SOS NERC
SOS NERC PREP RELIABILITY ACTUAL EXAM 2025
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
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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
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,SOS NERC
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
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, SOS NERC
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?
SOS NERC
SOS NERC PREP RELIABILITY ACTUAL EXAM 2025
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
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,SOS NERC
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
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,SOS NERC
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
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, SOS NERC
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?
SOS NERC
