SOS NERC Prep - RELIABILITY EXAM QUESTIONS & ANSWERS
The Reliability Coordinator just informed you of a slow time error correction which will
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
begin at the top of the next hour. Your EMS system will not let you changeyourscheduled
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
frequency.YourFrequencyBiasSettingis-100MW/.1Hz. What action should you
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
take?
‘
A) IncreaseNetInterchangeScheduleby20MWs. ‘ ‘ ‘ ‘ ‘ ‘
B) InformtheReliabilityCoordinatorthatyoucannotparticipate inthetimeerror
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
correction.
‘
C) DecreaseNetInterchangeScheduleby20MWs. ‘ ‘ ‘ ‘ ‘ ‘
D) IncreaseNetInterchangeScheduleby10MWs. -A)IncreaseNetInterchange ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
Schedule by 20 MWs.
‘ ‘ ‘ ‘
ABalancing Authority has asuddenloss ofa large blockof loadinits area.This losswillbe
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
seeninstantaneouslyinthechangeofwhichofthefollowing values?
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
1. ActualNetInterchange ‘ ‘
2. ScheduledFrequency ‘
3. ScheduledNetInterchange ‘ ‘
4. AreaControlError ‘ ‘
A) 4 only ‘
B) 1 & 3 ‘ ‘
C) 1 & 4 ‘ ‘
D) 3 & 4 - C)1 & 4
‘ ‘ ‘ ‘ ‘ ‘ ‘
MeteredDataincludedinthecalculationofACEare:dynamicschedules,pseudo ties,
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
actual frequency, and all
‘ ‘ . ‘ ‘ ‘
A) Tielines readings ‘ ‘
B) Generatorsoutput ‘
C) Scheduledfrequencyindications ‘ ‘
,D) Transformerload -A)Tielines readings ‘ ‘ ‘ ‘ ‘ ‘
Balancing Authority A is currentlyreading a systemfrequencyof 60.00 Hz. Its Net Actual
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
Interchange is +100 MW and its Net Scheduled Interchange is +200 MW. If Balancing
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
Authority A's frequency bias setting is 100 MW/0.1 Hz, what is ACE?
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
A) -100
B) 0
C) 10
D) 100 -A) -100 ‘ ‘ ‘
ABalancingAuthority hasaNetInterchangeScheduleof -250MWs from1200to 1600
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
on a summer day. The Net Interchange Actual for those same hours respectively were -
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
230 MW, -275 MW, -250 MW and -270 MW. What was the Balancing Authority's
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
Inadvertent Interchange for the 4-hour period?
‘ ‘ ‘ ‘ ‘ ‘
A) 6MWs out ‘ ‘
B) 25MWs in ‘ ‘
C) 25MWs out ‘ ‘
D) 6MWs in -B)25MWs in ‘ ‘ ‘ ‘ ‘ ‘ ‘
FortheACEequationtoworkproperly,dynamicschedules,pseudoties,
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
frequency, and all
‘ must be metered. ‘ ‘ ‘ ‘ ‘
A) Generation
B) Communications
C) Transformers
D) Tielines -D)Tielines ‘ ‘ ‘ ‘ ‘
If the frequency bias setting is set to a less negative value than the frequency responseofa
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
Balancing Authorityandafrequencyincrease iscausedbyasudden loss of load in an
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
external balancing area, what will be the result?
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
A) TheACEwillbezero andwill takeno AGC action
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
B) TheACEwillbeanegative valueandAGCwillincrease generation
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
,C) TheACEwill beapositivevalueandAGCwilllowergeneration
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
D) ThiswillnotaffecttheACE-B)TheACEwillbeanegativevalueandAGC will
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
increase generation
‘ ‘
Ifthefrequencybiassetting islessnegative thanthe frequencyresponseofa Balancing
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
Authority and a frequency decline is caused by a sudden loss of generation in an external
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
balancing area, what will be the result?
‘ ‘ ‘ ‘ ‘ ‘ ‘
A) TheACEwillbeanegativevalueandAGCwill increase generation.
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
B) ThiswillnotaffecttheACE. ‘ ‘ ‘ ‘ ‘
C) TheACEwill beapositivevalueandAGCwilllowergeneration.
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
D) TheACEwillbezero and will takeno AGCaction. -C)TheACEwill bea positive
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
value and AGC will lower generation.
‘ ‘ ‘ ‘ ‘ ‘
Itistheresponsibilityofwhichentity/entities todevelop,maintain,andimplement load
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
shedding plans?
‘ ‘
A) TransmissionOperatorsandBalancingAuthorities ‘ ‘ ‘ ‘
B) ReliabilityCoordinator ‘
C) LoadServingEntities ‘ ‘
D) BalancingAuthority-A)TransmissionOperatorsandBalancingAuthorities ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
ATransmission lineisloaded25%aboveitsSOL.Aparallellineisoutforroutine
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
maintenance and can be placed in service in 10 minutes. What is the first step the Operator
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
should take to reduce the line loading?
‘ ‘ ‘ ‘ ‘ ‘ ‘
A) Shedload atthedownstreambus. ‘ ‘ ‘ ‘ ‘
, B) Open the line. d
‘ d
‘
C) Re-Dispatch Generation. d
‘
D) Initiate the restoration of the parallel line. - D) Initiate the restoration of the
d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ ‘ d d
‘ d
‘ d
‘ d
‘ d
‘ d
‘
‘ d parallel line. ‘ d
As a Transmission Operator, you realize that the voltage level is starting to decline in
d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ ‘ d
the North West part of the system. Which of the following devices should you, as a
‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d
Transmission Operator, be able to operate, and/or have another entity operate to raise
‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d
the voltage level back to normal in the North West part of the system?
‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d
A) Transformer Underload Tap Changers d
‘ d
‘ d
‘
B) Shunt Capacitor Banks d
‘ d
‘
C) Generator Reactive Output d
‘ d
‘
D) All answers are correct - D) All answers are correct
d
‘ d
‘ d
‘ ‘ d ‘ d d
‘ d
‘ d
‘ d
‘
Voltage reduction for load relief should be made on the
‘ d ‘ d d
‘ ‘ d ‘ d d
‘ d
‘ ‘ d d
‘ ‘ d .
A) Distribution system d
‘
B) Entire Interconnection simultaneously d
‘ d
‘
C) Tie-lines with other Balancing Authority Areas d
‘ d
‘ d
‘ d
‘ d
‘
D) Transmission System - A) Distribution system ‘ d d
‘ d
‘ d
‘ d
‘
Under Frequency Load Shedding (UFLS) is to stabilize the imbalance between
d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘
generation and load that has been created by a system disturbance. This is
‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d
accomplished by
‘ d . ‘ d ‘ d
A) Tripping generation first d
‘ d
‘
B) Voltage reduction on the distribution system. d
‘ d
‘ d
‘ d
‘ d
‘
C) Shedding all load to arrest frequency d
‘ ‘ d d
‘ d
‘ d
‘
D) Shedding load prior to generation tripping - D) Shedding load prior to d
‘ d
‘ d
‘ ‘ d d
‘ ‘ d d
‘ d
‘ d
‘ d
‘ d
‘
generation tripping
‘ d ‘ d
The Reliability Coordinator just informed you of a slow time error correction which will
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
begin at the top of the next hour. Your EMS system will not let you changeyourscheduled
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
frequency.YourFrequencyBiasSettingis-100MW/.1Hz. What action should you
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
take?
‘
A) IncreaseNetInterchangeScheduleby20MWs. ‘ ‘ ‘ ‘ ‘ ‘
B) InformtheReliabilityCoordinatorthatyoucannotparticipate inthetimeerror
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
correction.
‘
C) DecreaseNetInterchangeScheduleby20MWs. ‘ ‘ ‘ ‘ ‘ ‘
D) IncreaseNetInterchangeScheduleby10MWs. -A)IncreaseNetInterchange ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
Schedule by 20 MWs.
‘ ‘ ‘ ‘
ABalancing Authority has asuddenloss ofa large blockof loadinits area.This losswillbe
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
seeninstantaneouslyinthechangeofwhichofthefollowing values?
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
1. ActualNetInterchange ‘ ‘
2. ScheduledFrequency ‘
3. ScheduledNetInterchange ‘ ‘
4. AreaControlError ‘ ‘
A) 4 only ‘
B) 1 & 3 ‘ ‘
C) 1 & 4 ‘ ‘
D) 3 & 4 - C)1 & 4
‘ ‘ ‘ ‘ ‘ ‘ ‘
MeteredDataincludedinthecalculationofACEare:dynamicschedules,pseudo ties,
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
actual frequency, and all
‘ ‘ . ‘ ‘ ‘
A) Tielines readings ‘ ‘
B) Generatorsoutput ‘
C) Scheduledfrequencyindications ‘ ‘
,D) Transformerload -A)Tielines readings ‘ ‘ ‘ ‘ ‘ ‘
Balancing Authority A is currentlyreading a systemfrequencyof 60.00 Hz. Its Net Actual
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
Interchange is +100 MW and its Net Scheduled Interchange is +200 MW. If Balancing
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
Authority A's frequency bias setting is 100 MW/0.1 Hz, what is ACE?
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
A) -100
B) 0
C) 10
D) 100 -A) -100 ‘ ‘ ‘
ABalancingAuthority hasaNetInterchangeScheduleof -250MWs from1200to 1600
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
on a summer day. The Net Interchange Actual for those same hours respectively were -
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
230 MW, -275 MW, -250 MW and -270 MW. What was the Balancing Authority's
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
Inadvertent Interchange for the 4-hour period?
‘ ‘ ‘ ‘ ‘ ‘
A) 6MWs out ‘ ‘
B) 25MWs in ‘ ‘
C) 25MWs out ‘ ‘
D) 6MWs in -B)25MWs in ‘ ‘ ‘ ‘ ‘ ‘ ‘
FortheACEequationtoworkproperly,dynamicschedules,pseudoties,
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
frequency, and all
‘ must be metered. ‘ ‘ ‘ ‘ ‘
A) Generation
B) Communications
C) Transformers
D) Tielines -D)Tielines ‘ ‘ ‘ ‘ ‘
If the frequency bias setting is set to a less negative value than the frequency responseofa
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
Balancing Authorityandafrequencyincrease iscausedbyasudden loss of load in an
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
external balancing area, what will be the result?
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
A) TheACEwillbezero andwill takeno AGC action
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
B) TheACEwillbeanegative valueandAGCwillincrease generation
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
,C) TheACEwill beapositivevalueandAGCwilllowergeneration
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
D) ThiswillnotaffecttheACE-B)TheACEwillbeanegativevalueandAGC will
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
increase generation
‘ ‘
Ifthefrequencybiassetting islessnegative thanthe frequencyresponseofa Balancing
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
Authority and a frequency decline is caused by a sudden loss of generation in an external
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
balancing area, what will be the result?
‘ ‘ ‘ ‘ ‘ ‘ ‘
A) TheACEwillbeanegativevalueandAGCwill increase generation.
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
B) ThiswillnotaffecttheACE. ‘ ‘ ‘ ‘ ‘
C) TheACEwill beapositivevalueandAGCwilllowergeneration.
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
D) TheACEwillbezero and will takeno AGCaction. -C)TheACEwill bea positive
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
value and AGC will lower generation.
‘ ‘ ‘ ‘ ‘ ‘
Itistheresponsibilityofwhichentity/entities todevelop,maintain,andimplement load
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
shedding plans?
‘ ‘
A) TransmissionOperatorsandBalancingAuthorities ‘ ‘ ‘ ‘
B) ReliabilityCoordinator ‘
C) LoadServingEntities ‘ ‘
D) BalancingAuthority-A)TransmissionOperatorsandBalancingAuthorities ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
ATransmission lineisloaded25%aboveitsSOL.Aparallellineisoutforroutine
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
maintenance and can be placed in service in 10 minutes. What is the first step the Operator
‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘ ‘
should take to reduce the line loading?
‘ ‘ ‘ ‘ ‘ ‘ ‘
A) Shedload atthedownstreambus. ‘ ‘ ‘ ‘ ‘
, B) Open the line. d
‘ d
‘
C) Re-Dispatch Generation. d
‘
D) Initiate the restoration of the parallel line. - D) Initiate the restoration of the
d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ ‘ d d
‘ d
‘ d
‘ d
‘ d
‘ d
‘
‘ d parallel line. ‘ d
As a Transmission Operator, you realize that the voltage level is starting to decline in
d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ ‘ d
the North West part of the system. Which of the following devices should you, as a
‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d
Transmission Operator, be able to operate, and/or have another entity operate to raise
‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d
the voltage level back to normal in the North West part of the system?
‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d
A) Transformer Underload Tap Changers d
‘ d
‘ d
‘
B) Shunt Capacitor Banks d
‘ d
‘
C) Generator Reactive Output d
‘ d
‘
D) All answers are correct - D) All answers are correct
d
‘ d
‘ d
‘ ‘ d ‘ d d
‘ d
‘ d
‘ d
‘
Voltage reduction for load relief should be made on the
‘ d ‘ d d
‘ ‘ d ‘ d d
‘ d
‘ ‘ d d
‘ ‘ d .
A) Distribution system d
‘
B) Entire Interconnection simultaneously d
‘ d
‘
C) Tie-lines with other Balancing Authority Areas d
‘ d
‘ d
‘ d
‘ d
‘
D) Transmission System - A) Distribution system ‘ d d
‘ d
‘ d
‘ d
‘
Under Frequency Load Shedding (UFLS) is to stabilize the imbalance between
d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘ d
‘
generation and load that has been created by a system disturbance. This is
‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d ‘ d
accomplished by
‘ d . ‘ d ‘ d
A) Tripping generation first d
‘ d
‘
B) Voltage reduction on the distribution system. d
‘ d
‘ d
‘ d
‘ d
‘
C) Shedding all load to arrest frequency d
‘ ‘ d d
‘ d
‘ d
‘
D) Shedding load prior to generation tripping - D) Shedding load prior to d
‘ d
‘ d
‘ ‘ d d
‘ ‘ d d
‘ d
‘ d
‘ d
‘ d
‘
generation tripping
‘ d ‘ d
