NERC Practice Test, Exam Questions & Answers
g g g g g g
Agtransmissionglinegisgoperatinggwithgagvoltagegphaseganglegdifferentgofg30gdegreesg
betweengthegsendinggVsgandgthegreceivinggbusgVr.gIfgthegreceivinggendgloadgisgsudd
enlygincreased,gthegvoltagegphaseganglegdifferencegwillgbe?g-
gThegphaseganglegwillgincrease.gWhengloadgisgincreasedgphaseganglegwillgincrease.
Agloadghasgagpowergfactorgofg0.9glagging.gIfgthegloadgdrawsg100gMVA,gwhatgisgtheg
MWgdraw?g-g90gpf=gmw/mva
Theghighgsidegofgagdelta-
wyegconnectiongtransformergisgconnectedgtogagpowergsystemgwithg199gkVgL-
Gghighgsidegvoltage.gWhatgisgthegvoltagegacrossgthegdeltagwindinggofgthegtransforme
r?g-gVl-l=gsquaregrootgofg3gtimesgVl-gg1.73x191=g345kV
Ifgagtransmissionglinegisgcarryingg400gMWgandg300gMVARgwhatgisgthegMVA?g-g3-
g4-5gtriangleg500gMVA
Thegprimegmovergisgthegcomponentgofgtheggeneratorgthatgcreatesgthegrotationalgforc
e.gIngagtypicalgcoalgfiredgsteamggeneratorgwhatgcomponentgspinsgthegrotor?g-
gTurbine
Reactivegreservegresponsegduringgagdisturbancegisgbestgobtainedgfromgwhichgdevise?
-gSynchronousgcondensers
ForgtwogidenticallygconstructedgtransmissionglinesgwheregLinegAgisg150gmilesglongga
ndglinegBgisg15gmilesglong,gifgbothglinesgareglightlygloaded?g-
gAgproducesgmoregreactivegpowergthangB.
Lightlygloadedgtransmissionglinesgessentiallygbehaveglike?g-gShuntgCapacitors
Yougreceivegangalarmgthatgindicatesglowgoilgpressuregongangundergroundgtransmissio
ngcable.gSCADAgshowsgthegpressuregisgcontinuinggtogdrop.gWhatgisgthegfirstgstepgyo
ugtakegtogprotectgthegline?g-gIsolategthegline
Computergsimulationsgshowgthatgforgag100gMWgschedulegfromgBusgAgtogBusgB,g6
3%gofgthegschedulegwillgflowgongthegscheduledgpathgandgthegremaindergwillgflow
,ongothergparallelgpaths.gWhatgisgthegdistributiongfactorgforgthegscheduledgpath?g-
g63%
WhichgstatementgbestgdescribesghowgreactivegpowergMVARgpowergnormallygflow
s?g-gHighgVoltagegtogLowgVoltage
WhichgofgthegfollowinggtypesgofgdatagaregBAgandgRCgnotgrequiredgtogsharegwithgoneg
another?g-gGeneratorgstartgupgcost
TOPgmustgdevelop,gmaintain,gandgimplementgformalgpoliciesgandgproceduresgtogpro
videgforgtransmissiongreliability.gWhichgofgthegfollowinggDOESgNOTgneedgtogbegad
dressedgingthesegpoliciesgandgprocedures?g-gPlannedgoutagesgofggenerationgunits
Ag1000gMVAgratedggeneratorgthatgproducesg800gMWgandg100gMVARgisgbestgdescri
bedgas?g-gOperatinggingaglagginggmode.gInductivegsystem
WhichgofgthegfollowinggtypesgofgMWgloadgisgthegmostgimpactedgbygangintentionalgfr
equencygreduction?g-gMotor
Assumegtheregaregtwog250gmileglonggtransmissionglinesgexportinggangexcessivegam
ountgofgMWgfromgaggenerationgareagtogagloadgarea.gOnegofgtheglinesgsuddenlygtripsg
andgthegareagpowergsystemgcollapsesgwithingagfewgseconds.gThegmostglikelygcausego
fgthegcollapse?g-gAnglegInstability
Thegphasegvoltagegingagwye-
connectedgloadgisg277gV.gWhatgisgtheglinegtoglinegvoltage?g-g480gV
Agsimplegpowergsystemgisgcomposedgofgthreeglinesgconnectingggenerationgtogload.g
Eachglinesgthegsamegimpedance,gisginitiallygloadedgatg200gMW,gandghasgagthermalg
limitgofg400gMW.gIfgoneglinegtrips,gwhatgthegloadinggongthegshortestgremaininggline
gbegandgwillgthegthermalglimitgeithergremainingglinegbegviolated?g-g300gMWgandgNo
Thegbestgpredictiongofgsystemgloadgisgthegloadgforecastgtoolgthatguses?g-
gForecastedgWeather
, Ifgthegphasegangelgatgangopengbreakergisgequalgtog1/10gofgagcycle,gthisgisgthegthegsameg
anglegas?g-g1/10gofg360gsog36
Ag
toolgisgusedgtogensuregthegpowergsystemgcangrespondgwithin
gacceptableglimitsgofgN-1g-gContingencygAnalysis
Whichgofgthegfollowinggactivitiesgwouldgnotgbegincludedgingthegproceduresgforgtrans
missiongreliability?g-gAncillarygservicegpricing
ThegtransmissiongOperatorgandgBAgshallgprovidegdocumentationgthatgoperating
gpersonnelghaveg
togimplementgrealgtimegactionsgtogensuregthegstablegand
greliablegoperationgofgthegBES.g-gPropergNERCgCertificationgCredential
Agutilitygdistributiongbusghasgthegfollowinggcustomergloadsgattached.gWhatgisgthegtot
algcustomergMWgloadgandgisgthegtotalgcustomergloadgcapacitivegorginductive?g5gMWg
1gMVARg&g3gMWg1gMVARg&g2gMWg-2gMVARg&g10gMWg3gMVARg-g20
mwgandgInductive
HowgmanygMVARsgdoesgag230gkV,g50gMVARgcapacitorgbankgprovidegwhengthegv
oltagegidg207gkVg-gActualgMW/gRatedgMWg^2gxgCapacitorgRating
40
Yougaregagsystemgoperatorgandgthegloadgforecastgisgforgangallgtimegsummergpeakg
loadgday,ggenerationsgandgreactivegresourcesgwillgbegtight.gWhichgscheduledgjob
gwouldgyougallowgtogproceed?g-g735gkVgshuntgreactorgmaintenance.
AgcontingencygresultsgingthegexceedancegofgangIROL.gWhatgcouldgbegthegresultgifgt
hegIROLgisgallowedgtogbegexceededglongergthangTgsubgvg-
gInterruptiongofgpowergtogaglargegpartgofgthegBES
Generatorsghavegthegabilitygtogbegusedgasgvoltagegcontrolgdevices.gIfgaggeneratorgrais
esgitsgVARgoutput,gthegsystemgoratorgshouldgexpectgsystemgstagegto?g-gIncrease
Thegactualgvoltagegisg362kVgongag345gbus.gWhatgisgthegp.u.gvoltage?g-g1.05
g g g g g g
Agtransmissionglinegisgoperatinggwithgagvoltagegphaseganglegdifferentgofg30gdegreesg
betweengthegsendinggVsgandgthegreceivinggbusgVr.gIfgthegreceivinggendgloadgisgsudd
enlygincreased,gthegvoltagegphaseganglegdifferencegwillgbe?g-
gThegphaseganglegwillgincrease.gWhengloadgisgincreasedgphaseganglegwillgincrease.
Agloadghasgagpowergfactorgofg0.9glagging.gIfgthegloadgdrawsg100gMVA,gwhatgisgtheg
MWgdraw?g-g90gpf=gmw/mva
Theghighgsidegofgagdelta-
wyegconnectiongtransformergisgconnectedgtogagpowergsystemgwithg199gkVgL-
Gghighgsidegvoltage.gWhatgisgthegvoltagegacrossgthegdeltagwindinggofgthegtransforme
r?g-gVl-l=gsquaregrootgofg3gtimesgVl-gg1.73x191=g345kV
Ifgagtransmissionglinegisgcarryingg400gMWgandg300gMVARgwhatgisgthegMVA?g-g3-
g4-5gtriangleg500gMVA
Thegprimegmovergisgthegcomponentgofgtheggeneratorgthatgcreatesgthegrotationalgforc
e.gIngagtypicalgcoalgfiredgsteamggeneratorgwhatgcomponentgspinsgthegrotor?g-
gTurbine
Reactivegreservegresponsegduringgagdisturbancegisgbestgobtainedgfromgwhichgdevise?
-gSynchronousgcondensers
ForgtwogidenticallygconstructedgtransmissionglinesgwheregLinegAgisg150gmilesglongga
ndglinegBgisg15gmilesglong,gifgbothglinesgareglightlygloaded?g-
gAgproducesgmoregreactivegpowergthangB.
Lightlygloadedgtransmissionglinesgessentiallygbehaveglike?g-gShuntgCapacitors
Yougreceivegangalarmgthatgindicatesglowgoilgpressuregongangundergroundgtransmissio
ngcable.gSCADAgshowsgthegpressuregisgcontinuinggtogdrop.gWhatgisgthegfirstgstepgyo
ugtakegtogprotectgthegline?g-gIsolategthegline
Computergsimulationsgshowgthatgforgag100gMWgschedulegfromgBusgAgtogBusgB,g6
3%gofgthegschedulegwillgflowgongthegscheduledgpathgandgthegremaindergwillgflow
,ongothergparallelgpaths.gWhatgisgthegdistributiongfactorgforgthegscheduledgpath?g-
g63%
WhichgstatementgbestgdescribesghowgreactivegpowergMVARgpowergnormallygflow
s?g-gHighgVoltagegtogLowgVoltage
WhichgofgthegfollowinggtypesgofgdatagaregBAgandgRCgnotgrequiredgtogsharegwithgoneg
another?g-gGeneratorgstartgupgcost
TOPgmustgdevelop,gmaintain,gandgimplementgformalgpoliciesgandgproceduresgtogpro
videgforgtransmissiongreliability.gWhichgofgthegfollowinggDOESgNOTgneedgtogbegad
dressedgingthesegpoliciesgandgprocedures?g-gPlannedgoutagesgofggenerationgunits
Ag1000gMVAgratedggeneratorgthatgproducesg800gMWgandg100gMVARgisgbestgdescri
bedgas?g-gOperatinggingaglagginggmode.gInductivegsystem
WhichgofgthegfollowinggtypesgofgMWgloadgisgthegmostgimpactedgbygangintentionalgfr
equencygreduction?g-gMotor
Assumegtheregaregtwog250gmileglonggtransmissionglinesgexportinggangexcessivegam
ountgofgMWgfromgaggenerationgareagtogagloadgarea.gOnegofgtheglinesgsuddenlygtripsg
andgthegareagpowergsystemgcollapsesgwithingagfewgseconds.gThegmostglikelygcausego
fgthegcollapse?g-gAnglegInstability
Thegphasegvoltagegingagwye-
connectedgloadgisg277gV.gWhatgisgtheglinegtoglinegvoltage?g-g480gV
Agsimplegpowergsystemgisgcomposedgofgthreeglinesgconnectingggenerationgtogload.g
Eachglinesgthegsamegimpedance,gisginitiallygloadedgatg200gMW,gandghasgagthermalg
limitgofg400gMW.gIfgoneglinegtrips,gwhatgthegloadinggongthegshortestgremaininggline
gbegandgwillgthegthermalglimitgeithergremainingglinegbegviolated?g-g300gMWgandgNo
Thegbestgpredictiongofgsystemgloadgisgthegloadgforecastgtoolgthatguses?g-
gForecastedgWeather
, Ifgthegphasegangelgatgangopengbreakergisgequalgtog1/10gofgagcycle,gthisgisgthegthegsameg
anglegas?g-g1/10gofg360gsog36
Ag
toolgisgusedgtogensuregthegpowergsystemgcangrespondgwithin
gacceptableglimitsgofgN-1g-gContingencygAnalysis
Whichgofgthegfollowinggactivitiesgwouldgnotgbegincludedgingthegproceduresgforgtrans
missiongreliability?g-gAncillarygservicegpricing
ThegtransmissiongOperatorgandgBAgshallgprovidegdocumentationgthatgoperating
gpersonnelghaveg
togimplementgrealgtimegactionsgtogensuregthegstablegand
greliablegoperationgofgthegBES.g-gPropergNERCgCertificationgCredential
Agutilitygdistributiongbusghasgthegfollowinggcustomergloadsgattached.gWhatgisgthegtot
algcustomergMWgloadgandgisgthegtotalgcustomergloadgcapacitivegorginductive?g5gMWg
1gMVARg&g3gMWg1gMVARg&g2gMWg-2gMVARg&g10gMWg3gMVARg-g20
mwgandgInductive
HowgmanygMVARsgdoesgag230gkV,g50gMVARgcapacitorgbankgprovidegwhengthegv
oltagegidg207gkVg-gActualgMW/gRatedgMWg^2gxgCapacitorgRating
40
Yougaregagsystemgoperatorgandgthegloadgforecastgisgforgangallgtimegsummergpeakg
loadgday,ggenerationsgandgreactivegresourcesgwillgbegtight.gWhichgscheduledgjob
gwouldgyougallowgtogproceed?g-g735gkVgshuntgreactorgmaintenance.
AgcontingencygresultsgingthegexceedancegofgangIROL.gWhatgcouldgbegthegresultgifgt
hegIROLgisgallowedgtogbegexceededglongergthangTgsubgvg-
gInterruptiongofgpowergtogaglargegpartgofgthegBES
Generatorsghavegthegabilitygtogbegusedgasgvoltagegcontrolgdevices.gIfgaggeneratorgrais
esgitsgVARgoutput,gthegsystemgoratorgshouldgexpectgsystemgstagegto?g-gIncrease
Thegactualgvoltagegisg362kVgongag345gbus.gWhatgisgthegp.u.gvoltage?g-g1.05
