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PROTECTION

GRID

PROTECTION

Customer Benefits

• Ideal for Neutral voltagedisplacement–detectionofE/Firrespectiveofearthingsystem.

• Tuned to fundamentalfrequency

• Operation annunciation intheformofflag

• Environmental friendlyElecting phoratic paintingprocess

• Drawouttypecase• Complete dust proof by

IP5Xclassprotection

Voltage Neutral Displacement RelayVDG 14

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Type VDG 14Voltage Neutral Displacement Relay

Features

• Insensitivetovoltagesatthirdharmonicfrequencies• Identicaltime/voltagecharacteristicsonalltaps• Simpleconstruction,easilyaccessible• Comprehensiverangeofauxiliaryunitratings

Application

Earthfaultprotectionofgeneratorsearthedthroughaneutralearthingtransformerandwhereimmunitytooperationonthirdharmonicfrequencyisessentialcapacitorbankprotectionetc.

General Description

Aheavilydamped inductiondisc relaywithanadjustable in-verse time/voltage characteristic. The coil circuit of the relayistunedtothesupplyfrequencybyaseriesconnectedchokeandcapacitor.Thesecomponentsareenergizedfromatappedauto-transformerwhichprovidesadjustmentoftherelayvolt-agesetting.Atvoltagesabovethesetting,thechokesaturatesanddetunesthecircuitgivingtherelayahighcontinousvolt-agerating.Dampingofthediscmovementisbyaremovablehighretentivitypermanentmagnet.

Theuniquemethodofwindingtheoperatingcoilensuresthatthe time/voltage characteristics are identical on each of thevoltage taps. Selection of the required voltage setting is bymeans of a plug setting bridgewhich has a single insulatedplug. Tunedwound shading coils are fitted so that the relaydevelopsmaximumtorqueatthesupplyfrequencyandismuchlesssensitivetovoltageatthirdharmonicfrequencies.

Therelayoperatingtimecanbeadjustedbymovementofthediscbackstopwhichiscontrolledbyrotatingaknurledmouldeddiscatthebaseofthegraduatedtimemultiplierscale

TypeVDG14relayisasinglepolerelayandisavailableinthesinglepoleversiononly.

Technical date

Ratings

110V,ac,50Hz

Settings

5.4,7.5,12.5and20V,ac,50Hz

Third harmonic rejection

Therelaywillnotoperateatthirdharmonicvoltagesupto20timesthesettingvoltageat50HZ

VDG 14

VDG 14 Withdrawn from the case

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VDG 14

Resetting voltage

Resetscompletelyat80%ormoreofvoltagesetting.

Time Settings

• Operatingtime

1.0-1.5secat5timesvoltagesetting.Time/voltagecharac-teristicsaregiveninFig1.

• Resettingtime

100secondsatTMS=1.0

Burden

Relay setting Lowest setting (5.4 volts)

Highest setting ( 20 volts )

VAburdensetting 0.22 0.27

VAburdenat110voltsac

17.00 2.30

Thermal rating• Continous

120voltsonanysettingfor60°Criseincoiltemperature

• Short time

200voltsonanysettingforthedurationoftheoperatingtime

AccuracyErrorclassindex–E5.0asperBS142–19665.0asperIS3231-1965

• TimingError

OperatingtimeatTMS=1.0Conformstotime/voltagechar-acteristicgiveninFig1,subjecttoatoleranceof+7.5%at5timesvoltagesetting

Auxiliary units and operation indicators

Auxiliaryunitwithtwopairsofselfresetcontactsarrangedtoreinforcethedisccontactandahandresetoperationindicatorprovided.

Shuntconnected,voltageoperated,aux.unitisfittedasstandard

Voltage coil ratings

• 30,110or220Vdcwithanominalburdenof3watts• Othercoilratingsavailableonrequest

Contacts

Type of contact Make and carry for 0.5 second

DiscContact 2500VAwithmaximaof10Aand660V,ac/dc

Auxiliaryunitcontact 7500VAwithmaximaof30Aand660V,ac/dc

InsulationTherelaymeetstherequirementsofIS3231-1965/IEC255-5seriesC-2kvfor1minute

External and internal circuit connections SeeFigure2

Figure 1 : Time / Voltage characteristics

Figure2:TypicalextrnalandinternalconnectionsfortypeVDG14,generatorstatorearthfaultrelay

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GRID

Case

1Dverticalcasesuitableforflushmountingandfinishedeggshellblackandtropicalised.Suitabletripinsolationswitchprovidedonthecradleassembly

Information required with order

1. Systemfrequencyandapplication2. Auxiliaryvoltage

ALSTOM T&D INDIA LIMITEDPallavaramWorks19/1,G.S.T.Road,Pallavaram,Chennai-600043Tel:91-44-22648000Fax:91-44-22640040

ALSTOM T&D Worldwide Contact Centre:http://www.alstom.com/contactcentre/Tel.:+44(0)1785250070

www.grid.alstom.com

VDG 14

Dimensions and weights

Relay Case size Maximum overall dimensions Approximate Gross Weight Kg.Height mm Width mm Depth* mm

VDG14 1Dvert. 233 170 203 6.5

*Add76mmformaximumlengthofterminalstuds,alternatively,29mmforterminalscrews.

Theappropriategrossweightgivenaboveisinclusiveofcartons,mountingappendagesandterminaldetails.

TherelayscomplyfullywiththerequirementsofIS3231–1965andaresuitableforuseinnormaltropicalenvironments.

Figure3:Caseandpanelcut-outdimensionsforcase1D(alldimensionsinmm)

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