeis

calledconductor.Conductors permitfree movement ofthe flow ofelectronsthrough

them.Theseareusedforthetransmissionofpowerorelectricalenergyfromone

place(generatingstation)toanotherplace (consumerpointwherepoweris consumed

bytheloads)throughsubstations.Conductors areofdifferenttypesandmostly aluminium

conductorsare preferred in practical power systems.

4] Insulators

Themetalwhichdoesnotallowfreemovementofelectronsorelectricchargeis calledas

aninsulator.Hence,insulatorsresistelectricitywiththeirhighresisting property.

Therearedifferenttypesofinsulatorssuchassuspensiontype,straintype,

straytype,shackle,pintypeandsoon. A fewtypesofinsulatorsareshowninthe

abovefigure.Insulatorsareusedforinsulationpurposewhileerecting electricpoles with

conductorsto avoidshort circuit and for other insulationrequirements.

5] Isolators

Isolatorisamanuallyoperatedmechanicalswitchthatisolatesthefaultysectionor

thesectionofaconductororapartofacircuitofsubstation meantforrepairfroma healthy

section in orderto avoid occurrence ofmoresevere faults. Hence,itis also

calledasadisconnectorordisconnectingswitch. Therearedifferenttypesofisolators

usedfordifferentapplicationssuchassingle-breakisolator,double-breakisolator,

busisolator, line isolator,etc.

6] BusBars

The conductorcarryingcurrentand havingmultiplenumbersofincoming and

outgoinglineconnectionscanbecalledas busbar,whichiscommonlyusedin substations.

Theseareclassifiedintodifferenttypeslikesinglebus,doublebusand ring bus.

7] LightningArrester

The substationequipmentsuchasconductors,transformers,etc.,are alwayserected

outdoor. Whenever light surges occur then, a high-voltage pass through these

electrical components causing damage to them (either temporary or permanent

damagebasedontheamountofvoltagesurge). Therefore,toavoidthisdifficulty,

lighteningarrestersareplacedtopasstheentirelighteningsurgestoearth. Thereare other

arresters which are used to ground the switching surges called as surge arresters.

8] Circuit Breakers

Fortheprotectionofsubstationanditscomponentsfromtheovercurrentsorover load dueto

shortcircuitorany otherfaultthe faulty section isdisconnectedfromthe

healthysectioneither manuallyor automatically.If oncethefaultis rectified,then

againtheoriginalcircuitcanbe rebuiltbymanually orautomatically.Differenttypes

ofcircuitbreakersaredesigned based ondifferent criteria and usage. Butingeneral

mostlyusedcircuitbreakersareOilcircuitbreaker, Aircircuitbreaker,SF6circuit

breaker,VacuumCircuit Breaker, and soon.

9] Relays

Relaysareusedfordisconnectingthecircuitsbymanualorautomaticoperation.

Relayconsistsofthecoilwhich isexcitedorenergizedandsuchthatmaking the

contactsofrelayclosedactivatesthe relayto break ormake thecircuitconnection. There

aredifferent typesof relayssuchasovercurrent relays,definite time over current

relays,voltagerelays,auxiliaryrelays,reclosingrelays,solid staterelays,

directionalrelays,inversetimeovercurrentrelays,microcontrollerrelays,etc. The

abovefigure showssomebasic relays and their operation.

10] Capacitor Bank

A Capacitorbankisasetofmanyidenticalcapacitorsconnectedinseriesorparallel withina

enclosure andisusedforthepowerfactorcorrectionandbasicprotection of substation.

Thesecapacitorbanksareactsasasourceofreactivepower,andthus,the

phasedifferencebetweenvoltageand current canbereducedbythe capacitorbanks.

Theywillincreasetheripplecurrentcapacityofthesupply.Itavoids undesirable

characteristics inthepowersystem.Itisthemosteconomicalmethodformaintaining power

factorand of correction of the power lag problems.

DistributionTransformers

A distribution

transformerorservicetransformerisatransformerthatprovidesthefinalvoltage

transformationintheelectricpowerdistributionsystem,steppingdownthevoltage

usedinthedistributionlinestothelevelusedbythecustomer. Theinventionofa practical

efficient transformer madeACpower distribution feasible.

Distributiontransformersnormallyhave ratingslessthan200kVA,although some

nationalstandardscanallowforunitsupto5000kVAtobedescribedasdistribution

transformers.Since distributiontransformers are energizedfor24hoursa day (even

whentheydon'tcarry any load), reducingiron losseshasan importantrole in their

design.Astheyusuallydon'toperateatfullload,theyaredesignedtohavemaximum

efficiency atlower loads.

Electricity Meter

Anelectricitymeter,electricmeter,electricalmeter,orenergymeteris adevicethat

measuresthe amountofelectricenergyconsumedbyaresidence,abusiness, oran

electrically powered device.

Electricutilitiesuseelectric metersinstalledatcustomers'premisesforbilling purposes.

Theyaretypicallycalibratedinbillingunits,themostcommononebeing the kilowatt

hour(kWh).They are usually read onceeachbilling period.

Whenenergy savings during certainperiodsaredesired, somemetersmay measure

demand,themaximumuse ofpowerin some interval. "Time ofday" metering allows

electricratesto bechangedduringa day,to record usageduringpeakhigh-cost

periodsandoff-peak,lower-cost,periods. Also,insomeareasmetershaverelaysfor

demandresponse load shedding during peakload periods.

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