SOS NERC Prep - RElIABILITY Exam
questions and answers 2025\2026
A+Grade
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.
- correct 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
- correct 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
- correct 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
- correct answer A) -100
A Balancing Authority has a Net Interchange Schedule of -250 MWs from 1200 to 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) 6 MWs out
B) 25 MWs in
C) 25 MWs out
D) 6 MWs in
- correct answer B) 25 MWs in
,For the ACE equation to work properly, dynamic schedules, pseudo ties, frequency, and all
________________ must be metered.
A) Generation
B) Communications
C) Transformers
D) Tie lines
- correct answer D) Tie lines
If the frequency bias setting is set to a less negative value than the frequency response of a Balancing
Authority and a frequency increase is caused by a sudden loss of load in an external balancing area,
what will be the result?
A) The ACE will be zero and will take no AGC action
B) The ACE will be a negative value and AGC will increase generation
C) The ACE will be a positive value and AGC will lower generation
D)This will not affect the ACE
- correct answer B) The ACE will be a negative value and AGC will increase generation
If the frequency bias setting is less negative than the frequency response of a 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) The ACE will be a negative value and AGC will increase generation.
B) This will not affect the ACE.
, C) The ACE will be a positive value and AGC will lower generation.
D) The ACE will be zero and will take no AGC action.
- correct answer C) The ACE will be a positive value and AGC will lower generation.
It is the responsibility of which entity/entities to develop, maintain, and implement load shedding plans?
A) Transmission Operators and Balancing Authorities
B) Reliability Coordinator
C) Load Serving Entities
D) Balancing Authority
- correct answer A) Transmission Operators and Balancing Authorities
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.
- correct 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
questions and answers 2025\2026
A+Grade
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.
- correct 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
- correct 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
- correct 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
- correct answer A) -100
A Balancing Authority has a Net Interchange Schedule of -250 MWs from 1200 to 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) 6 MWs out
B) 25 MWs in
C) 25 MWs out
D) 6 MWs in
- correct answer B) 25 MWs in
,For the ACE equation to work properly, dynamic schedules, pseudo ties, frequency, and all
________________ must be metered.
A) Generation
B) Communications
C) Transformers
D) Tie lines
- correct answer D) Tie lines
If the frequency bias setting is set to a less negative value than the frequency response of a Balancing
Authority and a frequency increase is caused by a sudden loss of load in an external balancing area,
what will be the result?
A) The ACE will be zero and will take no AGC action
B) The ACE will be a negative value and AGC will increase generation
C) The ACE will be a positive value and AGC will lower generation
D)This will not affect the ACE
- correct answer B) The ACE will be a negative value and AGC will increase generation
If the frequency bias setting is less negative than the frequency response of a 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) The ACE will be a negative value and AGC will increase generation.
B) This will not affect the ACE.
, C) The ACE will be a positive value and AGC will lower generation.
D) The ACE will be zero and will take no AGC action.
- correct answer C) The ACE will be a positive value and AGC will lower generation.
It is the responsibility of which entity/entities to develop, maintain, and implement load shedding plans?
A) Transmission Operators and Balancing Authorities
B) Reliability Coordinator
C) Load Serving Entities
D) Balancing Authority
- correct answer A) Transmission Operators and Balancing Authorities
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.
- correct 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
