SOS NERC PREP - RELIABILITY EXAM LATEST 2024-2025
ACTUAL EXAM 200 QUESTIONS AND CORRECT DETAILED
ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED A+
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 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 - 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 - 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 - 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. - 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 - 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. - 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
A Balancing Authority has a normal load of around 8500 MW. Its most severe single contingency is a
700-MW coal-fired steam unit. At 0810 the ACE value was at -55 MW when a 600-MW generator in the
Balancing Authority's northern area tripped off line as the result of a generator differential. This resulted
in a large negative ACE for the Balancing Authority. What value must the ACE return to and in what time
frame to avoid a DCS violation?
A) -55 MW ACE in 10 minutes
B) Zero ACE in 15 minutes
C) -55 MW ACE in 15 minutes
D) This did not constitute a reportable disturbance. - ANSWER-C) -55 MW ACE in 15 minutes
A Balancing Authority is performing Overlap Regulation Service for another Balancing Authority. Which
of the following statements applies to the Balancing Authority providing this service?
A) The Balancing Authority shall use the larger of the two Frequency Bias Settings in its ACE equation.
B) The Balancing Authority's Frequency Bias Setting shall be modified to reflect the combined Frequency
Bias Setting of both Balancing Areas.
C) The Balancing Authority shall not adjust its Frequency Bias Setting, but instead import the other
Balancing Authorities ACE reading.
D) The Balancing authority shall use the average of the two Frequency Bias Settings in its ACE equation. -
ANSWER-B) The Balancing Authority's Frequency Bias Setting shall be modified to reflect the
combined Frequency Bias Setting of both Balancing Areas.
In a capacity deficiency situation, which actions should be considered if time permits prior to Firm Load
Shed?
ACTUAL EXAM 200 QUESTIONS AND CORRECT DETAILED
ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED A+
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 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 - 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 - 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 - 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. - 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 - 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. - 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
A Balancing Authority has a normal load of around 8500 MW. Its most severe single contingency is a
700-MW coal-fired steam unit. At 0810 the ACE value was at -55 MW when a 600-MW generator in the
Balancing Authority's northern area tripped off line as the result of a generator differential. This resulted
in a large negative ACE for the Balancing Authority. What value must the ACE return to and in what time
frame to avoid a DCS violation?
A) -55 MW ACE in 10 minutes
B) Zero ACE in 15 minutes
C) -55 MW ACE in 15 minutes
D) This did not constitute a reportable disturbance. - ANSWER-C) -55 MW ACE in 15 minutes
A Balancing Authority is performing Overlap Regulation Service for another Balancing Authority. Which
of the following statements applies to the Balancing Authority providing this service?
A) The Balancing Authority shall use the larger of the two Frequency Bias Settings in its ACE equation.
B) The Balancing Authority's Frequency Bias Setting shall be modified to reflect the combined Frequency
Bias Setting of both Balancing Areas.
C) The Balancing Authority shall not adjust its Frequency Bias Setting, but instead import the other
Balancing Authorities ACE reading.
D) The Balancing authority shall use the average of the two Frequency Bias Settings in its ACE equation. -
ANSWER-B) The Balancing Authority's Frequency Bias Setting shall be modified to reflect the
combined Frequency Bias Setting of both Balancing Areas.
In a capacity deficiency situation, which actions should be considered if time permits prior to Firm Load
Shed?
