protection vdg 14 - system controls & switchgears neutral displacement...verse time/voltage...
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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VDG 14 Withdrawn from the case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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