NERC EXAM QUESTIONS with complete
solutions 2025
A .Balancing .Authority .notices .that .Operating .Reserve .has .steadily .declined
.throughout .the .hour. .What .is .the .most .likely .cause?
a) .Loss .of .a .large .generator .in .the .area
b) .An .inaccurate .load .forecast
c) .Loss .of .a .major .transmission .line
d) .A .malfunction .of .EMS .- .ANS✓✓-b) .An .inaccurate .load .forecast
Balancing .Area .A .notices .that .the .Interconnection .frequency .is .59.94 .Hz .and
.their .ACE .is .0. .Which .of .the .following .could .be .the .cause .of .this .reading?
a) .A .net .under-generation .in .Balancing .Area .A
b) .A .net .under-generation .in .the .Interconnection
c) .A .loss .of .load .in .Balancing .Area .A
d) .A .loss .of .load .in .the .Interconnection .- .ANS✓✓-b) .A .net .under-generation .in
.the .Interconnection
What .is .the .penalty .for .a .Balancing .Authority .violating .the .Disturbance .Control
.Standard?
a) .Must .carry .additional .Contingency .Reserve
b) .Must .develop .a .correction .action .plan
c) .Must .re-evaluate .and .change .its .Frequency .Bias .Setting
d) .Must .increase .its .Regulating .Reserve .- .ANS✓✓-a) .Must .carry .additional
.Contingency .Reserve
Your .ACE .is .a .large .negative .value .and .system .frequency .is .59.80 .Hz. .Your
.AGC .system .is .pulsing .your .units .down. .What .should .you .do?
a) .Place .AGC .in .flat .frequency .control
b) .Place .AGC .in .flat .tie .line .control
c) .Suspend .AGC .and .investigate
d) .Do .nothing .as .this .is .normal .- .ANS✓✓-c) .Suspend .AGC .and .investigate
When .two .identical .generating .units .are .operated .in .parallel .on .governor
.control, .and .on .machine .has .a .5% .droop .and .the .other .has .a .10% .droop, .the
.unit .with .the .greater .(10%) .governor .droop .will:
, a) .Respond .less .to .frequency .deviations
b) .Respond .more .to .frequency .deviations
c) .Respond .the .same .to .frequency .deviations
d) .Not .adjust .for .frequency .changes .- .ANS✓✓-a) .Respond .less .to .frequency
.deviations
On .a .radial .transmission .system .a .generator .has .a .capacity .of .600 .MWs. .The
.Droop .characteristic .is .at .5% .and .the .generator .is .currently .loaded .at .300
.MWs. .If .frequency .suddenly .drops .to .59.3 .Hz, .what .would .be .the .total
.generator .output?
a) .350
b) .400
c) .440 .
d) .600 .- .ANS✓✓-c) .440
What .is .the .main .purpose .of .the .Frequency .Bias .Setting .in .the .ACE .equation?
a) .Control .frequency .to .60 .Hz .for .the .entire .Interconnection
b) .Assist .with .arresting .frequency .deviations
c) .Restore .frequency .to .60 .Hz .after .a .disturbance
d) .maintains .frequency .between .59.95 .and .60.05 .Hz .- .ANS✓✓-b) .Assist .with
.arresting .frequency .deviations
A .Balancing .Authority .has .a .Frequency .Bias .Setting .of .-200 .MW/.1Hz. .What .is
.the .Balancing .Authority's .Frequency .Response .for .a .frequency .of .59.95 .Hz?
a) .10 .MWs
b) .50 .MWs
c) .100 .MWs
d) .200 .MWs .- .ANS✓✓-c) .100 .MWs
Scheduled .Interchange .is .250 .MWs .and .Actual .Interchange .is .285 .MWs. .The
.Bias .Setting .is .35 .MW/.1Hz .and .frequency .is .60.00 .Hz .with .no .time .error
.correction .in .effect. .Frequency .suddenly .drops .to .59.80 .Hz. .What .does .ACE
.indicate .after .the .disturbance?
a) .70 .MW .under-generating
b) .70 .MW .over-generating
c) .35 .MW .under-generating
d) .35 .MW .over-generating .- .ANS✓✓-d) .35 .MW .over-generating
Inadvertent .energy .accumulation .occurs .due .to .a .difference .in .Net .Actual
.Interchange .and .Net .Interchange .Schedule .over .time. .This .energy .accumulation
.can .be .paid .back .unilaterally .by .adjusting .delivery .of .power: .
a) .During .off-peak .periods
b) .During .periods .corresponding .to .those .in .which .the .inadvertent .energy .was
.accumulated
solutions 2025
A .Balancing .Authority .notices .that .Operating .Reserve .has .steadily .declined
.throughout .the .hour. .What .is .the .most .likely .cause?
a) .Loss .of .a .large .generator .in .the .area
b) .An .inaccurate .load .forecast
c) .Loss .of .a .major .transmission .line
d) .A .malfunction .of .EMS .- .ANS✓✓-b) .An .inaccurate .load .forecast
Balancing .Area .A .notices .that .the .Interconnection .frequency .is .59.94 .Hz .and
.their .ACE .is .0. .Which .of .the .following .could .be .the .cause .of .this .reading?
a) .A .net .under-generation .in .Balancing .Area .A
b) .A .net .under-generation .in .the .Interconnection
c) .A .loss .of .load .in .Balancing .Area .A
d) .A .loss .of .load .in .the .Interconnection .- .ANS✓✓-b) .A .net .under-generation .in
.the .Interconnection
What .is .the .penalty .for .a .Balancing .Authority .violating .the .Disturbance .Control
.Standard?
a) .Must .carry .additional .Contingency .Reserve
b) .Must .develop .a .correction .action .plan
c) .Must .re-evaluate .and .change .its .Frequency .Bias .Setting
d) .Must .increase .its .Regulating .Reserve .- .ANS✓✓-a) .Must .carry .additional
.Contingency .Reserve
Your .ACE .is .a .large .negative .value .and .system .frequency .is .59.80 .Hz. .Your
.AGC .system .is .pulsing .your .units .down. .What .should .you .do?
a) .Place .AGC .in .flat .frequency .control
b) .Place .AGC .in .flat .tie .line .control
c) .Suspend .AGC .and .investigate
d) .Do .nothing .as .this .is .normal .- .ANS✓✓-c) .Suspend .AGC .and .investigate
When .two .identical .generating .units .are .operated .in .parallel .on .governor
.control, .and .on .machine .has .a .5% .droop .and .the .other .has .a .10% .droop, .the
.unit .with .the .greater .(10%) .governor .droop .will:
, a) .Respond .less .to .frequency .deviations
b) .Respond .more .to .frequency .deviations
c) .Respond .the .same .to .frequency .deviations
d) .Not .adjust .for .frequency .changes .- .ANS✓✓-a) .Respond .less .to .frequency
.deviations
On .a .radial .transmission .system .a .generator .has .a .capacity .of .600 .MWs. .The
.Droop .characteristic .is .at .5% .and .the .generator .is .currently .loaded .at .300
.MWs. .If .frequency .suddenly .drops .to .59.3 .Hz, .what .would .be .the .total
.generator .output?
a) .350
b) .400
c) .440 .
d) .600 .- .ANS✓✓-c) .440
What .is .the .main .purpose .of .the .Frequency .Bias .Setting .in .the .ACE .equation?
a) .Control .frequency .to .60 .Hz .for .the .entire .Interconnection
b) .Assist .with .arresting .frequency .deviations
c) .Restore .frequency .to .60 .Hz .after .a .disturbance
d) .maintains .frequency .between .59.95 .and .60.05 .Hz .- .ANS✓✓-b) .Assist .with
.arresting .frequency .deviations
A .Balancing .Authority .has .a .Frequency .Bias .Setting .of .-200 .MW/.1Hz. .What .is
.the .Balancing .Authority's .Frequency .Response .for .a .frequency .of .59.95 .Hz?
a) .10 .MWs
b) .50 .MWs
c) .100 .MWs
d) .200 .MWs .- .ANS✓✓-c) .100 .MWs
Scheduled .Interchange .is .250 .MWs .and .Actual .Interchange .is .285 .MWs. .The
.Bias .Setting .is .35 .MW/.1Hz .and .frequency .is .60.00 .Hz .with .no .time .error
.correction .in .effect. .Frequency .suddenly .drops .to .59.80 .Hz. .What .does .ACE
.indicate .after .the .disturbance?
a) .70 .MW .under-generating
b) .70 .MW .over-generating
c) .35 .MW .under-generating
d) .35 .MW .over-generating .- .ANS✓✓-d) .35 .MW .over-generating
Inadvertent .energy .accumulation .occurs .due .to .a .difference .in .Net .Actual
.Interchange .and .Net .Interchange .Schedule .over .time. .This .energy .accumulation
.can .be .paid .back .unilaterally .by .adjusting .delivery .of .power: .
a) .During .off-peak .periods
b) .During .periods .corresponding .to .those .in .which .the .inadvertent .energy .was
.accumulated
