SOS NERC PREP - REliability Exam QuEStiONS aNd CORRECt
dEtailEd aNSwERS (VERifiEd aNSwERS) | latESt uPdatE
2026/2027||RaNkEd !!.
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 change your scheduled frequency. Your Frequency Bias
Setting is -100 MW/.1Hz. What action should you take?
A) Increase Net Interchange Schedule by 20 MWs.
B) Inform the Reliability Coordinator that you cannot participate in the time error correction.
C) Decrease Net Interchange Schedule by 20 MWs.
D) Increase Net Interchange Schedule by 10 MWs. - aNSwER-A) Increase Net Interchange Schedule by
20 MWs.
A Balancing Authority has a sudden loss of a large block of load in its area. This loss will be seen
instantaneously in the change of which of the following values?
1. Actual Net Interchange
2. Scheduled Frequency
3. Scheduled Net Interchange
4. Area Control Error
A) 4 only
B) 1 & 3
C) 1 & 4
D) 3 & 4 - aNSwER-C) 1 & 4
,Metered Data included in the calculation of ACE are: dynamic schedules, pseudo ties, actual frequency,
and all __________.
A) Tie lines readings
B) Generators output
C) Scheduled frequency indications
D) Transformer load - aNSwER-A) Tie lines readings
Balancing Authority A is currently reading a system frequency of 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 - aNSwER-A) -100
A Transmission line is loaded 25% above its SOL. A parallel line is out for routine 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)Shed load at the downstream bus.
B) Open the line.
C) Re-Dispatch Generation.
D) Initiate the restoration of the parallel line. - aNSwER-D) Initiate the restoration of the parallel line.
,As a Transmission Operator, you realize that the voltage level is starting to decline in the North West part
of the system. Which of the following devices should you, as a Transmission Operator, be able to
operate, and/or have another entity operate to raise the voltage level back to normal in the North West
part of the system?
A) Transformer Underload Tap Changers
B) Shunt Capacitor Banks
C) Generator Reactive Output
D) All answers are correct - aNSwER-D) All answers are correct
Voltage reduction for load relief should be made on the __________.
A) Distribution system
B) Entire Interconnection simultaneously
C) Tie-lines with other Balancing Authority Areas
D) Transmission System - aNSwER-A) Distribution system
Under Frequency Load Shedding (UFLS) is to stabilize the imbalance between generation and load that
has been created by a system disturbance. This is accomplished by ____________.
A) Tripping generation first
B) Voltage reduction on the distribution system.
C) Shedding all load to arrest frequency
D) Shedding load prior to generation tripping - aNSwER-D) Shedding load prior to generation tripping
Failure to meet the DCS criteria of recovery within 15 minutes results in which consequence for a
specified time period for the Balancing Authority's failure to recover?
A) Increased Contingency Reserve requirements
B) Decertification as a Balancing Authority
, C) Not allowed to supply regulation services
D) Expulsion from the Reserve Sharing Group - aNSwER-A) Increased Contingency Reserve
requirements
A Balancing Authority foresees or is experiencing conditions where all available resources are committed
to meet firm load, and firm transactions. The BA should request which level of the Energy Emergency
Alerts?
A) Energy Emergency Alert Level 2
B) Energy Emergency Alert Level 4
C) Energy Emergency Alert Level 1
D) Energy Emergency Alert Level 3 - aNSwER-C) Energy Emergency Alert Level 1
Preparations are being made to tie two islands together during restoration. Island "A" has a frequency of
58.95 Hz and Island "B" has a frequency of 59.97 Hz. What action should be taken to synchronize the two
islands?
A) Shed load in Island "B"
B) Shed load in Island "A".
C) Disable the Synch Check Relay.
D) Increase generation in Island "B". - aNSwER-B) Shed load in Island "A".
You experience a full system shutdown. You are in the process of restoring load and you are concerned
about re-collapsing the system. Which is the best approach in the restoration process that will help
ensure your system will be restored successfully?
A) Maintain frequency between 59.5 HZ and 60.5 HZ.
B) If the system has stabilized at below 60 HZ, shed 15% - 20% of the load to raise the frequency to 61
HZ.
dEtailEd aNSwERS (VERifiEd aNSwERS) | latESt uPdatE
2026/2027||RaNkEd !!.
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 change your scheduled frequency. Your Frequency Bias
Setting is -100 MW/.1Hz. What action should you take?
A) Increase Net Interchange Schedule by 20 MWs.
B) Inform the Reliability Coordinator that you cannot participate in the time error correction.
C) Decrease Net Interchange Schedule by 20 MWs.
D) Increase Net Interchange Schedule by 10 MWs. - aNSwER-A) Increase Net Interchange Schedule by
20 MWs.
A Balancing Authority has a sudden loss of a large block of load in its area. This loss will be seen
instantaneously in the change of which of the following values?
1. Actual Net Interchange
2. Scheduled Frequency
3. Scheduled Net Interchange
4. Area Control Error
A) 4 only
B) 1 & 3
C) 1 & 4
D) 3 & 4 - aNSwER-C) 1 & 4
,Metered Data included in the calculation of ACE are: dynamic schedules, pseudo ties, actual frequency,
and all __________.
A) Tie lines readings
B) Generators output
C) Scheduled frequency indications
D) Transformer load - aNSwER-A) Tie lines readings
Balancing Authority A is currently reading a system frequency of 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 - aNSwER-A) -100
A Transmission line is loaded 25% above its SOL. A parallel line is out for routine 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)Shed load at the downstream bus.
B) Open the line.
C) Re-Dispatch Generation.
D) Initiate the restoration of the parallel line. - aNSwER-D) Initiate the restoration of the parallel line.
,As a Transmission Operator, you realize that the voltage level is starting to decline in the North West part
of the system. Which of the following devices should you, as a Transmission Operator, be able to
operate, and/or have another entity operate to raise the voltage level back to normal in the North West
part of the system?
A) Transformer Underload Tap Changers
B) Shunt Capacitor Banks
C) Generator Reactive Output
D) All answers are correct - aNSwER-D) All answers are correct
Voltage reduction for load relief should be made on the __________.
A) Distribution system
B) Entire Interconnection simultaneously
C) Tie-lines with other Balancing Authority Areas
D) Transmission System - aNSwER-A) Distribution system
Under Frequency Load Shedding (UFLS) is to stabilize the imbalance between generation and load that
has been created by a system disturbance. This is accomplished by ____________.
A) Tripping generation first
B) Voltage reduction on the distribution system.
C) Shedding all load to arrest frequency
D) Shedding load prior to generation tripping - aNSwER-D) Shedding load prior to generation tripping
Failure to meet the DCS criteria of recovery within 15 minutes results in which consequence for a
specified time period for the Balancing Authority's failure to recover?
A) Increased Contingency Reserve requirements
B) Decertification as a Balancing Authority
, C) Not allowed to supply regulation services
D) Expulsion from the Reserve Sharing Group - aNSwER-A) Increased Contingency Reserve
requirements
A Balancing Authority foresees or is experiencing conditions where all available resources are committed
to meet firm load, and firm transactions. The BA should request which level of the Energy Emergency
Alerts?
A) Energy Emergency Alert Level 2
B) Energy Emergency Alert Level 4
C) Energy Emergency Alert Level 1
D) Energy Emergency Alert Level 3 - aNSwER-C) Energy Emergency Alert Level 1
Preparations are being made to tie two islands together during restoration. Island "A" has a frequency of
58.95 Hz and Island "B" has a frequency of 59.97 Hz. What action should be taken to synchronize the two
islands?
A) Shed load in Island "B"
B) Shed load in Island "A".
C) Disable the Synch Check Relay.
D) Increase generation in Island "B". - aNSwER-B) Shed load in Island "A".
You experience a full system shutdown. You are in the process of restoring load and you are concerned
about re-collapsing the system. Which is the best approach in the restoration process that will help
ensure your system will be restored successfully?
A) Maintain frequency between 59.5 HZ and 60.5 HZ.
B) If the system has stabilized at below 60 HZ, shed 15% - 20% of the load to raise the frequency to 61
HZ.
