ML18038A375

Niagara Mohawk Nine Mile Point Unit 2 Event of 910813.

ML18038A375
Person / Time
Site:	Nine Mile Point
Issue date:	09/05/1991
From:	CRENSHAW M L GENERAL ELECTRIC CO.
To:
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ML18038A373	List: ML18038A372 ML18038A374 ML18038A375
References
CON-IIT07-751-91, CON-IIT7-751-91 NUREG-1455, NUDOCS 9109110283
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{{#Wiki_filter:NiagaraMohawkNineMi>epointUnit2Eventof13August]991Reportby:MelvinL.CrensbamConsultingEngineerPo~erSystemsEngineeriagDepartmentGeneralElectricCompanySchenectady,NY8September1991 40 5iagaraMohawk5ineMilePointUnit2Eventof13August199105:4SQnAugust13,1991,at5:48AbftheUnit2phaseBgeneratorstep-uptranstormerfailed.OscillographicrecordsoftheeventareavailablefromadigitaldatarecorderattheScribaSubstation.Theyshowvarious345kVand11V5ksystemvoltagesandcurrents.FigureAwithnotationsisattached.Thefourcyclesprecedingthefaultshownosignsofagradualdegradationoradevelopingdisturbance.Theoscillographictracesandstationprotectiverelaytargetsreported,indicateagroundfaultoccurredonthehighvoltagewinding.Depressionofthe345kVphase8busvoltagetoabout39%ofthepriorvaluewasobservedfromtheoscillographictrace.Thissuggeststheinvolvementofonlyaportionoftheentirewinding.The345kVlinecurrentsandvoltagesshowrapiddevelopmentofthegroundfaultbeginningatpoint1withthegroundcurrentreachingaconstantvalueof1,300amperesin11/2cyclesatpoint4,Theflashoverinthefaultedtransformeroccursjustprecedingamaximuminphase2toneutralvoltage(aswouldhavebeenexpected)atpoint2.The345kVlinecurrentinanunfaultedphaseincreasesinstepfunctionmannerto350/ooftheprefaultvalueatpoint3,Nohighspeedrecordingsofvoltagesorcurrentswithintheplantwereavailable.Nosequenceofeventrecordingswereavailabletocorrelaterelayoperationtimes.Duetothelargeamountofmagneticenergycouplingthegeneratorrotorandstator,andknownelectricalparameters,thcdecayoffaultcurrentcontributedbythegeneratortothesolidlyconnectedtransformerwouldhavespannedanumberofsecondsasthcfielddecayed.Relayoperationtargetsreportedwere:l.TransformerDifferentialRelay(TypeBDD)onTransformer2MTX-XM1B.2.TransformerNeutralCurrentRelay(TypeIAC).3.OverallUnitDifferentialRelays(TypeBDD)inphases2and3.4.GeneratorPhaseOvercurrentRelays(TypePJC)inphases2and3. r FvFollowingisolationofthegeneratorandfailedtransformerfromthepowergrid,marked5onFigureA.onlyasingle345kVphasetogroundvoltagerecordisavailable.Themagnitudeofthisvoltageonanunfaultedphaseis74foofthepre-faultvalue.Sincegeneratorneutralcurrentislimitedtolessthan8amperes.itisknownthatthefaultedtransformerappearsasalinetolinefaultwithsomeimpedancetothegenerator.Bytrialanderrorcalculation,generator.linecurrentsarefoundtobe0,1.9and1.9,multiplesoftheratedvalueof31,140amperes.Theline-to-linevoltageshavemagnitudes74lo74lo,and25%oftheratedvalueof25,000volts.Thedecayofthisvoltagefor0.2Ssecondsoftherecordinghasameasuredtimeconstantof2.7seconds.Thecalculatedvalueoftheimpedanceofthefaultedtransformerasseenbythegeneratoris0.23perunit.Conditionsprevailingduringthesixcycletimeperiodfollowingthefault,marked2onFigureA,cannotbedeterminedwithcertainty.Theexactnatureofthefaultwithinthetransformerisnotknownandthephysicalevidencewillbestronglyaffectedbythecontinuedflowofenergyfromthegeneratorduetotheinherenttimeconstant.TheflashoverofonlyaportionoftheHVwindingisevidentsincethe345linevoltagestoneutralremainat39%o,867oand86'1oofthepre-faultvalues.Thepresenceof"residual"inthemeasured345kVlinecurrentsprovidestheevidenceoftransformerneutraltogroundcurrent.Thisrequiresthatthefaultinvolvesapathforcurrenttogroundfromthehighvoltagewinding.Recordedvoltagesandcurrentsshowastepchangetonewvaluesandnodramaticchangeduringthetimeperiodoftherecord,whichtotalssomewhatlessthan1/2second.Itcouldbesaidtheyare"cleaner"andlessdistortedthancommonlyseenoscillographrecordingsoffaults.Giventheseobservationsandsinceboththegeneratorandthesystemweresupplyingfaultcurrentintothefaultedtransformer,generatorline-to-linevoltagesprecedingisolationwouldbeexpectedtobegreaterthanthoseimmediatelyfollowingisolation.Ithasbeenspeculatedthatveryhighfrequencyenergy(mHzregion)mayhavecausalmalfunctionoflogicandcontrolcircuitryintheUPSequipment.Abroad-rangeoffrequencieswouldbeexpectedinanyarcingphenomenonsuchasoccurredinthisfai1ure.Nothingintheavailabledataordesignparametersoftheplantequipmentwouldsuggestanextraordinarygenerationorpropagationofhigherfrequencycomponents.'Ihefailureofatransformerandinternalarcingisnotarareoccurrence.Comparisonofoscillographiccharts 'Ijj fromsimilareventsinotherplantsshownothingunexpectedorunusualinthisparticularfailure.Itmustbeborneinmindthatthesamplingrateoftherecorderislistedas5.814kHzandfrequencycomponentsinexcessofperhaps500Hzwouldnotbeaccuratelyportrayed.GEexperienceintestingoftypicalpowertransformers(suchastheLnitAuxiliariesTransformers)providesanindicationoftheexpectedcouplingbetweenwindingsatradiofrequenciesintheregionof1megahertz:Theattenuationfactorsrangefrom1,000:1to10'softhousands:1.Directmeasurementscouldbemadeinthisplanttodetermineattenuationfactorsforindividualtransformersoverarangeoffrequencies.Thesetestswouldbemadeonnon-energizedtransformersusinganRFsignalgeneratorandasensitive,calibrateddetector.Attachedrecentarticlesonelectro-magneticinterference.Reference1discussesIEC801,4andthecharacteristicsofelectricallyfasttransients.Reference2discussestestingofgroundconnections.ViThepossibilityofelevationofthcstationgroundingsystemasaresultofthisdisturbancewaspostulated.Therelativelyhighlevelofgroundfaultcurrent,estimatedat1,300ampercsfromtheavailablerecording,wouldnothavebeenconductedintotheplant.ThiscurrentcanonlyfiowinRomthe345kVsystemforthe6cycleperiodrequiredforrelayandcircuitbreakeroperationtoachieveisolation.Thegeneratorgroundcurrentwouldhavebeenlimitedtolessthan8ampcresbytheneutralgroundingequipmcnt.Elevationordifferencesingroundpotentialwithintheplantwouldthereforenothavebeenexpectedduringthisevent.Reference1discussestheproblemofachievinga"super"groundandconcludesthatastablegroundreferenceforinterconnectedequipmentisofgreatersignificance.Sincenormallycirculatinggroundcurrentsarenotexpected,testingwithverylowvoltagesandcurrentsisrecommended.Noteespeciallytherecommendationtotestwithafrequencynon-harmonicallyrelatedtothepowerline&equcncy.Thetransformerssteppingthevoltagedowntosuccessivelylowervoltagelevelsareconnectedinamannertominimizecouplingofpowerfrequencyandhigherfrequency.componentsbetweenthcvariousbusses.Specificconfigurationsare: 1IIV l.NormalStationServiceTransformer-delta25kVtowye13.8kVwith400ampereresistivegroundingonthe13.8kVside.2.LoadCenterTransformers-delta13.8kVtowye4.16kUwith4Rampereresistivegroundingonthe4.16kVside..3.LoadCenterTransformers-delta13.8kVor4.16kVtowye600voltswithneutralsolidlygroundedonthe600voltside.4.ReserveStationServiceTransformers-wye115kV,delta4.16kV,wye13.8kV,The13.8kVneutralis400ampereresistivegrounded.The4.16kVcircuitisconnectedtoazig-zaggroundingtransformerwitharesistorintheneutralconnection,presumablyfor400amperes.Theseconfigurationsprovide"effectivelygrounded"distributionbussesasdefinedinTEEStandard142andwillservetolimittransientovervoltages.Thisisinaccordancewithdesignpracticesdeemedprudentandconservativewithinthepowerindustry.Theindustrycontinuestoreviewtheeffectsofgeomagneticdisturbancesonpowertransformers.Whilenoevidenceisseenofvoltagedistortioninthefourcyclespreceedingthefailure,excessivedutycouldhaveoccurredifthesetransformershadbeensubjectedtolowleveldirectcurrentpreviously.References3and4areattachedforperusal.

I~~.rT~v!LALI4>EII>3~La+~II,ed'-.~>J444Jape.2VIV'gn:~I'.!i'VVV>.pi~~cIC.IIIC(IVI.-$LJIC9.cpNil(lt~IH0L~IJ~h'~r>>t.SkAVCIIOOI>>I>>IsccrrMFeudsAJtI>latir~gg(.CrCeShr>>J I1~~ fncfustrfalEqufpmentEISCtt'OfllCSIlllndLIStl'IgfAPPIiCatienSADiscussionofFundamentafENlCPrincfpfesforElectronicControllerslnanindustrialEnvironmentBy4t'iHiam0.Kimmel.PEKimmeiGerkeAssociates,LtdEDDICproblerrsi~:h:ndustra!ccnuoisareaggravatedbyharsheni.ronments.mixed:ec.'".noiogiesandalaclcofumformE!ifCguidebnes.T:isarLicie'>elconcentrateon;hecommonas;ec:sofelectroniccontrolsinan!ndustnalen>".ronment.whichisgenerallymucnharsher:bantheofGceenvirOnmenLWhatistheindustrialenviromentandwhatcanbecoreaboutit!Theenvironmenincludestheentiregamutof'.hebasicthreats.powerdisturbances.RFI.andESD.RFIandpowerdisturbancesmaybelocallygeneratedornot.Mixedtechnolo-giescompourd:heproblem.Digitalcircuitsareusedtoswitch."nevoltagesviarelays.Analogsensorsareinputdevices:odigitalcontrols.Increasingly.thereisaneedfora:ooperauveeffortbetweenthedesigners.manufacturersandinstailerstocomeupwitharock-solidsystem.Acommoncomplaintisthatthemstallersormainte-narcepeoplewon'tfollowtheinstaUationrequirements.Thismaybetrue,butitmustchange.smcethereareproblemswhichcannotbesolvedattheboardlevel.Itisalsotruethatmanufacturersoftenspecifyinstallation.equirementswhicharenotpracticaltoimpleinent,andtherearedocumentedcaseswheretheprescribedinstallauonprocedureswil!causerathertitancureaprobietts.The!adtofumikenguidelineshasham-peredEMCprtilessintheindustriatarena.Fortunately,theEuropeanCommu-nityisworkingtoadopttheIEC801.xspecilications.anddomesticcompanieswouldbewisetoadoptthem,evenifthereisnointentiontoexport.TheBasicThreatsThethreebasicthreatstoindustrialelectronicsarepowerdisturbances,radiofrequencyinterference,andESD.PowerDisturbances.Powerdistur-EMCTest4DesignbancesareaweHknownirdustralproblem.Iniac:.whenaproblemoccurs.ketirstthough':is:oblamethepowercompany.Oftenpowerqualityisaproblem(especiallyifgroundingissuesareinciudedl.buttheproblemisalmostalwaysgeneratedbyadjacentequipment.Tradiuonalproblemswithpowerincludespikesandtransients,sagsandsurges,andoutages.whichthreatentheeiectroiucsviathepowersupply.TheseproblemsarefairlyweildocumentedandareoftensolvedusingpowerconditionersorUPS.Themostcommonpowerproblemsconfrontingelectronicstodayisthesagwhich~icailyoccursduringturnonandthespikeswhichtypicallyoccurduringturnoffofheavyinductiveloads.~<..esagssimplystarvetheelectronics.ThehighfrequencyttansientsbarrelrightthroughthesupposedlySteredpowersupplytoattacktheelectronicsinside.Digitalcircuitsaremostvuhierabletospikeswhichcausedataettorsorworse.AnalogcircuitsaremostvukierabletocontinuousRFridingontopofthepower.FIPSPUB94providesguidelinesoneiectricalpowerforcommercialcomputers.Thisisgoodinfortnation,butbewarethatfactorypowerismuchnoisierthancommer-cialpower.TheguidehcesofIEC801.4speci5esanelectricallyfastuansient(EFT)thatsimu-latesarangandotherhighspeednoise.Ebsarequiteshortranged-theydiminishrapidlywithdistanceduetoinduc.tanceintheline.Butatshortrange,theyaredevastatmg.Unfortunately,attentionisplacedonthefrontendoftheelectronics,thepowersupply.Withindustrialcontrols,theprob-lemisthecontrolledelements.Iftheelectronicsiscontrollinglinepower,thedisturbancessneakinthebackendwherelittleornoprotectionexists.Systemground,whilenotbeingspecifl-callyapowerdisturbanceprob'.em.:s:.thecar..erofresidualeiiectsofo-.disturbances.Any'ind;sinaiorcommer:suucturehassigiu8cant.'ow~equencurrentscirculating:hrought.".egrousystem.sometimesbecausethe.nergyintentionallydumpedontotheground(s.aswithanarcweider)andsomeur..becauseofunintenuonalcouplingorvaninadvertentconnectionbetweenneuandgroundsomewhereinthe!aciiity.RadioFrequencyInterference.Rdiofrequencyinterfer~nceaffectsboanaloganddigitalcircuits.withana'ccircuitsbeinggenerallymoresusceptiblSurprisingtomany,thepnncipiethreatnottheTVorFMstauondowntheroaibutratheritisthehandheldL~snut:~carriedaroundbyfacilitiespersonnel.Aor.wattradiowillresultinanelectncne!d~(Nevolts/meterataonemeterdistanceenoughtoupsetmanyelectromcssystemsIEC801.3speciGesimmunitytoelec".Geldsofonetotenvoltspermetedependingontheequipment.withtivevoltspermeterbeingSelevelfortypicequipment.Ascanbeseenfromtheabovapproximation,threevoltspermeterisncanexcessiverequirement,andeven:evoltspermeterisfairlymodest.ElectrostaticDischarges.EiecLcstaticdischargeisanintenseshortdurauoipulse,havingariseameofaboutonenanosecond.Thisisequivalent:oaburs.of300MHsinterference.Staticbuildup.of15kVarenotuncommon.Dryclimates,includingnorthernclimate'.WhamKimmelisapn'ncipalwithKimme.GeromeAssociates.Ltd.Thefirmspecial.i@cainpreventingandsolvingelectromag.neticinterferenceandcompaabQity(E.MhEMC)problems.Mr.Kimmeicanreachedat3544NPascal,St.PauL.~i~55108,ortelephone612.330-3728. i ~~VcclinepouerItIiITRIACsuitcl.epiouerF:g.'re'..Amp'.'Gerdetnodulanon.Figu:e2.Transient!eedbackpath.:n~".nter.offeropportumty!orESD.Industnaienvironments.withthe:rmovingeqipment.areloadedwithpotenualESDsources:rubberrogers.belts,andproduc-uonou'.putsuchasplasncandpaperroUs.alladdup!oarealESDth:eat.andt."isr."meatismorelikelytooccurevenm;elanvelymoistenvironments.Look:oIEC801.2.'orESDstandards.Elec!ronicsDesignElectronics:sgenerallytheultimatevictimof:nterference.Thehter.'erenceGndsitswaythroughvariouspaths:otheelectronicsequipmentitself.Let'sconcen-trateonw'ratcannappentoyourelectronicsfrom!hebackdoor.thatis.bydirectradiationintotheelectronicsandbycon-ducted:nterferencethrough:hesignalandcont:oilines.Sensors.Lowlevelsensors.suchasther...ocouples.pressuresensors.etc..arecharacterizedbyverylowbandwidtbsand!owsignallevels.AmajorMeattothesesensorsisradiofrequencyinterference.eitherfromnearbyhandheldtransmittersormoredistancelandmobileorGxedtransmitters.But:hesearehighl'requency,muchabovethebandpassofyouramph6er.right?Wrong!Lowfrequencyamplifiersareplaguedbytwo,ybeaomena:outofbandresponseand<<stsorectification.Thesecombinetoprovidefalseinformationonlevelstothesystem.Allamplifiershaveanormalbandpass,typi6edbya20dB/decaderoUoformoreatthehighend.ButresonancesduetostrayinductanceandcapacitancewillgiverisetoamplifierresponseGveordersofmagnitudeormoreabovethenominalbandpassoftheamplifier.ThismeansanaudioamplifierwillrespondtosignalsinthehundredsofMHz.ThesecondaspectoccurswhenRFencourtersanoriinearitysuchasasemicon-ductordevice.AllsuchdevicesgiverisetoaDClevelshiftwhenconfrontedwithRF.lnaradioreceivertheyarecalleddetec-tors.Noniinearitiesareminimizedinlineardevices,but:hereisalwaysenoughtocauseproblems.Theupshotisthattheampli6erdemodulatestheRF.generatesanerrone-oussignal.andpassesthiserroron.Thiseffec'.isshowninFigure1.Outputhnesaresimilarlyaffected,withcapacitivecouphngbacktotheinput.ThesoluuonistopreventtheRFfromgettingtotheamplifier.eitherbyshieldingorfiltering.Themostcommonpathtotheamplifierisviaanexternalsignalinefromthesensor.butiftheekctronicsisnotshielded.directradiationtothecircuitboardmayalsopresentaproblem.Assumingfilteringisthesekctedmethod.useahigh~frequencyGlter,designedtobkicksignalsupto1GHzorevenmore.Usefemtesandhighfrequencycapacitors,DonotrelyonyourlowfrequencyGltertotakeoutRF.Attheopamp.youshouMalsodecoupleyourplusandminuspowertogroundattbechip.IfyourgroundiscarzyingRF,youcananticipatethesameprobkmmentionedabove,sinceitwillcomtptthereferencelevel.DataLines.DigitaldatalineswiUbeupsetbytheRFproblemasinanakig,buttbelevelsnecessarytoupsetarehigher.Instead.digitaldatalinesaretnucbmoresusceptibletotransientghtches.Allsignallinesshouldbe6lteredtopassonlythefrequenciesnecessaryforoperation.Ifthethreatliesinthebandpassoftbesignal,thenshieldingoropticallinkswillbeneeded.SwitchedPowerLines.Thisrefersspecificallytothepowerbeingcontro9edbythecontrollerdevice.Industrialcontrol-lersarecommonlytaskedtocontrolpowertoheavyequipment.wtuch.s;itc.-.hyheavystarting.'oadsandinducnve.a<<wnofTyptcaUYthee!ectroniccon:rswitchUnepowerusingrelaysor;;.-.Thisexposesthebackendofthecont;=tosubstantiallinetransients.whichcoi-backtothecircuitpowerandgrounddisruptthedigitalcircuitryasshownFigure2.Itismandatorythatthetransient:rentsbedivertedorblocked.since'igitalsystemcannotwithstandt.".e.-.~gtudeslikelytooccurwithaninducuvek:iunlessspecialstepsaretaken.SelfjamniingcanbeUnutedbycontrcliwhenyouswitch!heUne.usingzecrossingdevices.Ofpartic~importanisthemrnoff.sincedtatiswheninductivekickoccurs.lfa6powerswitchingusedzerocrossudevices.thetransientlevelsinthefactowoukibedramaticailyreduced.Unfor.nately,thatgoaliswelloffinthefutu:Untilthen,expectthathighvoltagepowtransientswlloccur,andtheymustbedewldl.Opticalcouplersandrelaysdonotprovisufficientisolationbythemselves.Ththighcapacitanceprovidesanexcegenthiifrequencypath,andiftheyarestackedtinanarray,tbecapacitancewi6adduppasssurprisinglylowfrequencies.The:capocitancesan'tbeelim'mated,butyccandesignyowcontrolcircuitstominimizcouphngpathsandtomaximizelowimpe<ancealternatepaths.Transientsuppressorsshouldbeinstalleattbekiad,whichisthesourceofthespihbuttheycanbeinstalledatthecontroUtasweal.AninterestmgeffectoccurswhenconbiningzerocrossingSCRregulatorswulowlevelMnsorswhichuselinefrequercnoisecanceHngtechniques.Veryseftsitivsensorssometimesaresampled.fortJQIL"Augusta~! i4II' 'f80VACHighCurrentDC,burrouPouerIwlcCarinaPSElectroni>>:sFir're3.Commonindustnaipowe.supply.Figure4.awful:rplegroundpaths.enurepoweryc!etocanceitheinefreq'ncyconipohent.Ift..esamp!eoccursco.","u;.entlywi:hirepowersw'.tchingonoroif.:heaverage:orhesensorwillbe.pse'..andane.-.or~4"erecorded.SystemDesignandInstallationOnce>eelect:onicsisdesigned.itbecomesap.oblemof!hesystemintegratarandinstaller:oersurethatthcelectranicsiscravidedwuhtheenvironmentfarwhichitwasdes;gned.Mostofthcumc.thisworkisperformedbypowerexpertsandclectricians.andtheyarenotalwaysawareof:heintcrfererceprobkm.Often,onsite.rhepowerqualityisblamedforthcequip.rrentanomalies.Buttheproblemcanoftenbeavoidedbyfollowinga(ewbasicprina-ples.Theindustrialconuoldeviceiseitherintegratedintoasystemat!hefactoryorinstaL'edseparatelyonsite.Controllershandleavarictyofdevicessuchasmotorspeedcontrols.positioningdevices.weld-ers,etc.fnterferenccpresentedtotheelectronicscanbesigniGcandyreducedbyappropriatemeasuresoutsideoftheelec-uonicsbox.Thereisnowaytoaccuratelyassessdierhreatwithouttestdata.Butrcgardlcssofthebr(orationavai!ab!c.muchcanbeaccomplishedbycorrectinstagation,anditdoesn'tcostmuchifdoneatthestart.RetroGtsbecomecosdy.especiallyifac-companiedwithfactorydowntime.Let'sconsiderdscsameprob!cmsfromasystemstandpat.Yourgoalistolimittheinterferencewfskhmustbehandledbytheelectronics.Directradiationtotheelectronicsisnotoftenaprobleminanindustrialenviron-ment,butitdoesoccur,andmostoftenwithaplasucenclosure.TheNEiMAtypeenclosuresprovideenoughshieldingformostmdusuialneeds.Ifyoudon'twanttouseametalenclosure,besure!ogetelecuonicswhichwillwithstandtheRFwhichwilloccur.l(oreor'.eh'.heproblemisconducted.eirher'aapowerorgraurd.Theproblemoccursdue:opowerandg.ounddistur-bancescausedbytheequipment.Itisanalltoocommonpracdcetodrawcontroiierpowerf;omthesamesourceasfeedsthepowereqtupmcnt.T."ispowermayprovide:herecessaryenergytodrivetheequip-ment.butitisnotsuitabletopowertheelectroiucslFigurc3).Hopefully,allindusuialequipmentwiUhaveelectronicspoweredfromaseparatelowpower120voltcircuit.Itsolvesseveralproblems.First.itseparatestheelectron-icspowerfromtheprobablyverynoisyindusu@gradepower,prevendngtheswitchingtransientsandstartupsagsfromgenugtotheelectronics.Second,ifitisnecessarytoconditiontheelectronicspo~erfromanextet".Aproblem,itistarcheapertocondiuonthewattsnecdcd(orelectronicspowerthanitistoconditionthckilowansrequiredbythesystem.Ifpowercannotbeseparated.thenitisnecessarytoprovideabu!letproafpowersupply.preferablyincbrdinganisolationtransformer,toseparatetheentirepowersupplyfromtheelectricalequipment.GroundNoise.Groundnoise,inevita-bleinindustrialenvironments.mustbedivertedfromtheelectronicsmodu!c.MultiplegroundsinasystemwiGoftenresultingroundcurtentscircu!stingthroughthecquiprnent.andgroundnoisecircuhtingthroughthcelectronicspathwillcausernalfuncuon.Figure4showssometypicalgroundloopsituations.Acommonapproachistodemandasuper~arthground.Thisisgood,butitisnotacureall.andoftenasupergroundcannotbeachieved,nomatterhowyouuy.Howdoyougetasupergroundfromthethird4oor?Therealneedistogct'astablegroundreferencetoallinterconnectedequipments.Ifthisequipmentiscloselylocated,thenaverylowimpedanceinterconnectisfeasi-ble.Powerconditionersareo(tentaskedtoeliminateRFofg.oundnoise...atwork,but:heseproblemscanberc.withanisolat:onrant(armer:o=".-..-neutraltogroundnoiseand~~rh"~IIpo;lincGlters.Soyoumaywan:;otryinexpensiveapproachnrst.DataI.inks.Datalinksaresu.~ngovertheer'.tire!acirty.exposingther.:twoprinciplee((ects.groundraisearepickup.Groundnois>>;willcausedataer.-unlesstheelectronicshasbeendesigne"accornmodatcpotentialdifferencesof->>eralvoltsormore.Thisisaccampbs;withdif(crentialdriversandreceivers:f=.mustbedirectcoupled.Optical'hnks-eventuallytakeovertheselinks.TheotheraspectisRFpickup.Inexpesiveshieldedcableissuitable(ar:.'urpose.Groundborhends!DonotappsinglepointgroundtechniquestoRF.i!Iawfrequencygroundloopproblem:sthreat.thenoncendcanbecapaciuveSummaryIndustrialelectronicsaresubjectedrcharshenvironment.Gooddesignandinst.!ationtechniqueswillminimiaeproblemsthcGeld.AdhcrencctotheEurope;standards,IEC801.xisagoodstart,ev>>ifyouareonlymarkeunginthcUSA.BibliographyFIPSPUB94,GuidelineonElec'ac:PowerforADPInstallauons.Scptcmber1983,IEC801-2.Electromagneticcompatibilit.(orindustrial.processmeasurementan<controlequipmcnt,Elcctrostaucdischargrrequirements,1984.(EC801-3.Electromagneticcompatibi!it!(arindustrial.processmeasurementanIcontrolequipment,RadiatedelectromagceticGeldrequirements,1984.IEC8014,Electromagneticcompatrbilit:(orindustrial-processmeasuremcntar.:controlcquipmcnt.Electricalfast:ransrehtburstrequirements.1984.EMCTest8cDe.<n e industrialFquipmentEquipmentGroundBondlng-DesigningforPerformanceandLifeADiscussionofGroundConnectionFundamentalstoControlEMlByD.B.L.DurhamDytecnaLtd,UKTheproblemofachievingsatisfactoryearthbondsorgroundconnecuonshasplaguedEMCengineersformanyyears,notonlybecausethebondsareoftenvitalfortheachievementofsatisfactoryequipmentpei-formancebutbecausetheyaffectthelongtermperformanceofequipmentafterithasbeenintroducedintoservice.Recommendationsonbondinghaveex-istedintheformofmilitaryspeciBcations,suchasMilStd1310.Mil188-124AandMil-B.5081(ASG)forsomeyearsandthesehavegenerallyprovedsatisfactoryformostnewbuilds.However.thesespeci6cationshavecertainlimitationsinthattheygener-allydonotspectfyconsistentlylowlevelsofbondimpedance.norasuitabletestmethod.TheintroductionofncwEMCspeciGcationsinEuropewiththeEECDirectiveonEMCandtherequirementsforiongtennstabilityinEMCcharacteristicshasdirectedtheUKnuTitarytoreviewcidsutlgspcciEcaQonsandIntroduceancwDefenceStandardtotightenupperfonn-ancerequirementsfornurttaryequipment.DcfStan~(Part1)/1hasbeenintro-ducaltoaddressthiaareaasfarasmob9eandtranspottablccanmunicationsinstalla-tionsareconccnteia.buttherequirementsshouklhaveimplicationsinindustrialapph-cationsandoverthewlxHeekctronicsmarketiflongtermproductperformanceistobeguaranteed.BondDegradationEarthorgroundbondsaregeneraHyconsideredessenualnotonlyforsafetyreasons.butasameanofdivertingEMcurrents,"locking"circuitboardsand38eqtdpmenttoastablegroundpoint.achiev.ingadequatelevelsofcabkshiekhngandformanyotherreasons.Manydesignersun-derstandtherequirementforshort.fatbondleadstominimiacgroundinductance,butfewappreciatethatacriticalaspectistheconnectionresistancewithwhichthebondstrapisattachedtotheequipmentgroundpoint.Thcbasicrequirementofanybondisthatitshouldhaveaslowanimpedanceaspossible(uille55itisadchbcratcinduc-tivebondtolimitgroundcurrents).Tbeimpedanceisacombinationoftheresistiveandtheinductivecomponents.Thcresis-tiveelementisafuncnonofthcbondstrapresistivity,crosssectionalareaandlength.seeEquation1.whihttheinductivecompo-nentisamorecomplexfunctionofthcbondstrapcharacteristicsasshowninEquation2.R~-qf0AL-~ln-+05+02235-jiZ,j'fb+c"2icLb~c2fJ(2)whereRresistance,g~resistivity,f>length.A~area,p,pcrmeabiEtyoffreespace,L~inductance.p~feLttivcpermcabiTity,bstrapwidth,andcstttpthickness.Thefrequencyatwhichtheinductiveekmentdominatestheimpedanceexpres-sionwhencalcu!atingthctotalinductanceis,fromEquation3,typically1kHs.ltwglbeseenthereforethattoalintentsand"purposesthcbondexceptatDCandpowerfrequencies,maybeassumedtobeaninductance.Atveryhigh~equencies:rstraycapacitanceacrossthestrapdonunate.Thismeansthatthevolt"-:acrossabondisgenerailyafuncuoninductanceandfrequency.BasedonOhr.".LawthisvoltdropisshowninEquador.~Fortransientsthevoltagedropisgiver..Equation5.ZRt+cutLSVIZ~jauUd1dt(5whereZ~strapimpedance.cu~tacomafrequency,V~voltage,and1~current.Fromthis.thehigherthcinductancethmoreisolatedthecircuitorboxbecomefromground.Thscanhavesigru6caneffectsoaequipment.inchdingenhancementofnoiseinjecbonontoarcuits,reduc=nonofSterperformance,andlossoicoaunlmicationrange.FromaTEMPESTstandpointitmayresultinmoreradiationfromemanent.ltwouldseemfromthisthatthecntcriatoranybondistheinchlctanccandhencethcchoiceofshortfatDavidDuganservedfor21yeanitttheBrrtiabAnny,wherehcgainedhisChgreeiadectricafcnginceting.AfterserviceinavarietyofappointmentshcretiredtojointheRecalls'EScompanyastheTechmca/Mtnsgcrrcspottsiblc/orthecfes/gnanddevclopnsetttofcommcttticationsystems.fn198$hejainefDytecnaastheiManagerofthe&ginecnttgDivision.andnowtscurrcntfyTchtaica/MarftctingManage..JulytAugust!991 5P sc';orc(cgq(r~rri.~~~cwc"-av~l-l'sis~fNf$QskgRrrfNT'N,ff'Srnryort:4icsir:i.rrenl',:!0iQA.osJVA5Hf5rrlltfRscarc5errVOUAGE&ifASI'REhlENTFigure!.Bondresisurce.Figure2.Fourwirebridgemethod.bondstraps.However.ananaiys'sof:hebondinductancfshowsJiatI'orabondstrapof100mm!org,15mm~~deand2mmIhcktheimpedanceat1MHawillbe3.8Ohms.Itsoundsextremelysin:pie.butworkperformedin'.heUSA'ndI:Kshowsthatifanetrotismade'inthewaythestrapisternunatedthenaprogressiveincreasein:heresisunceofthebondstraptoboxjuncnoncanoccurastheequipmentages.Eventuailytheresisuncewillbegintoexceedhundredsofohmsandmayeventu-allygoopenccuit.ThiscannegatethceffectofthebondstrapcompletelyaspartoftheE!rIIprotecdon.tVhathappenswithbondstocausethischange!Essentiallyagroundconnecuonisaseriesofirrpedancesfromthcstrapthroughtothegrourdmaterial,asshowninFigure1.Eachpointofcontactcontrib-utestothetotalbondper'.onnancc;.Asaresult.achangeinanycontactconditioncanresultinachangeinthetotalbondresistance.Asisweilappreciated,the"contactresistancebetweentwometalsur-facesisahnctionofthepressure.Thepressureexertedbythetipofadrawingpinisvastlygreaterthanthatfromthethumbpressingbyitself.Thusthecontactfromasharppoultgivesatsochhigherprcssuret.'unaOatpointand4gtiforclowercontactresisuncc.MeasutetatahaveshownthatsharppointsenableContactrcsisunccofafewnicroohmtobeachievedwhilstsimilarpressuresonOatsurfacesresultinmil-liohmsofconuctresistance.Itmightbefeltthatthereislittleornodifferencebetweenthesevalues,butinrealitythereis.Anessennaiaspectofagoodbondisthatitshouldremainsoaftertheequipmenthasenteredusc.Highpressuresalsohavetheeffectolsqueesingoutcorrosivemateri-alsandinsulating6lms.TheformercausesEMCTest&Designprogressivedegradationntbonds,whilstthelattercanreducetheef'ciencyofthebondf;omthemomentitisinstalled.Itisparticuiariyimportantincommunicationssystems,where6ltersareinsuiiedandshieldedcableternunationsaremadeJiatthebordsareof',owresistanceandreuintheirperfonnance.BondPerformanceandMtaalaremcntExperiencehasshownoveranumberofyearsthatforlongtennconsistentbondperformancealowvalueofresistancemustbeachieved.Thisistypically1-5milhohms.InDefStan~(Part1)/1thevahiehasbeensetatamaximumol2miUiohms.Thislevelismeasuredthroughtheindividualbonds.Thclogicbehindthislevelistwoloid.Firstly.experienchasshownthatwithcommunicaionsequipmentinparticu-larthisvalueolbondresisunceisrequiredifconsistentperformanceistobeachievedintermsofreceptionef6ciencyandtrans-missioncharacteristic.ThisisparticulartysoforTEMPESTprotectedequipments.Tbesecondpointisthatifthebondhasahigherresistancethenthereisasigni8cantlikelihoodthatprogressivedegradationwilloccurandthebondresistancewigincreaseinvalue.Therewillthenbeaprogressivelossinperfonnance.Themainproblemwithmeasuringbondresistancesisthatitshouldbcmeasuredusingalowvoltage/curtenttcchtilquc,Moattechniquestodateforassessingsafety'nvolvesdrivingalargecurrentthroughthebond.Thischecksthebond'sabiRtytocarrycurrentbutdoesnotnecessarilycheckitsEMIprotectionperfonnance.Therea-sonisthatmanybondsmaywheninnormalusehaveahighresistanceduetooxideandgreasy6lms.butwhensubjectedtoahighcurrentthclayersheatupandarevapo-rised.Afterthecurrentisremovedt.".eSmcanreturn.Thushighcurrerttechmquesarenotrecommendedror:esangEMIbonds.ThenewDefenceStandardintheUKspeci6esamaximumprobevoitageoi100mictovolts.Thisreprcsenutypicallyaprobecurrentol50milliampsundershorcitciit(<1mQ)condiuons.This-:sinsuf6cienttodestroysurface5lms.Thechssicmethodformeasuringlowresisuncehasbeentouseafour:erminalbndgeasshowninFigure2.Inthiscase'thecurrentisdrivenbetweentwopointsandAeVOltageaCtOSStheSampleiSmeaSuredwitNahighresisunceprobe.ThisremovesJiecfcctsotthcptobecontactresistanceandleadresistance.Thisisgenerallyconsid-eredtobealaboratorymethodastheuseoffourcontactscanbeawkward.Iftheleadresistancecanberemovedbyacalibrauonteclniqucthenthcfourterminalsmaybereplacedwithatwoterminalsystem.hfurtherpossiblere6ncmenttothetecluiqueistouseafrequencythatisnotDCor50/60/iOOHx.Inthiscase10.4Hahaabeenchosen.Ifanactive6lterisusedtoSterouta9otherelectricanoise,thenitisposgblctousethebondresistancemeteronpoweredupsystems.Itisworthnotingthatatthisfrequencytheimpedanceiastolhtgclyrepresentedbyresistanceratherthaninductance.ThetwotermmalmethodisshowninFigure3.TheintroductionofnewEMC/EMIspcci6cationsinEuropehasmadeitmoreimportantthatoncemadethebondshavecoilslatentlong'tcrlilperformance.ThsmeansmeasurinonperiodicinspecnonardaRctmaintenance.Itisanessentialaspectofinsutmgconsistentperfonnance.IthasbeenshownthatwithinmonthsapparenJygoodbondscandeteriorateto.-ighresis.

AAeqT~ic'oKue45uI>eNreiieootsisascg0FIXEDRKSlSTANCELEAOSFigure3.Twotermmalbridgemethod.404y4Ic<~~4cc>~~~c~(olnpi4lllAQ~+c~~(4eeoc4((i+yo~befit%CUSTOMQAGTi4.++++"9t~o'4+a~~>tiQNCQMNCRfAC.0odgottc~'e+b~+.=nuators,CoaxialTerm.%/@<y<c<4~connectors,~4.~b,~Cata~pc+q4.attestlE11?0-1?bnCOlnAvenue.FOlbrOOk.;4Y11741(S16)~85.)4tX1FAXi16.~BR>l14INFO/CARO29tance.Ther.io.et.'ivcesii'-.~suo)ecttotestingand.xa.-..;.-.a:.cn-asama:ntenancetas~.LK~militaryExperienceTherehaveoeen'.wo~lcr-.::causedbypoorbonusexpenencedegradauon.nericrmance~ready-uonedin:tusa.-.icle.The:ossi;cir,-cationrange.poorEMlpe.",'ormanceothereifectsaL'onrnbu'.etoacons:dertreductionmequi".-..entNc:encyanna.ability.Thesecordei;ectwnichis-.difficulttodenufy:s:hataiNoFaultF.(NFF)problems.AnanalysisofreN'."failuresfrommilitaryreiiaLiitydata.shownthatNFFinc:dentscanaeextre.-.high,particulariy:nhunud;timates.hasbeenpartiallyconfirtnedbyreports.':theGulfSarwhenaHforcesrepor-.e.increaseinavailabilityofequipmen:.;.'rierclunate.Manyfau!tsaredueto"electricacontactsinconnectors.bu:alarnumberhavebeenidenufiedasexcess:EMIinducedthroughpoorgroundonncThismaybecausedbyeitheraloosegroistraporconnectorterminauonto:he':cAsignificantimprovementInequipmeavailabilityandperfonnanceisexpec:ewhenmorerecentstatisucsareanalysed.Theintroduction:ntotheBnushAr.-.serviceofAeDyteaaBondResistancTestSet-DTl09hasenabledtheL":mihtarytomeasurebondresistancesinstalledequipmentandreduce;hecurancesofNFFerrors.TheUKmi:armeasurementprocedureusesatwo:er-...:nalbridgemethodandanaccuratemiiliohmcalibrationstar.dard.ThismeasurementprocedureandequipmentisalsinusebyotherNATOnationsande!sewherebyiniTitaryandnavalforceswrohavrecognizedthesameproblem.CottclueiottaTheproblemswithgroundbondshavebecomesignificantwiththedevelopmento:sensitiveandsecurecommunicationsequi"-ment.ThiscoupledwithanincreasingreedtoachievehigherandhigherlevehofKMfprotectiwthasleadtoanincreasedemphasisbengplacedontheeffectivenessofalltypesofsystetttgrounds.These.furthercom-binedwitharequirementtoensurethelonglifeofsystemsonceinservice.haveresultedintheassessmentthatbondsandterminationsareoneoftheprimarycausesofEMfaBuresinsystems.Therequire-menttotesttheseisclear.howeverthemeanstodosohavenotalwaysbeenavailabletoengineers.July.Aug.st'.9o'.

PanelSessIonPESSummerMeeting,JulylQ,1988LongBeach,CaHforniaJohnG.Kappenman,ChairmanPowerSystemSusceptibilityToGeomagneticDisturbances:PresentAndFutureConcernsJohnC.Kappenman,MinnesotaPowerTheeffectsofSolar.GeomagneticOlaturbanceahavebeenobservedfordecades.onpowersystems.However,thepro-foundimpactoftheMarch13,1989geomagneticdistur-bancehascreatedamuchgreaterlevelofconcernaboutthephenomenainthepowerindustry.Severalman.madesystemshavesufferedd)eruptionstotheir-normaloperationd)aatotheoccurrenceofgeomagneticphe-nomena.Moatoftheman~esystems,suchaacommu-nications,havebrettmadelesssusceptibletothephenom-enathroughtechnologicalevolution(microwaveandfiber-optlchavereplacedmetall)cwiresystems).However,thebulktransmissionsystem,Ifanything,ismoresusceptibl~todaythaneverbeforetogeomagneticdisturbanceevents.Andlfthepresenttrendscontinue,itlalikelythebulktrans-missionnetworkwillbecomemoresusceptibleInthefuture.Someofthemostconcerningtrendsare:1)Th>>transmissionsystemsoftodayspangreaterdistancesofearth-surface-potentialwhichresultIntheflowoflargergeomagneticaily-IEEEPowerEalineeciagReview,October1989Induced.currentsinthesystem,2)theinterconnectedsys-temstendtobemorestressedbylargeregion-to.regiontransfers.combinedwithGICwhichwillsimultaneouslyturneverytransformerinthebulksystemintoalargereactivepowerconsumerandharmoniccurrentgeneratorand3)ingeneral,largeFHVtransformers,staticvarcompensstorsandrelaysystemsaremoresusceptibletoadverseinfluenceandmicroperationduetoQIC.TRhNSFORMEROPERhTIONTheprimaryconcernwithGeomagnetlcally-InducedCur-rentslatheeffectthattheyhaveupontheoperationoflargepowertransformers.ThethreemajoreffectsproducedbyGICintransformersIa1)theIncreasedvarconsumptionottheeffectedtransformer,2ltheincreasedevenandoddharmon-Icageneratedbythehalf.cyclesaturation,and3)thepossi-bilitiesofequipmentdamagingstrayf)uxheating.Asisweildocumented,thepresenceofevenasmallamountofGICI20empaorless)wNcausealargepowertransformertohalf-cyclesaturate.Thehaif~c)esaturationdistortedexcit-ingcurrentlsrichlnevenandoddharmonicawhichbecomeintroducedtothepowersystem.Thedistortionoftheexcit-ingcurrentalsodeterm)nestherealandreactivepowerre-quirernentsofthetransformer.Thesaturationofthecoresteel,underhaif~c)~saturation,cancausestrayfluxtoen-terstructuraltankmembersorcurrantwlndlngswhichhasthepotentialtoproduceseveretransformerheat)no.15 tI tr:rscsŽrrei'-ryes.-e'io:est'esul!Strct~:ste'.na;StogieCnaSesr5.'"r-..erS;ai'CVCleSaturatemuCnmereeasilvano!04-"cngreatercegree;hanccrricarable.;nreeonaseunits.."ese:.ansformersproducehighermag.nnucesofharnonicsand"orsume!argeramountsofrese-!rvepowerwhencomPareOwiththreephasedeslgnS.ItELhyHANDPROTECTIVESYSTEMS>herearethreeba5icfaitiremodesofrelayandprotectiveSvs!ems:natcanoeattr:buteotoggeomagheticdistur-bances:r~u~>>~neear!:id,<<3g.4!'4C4drageonag,"et.'cstormswhen!heyare--4,~de~~"~SUNSPOTCYCLEShNDGEOMAGNETICDISTLRBhNCECYCLESOntheaverage,solaractivity.asmeasuredbyt."enuroer".monthlysunspots.followsan11yearcvcl'e.he"esen!sunsootcycle22haditsminimumtnSeoten.oer1986.a."cisexoectedtooeakin1990-1991.Geomagnetic'elao5~tvrbancecyclesdonothavethesameshaoeas:nesunscotnumbercycles.eventhOughtheyarecyclical.FSure1snowsthenatureofthesunspotnumbersandgeomagnetic3C!i"".v~.alseOperationof:."eprotectionsystem.suchashav-ingOCCurreOrOrSVC.CabaCitarandlinerelayOpera-tionswhere:te!towofharmoniccurrentsaremisin-:erpreter2OVthereiaVaSaraultOrOVerlOadCOnditicn.Thisisthemostcommonfailuremode.~FailuretoOperatewhenanoperationisdesirable,thishasshowntobeaproblemfortransformerdifferentialprotectionschemesandforsituationsinwhich;heoutputofthecurrenttransformerisdistorted.~SlowerthanDesiredOperation.thepresenceofGlCcaneasilybuilduphighlevelsofoffsetorremanentttuxinacurrenttransformer.ThehighGICinducedoff-setcansignificantlyreducetheCTtime.to.saturationforoffsetfaultcurrents.4uit'ocrorC(rtwortsCctrsrrrrapr25SurtsIre4i431~1444Cyclei7CyclelaCycleiaCyote20Cyci~21iIr~)40;120lirumoereliOlslureetdOdyVyear150tISuitspoiHumber~00IIiiIii)IrIIl00j50j,~~d0Iidei40I~20~~.~014540uiII\!40035eecSMostoftherelayandprotectivesystemmisoperationsthatareattributedtoGICaredirectlycausedbysomemalfunc-tionouetotheharshharmonicenvironmentresultingfromlargepowertransformerhalf-cyclesaturation.Currenttrans-formerresponseerrorsaremoredifficulttodirectlyassociatewiththeGICevent.ForexampfeinthecaseotCTremen-encc.theCTresponseerrormaynotoccuruntilseveraldaysaftertheGlCeventthatproducedtheremanence.Therefore.thesetypesoffaituresaremoredifficulttosubstantiate.50554045707540Figure1.VaitstfonsoftheYearty-AveraeedSunspotNumberenidQetsmaenettealtyOlsturbedOaysfrom'1932-1SBB.cyclesfrom1932to1988i2,3l.NotethatthegeomagneticdleturbanCeCyCleeCanhaVeadOublepeak,OneOfWhiChCanlagthesunspotcyclepeak.Whilegeomagneticactivityinthepresentcycleisexpectedtomaximizeinapproximately1993-1994,severegeomagneticstormscanoccuratanytimeduringthecycle;theK-9stormofMarch13,1989wasastrikingexample.CONCLUSIONSAsevidentbytheMarch13thblackoutintheHydroQuebecsystemandtransformerheatingfailuresintheeasternUS,thepowerindustryisfacinganimmediateandseriouschal-lenge.Thepowerindustryismoresusceptiblethanevertotheinfluenceofgeomagneticdisturbances.Andtheindustrywillcontinuetobecomemoresusceptibletothisphenome-nonuntessconcenedeffortsaremadetodevelopmitigationtechniques.EhRTHQURFhCE.POTENTIhLhNDGEOMhGNETIChLLY.INDUCEDWURREVTSTheauroralelectrojeteproducetransientfluctuationsintheeanh'5magnettcfieldduringmagneticstorms.Theearthisaconductingsphereandportionsofftexperiencethistime-varyingmagneticfield,resultinginaninducedearth-surface-potentlallfSP)thatcanhavevetueeof1.2to8volta/kmt2to10volte/mile)duringseveregeomagnetfcstormsinre-gionsoflowearthconductivityl4),GeomagneticDisturbanceCausesAndPowerSystemEEectsflectricpowersystemsbecomeexposedtothe8SPthroughthegroundedneutralsofwye-connectedtransformersattheoppositeendsoflongtransmissionlines,aeshowninFigure2.ThefSPactaaeantdealvoltagesourceimpressedbe.tweenthegroundedneutrateendhasafrequencyofonetoafewmittfhene.Thegsomagnetlcally-fnducedcurrentslGIC}arethendeterminedbydividingtheESPbytheequivalentdcresistanceoftheparalleledtransformerwindingsandlineconductors.TheGIClssques%tractcurrent,andvaluesinexcseeof100empersehavebeenrrNaeuredintransformerneutrals,VernonD.Albettsw2UniversityofiiIJnaaotaPOWERSYSTEMEFFECTSOFGICThepsr.phsesGlCinpowertransformerwindingscanbeIEEEPowerEngineeringReview.October1989SOLhRORIGINSOPGEOMhGNETICSTORMSThesolarwindiesrsrffiedplasmaofprotonsandelectronsemittedfromthesun.Thesolarwindfsaffectedbysolarflares,coronalholes,anddisappearingfilaments,andtheso-larwindpanicleeinteractwiththeeenh'emagneticfieldtoproduceauroralcurrents,orauroraletectrojste,thatfoltowgenerallycircularpathsaroundthegeomagneticpate!atal-titudeeof100kilometersormorel1).Theauroraborealisievisualevidenceoftheauroralelectrojetsinthenorthernl6 1~ 44~Inaia.sat~tat.ahn-richI:.tarsgr~ersauseclaymisoperatontet~44Al=.sr~ti.RFACS~I~9T-SARvii-SuRFACS<T5hti41.~t'igui~2.Induced5aich.Surtact-PoitntialISSP)ProducingQtamtg.htticaliyInducedCunehisIQICIinPowerSytttmt.io.aimanytimeslargerthan:heRMSacmagnetizingcurrent,re-sultinginadcbiasaftransformercoreflux,asinFigure3.IIlo,plI~REFEHENCES1.Akasatu.S.I"TheOyhtmiCAurcra,'ciehutCAme":~Mageziht.May1989.pp.90972.Jactlyh.J.A.."Reel-TimePtedicuchotGfcbalGoonagrtiActivny,SaltrWindMagnetosphereCauphi'g,"p.141.TarrtSciehuflcPublishingCompany.oxvo.'986.3Thompsah.R.J.,"TheAmplitudeatSaiarC.cie22,RiidiaehdSpaceSewiciisTtchhiCalReportTR8703,ctcbti1987.4V.O.AlbertganehdJ.A.VthBatten,"Utcuicphdhlaghe.;iFieldsatthtStnh'sSurfacedutioAurartlCunenls."i55iTcahaaCIiohsahPowerApparatusandSystems.Val.PAS39hia.2.April1970.pp.578-584.5.J.Q.Kappehmtn,V.O.Albtrtaon.9.Mohan."CurserTrahatarmtrahdRelayPtrtolmtnCtihthePresenceotGtcmagneticallyInducedCurrents."ISEETriiheactiansahPawe~ApparatusahdSystems,Vai.PAS.100.No.3,pp.1078-1088.March1981.TheHydro-QuebecSystemBlackoutOfMarch31,l989<<ICI<<r~Rgurt3.OCBtt!afTrtntfarmtrCartRulcOuttoQIC.Thehalf.cyclesaturationoftransformersonepowersystemisthesourceofnearlyalloperatingandequipmentproblemscausedbyGIC'sduringmagneticstorms.Thedirectconse-quencesafthehalf-cycletransformersaturationere:~Thetransformerbecomesarichsourceofevenandoddharmonics~Agreatincreaseininducttveversdrawnbythetrans-former~Possibledrasticstrayleakagefiuxeffectsinthetrans-formerwithresultingexcessivelocalizedheating.Thereareanumberofeffectsduotathogenerationofhighlevelsofharmonicsbysyatimpowertransformers.includ-ing,Overloadingotcapacitorbanda~Possiblerntsaperottanofrelays~Sustainedovervoltogosonlang.lineenergizattanHighersocondoryarccurrentsduringsingle.poleswitching.~HighercfratffCMakerrecoveryvoltage~OvorlaadtnoofharmonicfttfyrsofHVOCconverterter-minals,anddtotantanintfioacvoltagewaveshapethatmayresultinlossotdcpowertransmission.Theincreasedtnductfvovoradrawnbysystemtransformersduringhalfwycl~soturat)anaresufficienttocauseintoler-abtosystemvoltagedepression,unusualswingsinMWandMVARflowontransmissionlinea.andproblemswithgener-atorvarlimitsinsomeinstances.Inadditiontothehalt-cyclosaturationotpowertrans-formers,highlevelsofGICcanproduceadlstartedresponseIEEEPowerEngiaeerintfReview,Octoberf989DanielSaulier,Hydro-QuebecOnMarch13.1989.anexceptionallyintensemagneticstormcausedsevenStaticVarCarnpensatorsISYC)onthe735-kYnetworktotriporshutdown.Thesecompensetorsarees-sentialforvoltagecontrolandsystemstability.Withtheirloss.voltagedroppedandfrequencyincreased.ThistedtosystarttinstabilityandthetrippingofalltheLaGrandetrans-missionlinestherebydeprivingtheHQsystemof9500MWofgeneration.ThoremainingpowersystemcallapsedwithinsecondsoftholossoftheLaGrandenetwork.Thesystemblackoutaffected~itbutafewsubstationsisolatedantolo-calgene~stingstations.Pawerwasgraduallyrestoredoveraninehoursperiod.Oe-leyainrestoringpowerworeencountereabecauseofdam-agedequipmentonthoLaGranden>>twarkandproblemswithcaidloadpickup.SYSTEMCONDITIONPRIORTOTHEEVENTSTatalsystemgoneratfonpriortotheeventswas21500MW.mastofitcomingfromremotepower-generatingstationsatLaGrande,MantcouagonandChurchf8Felts.ExportstoneighboringSystemstotalled1848MWofwhich1352MWwereonOCinterconnections.The735-kVtransmissionnet-warkwasladedat90%ofttsstabilitylimft.SEQUENCEOFEVENTSAt2:45o,m.onMarch13,averyintensemagneticstormtedtotheconaequortttaltrtporshutdownofsevenSVC's,Contafnlngthoimpactofthoeventthroughoporatarinter-yentionwasimpassibleattSVC'ahavingtrippedatcaaaodtofunctionwithinoanominuteperiod.Afowsecondsl8-8s.)aftertholossaftholastSVC,~IIfive735.kVlinesoftheLoGrandetransmissionnetwarktrippedduotoanoutofstepcondition.TheseItnetripsdeprivedthesystemot9500MWotgenerationandsubsequentlytedtoacamptetosystemcattapao.17 1\ iO~:ecuonancere~airir9'curSVC'ssnotsownovcaoactor~oitageuncaianceprctec::o.">>aivsisotvootageanocur.rentosc:itogramstaxenat:neCtioougamausitebeforetneSVCtnpssnowedtne'.oitowingnarmoniccontents..wC,hCCurrentarl6kyHarnaiiicVcliageOrderat.35kyTCABraccheTSCBrasche100'"o1OO3'ioa~Iifo3~o'Ã"9ofIOof5OofI~3~oI00~o36~o24~}6~o5%16ifoaffQuasiDCcurrentsgeneratedby:hemagneticdisturbance,saturatingintneSVCcouplingtransformersarethoughttobethecauseforsuchatargesecondharmoniccomponentofcurrantintheTSCbranch.DIsturoancesOnPoiyerTransformersHooertJHingjceJamesB.StewartPowerTechttoloip'esInc.Thisdiscussionaddressestheeffectsofgeomagnet:ccistii"oancesonpowertransformers.Theprimarveffect:scuetccoresaturationresulting!romgeomagneticaltvincuceacr~rents.GICs.Coresaturationcanimooseseveretemoeratureproblemsinwindings.ieads,tankplateanastructuraimer.-barsoftransformersandplaceheavyvarandharmonicoi.r~densonthepowersystemandvoltagesupportequiprriant.GIC'sof10to100amperesaremore:henmerenuisancesinthaoperationofpowertransformers,thernanr.erof!Iowcanresultinsaturationofthecoreandconsequentchangesinsystemvarrequirements.increasesinharmoniccurren.magnituctes.increasedtransformerstrayanaeadytosses.andproblemswithsystemvoltagecontrol.GENEAhLOBSEAVhTIONSONTHESYSTEMBEHhVIOAThesystemblackoutwascausedbylossofallSVConI.aGrandeNetwork.SevenSVCtrippedorstoppedfunctioning.PriortoandduringtheeventalltheOCinterconnectionsbe-havedproperly.Norelayfalsetripsormisoperationofspecialprotectionsystemswereobserved.Telecommunicationswarenotaffected.Noequipmentdamagewasdirectlyattrib-utabletoGICbutoncethesystemsplit,someequipmentwaadamagedduetoloadrejectionovervoltagea.RF'VIEDIhLhCTIONSThKEViSincetheevent.thefollowingactionswereimplemented:~SVCprotectioncircuitshavebeenreadjustedonfourSVC'ssoastorendertheiroperationreliableduringmagneticstormssimilarworkisbeingperformedonthefourremainingSVC's,~Energy,MinesandResourceCanadanowprovidesHy-dro.Quebecwithupdatedforecastsontheprobabilityofmagneticdisturbances.ThaaoforecastsareusedbytheSystemControlCenterdispatchertopositionthetransmissionsystemwithinsecurelimits.~A.C.voltageasymmetryiamonitoredatfourkoylo-cationsonthesystem(Bouchorvitto,Amaud,LG2,Chhtgeaguay).Upondetectionofo3%voltageaaym-rnetryatanyonalocation,theayotomcontrolcenterdispatcheriaalarmedandwillimmediatelyta'koactiontopositionsystemtranaforlevelswithinsecurelimitsifthishaan'talreadybeendanebecauseofforecastedmagneticactivity.OPERhTINGLIMNIDURINGMhGNETICDISTURShNCES(hNDhLERTSITUhTIONS)Thefallowingoperatinglimitsarenowbeingappliedt~10%safetymarginshallbeappliedonmaximumtrans-ferlimits.'Maximumtransferlimitsshellnottakeintoaccountthoavailabilityofstaticcomponaatorsdeemedunreliable.~AdjusttheloadingonHVOCcircuitstobewithintho40%to90%,orloaa.ofthonormalfullloadrating.l8CICEFFECTSVERSUSCOREhNDWIIOoDINCCOiVFIGURhTIONSPrincipalconcernsinthisdiscussionareforEHVsystemswithgroundedYtransformerbanksprovidingconductingpathsforGICandzerosequencecurrents.Coraandwindingconfigurationsresponddifferentlytozerosequenceopen.cir-cuitcurrentsendtoGICa.Note:aausedhere.theterm"opencircuit"referstotestsperformedwithalldeltaconnectionsopenedor"broken."Forexample,thethree.phasethreelegcoreformtransformersarolesspronetoGICinducedsatu-rationthanthree-phaseshallformtransformers.But.bothcoreformandshellformsinglephasetransformersaresus.ceptibl~toGICinducedsaturation.WindingandleadarrangemantaresponddifferentlytoGICinducedcoresaturationaawell.Forexample,thecurrentdis-tributionwithinpareil~Iwindingpathsandwithinlowvoltageloadsdependsupontheleakagefluxpathsandmutualcou-pling.Loaaeawithinwindingaandleadsmaychangesignifi-cantlyunderGICinducedsaturationowingtothechangeinmagneticfieldintensity.H,andtheresultantchangesintheboundaryconditionsfortheleakagefieldpath.EDDYLOSSESINSTEELMEMBERSThechangesinthemagneticintensity.H,andthemagneticboundaryconditionaresultingfromtheGICexcttationbiascanincreasetholoaaoainsteelplate,thelossesforfieldsparalleltotheplaneoftheplatoincreasenearlyaathesquareofH.Notealsothattheleveloflossesincreaseapproxi~matelyaathesquarerootofthefrequencyotH.owingtotheeffectofdepthofpenetration.ThomagneticfieldalongyokeclampsandlegplatesincoreformtransformersandinTeebeamsandtankplateInahoNformtransformerscloselymatchesthomagneticgradientlnthocore.Areasofthetankandcoreclampsaresubjectedtothowindingleakagefield.Ifthecorosaturates,themagneticfieldimpresseduponthesteelmembersmayrisetontoonehundredtimesnormalduotothesaturationandtheoffoctooftheleakagefield.Theloaaoointhestoolmomborowillriaohundredsoftimesnor-mal,evenunderhalf-cyclesaturation.Onthosteelsurfaces.eddylosedensitymoyrisetontothirtywattsparsquareinch,approachingthethermalfluxdensityotan~lactricrangeele.ment.SurfacetemperaturesriaorapidlywiththisthermalfluxandcanresultindegradationofinsulationtouchingtnesteelIEEEPowerEatpaeeriagReview.Octoberl989 r DestgnOcftcfencyOcllrlentvendoraafma1UPShaSnobatterytestCII'CUItVendornaINIa1naintenancesectloAdocsAOIQCAtIOAbatteries.DesignDeficiencyBattefieshavenotbeenreplacedin6ycafsDesignDeficiencyACinputtologicpoucrsaltyisnaihtchahccpreferredBackupbatteriesdegradedordeadk.Srelaycharactertst-ICSPfCveAtStransfertoinverteroutput.BreakerffcIctionperdesignGroundfaultoccursonBphaseofaaintransfofncrVoltagctraflicntoAstatloflACpouersteeplyACpouertologicnoduleforUPStA.D,GcspcrIchccsthetransientoutpu'IvoltagegoestoulogictripsOApoucrSISIPtyfailure.2VSSUPStA,S,C,O,GtripBreakersCS-I,23open;Ch-Cdoesnotcloseupsloadsdohotautotransfertomint.supplylossofallloadsonUPS1AD,riFault1$clcafcdin6cycles;transfercocptetcdin12cyclesPernisstvesprohibItCSCbreakerfrozeclo>IngCS'4ncsvh<toIfunsfernaIntsullplytolnvcltcfoutput r 1.StaticDCtestingwasperformedonindividualchipsfromtheeffectedcircuitsinordertocharacterizeLatch-upsusceptibility.Statictestingisperformedwithfixedvoltagesettings.Thetestingwasperformedonthe4049,4011,4044and4068devices.Thetestschemeincluded:A.OutputvoltagebelowVss(Vssisthegroundornegativepowersupply).B.OutputvoltageaboveVdd(Vddinthepositivevoltagepowersupply).C.InputvoltageaboveVdd.D.Powersupplyovervoltage.Vss>>VddThetestingrevealedthatpermanentphysicaldamagewasinducedbytestsCandD.TestBdidnotinducelatch-upbuttestAconsistentlyinducedlatch-uponthe4049andathighervoltagedifferentialsontheotherdevices-The4049wasquitesensitivetothistest.2.VoltageDropouttesting,wheretheVddwascutoutandrestoredduringtimeperiodsrangingfrom20mSto2secondsdidnotresultinlatch-upbehaviorontheindividualcomponents.A"breadboard"testcircuitwasfabricatedtosimulateatypicalcircuitpath,i.e.a4044latchdrivinga4049invertordrivinga4068gatedrivinga4011gatedrivinganMC1615lampdriver.Slowratedropouttestingofthetestcircuitdidnotresultinlatch-uporotheranomalousbehavior.3.BoardleveltestinghasbeenperformedontheA13A21cardsf'romUPSunitsA,BandG.Astockcardhasalsobeentested.Atestfixturewasfabricatedtoholdthecardsandsupplypaverandinputselectionandoutputmonitoring.AnMC1615lampdriverchipwithLED's(lightemittingdiodes)wasconnectedtothecardoutputs.StaticboaeftestingrevealednoanomaliesontheAcard,adamagedU104049oNtheBcard,NoanomaliesontheCcardandafailuretoset,anyofthe4044latchesontheGcard.(Notethatlatchingofthe4044chipsisnormalwhilelatch-upisanabnormalcondition.)The.functionalfailureoftheGboardhasbeentracedtotheKlrelayand/ortheSW1resetsvitchonthecircuitboard.FailuresimulationtestingonthefunctionalAboardhasrevealedthatthelightingpatternreportedduringtheincident,wherothelampsonthecardwereextinguishedand"downstream"lampsremainede

illuminated,hasbeenduplicatedbysettingthePSF-notlatch,loweringtheDCvoltagetoapproximately4VDCandlifting(floating)theDCgroundforseveralseconds.IftheDCvoltageremainslowafterthegroundfaultthelampsontheboardwillresetandtheexternallamps(UPSfail,LogicfailandtheSSTRlines)willremainilluminated.Thesimulationconditionsareunlikelytobethoseofthefailureevent,however,ithasbeendemonstratedthattheboardcanoperateinanthisillogicalstate.Amorecomplicatedfailuresimulation(approximatingtheactualevent)mayproducethesameresults.4.HighSpeedtransient.testingonthepowerlinesisplannedanddelayedpendinglaboratoryanalysisofthedegradedsamplesdiscussedinthefollowingsection.MC0A.NEGATIVEVOLTAGEONTHEOUTPUTOFTHE4049MILLINVARIABLYCAUSELATCH-UP-INJECTINGNEGATIVEVOLTAGEINTOTHEOUTPUTISIDENTICALTORAISINGTHEGROUNDVssABOVETHEOUTPUT.B.THEINITIALFAILURECONDITIONINTERMSOFTHELAMPSETTINGSCANBEDUPLICATEDUNDERUNLIKELYCONDITIONSANDMAYBEPOSSIBLEUNDERMOREPLAUSIBLECIRCUITCONDITIONS.Thefollowingsampleshavebeensubmittedforlaboratoryanalysis:1.Onebatterypack.Batterypack1fromUPS1C.n'.Two(2)integratedcircuitsfromafailedA20card.A4049anda4011.3.AfailedU104049fromtheA13121,UPSBcard.4.TheU104049fromtheA13A21cardsfromUPS'sAandG5.TheUPS6KlrelayandSWlswitch.Thefollowingresultshavebeenobtained.1.Two(2)oftheThree(3)batteriesfromUPS1Cweredriedout.Waterwasaddedandchargingdidnotresultinrecoveryofthecell.Itisconcludedthatthecellfaileddueoldagewearout.Analysisiscontinuingontheothertwo(2)cells.2.The4011fromtheA20cardiselectricallygood.Internal IJ~~I ~~~lj~.inspectionoftheDierevealednoanomalies.The4049is'electricallybad.Acatastrophicfailure.InternalinspectionofthedierevealedseveredamagecenteredontheVssandVddpowerlinesandseveralinput/outputs.TheinitiatingoverstresswasintroducedontheVddorVsslinesasindicatedbyarc-overdamageacosstheoxidebetweenthetwopowerlines.3.ElectricaltestingoftheU104049fromA13A21,UPSBrevealedthatitwasnotfunctional.Internalinspectionofthedierevealedafusedaluminummetallizationlinetoonepartoftheinternalcircuitry.Probingrevealedno)unctiondamageoneithersideofthefusesite.ThisdamageischaracteristicofclassicSCRlatch-up.4.Electricaltestingofthetwo(2)additional4049'swasperformedduringcircuitboardtest.Thedeviceswerefunctional.Internaldieexaminationrevealednodamageoneitherdevice.5.ElectricaltestingoftheA13A21circuitboardfromUPSGrevealedthatSW1wasintermittentlyopencircuitedinthenormallyclosedposition.Thisconditionwouldprovidecontinuousresetsignalstothe4044latchesthroughtheK1relay.TheswitchwasisolatedandagoodswitchwasplacedacrosstheKlrelay.Thecircuitboardinputsstillwouldnolatchthelamps.TheKlrelaywasremovedandtestingrevealedthatitwaselectricallygood.ThefindingsrevealthateithertheKlrelayiseitherintermittentlybadorthereareotherproblemcomponentsonthecircuitboard.Analysisiscontinuing.R0U0A.THEDAMAGENOTEDONTHE4049FAILEDINTEGRATEDCIRCUITFROMUPSBWASINDUCEDONTHEVss(GROUND)SIDEANDSUGGESTSAGROUNDTRANSIENTMAYHAVEOCCURRED.THEDAMAGEONTHE4049FROMTHEA20.BOARDINDICATESTHATTHEDAMAGEWASINITIATEDBYATRANSIENTONEITHERTHEVddORVssLINE,BUTITMAYALSOHAVEBEENINITIATEDBYLATCH"UP.B.ATLEASTONEOFTHEBATTERIESFAILEDDUETOOLDAGEWEAROUT.C.THECAQNEOFTHEFAILUREOFTHEUPSGTOSETTHELATCHESZSUNKNOWNATTHISTIME.THESWSWITCHHASBEENFOUNDTOBEDEFECTIVEANDANALYST'SWILLDETERMINEIFTHECOMPONENTISRELIABILITYRISK. I -UPSlA1B1GTESTSUMMARYpage1Purpose:ToprovethattheDClogicpowerfortheExideUPSispoweredfromtheB-phasemaintenancesupply.TheK-5pickupanddropoutvoltagesandtheDCtrip-pointo=theDClogicwillberecordedforUPSlA,notforUPS13andUPS1G.Theinternalbatterieswillbetestedandreplaced.ResultsSummary:1.)OnUPS1A,UPS1BandUPS1G,itwasverifiedthattheDClogicpowersuppliesarefedfromtheB-phasemaintenancesupply.2.)TheK-5relaydropoutandpickupvoltageswererecordedforUPS1AandtheywerefoundtobebelowthetrippointoftheDClogicpower.3.)OnUPS1A,UPS1B,UPS1G,themaintenancesupplywasopenedwiththeUPSfeedingtheloadsandnoUPStripsoccuzredo4.)OnUPSlA,UPS1BandUPS1G,thebatterieswerereplaced.CONCUThistestprovesthattheDClogicpowerisfedbytheByhaaemaintenancepower.ItprovesthattheinternalbatCOrieswereeffectivelydead.ForUPS1Aitprovesthatonaslowtransientthat.theDClogicpowerwilldropoutbeforetheK-5relaywilltransfertoUPSpower.

NumericalResults:page21.)TheUPS1ADClogictripsat<16.7VDC.(with.75.6VAConinput).2.)UPS1A:K-5relaydropout-47VDCK-5relaypickup-52VDC4.)Theinternalbatteryvoltagewasmeasured:UPS1A:UPS1B:UPS16:Positive-Negative-Positive-Negative-Positive-Negative-0.546.218.30.69 )J 2VBB-UPS1CTESTSUMMARYpage1Purpose:ToprovethattheDClogicpowerfortheExideUPSispoweredfromtheB-phasemaintenancesupplyandthatifatransientoccursonthemaintenancesupplyitcaneffecttheDClogicsuchthatitwilltriptheunit.Thistestisdonewiththeoldinternallogicbatteriesandthenrepeatedwithnewones.EachoftheinvertertripswillbetestedtoverifythateachcircuitisstillintactexceptDCOV.,AnACinputtransienttoUPSwillbesimulatedtoverifythattheunitcan"rideout"anormalACinputtransientwithouttripping.TheK-5relaypickupanddropoutvoltagesandtheDCtrip-pointoftheDClogicwillberecorded.ResultsSummary:1.)ZtwasverifiedthattheDClogicpowersuppliesarefedfromtheB-phasemaintenancesupply.2.)ArapidopenandclosingoftheupstreamnormalACinputbreakertotheUPSwasdoneandtheunitdidnottriporgoonbattery.NonoticeableeffectwasseenontheUPSoutput.3.)EachinvertertripcircuitexceptDCOVwastestedandeachfunctionedasdesigned.4.)Fasttransienttests:Withtheoldbatteriesstillinstalledavoltageinterruptionof100-150msecdurationwasgiventotheACinputtotheDClogicofUPS1C.TheDClogicwasinitiallyat19.86VDC.Theunittripped3outof4times.Thiswasdonefirstwiththeloadson.xaintenancesupplyandthenalsowiththeloadsonUPSpower~Withthenewbatteriesinstalledtherewasnotripwhenthefasttransienttestwasperformed25successivetimes.TherewerenotripsbutarepeatedSCRshortalarmoccurredwhichisindicativeofnoisespikeswithintheunit.

page25.)TheK-5relaydropoutwasrecordedandwasfoundtobebelowthetrippointoftheDClogicpower.6.)Normaltransfersweredone,UPStomaintenanceandmaintenancetoUPS,withdeadbatteriesandtherewerenotripsoftheUPS.ThemaintenancesupplywasopenedwiththeUPSfeedingtheloadsandnoUPStripsoccurred.CONCLUSZONThistestprovesthattheDClogicpowerisfedbytheBphasemaintenancepowerandthatitissusceptibletovoltagetransientsonthemaintenancesupply.Ztmaybesusceptibletoothertransientsaswellbecauseitisdirectlytiedtomaintenancesupply.ThetestDOESNOTprovethelevelofsusceptibility,thatis,itdoesnotprovethatthetransientwasofanysetvoltageorduration.Thetestimpliesthatthebatteriesmayhavemitigatedthetripbutisnotconclusive.Eachtripcircuitwastestedsuccessfullysonofailuretoanyoftheseoccurredthatcausedthetrip.Thefastopen/closeofthenormalACinputbreakerprovesthattheunitwouldwithstandanACinputtransientwithoutfailureorwithoutgoingonbatterypower. I'5~ NumericalResults:1.)FastTransientTests-a.)W'texistinbatteriespage31.)Withloadsonmaintenance:At19.86VDC(90.0VAC)-~tri(150msec.)At19.86VDC(120VAC)-~t'150msec.)2.)WithloadsonUPSpower:2Tries,1~ti(200msec.)b.)W'tnewbatter'es-1.)Approx.20.0VDC-25times,~notri.(100msec.)2.)TheDClogictripsat<16.9VDC.(with84.59VAConinput).3.)K-5relaydropout-45VACK-5relaypickup-**notrecorded4.)Thefollowingtripstestsweredone:a.)b.)c.)d.)e.)f.)g)h.).OV/UVACUVACOVDCUVFrequencyfailLogicFailurePowersupplyfailureClockfailure5.)Theinternalbatteryvoltagewasmeasured:Positive-+0.6Negative-+0.04 l~45 5.)Xndividualcellvoltages:page41.)2.)3.)4.)5.)6.)BatteVoltae1.192.482.240.170.791.78NewBatteVoltae6.106.076.106.096.106.12

V-UPDSSpagePurpose:ToprovethattheDClogicpowerfortheExideUPSispoweredfromtheB-phasemaintenancesupplyandthatifatransientoccursonthemaintenancesupplyitcaneffecttheDClogicsuchthatitwilltriptheunit.Thistestisdonewiththeoldinternallogicbatteriesandthenrepeatedwithnewones.TheK-5pickupanddropoutvoltagesandtheDCtrip-pointoftheDClogicwillberecorded.ResultsSummary:1.)Itwasverifiedthatthe'ClogicpowersuppliesarefedfromtheB-phasemaintenancesupply.2.)Fasttransienttests;Withtheoldbatteriesstillinstalledavoltageinterruptionof100-150msecdurationwasgiventotheACinputtotheDClogicofUPS1D.TheDClogicwasat20.9VDC.Theunitwouldnottrip.TheACinputvoltagetotheDClogicwasthenreducedsuchthattheDClogicwasat20.0volts.WhenthetestwasperformedwiththeDClogicpowerat20.0VDCtheunittripped.ThiswasdonefirstwiththeloadsonmaintenancesupplyandthenalsowiththeloadsonUPSpower.WiththenewbatteriesinstalledtherewasnotripwhenthefasttransienttestwasperformedthoughtherewassignificanthitsshownontheDClogicpowerbusasseenbytheoscilloscope.3.)TheK-5relaydropoutandpickupvoltageswererecordedandtheywerefoundtobebelowthetrippoint.oftheDClogicpower.4.)Normaltransfersweredone,UPStomaintenanceandmaintenancetoUPS,withdeadbatteriesandtherewerenotripsoftheUPS.ThemaintenancesupplywasopenedwiththeUPSfeedingtheloadsandnoUPStripsoccurred. Ia pllt4iV1i,~CONCpage2ThistestprovesthattheDClogicpowerisfedbytheBphasemaintenancepowerandthatitissusceptibletovoltagetransientsonthemaintenancesupply.Itmaybesusceptibletoothertransientsaswellbecauseitisdirectlytiedtomaintenancesupply.ThetestDOESNOTprovethelevelofsusceptibility,thatis,itdoesnot,provethatthetransientwasofanysetvoltageorduration.Thetestimpliesthatthebatteriesmayhavemitigatedthetripbutthatisnotconclusive. ta0 NumericalResults:1.)FastTransientTestsa.)W'teistinbatteriespage3Withloadsonmaintenance:At20.9VDC-fivetries,notrips.At20.7VDC-onetry,one~tri.(150msec.)2.)WithloadsonUPSpower:At20.06VDC-one~t'(100msec.)b.)W'tnewbatteries1.)At20.05VDC-Fivetries,~sotris.-noticeableDChitoneachtransient.2.)TheDClogictripsat<17.3VDC.(with84.5VAConinput).3.)K-5relaydropout-42VDCK-5relaypickup-55VDC4.)Theinternalbatteryvoltagewasmeasured:Positive-Negative-+0.6+0.14(thenegativebatterysetwasactuallyslightlypositive).5.)individualcellvoltages:tVtaewBatteVotae2.)3.)4~)5.).254.5701.03.071~176'06'66~106'06'3 t0 It6.)1.396'9, 1 resulteduntilsuchtimethepowertotheseUPS'swasrestored.However,oneormoreoftheotherlightingsystemsnamely,emergency,normaland8hourbatterypackwereavailableinthesea'reasduringthisevent.Thestairwellsareprovidedwithessentiallightingonlyexceptwhere8hourbatterypacklightingisaddedforAppendixRcompliance.IlluminationtothesestairwellswasnotavailableduetolossofnormalUPS.The8hourbatterypacklightingdidnotenergizebecausetherewasnolossofnormalpower.EventEvaluationTherootcauseoflossofpowerfromnormalUPSisevaluatedseparatelyinanotherreport.Duringtheevent,someareasoftheplantlostpartialilluminationsprovidedbyessentiallightingforsometime.AreascriticalforsafeshutdownwherethislightingareidentifiedareprovidedinAttachment7.Duringthiseventtheplantwassafelyshutdownfromthecontrolroom.Becausethecontrolroomisprovidedwithadequatelightingwithouttheessentiallighting,lossofessentiallightingdidnotadverselyaffecttheoperatoractionsneededtobringtheplanttosafeshutdown.TheaccessrouteusedbytheoperatorsduringthiseventforrestorationofthenormalUPSpower(Attachment8)supplieswasilluminatedfromnormallightingexceptforthestairwellwhereportablehandheldlightswereused.(FSARSec.9.5.3.3allowstheuseofportablelightingintheformofhandheldflashlightsforshortexcursionsintotheplant).ThenormalUPSlocationswereilluminatedbynormallighting.Therefore,restorationofUPSpowerwasunaffectedbylossofessentiallighting.EventhoughtheessentialandegresslightingarepoweredbythreenormalUPS's,during,thiseventduetomultiple'ailuresofallnormalUPS's,essentialandegresslightingsystemswerenotavailable.Theexistingessentialandegresslightingdesignisadequate,however,therootcauseofthemultiplefailuresofthenormalUPS'swillbedetermined/evaluatedandappropriatecorrectiveactiontakenifrequiredtoensurethatmultiplenormalUPS'sfailurewillnotreoccur.Theproposedplantmodification89-042willenhancethereliabilityofstairwelllightingwhere8hourbatterypacklightingisprovided.NSK214

StatusofNormalReactorBuildinLihtinDuringtheeventonAugust13,1991,itwasreportedbytheoperatorsinthereactorbuildingthatsomeareasofthereactorbuildinglostlightingmomentarily.EventEvaluationNormallightingforreactorbuildinggeneralareas,workarea'sandelectricalequipmentareasisprovidedwithlowwattagehighpressuresodiumvaporlights.Intheeventofpowerinterruptionsorvoltagediplastingformorethanonecycle,thesefixturesextinguishanddonotrestartuntilthelampcoolsandpressuredecreases.Whenapowersupplytocontinuouslyenergizedsodiumvaporlightisinterrupted,ithasacooldownperiodbeforearestrikeofthelightingcanoccur.Thecooldownperioddependsupontheratingofthelightbulbs.Duringtheevent,theemergencydistributionsystemexperienceda,transientduetothefaultonthePhaseBmaintransformer.Duringtheevent,theReactorsBuildingnormallightingincertainareaswherethesehighpressuresodiumvaporfixturesareprovided,wasinterruptedforapproximately30seconds.Thismomentarylossoflightingwasduetotheinherentdesignoflowwattagehighpressuresodiumvaporlightingwhichrequirescooldownperiodpriortorestrikewheneverpowerisinterrupted.Thesamescenariocouldoccurintheplantwhereverpowersupplytohighpressuresodiumvaporfixtureisinterruptedmomentarily,however,thereisnoindicationofsuchalossinotherareasoftheplant.Therefore,itisconsistentwithNMP2lightingdesignandUSARSection9.5.3.h)Grou9IsolationValvesClosureThegroup9primarycontainmentisolationvalvesarepartofcontainmentpurgesystem.ThesevalvesarelistedinTechnicalSpecificationTable3.6.3-1,Page3/46-24andUSARTable6.2.56,Pagellof24.Thefunctionofgroup9isolationvalvesistolimitthepotentialreleaseofradioactivematerialsfromprimarycontainment.Theseisolationvalvesareopenedduringpoweroperationonlyatinfrequentintervalstoallowinjectionofnitrogenintoprimarycontainmenttoinertorde-inerttheprimarycontainmentatadesiredpressure.Thesevalves,ifopen,receivesignaltocloseifanyofthefollowinghappen:NSK215

a)Highradiationthroughstandbygastreatmentsystem(SGTS).TheSGTSradiationmonitorlocatedinthemainstackisdesignedtocontinuouslymonitoroffsitereleaseandprovideisolationsignalstotheseisolationvalves.b)Highdrywellpressure.c)Reactorlowwaterlevel.d)Manualisolationofmainsteamisolationvalves.EventEvaluationDuringthisevent,thegroup9primarycontainmentisolationvalvesclosed.Thisisolationisthesafemodeofoperationlimitingpotentialreleasesofradioactivematerialfromprimarycontainment.Theinitiatingconditionforthesevalvesoccurredasaresultoflossofpowertoradiationmonitor2GTS-RE105whenUPSpowertotheDRMScomputerwasinterrupted.TheactualisolationoccurredwhenthelogicwasreenergizeduponrestorationoftheUPSpowersupplytothemonitor'sauxiliaryrelaycircuit.Therefore,group9isolationvalvesclosedasdesignedandisconsistentwithUSARSection6.2.5.2.4,Page6.2-77.j)ReactorManualControlSstemThereactormanualcontrolsystem(RMCS)providestheoperatorwithmeanstomakechangesinnuclearreactivityviathemanipulationofcontrolrodssothatreactorpowerlevelandcorepowerdistributioncanbecontrolled.Thissystemisapowergenerationsystemandisnotclassifiedassafetyrelated.TheRMCSreceiveselectricalpowerfromthe120VACnormalUPS.TheRMCSdoesnotincludeanyofthecircuitryordevicesusedtoautomaticallyormanuallyscramthereactor.TheRMCScontrolandpositionindicationcircuitryisnotrequiredforanyplantsafetyfunctionnorisitrequiredtooperateduringanyassociatedDBAortransientoccurrence.Thereactormanualcontrolcircuitryisrequiredtooperateonlyinthenormalplantenvironmentduringnormalpowergenerationoperations.ThediscussionofRMCSisconsistentwithUSARSections7.7.1.1,Pages7.7-1,2,14.NSK216

EventAnalsisTheRMCSwaslostduringthiseventbecauseitspowersource,thenormalnonsafetyrelatedUPS,waslost.ThelossofRMCSisnotaconcernduringthisevent.Sincetheplantwasautomaticallyscrammedduringthisevent,theRMCSneednotperformanyfunctionafterthescram.ThisRMCSisusedbyoperatoronlyduringnormalplantoperations.Therefore,iftheplanthadnotautomaticallyscrammedduringtheevent,lossofRMCSwouldnothavecausedasafetyconcernbaseduponthefollowing:2)EOP'sprovideguidancetotheoperatorundersituationsinvolvingfailuretoscram,andvariousATWSmitigatingdesignaspectsoftheplantwerefullyoperablethroughouttheevent.Althoughthissystemwaslost'duringthisevent,itsimportancediminishedoncetheautomaticscramoccurred.ThereforeitisconcludedthattheRMCSfunctionwasconsistentwithUSARSection7.7.1.1.k)FeedwaterControlSstemThefeedwatercontrolsystemcontrolstheflowoffeedwaterintothereactorvesseltomaintainthevesselwaterlevelwithinpredeterminedlimitsduringallnormalplantoperatingmodes.Duringnormalplantoperation,thefeedwatercontrolsystemautomaticallyregulatesfeedwaterflowintothereactorvessel.Thesystemcanbemanuallyoperated.Thefeedwaterflowcontrolinstrumentationmeasuresthewaterlevelinthereactorvessel,thefeedwaterflowrateintothereactorvesselandthesteamflowratefromthereactorvessel.Duringautomaticoperation,thesethreemeasurementsareusedforcontrollingfeedwaterflow.ThefeedwatercontrolsystemreceivesitsnormalpowersupplyfromthenormalUPS.Thefeedwatercontrolsystemisdesignedtolockinitslastpositionuponalossofpowertoitscontrolelectronics.ThefeedwatercontrolsystemisdiscussedinUSARSection7.7.-1.3,Page7.7-23.EventAnalsisDuringthisevent,uponlossofthenormalUPS's,thefeedwatercontrolsystemperformedasdesignedandfailedinitslastposition.Therefore,itisconcludedthatthefeedwatercontrolsystemfunctionwasconsistentwithUSARSection7.7.1.3.NSK217 h'1 l)FeedwaterPumTriFeedwaterisprovidedtotheReactorPressureVessel(RPV)viatheCondensatePumps',CondensateBoosterPumpsandtheReactorFeedPumpsshowninAttachment9.TheCondensatePumpdrawscondensatewaterfromtheCondenserandprovidesthenecessaryNetPositiveSuctionHead(NPSH)fortheBoosterPumps.TheCondensateBoosterPumpsprovidethenecessaryNPSHfortheReactorFeedPumps.Aminimumflowcontrolheaderisprovidedoffthedischargeheaderofeachpumptoensurethattheminimumflowismaintainedthroughtheassociatedpump.Theminimumflowcontrolvalvesandassociatedinstrumentationactuatestomaintainthisminimumflow.Themainfeedwatercontrolvalves(LV10),locatedonthedischargeheaderoftheReactorFeedPumps,modulatetocontrolreactorwaterlevel.ThefeedwatercontrolsystemispoweredbynormalUPSpowersupplies.TheabovediscussionisconsistentwithUSARSection10.4.7.EventEvaluationItwasreportedduringthiseventthatfeedwaterpumpstripped.AnevaluationofthisconditionrevealsthatreportedhappeningsareconsistentwiththesystemasdesignedandisinconsistencewithUSARSection10.4.7.Theinstrumentationcontrollingtheminimumflowrecirculationvalvesonthecondensate,condensateboosterandthefeedwaterpumpsispoweredfromthenormalUPS's.Theseinstrumentsarealsodesignedtoopenthevalveuponlossofpowerinordertoprotectthepumps.UponlossofnormalUPS,thefeedwatercontrolvalvesfaillockedintheirlastposition.Followingtheturbinetrip,anATWSsignalwouldattempttodrivethefeedwatercontrolvalvesclosed,howeversinceanATWSsignalwasnotpresent,thisdidnotoccur.Withthefeedwatercontrolvalvesfailedlockedandtheminimumflowcontrolvalves(FV2)drivenfullopen,feedwaterflowincreasesandapproachespumprun-out.TheReactorFeedPumpNPSHdecreasestothelow-lowpressuretrippoint,trippingtheFeedwaterPumps.TheFeedwaterpumpcontrolcircuitdoesnotutilizeanautotransferlogictostandbyFeedwaterPump;therefore,feedwaterflowislost.TheinstrumentationcircuitsforallotherminimumflowcontrolvalvesarealsopoweredbynormalUPSpowersupplies.ThesevalvesallfailintheopenpositionwiththelossofUPSandcontributetothelossofFeedwaterpumpandcondensateboosterpump.ThisisconsistentwithUSARSection10.4.7.NSK218 'II m)AnnunciatorsandComutersTheplantannunciatorsystemprovidesinformationtotheplantoperatorsbywindowslocatedonthemainoperatorpanelboardsandonbackpanelswithinthePowerGenerationControlComplex(PGCC).Thissystemdoesnotincludeannunciatorsonlocalpanelsthroughouttheplantandonspecialpanels,e.g.,fireprotection,withinthePGCC.Theplantannunciatorsystemisnon-safetyrelatedandisconnectedtothenormalpowerdistributionsystemthroughnormalUPS's.TheplantannunciatorsystemisnotdiscussedintheUSAR.Severalcomputerdisplays,withinter-activekeyboards,arelocatedinthePGCC.Thesedisplaysarefromthefollowingcomputersystems.PMS-PlantProcessComputerLWS-LiquidRadwasteComputer,whichhasthefollowingsubsystems:LWS-LiquidRadwasteControlGENTEMP-GeneratorTemperatureMonitoringERF-EmergencyParameterDisplaySystemSPDS-SafetyParameterDisplaySystemDRMS-DigitalRadiationMonitoringSystem3DMonicore-AsystemusedprimarilyforcorecalculationsandmonitoringInaddition,noblegasinformationisprovidedtotheplantoperatorsfromtheGEMS(GaseousEffluentMonitoringSystem)computerbychartrecordersonabackpanel;andtheoperatorshaveaccesstotheGETARS(GeneralElectricTransientAnalysis&RecordingSystem)computer.Alloftheabovecomputersystemsarenon-safetyrelatedandareconnectedtothenormalpowerdistributionsystemsthroughnormalUPS's.TherearesomesafetyrelatedradiationmonitoringskidsthatprovideinputtotheDRMScomputer.However,theseskidsalsoprovidesafetyrelatedindicationinthePGCCthatisindependentoftheDRMScomputer.NSK219

ThePlantProcessComputerisdiscussedinSection7.7.1.6oftheUSAR,whereitismentionedthatthecomputerisnon-safetyrelated.USARSection11.2.1.2coverstheLiquidRadwasteSystemdesignbasisandstatesthatthepowersupplyforallRadwasteSystemcomponentsisprovidedfromnon-Class1Epowersources.ThisiscompatiblewiththeSafety-ParameterDisplayrequirementssinceNUREG-0737,Supplement1statesthattheSPDSneednotbequalifiedtoClass1Erequirements.Theprocessandeffluentradiologicalmonitoringandsamplingsystems,whichincludetheDRMSandGEMScomputers,arediscussedinUSARSection11.5.Thissectiondefineswhichmonitorsaresafetyrelatedandwhicharenon-safetyrelated.TheDRMSandGEMSdesigncomplieswiththisUSARsection.Arearadiationandairborneradioactivitymonitoringinstrumentation,whichincludetheDRMSandGEMScomputers,arediscussedinUSARSection12.3.4.1.Thissectiondefineswhichmonitorsaresafetyrelatedandwhicharenon-safetyrelated.TheDRMSandGEMSdesigncomplieswiththisUSARsection.Adescriptionofthe3DMonicorecomputersystemwasaddedtoUSARSection7.7.1.6byLDCNU-1235.ThisLDCNstatesthatthe3DMonicoresystemisnon-safetyrelated.Thedesignationofthecomputersystemsmentionedaboveasnon-safetyrelatedisconsistentwiththeexplanationoftheUninterruptiblePowerSupplySysteminUSARSection8.3.1.1.2.Inthissectionitisstatedthat2VBB-UPS1Afeedstheradwastecomputerhardware,2VBB-UPS1Bfeedslocalnon-safetyrelatedradiationmonitoringmicroprocessors,and2VBB-UPS1Gfeedsplantcomputerloads.EventEvaluationWiththelossofthenormalUPS's,theplantannunciationsystemandthecomputersystemslistedabovebecameinoperativeduetothelossofpower.ThisisconsistentwiththeplantdesignandthedescriptionoftheplantintheUSAR.Thesesystemsarenon-safetyrelatedand,hence,arenotrequiredtoshutdowntheplantfollowingadesignbasisevent.NSK220

CONCLUSIONBasedontheaboveevaluation,itcanbeconcludedthattheplantresponsesduringtheeventon8/13/91isconsistentwithUSARdescriptions..RECOMMENDATIONSBasedontheaboveevaluation,thefollowinglongtermrecommendationsareprovided.1)PlantOscillograph-Thein-plantoscillographshouldbereplacedwithamorereliableandfunctionalunit.Ifthisoscillographwasfunctionalduringtheeventon8/13/91,adequatedatacouldhavebeenavailabletoaccuratelyevaluatethecauseofthedisturbance.2)EssentialLighting-Theproposedmodification89-042shouldbeimplementedassoonaspossibletoenhancetherel'iabilityofstairwelllightingwhere8hourbatterypacklightingisprovided.3)ControlPowerSupplies-DuringtheElectricalDistributionSystemevaluation,itwasrevealedthatmostofthesystemsimportanttoplantoperationssuchasfeedwatersystem,annunciationsystem,etc,receivetheircontrolpowerfromeithernormalUPS1A,1Borboth.ItisrecommendedthatcontrolpowersuppliesforthesesystemsbeevaluatedandreconfiguredtoavoidplanttransientduetolossofsinglenormalUPS.4)MainGenerator-Itisrecommendedthatathoroughvisualinspectionbeperformedofthegeneratorstatorandwindingsupportsystemduringthenextrefuelingoutage(seeAttachment10).NSK2

345KVTOSl"ASTATIONLINE23)ATTACHMENT'-1115KVSOURCE'A'LINE5)345/25KVUNITTRANSF.498HVAEACHSPARE115KVSOURCE'8'LINE6)115KVSOURCE'B'OR'A'2/56/78HVARESERVEBANK'A'WJGKVUNIT25KV~~NORMALSTA.TRANSF.24.')KV/13.8KV199-59/59HVA42/56/79MVARESERVEBANK'8'UXBOILERNOCUBONLY2NPS-SWG99113.BKVNORHALAUX.TRANSF.CUB.ONLY2NPS-SWG993AUX.TRANSF.NC.~13.BKVAUX.BOILERBUS2NPS-SWG892NONORHAL4J69KV2NNS-6WG9142NNS-SWG9152NNS-SWGBII2NNS-SWG8122NNS-SWG9134J6KV0.16KVNOSTUBBUSSTUBBUSWJGKV~CUILONLYNC2ENSiSWGIB)iJ69KVOIV.I>EHERGENCYBUSEGIOIV.14489KW2ENS~SWGI92~4.169KVDIV.3EHERGENCYBUSEG2DIVE2688KW2ENS~SWG1934.168KVOIV.2EMERGENCYEG3BID4489KWONSITEA.C.POWERSUPPLY 5 BIIKLELQKFORNN-IEtPSIAIILICJOol(LI)L3(L382NPS-SWGB8)ONV)2NPS-SWG88303.8KV)2NPS-SWGBBIa@SKY)2NPS-SWGM3(688V)2NJS-US4(688V)2NJS-US3BUS82NJS-US3BUSA2VBB-TRSIAUTOHATICTRANSFERSWITCH(688Vl(688V)(6MV)2LAT-PN.3882VBB-PNL3812NHS-NCC996BUSANNNUPSUPSBAT-IC(688V)A(6BSV)A(688V)2NJS-US62NJS-USS2NJS-US6ASUPSUPSBATIBIOBAT-IAICBAT-IAIABAT-IC2NJS-USIBUSC2NJS-US4BUS8UPSIN~BAT-ICUPS3ABAT-18UPS3BN(6MV)(688V)(688V)2NJS-PNL')812NJS-PNL5M2NJS-PNL688(688V)(688V)~INTERNALBATTERYNO2LAT-PNL1882NJS-PIL482ALTERNATE2%S-SWGBISHJGKV)2NNS-SWG914HJ6KV)(4JSKV)2NNS-SWG815(6MV)(688V)2NHS-HCCB)62NJS-USSBUSB(6MV)2NJS-US603J)KV)2tfS-SWGM32NPS-SWGBBI03.8KV)2NPS-SWG8830XSKV)(689V)(4J6KV)HJ6KV)2NJ6-US')2NNS-SWG8142NNS-SWG915BUS8SINGLELINEFORCLASSIELES-2(L2BOXSKV)03J)KV)2NPS-SWMBI2NPS-SWG883HJSKV)HJQOO2ENSiSWGIBI2ENS+SWG)83(688V)2EJSiUSI(6MV)2EJSiUS3(6MV)2EJS+PNLIBBA2EJSiPNL38BABAT-2AUPS2ABAT-28UPS28(6MV)(688V)2LACiPNLIMA2LACiPNL3M8(688V)2EJSiUSI(688V)2EJSiUS3(4J6KV)HJGKV)2ENSiSWGI912ENSiSWGI93

3889.5A2SPUY823889-5A2SPMXBI2HTX-HIAHAINXFHR292KV-24~KV498/457MVAOA/FOA&89-SACOREGAP2SPHXBI63-163-1pe65HGA25989-5A39-139-1HAA3898-SA3898-SA2MTX-HIB63-63-pe65HGA258M-SA39-39-3BM-SA2MTX-HIC63-63-pe65HGA25889-5A8-2SPUZBI1289-SA2SPMZBIpe662HTX-MIDSPARE5951IAC22-2YXCNBI63-463-4pe65HGA8787PB65BDD39-439-cP864BDOHAA86-1P866HEAI[6Ipe66~HEAIP866HFAI86-1IP864~HEAIP864~HEAPSa<~MFAI86-1IPBSS~HEAIPBSS~HEAP865HFA-15889-SA2SPGZB245989-5ACOREGAP2SPUY922GHS-GlGEN.13<e.iMvnBPFFIELD25K'BBRpM75PSIGH23PH6BNZIpe67pscz2-2YxcNBIIr-86-1P867~HEAI6-P867~HEAIP867~MFA45988-5A2SPUY822STX-XNSIAwhcHeemgPACjpg~gATTACHHENTQ

LISTOFPROTECTIVERELAYACTUATEDONAUGUST131991UnitProtectionAlt1ProtectiveRelaLockoutRelaActionRef.Dwg,87-2SPMX01MainTransformerDifferentialProtectionRelay86-1-2SPUX0186-2-2SPUX02~InitiateTurbineTripESK-8SPU01~InitiateFastTransferESK-8SPU02toReserveStationESK-5NPS13TransformerESK-5NPS14UnitProtectionAlt2ProtectiveRela87-2SPUY02UnitDifferentialProtectionRelayLockoutRela86-1-2SPUY0186-2-2SPUY01Action~InitiateTurbineTrip~InitiateFastTransfertoReserveStationTransformerESK-8SPU01ESK-8SPU03ESK-5NPS13ESK-5NPS1463-2SPMY01FaultPressureTransformerUnitProtectionBackuProtectiveRela86-1-2SPUY0186-2-2SPUY01LockoutRela~InitiateTurbineTripESK-8SPU03~InitiateFastTransferSh.2toReserveStationESK-8SPU03TransformerSh.1ESK-5NPS13ESK-5NPS14Action50/51N2SPMZ01ProtectionRelay86-1-2SPUZ0186-2-2SPUZ01~InitiateTurbineTripESK-8SPU04~InitiateSlowTransferESK-5NPS13After30Sec.ESK-5NPS14BlockFastTransferAfter6CyclesGeneratorProtectionProtectiveRelaGen.PhaseOCDuringStartup50-2SPGZ02LockoutRela86-1-2SPGZ0186-3-2SPGZ01Action~InitiateTurbineTrip~InitiateSlowTransferAfter30Sec.BlockFastTransfer~ThisRelayPicksUpOnlyWhenUnitisOffLineRef,D~ESK-8SPG01ESK-8SPG04ESK-5NPS13ESK-5NPS14HSKl II AXTACEKNT3PAGE3of3Switchear2ENS*SWG103DegradedVoltageLockoutRela27BA-2ENSB2427BB-2ENSB2427BC-2ENSB24ActionNoActionTookPlaceDegradedVoltageStaysDuringFaultConditionsRef.DwESK-5ENS18ESK-8ENS022ENS*SWG10127BA-2ENSA2427BB-2ENSA2427BC-2ENSA24NoActionTookPlaceDegradedVoltageStaysDuringFaultConditionsESK-5ENS14ESK-8ENS012ENS*SWG10227BA-2ENSC0827BB-2ENSC0827BC-2ENSC08NoActionTookPlaceDegradedVoltageStaysDuringFaultConditions807E183TYSh7NSK1 J' 4~aAgeeF,-+0c~pgLc~ePi2~Le~z)K&~a>tF<.lg1vXPrPV~4UPVv>>'PiJN;x~,:'NfV,i'lgl/lj/>VL~~~xs83lLgveg./4/g[Q}l~eZ0fle~-reSfCJtNC,/'(,<3gA

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/s~t3n9Ee.<ep4XII8FoIgglPAAVLt~eGJgg~g6Cg.AI'tvV-)(1()iiQ(:)i)~')g)VU~, 4 A~7ACLW64'$VOLTAGEPROF[LEFORTHENORMALSUPPLYPPCE4opyTOUPSDURINGFl-"[ULTEOCONDITION345/,Qi23,85K7345KV2MTX-XMIA4BoC2GMSG1FOULTEOCol;OITION[Qi[88KVN,232KVx82.5KV2232KVKvi[6<V21.55KY[6KV03i3.sKv24.9/2NPS~2STX.XNSI7,5%SMG8830316KV21.55KV16KV8.9KV[II[[.9KV8.9KVQ3i3.53/4.16KV~2ATX-XS3~ii5.57.0'.9KV11.9KVN2,8KY04688V2NJS12VQROP688/~288.128VUS6A2NJS-X3E5.75%~2VBB-XQ6885.540>>38.9KY2.58KV23.46KV2.58KV2.58KV368V482V368VREGULATING05348V478V89V[[4V!UPS2VBB-UPS10348V65V114V45V154VFROMSCRIBASUBSTATIONOSCILLOGRAPHRECORO12VQROPALLO[[iIEOINTHECABLEFROMTHELOAOCENTERTOTHEUPS

~I/ZC(CPgI'gQQLJLIIWPiZBTECTIONQL~IJA+21.Q,E.HI3-P84'4FiA.(OIirl:CrrrQAI(r(~popXPIRR.8~X-XKl5DiFFERE(vT(AI-p~TEcAQLJl~uT%~LA'(pg,~~owI~~unR<~'(I/ZC~-PNL.8L+-u<n><oTET(o<ALTa<Nhr~Z~.Q.HIP-PS45LA(5I(~('.(DL(v(TP((ALE7.L((FFcRoLT'IIAI-VV(T7(r((OEgrLFrFSR'OV(T*L~9Uun7aeTEcaouLcc.Kb~~~E~YLluW'7(OOTS'T(oNLOLLOvFfTELA.YZ.@SABA(NSrEPL(pXPA(E..H'TX-Xg((3FAO(-TPr<<<E(LO3)(Z)>(b3'/2.)ZCE(.-'PNLglobo-UNIT%fTKCT(QiUpAL(rgpc.e.His-PRt'"'r(VlA(L(~PL'PXPPIR.HFX-XM(345KYLIGuT.('ROOLIQC(.C.((~~T)5c~'.C.EcPdL-.Ffo7-"&E(vERATc(I2PR.oreczog(@pc(LuP)'15-Pg47ML&lrv:~i(rr~((ORATORSTAILFVPP((AOEP(LCrfKCWo(v(h((OILSkpicItlPiAOIS)CQ(oEoEILATARDAcJvPP<'-o<ELofoLILoeKovTgE~j8~vPEe~M0<W<~v'cR&-4-Y2p~P"f~5P&POf4OFZ.

2E,k/5~SvJcto~Z~t'3.RlNX,Fphg,.FOR..ZCSS-rom-(u~bMAo~&CCRE.MYF'~5ixou')27SAZEUSSZQ~)zqipsez.c+5g)~grgb2.EU&5M&[G[xF~<.FaR.2EZ'5XIA[Q(-lQU~b~VsaAC.E,RE~A'tPc4<5i.)zqi&+zealp~<2)Zjpl@Z.~ggpZg2.EACHA>'6plows~s~~i.~uncsQs~~i~cC.ursic~~V~bcR.vo~<Aca'Sm9SFLA(5la;l.)21BAz.)z,zzs~)z~eczavs-s~~ccz.p.vy.SetL.BIZ.<)ppg-+I+SuJ&.OQ2-%i-2.-ZA6+55l(j.EST;)F~+~p~~p+~~spP6Kz.iA

lNTHINAl.CONIRSfONDSHCINON11154%~I$41MOPROgh.R.-.LAk~ToDistrQT~kCHei~PREi~FWgv>~~~NineMilePointNuclearstationOATL15August91FfLXCOalNineMilePointFireprotectionProgramPostEventXnterviewsAfterinterviewsconductedtodaywithFireChiefBernieHarvey,andFiremenFatBrennanandNarkLocurcio,andconcurrencewithTerryVermilyea,SystemExpertPireDetectionandJohnPavlickoofCautionEquipmentEnc.,Xhavereachedthefollowingconclusions.1~Ofthe20firepanelsatUnit2,18maintainedanormalpowersupplyo2a.TwoCirepanelsLFCP113and123transferredtointernalbatterybackup.'b.Thesetwopanelswb'ileonbatterywillstillfunctionnormallyaslongasthe120VACisavailableintheLPCF,whichitwas.Therewasnointerruptionordecreaseoffireproteotionidetection/suppressionatthelocalfirepanels.FirePanels849and200/1beingfedfromQNdidhaveapowerinterruption.ThiswouldhaveleftthecontrolswitchesoperableatPanel849,(astheyarefedfromLPCP),butcontrolRoomwithnoCireannunciation.Anyfiresuppression/indicationcouldalsohavebeeninitiatedlocally.ABA:dlcT,TomlinsonA.Julka(FAX7225-SN)D.Pringle

QJQ15'9115'ttttKTNaÃCSs~DTSINTSHNALCOhllSNKNDRNCKINN'tMAeSNpg4gyLoen~ToFiISUSJCCT+~AD-+8'~4CLopfg7P.3NineM5.1ePointNuclearStation15'AugustQlRLRCOOINin<<MilePoint,Unit2FireProtectionProgramFeetRvent8/13/91Interviews?ireDept.PersonnelInterviews(PoetIveatofaugust13(1901BernieHarvey-Chieflnearlyfoxcoverage,interviewedforlosscfpowerinContxolBuilding.Lightsblinked,loudnoise(louderthaneverheardinplant),wasinFireDept.office(toldshifttogetoutintoplant.PatWilsonwasinRxBldg>switchedradiostoChannel10,standardFireDept.practiceifsuspectloseofrepeator.PatBxennanwasintheFoamRoomandproceededtotheChief(sdesk.ChiefHarveyheardfirepanelalarmingwhenhegottoControlBuilding.WentpastFir~Panel114inTurbinebuildf.ngpassageway(noaudiblealarms(seemednormal.Mar}cLocurclowenttoPanel12d-214elev.whileChiefHarveywenttoPanel127>>244elev.ttheseweresoundingtroublealarmandD&wasclear.WentpastPanels120(121(128ftheywerenormal-noaudible.PxiortoSiteAeaEmergency(SAE)messageandevacuationbeingannounced-PatbrennanreportedPanelsR.B.normal,calledcnGaitronics-hadtosilencePanels113onI,B.250andthansilencedallFaneleinR.Be(Panels101,103(104(105(10d(10>andXQ8.ChierHarveywaeCofnptotri~eetagewetlnRh.a.ndhaveaaninR.s.cnardeLynnRoon,accocpanledhyLarrycchaner,calledhfasupervisor,whentheysawtransformerblow.ChiefHarveywou14havelikedtOgettotransfcrmerquf.okerfor".ireevaluation.Hefeelsitwasatleastonehourbefore,'OV41QLCiOt1ech'fHarveyfeelsFireDept.shouldhavebeenpartof'nlinvestigation/inspectionteamwithOperationse

QJQf5'9t15~41tt%JKTl%WT&CCttlDTS19911'nterviev(Cont'4)P.45'ff'Acp-m~y-gp~r-ggpgPatPatminfoamRoomapproximately0550>heardloudnoise,venttoChief"'sofficeandaskedwhatnoisewas.Lightingdimmed,onestringoflightsoff(NOTE:thesefeedframEmergency-UPSshouldhavegoneoff)Thenheventonrover-heardalarms-whichvereonvatertreatmentsystempanel,thenventtoPanel123.TherewerenodisplaysonDAXpanel,vasblanknolightsvereon.Powerlightsvoreoff.TrouhleLightblinking.RenttoT.S,261NN,eignedsheet,stairtowerdark'noproblem,knewvayaround),TurbineTraokBay4imlylighted.WonttoT.S.306-OK,sign>>4sheetTBSvgr277OK)signedsheetT.Q.250byFeedpumps-notednotrunningbyPanel113-noLightson,noaudibleortroublealarmestimat>>stimeapproximately0605ContinuedraverroundstoPanel106SouthStairtoverR.S.249vasalarmingdisplaysai4"oninternalclock"hadtvotroublesdisplayedWenttoQ.B.215tirepanel103alarming-silencedR.B.190Fir~panel101alarmingsilencedbothpanelswereintrouble-unknovnR.B.175SignedsheetR.B.261SBCTS-OXPanel105-silencedtroublesCQ2Room,aboutt?)istime,evacuationalarmsoundedwenttoUnit2ControlRoomassemblypointWalkedaroundwithPatBrennanon8-15-91taPanel123andPanel113,poweronlightvasburnedoutonPanel123."Poweron"Lightwason,onPanel113~

.AJG15'9115:41N1leMGKIScCOPFlDTSP.5Aff~Alm8NggP08+opppostI+gtkuy.13,1991Xnterview(Cont'4)CMarkZcNtok,o(Calle4athome)HaslocatedintheFireDept.Officewhenlightsflickeredandnoisewasheard.Radiocommunicationwasgone,HearHerewasout.ChiefHarveydirectedpersonneltocovervitalareas.PatwilsonwasinRXBldg.PatBrennanwasrovingT.B.BerniefHarkweretccoverControlBldg.TriptoC.B.uneventfulPanelsPassedinroute)Panel114Elect.BayElv.261'anel120C.5~Elv.261'anel128C.5.Elv.261~Panel121C.B.Elv,261'anel125C.B.Zlv.261'anel127C.B.Elv.2i4'anel126C.B.Elv.214'ormalNormalNormalNormalNormalTrouble,Hornsounding-SU,enaodTroubleHornsounding-lilenoed,alsoanamberlightwaslitonpanelCheckedvalveroomonC.b.elv.2ii'ightwasoninroom.Noindicationofsystemactuation.stairwellsweredark,Elv,261'.B.wasdark.s.A.E.announcementandreportedtoControlRoom. I A<7~mgur7pt)c,pk~NMP2LIGHTINGSYSTEMPOWERSOURCEANDMINIM)StILLUHINATIONAVAILABLE-CRIT]CALAREASMODESOFOPERATIONPAGEILOCAStSEISMICWITHLOOPTRANSIENTWITHOUTLOOPILLIILSIXRCE6PROVIDEDBYPOWERSIXRCEMIN.AVAIL(FOOTCAN)LE)XMIN.POWERAVAIL.SDUIKES~~~<FOOTBYPOWERCANDLE)SIXRCEPOWERSIXRCESXHIN.AVAIIPOWERBYPOWERCANDLE)PROVIDED)FOOT~ESSOURCEXOFPROVIDEDCANDLE)(FOOTSOURCEXOFPOWERSOURCESPROVIDEDSOURCEMIN.ESSENTIALAVAIL.LIGHTING(FOOTUPSPAtELCANDLE)ILCIXITROLROOHIDPERATINGAREA5RELAYPANELAREA)CONTROLBLDLEL.336'E-65EN)RMAL58ESSENTIAL)9EHEROE498NXRBAT.PACK~ESSENTIAL188NXRBAT.PACK159NORMALESSENTIALEMERGE8NXRBAT+PACKESSENTIAL8NXRBAToPACKNORHAL58ESSENTIAL18EHERGENC48SNXRBAT.PACKNONESNXRBATT.PACKHANXACTIRER-EXIDI(TYPICAL)CONTROLROONMRTM-SOUTHCDRMDORS)CONTROLBLDLEL3P&'E-&5ECONTROLROOM(SHIFTSLPERVISOROFFICE)CINTROLBLDLELo3P&'E-65ERELAYANDCO)4'UTERROOMRELAYPAMPAS)CONTROLBLDLEL28F-6'E~RELAYANDCOtPUZERCQ4%6EAIKXNOCONTROLBLDG.EL288'-6'E-650HORHAL189BAT.PAtxNONE8NXRNRHAL58BAT.PA)XNONESNXRSNXRBAT+PACKSNXRBATPACK8NXRBAT.PACKNORHAL58ESSENTIAL18SNXRBAT.PACKNORHAL58ESSENTIAL18EMERGENC49SNXRBAT.PACKNORHAL'QESSENTIAL188NXRBAT.PACKSNXRBAT.PACKNORHALESSENTIEMERGENCSNXRBAT+PACKNORHALESSENTIALSNXRBAT.PACKESSENTIA.SNXRBATePACKYES16SNXRBAT+PACKNORHALEHERGESNXRBAT.PACKESSENTIALEHERGESNXRBAT.PACKSNXRBAT+PACKYES16SNXRBAT.PA)XNORMAL58ESSENTIAL18EMERGENCi8SNXRBAT.PACKESSENTIAL18EMERGENC<9SNXRBAT.PACKESSENTIAL188'NXRBAT+PACK2VBB-UPSID2VBB-UPSID2VBB-UPSIDNTHELIGHTINGWINGS,CIRCUITSTARTINGWITHAN'NICATENRMALPOWIWITHA%'H)ICATEESSENTIALPOWER,WIT)AN'E'INDICATEEMERGEN:YPOWER.

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NMP2LIGHTINGSYSTEHPOWERSOURCEANDMIHINJMILLUMINATIONAVAILABLEMODESOFDPERATIDNPAGELOCA4SEISHICWITHLOOPTRANSIENTWITHOUTLOOPTLRB.BLDG.GRMM)FLOORCORfODORELe258'E-66BPOWERSOURCESESSEHTIALXILLLÃ.PROVIDEDBYPOWERSOLRCEMIN.IAVAIL.POWERILL(FOOTSOURCESPROVIDEDCA)K)LE)BYPOWERSDLRCENORMALYESESSEHTIALYESMIH.AVAIL.IFOOTCANDLE)POWERAVAIL.SOURCESIFOOTBYPOWERC~E)SOURCEHORMALNONEESSENTIALNONEPOWERSOURCESNORMALESSENTIALOFPROVIOEOBYPOWERC~E)(FOOTSOURCEYESPOWERSOURCESESSENTIALILLU)LXOFpRovloEoAVAIL.BYPOWERC~E)(FOOTSOURCEYESYESESSENTIALLIGHTINGO'SPANELID.2VBB-LPS1DSAFES)IJTDOWNPATHO)l.YNoELXJIPPKNTTURLBLDLCLEANACCESSAREAEL.2QYEL2Q'L.288'-8'L.396'E-66HTtSLBLOLCLEANACCESSAREASTAIRSEL+258'L2Q'L288'-8'L386'E-66H8NXRBAT+PACKNORMALESSENTIAL8)KXRBAT.PACKbHOLRBAToPACK8HLXRBAT+PACKNORMALYESESSENTIALYES8HL)LRBAT.PACKESSEHTI)V.YES8HOLRBAT.PACK8HOLABATsPACKYESSHXRBATPACKYESESSENTIALNONE8HXRBATPACKNORHALNONEESSENTIALNONE8NXRBAT+PACKNORMALESSENTIALS)NLRBAT.PACKSHOLRBAToPACKYESYES8HOLRBATePACKNORMALESSENTIALSHOLRBAT.PACKESSENTIAL8HOLRBAT.PACKYESYESYES2VBB-UPSIO2VBB-UPSIC2VBB-UPSICSAFESHUTDOWNPATHD)LYNOEOUIPMENTSAFESWTDOWNPATHM.YNDEIXJIPPKNT IU ACCESSROUTETAKENBYOPERATORFROMCONTROLROOMTOUPSROOMINNORMALSWITCHGEARBUILDINGON8-13-91ThefollowingroutewastakenbyoperatorfromcontrolroomtogotoUPSroominswitchgearbuildingtotransferalternatepowersourcetoUPSunits,OperatorleftthecontrolroomEL306throughsouthdoorandproceededtowest.Thenheturnednorthalongthecorridoronthewestsideofthecontrolroom.ThenheexitedthecontrolroombuildingthroughnorthwestdoorEL306toAuxiliarybuilding.HethentookthestairwayjustsouthoftheelevatortogotoEL261.ThenatEL261ofAuxiliarybuilding,heproceededtosouthandenteredthecorridor(ElectricalequipmentTunnel).FromthecorridorheenteredthenormalswitchgearbuildingEL261andproceededtostairwaylocatedinthecenterofthebuilding(Westhalf)downtoEL237wheretheUPSunits2VBB-UPS1A,1B,1Cand1Darelocated.HethentransferredtheUPSpowertomaintenancepowersource.AfterrestoringpowertotheaboveUPSunits,theoperatorproceededtoUPS2VBB-UPS1Gviathedoorontheeastendoftheroom,wentsouthdownthehall,throughthedooronhisleft(eastside)andenteredthecontrolbuilding.HethentookthestairsdowntoEL214whereUPS2VBB-UPS1Gislocatedandtransferredthepowertothemaintenancepower.

CONDENSATE/FEEOMATERSIMPLIFIEDSKETCHlCQOCMJEANSFEll4IIIIIIQlZEMSATEBOOSTERIIFVRi)FOI)MFlOPAWLIIIIIIIIIIIiFEEOvATERCOMlROLLOO)C)II)IILVIBFLFVgPRESS)I)REDREAC)TX)VESSELO'RVIC(ÃH6ATEPAPHIM.FLOMIEgKRICQI+QNCOMPENSATE)MISTERPNTPHDLFLOMTEAOERFEEOPUH'lM.FLOVTRACERFOXBOROPANELTRAINA-2CEC-PNL825TRAINB-2CEC-PNL826TRAINC-2CEC-PNL827FEEDWATERCONTROLPANEL2CEC-PNL6I2(TYPICALTRAINA,8,8,CCROSSOVERHEADERSBETWEENTRAINSPROVIDECROSSOVERFLOW

OeGEIndustrialA,TrAQftttl+IIf'/QapowerSystemsPROPomrGenerationServicesDepartmentGeneralElectricCompany3532JamesSt..PO.Bott484t,Syraorse.Nyt322tNIAGARAMOHAWKPOWERCORPORATIONNINEMILEPOINTNUCLEARSTATIONUNITg2rGENERATORg180X632GENERATORINSPECTION-POSSIBLEPHASE-TO-PHASEFAULTcc:NIAGARAMOHAWKPOWERCORP.R.AbbottN.KabarwalM.McCormickGENERALELECTRICCOMPANYAugust28,1991L.Jordan(37-3)W.JuddS.KolbR.SmithW.TurkMr.AnilK.JulkaNIAGARAMOHAWKPOWERCORPORATION301PlainfieldRoadNorthSyracuse,NewYork13212

DearMr.Julka:

DuetotheAugust13,1991failureofthephaseBstep-uptransformeronNineMilePointUnitg2,GeneralElectricGeneratorEngineeringrecommendsperformingathoroughvisualinspectionofthegeneratorstatorendwindingsupportsystematthenextconvenientopportunity.Theinspectionshouldincludeallaccessiblecomponentsofthestatorendwindingsupportsystem,includingstatorbarendarms,blocks,tiesnoserings,andouteraxialsupports.ThisinspectionshouldbeaccomplishedbyaGEGeneratorSpecialisttrainedtodetectthepotentiallysubtleindicationsofdamage.Theaboverecommendationisbaseduponthepossibilityofphase-to-phasegeneratorshortcircuitcurrentsthroughthefailedtransformerashighas5pu.Theinitialrecommendationfortheimmediategeneratorinspectionconsideredthepossibilityofhighercurrents,resultinginseveraltimesgreaterendwindingforces.Physicalevidenceofhighcurrentforcesatthetransformer.lowsidewastheprimarydriverforthisrecommendation,sincemeasurementsofgeneratorcurrentswerenotavailable.Ourengineerscontinuedtoreviewthelimiteddataavailableandsubsequentlyconcludedthatcurrentshighenoughtodoprobabledamagetothegeneratorwerenotlikely.Thisconclusionwasreachedprimarilybyconsideringameasurementofdepressedgeneratorvoltageduringtheincident,inferringgeneratorcurrents,andspecificcapabilitiesofthegeneratordesign. 'k PageIIMr.,AnilK.JulkaAugust28,1991Shouldyouhaveanyquestionsregardingthisrecommendation,pleasecontactme.VeryrulyyoursJeph.KirchMaagerEngineringServicesPowrGeneratioServices"SYRACUSEOFFICEJAK/bsJAK-059 .rI~T }}