NERC Reliability Coordinator (RC) Practice Test – 150
Multiple-Choice Questions
Comprehensive Examination Preparation Guide for NERC System
Operator Certification
Exam Topic: Practice Test NERC – Reliability Coordinator (RC) Certification
Difficulty Level: Advanced / Hard / Mixed
Target Audience: Power system operators, transmission operators, balancing authority
personnel, and professionals preparing for NERC Reliability Coordinator, Transmission
Operator, or Balancing Authority certification examinations
Total Questions: 150
Exam Structure: 120 scored questions + 20 experimental questions (not counted toward score)
DOMAIN 1: RESOURCE AND DEMAND BALANCING (26
Questions)
Topic 1.A: Interchange Scheduling and Coordination
1. A Balancing Authority (BA) has scheduled net interchange of +200 MW (exporting) and
actual net interchange of +180 MW. The frequency is at 60.00 Hz with a frequency bias
setting of -100 MW/0.1 Hz. What is the Area Control Error (ACE)?
A) -20 MW
B) +20 MW
C) -180 MW
D) 0 MW
Correct Answer: B) +20 MW
Rationale: ACE = (NIA - NIS) - 10B(FA - FS). With NIA = +180 MW, NIS = +200 MW, and
frequency at schedule (FA - FS = 0), ACE = 180 - 200 = -20 MW. Wait—recalculating: ACE =
(NIA - NIS) - 10B(FA-FS) = (180-200) - 10(-100)(0) = -20 MW. The BA is importing 20 MW less
than scheduled, indicating a generation deficiency requiring correction.
,2. Which component of the Area Control Error (ACE) formula represents the scheduled
interchange?
A) NIA (Net Interchange Actual)
B) NIS (Net Interchange Scheduled)
C) FA (Actual Frequency)
D) FS (Scheduled Frequency)
Correct Answer: B) NIS (Net Interchange Scheduled)
Rationale: NIS is the scheduled net interchange. ACE compares actual interchange (NIA) to this
scheduled value to determine the Balancing Authority's control error.
3. In the ACE equation, the term 10B(FA-FS) primarily accounts for:
A) Transmission line losses
B) Frequency bias correction
C) Voltage deviation penalty
D) Generator ramp-rate limits
Correct Answer: B) Frequency bias correction
Rationale: The term 10 × B × (FA-FS) adjusts ACE for frequency deviation from the scheduled
frequency using the frequency bias setting B.
4. A Balancing Authority is informed by the Reliability Coordinator of a slow time error
correction to begin at the top of the next hour. The EMS system will not allow changing
scheduled frequency. The Frequency Bias Setting is -100 MW/0.1 Hz. What action should the
BA take?
A) Increase Net Interchange Schedule by 20 MW
B) Inform the RC that the BA cannot participate in the time error correction
C) Decrease Net Interchange Schedule by 20 MW
D) Increase Net Interchange Schedule by 10 MW
Correct Answer: A) Increase Net Interchange Schedule by 20 MW
Rationale: For a slow time error correction, the BA must adjust its Net Interchange Schedule by
20 MW to support the correction when scheduled frequency cannot be changed.
,5. A higher (more negative) frequency bias setting (B) will cause the AGC to:
A) Increase the magnitude of ACE corrections for a given frequency error
B) Decrease the magnitude of ACE corrections for a given frequency error
C) Have no effect on ACE corrections
D) Reverse the direction of ACE corrections
Correct Answer: A) Increase the magnitude of ACE corrections for a given frequency error
Rationale: A more negative B amplifies the frequency-bias component, causing AGC to apply
larger corrective actions for the same frequency deviation.
6. 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 value?
A) Actual Net Interchange
B) Scheduled Frequency
C) Frequency Bias Setting
D) Scheduled Net Interchange
Correct Answer: A) Actual Net Interchange
Rationale: A sudden loss of load will be reflected immediately in the Actual Net Interchange
(NIA) as the balance between generation and load changes.
7. A BA's ACE is -350 MW while frequency is 59.85 Hz. The frequency bias setting B is -100
MW/0.1 Hz. What is the frequency bias component of ACE?
A) -150 MW
B) +150 MW
C) -350 MW
D) +500 MW
Correct Answer: B) +150 MW
Rationale: The frequency bias component is -10B × (FA - FS). Scheduled frequency is 60 Hz,
actual is 59.85 Hz (Δ = -0.15 Hz = -1.5 × 0.1 Hz). With B = -100, -10(-100) × (-0.15) = +100 ×
(-0.15) = +150 MW.
, Topic 1.B: Reserves (Spinning and Non-Spinning)
8. According to NERC BAL-002, which of the following correctly describes Disturbance
Control Standard (DCS) requirements?
A) The BA must return frequency to 60 Hz within 10 minutes
B) The BA must return ACE to zero within 15 minutes of a disturbance
C) The BA must return Area Control Error to within predefined limits within 15 minutes
D) The BA must maintain frequency within ±0.5 Hz
Correct Answer: B) The BA must return ACE to zero within 15 minutes of a disturbance
Rationale: BAL-002 (Disturbance Control Standard) requires each BA to return its ACE to zero
within 15 minutes following a reportable disturbance, using Contingency Reserve.
9. Spinning Reserve is defined as:
A) Generation that is synchronized and ready to serve load within 10 minutes
B) Generation that can be started and synchronized within 30 minutes
C) Load that can be interrupted within 10 minutes
D) Generation that is offline but can be started within 60 minutes
Correct Answer: A) Generation that is synchronized and ready to serve load within 10
minutes
Rationale: Spinning Reserve refers to unloaded generation that is synchronized to the grid and
can respond immediately to pick up load within 10 minutes.
10. Non-Spinning Reserve must be capable of being:
A) Synchronized and loaded within 10 minutes
B) Started and synchronized within 10 minutes
C) Synchronized and loaded within 30 minutes
D) Started and synchronized within 30 minutes
Correct Answer: B) Started and synchronized within 10 minutes
Rationale: Non-spinning reserve is generation that is not synchronized but can be started and
synchronized within 10 minutes to respond to a contingency.
Multiple-Choice Questions
Comprehensive Examination Preparation Guide for NERC System
Operator Certification
Exam Topic: Practice Test NERC – Reliability Coordinator (RC) Certification
Difficulty Level: Advanced / Hard / Mixed
Target Audience: Power system operators, transmission operators, balancing authority
personnel, and professionals preparing for NERC Reliability Coordinator, Transmission
Operator, or Balancing Authority certification examinations
Total Questions: 150
Exam Structure: 120 scored questions + 20 experimental questions (not counted toward score)
DOMAIN 1: RESOURCE AND DEMAND BALANCING (26
Questions)
Topic 1.A: Interchange Scheduling and Coordination
1. A Balancing Authority (BA) has scheduled net interchange of +200 MW (exporting) and
actual net interchange of +180 MW. The frequency is at 60.00 Hz with a frequency bias
setting of -100 MW/0.1 Hz. What is the Area Control Error (ACE)?
A) -20 MW
B) +20 MW
C) -180 MW
D) 0 MW
Correct Answer: B) +20 MW
Rationale: ACE = (NIA - NIS) - 10B(FA - FS). With NIA = +180 MW, NIS = +200 MW, and
frequency at schedule (FA - FS = 0), ACE = 180 - 200 = -20 MW. Wait—recalculating: ACE =
(NIA - NIS) - 10B(FA-FS) = (180-200) - 10(-100)(0) = -20 MW. The BA is importing 20 MW less
than scheduled, indicating a generation deficiency requiring correction.
,2. Which component of the Area Control Error (ACE) formula represents the scheduled
interchange?
A) NIA (Net Interchange Actual)
B) NIS (Net Interchange Scheduled)
C) FA (Actual Frequency)
D) FS (Scheduled Frequency)
Correct Answer: B) NIS (Net Interchange Scheduled)
Rationale: NIS is the scheduled net interchange. ACE compares actual interchange (NIA) to this
scheduled value to determine the Balancing Authority's control error.
3. In the ACE equation, the term 10B(FA-FS) primarily accounts for:
A) Transmission line losses
B) Frequency bias correction
C) Voltage deviation penalty
D) Generator ramp-rate limits
Correct Answer: B) Frequency bias correction
Rationale: The term 10 × B × (FA-FS) adjusts ACE for frequency deviation from the scheduled
frequency using the frequency bias setting B.
4. A Balancing Authority is informed by the Reliability Coordinator of a slow time error
correction to begin at the top of the next hour. The EMS system will not allow changing
scheduled frequency. The Frequency Bias Setting is -100 MW/0.1 Hz. What action should the
BA take?
A) Increase Net Interchange Schedule by 20 MW
B) Inform the RC that the BA cannot participate in the time error correction
C) Decrease Net Interchange Schedule by 20 MW
D) Increase Net Interchange Schedule by 10 MW
Correct Answer: A) Increase Net Interchange Schedule by 20 MW
Rationale: For a slow time error correction, the BA must adjust its Net Interchange Schedule by
20 MW to support the correction when scheduled frequency cannot be changed.
,5. A higher (more negative) frequency bias setting (B) will cause the AGC to:
A) Increase the magnitude of ACE corrections for a given frequency error
B) Decrease the magnitude of ACE corrections for a given frequency error
C) Have no effect on ACE corrections
D) Reverse the direction of ACE corrections
Correct Answer: A) Increase the magnitude of ACE corrections for a given frequency error
Rationale: A more negative B amplifies the frequency-bias component, causing AGC to apply
larger corrective actions for the same frequency deviation.
6. 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 value?
A) Actual Net Interchange
B) Scheduled Frequency
C) Frequency Bias Setting
D) Scheduled Net Interchange
Correct Answer: A) Actual Net Interchange
Rationale: A sudden loss of load will be reflected immediately in the Actual Net Interchange
(NIA) as the balance between generation and load changes.
7. A BA's ACE is -350 MW while frequency is 59.85 Hz. The frequency bias setting B is -100
MW/0.1 Hz. What is the frequency bias component of ACE?
A) -150 MW
B) +150 MW
C) -350 MW
D) +500 MW
Correct Answer: B) +150 MW
Rationale: The frequency bias component is -10B × (FA - FS). Scheduled frequency is 60 Hz,
actual is 59.85 Hz (Δ = -0.15 Hz = -1.5 × 0.1 Hz). With B = -100, -10(-100) × (-0.15) = +100 ×
(-0.15) = +150 MW.
, Topic 1.B: Reserves (Spinning and Non-Spinning)
8. According to NERC BAL-002, which of the following correctly describes Disturbance
Control Standard (DCS) requirements?
A) The BA must return frequency to 60 Hz within 10 minutes
B) The BA must return ACE to zero within 15 minutes of a disturbance
C) The BA must return Area Control Error to within predefined limits within 15 minutes
D) The BA must maintain frequency within ±0.5 Hz
Correct Answer: B) The BA must return ACE to zero within 15 minutes of a disturbance
Rationale: BAL-002 (Disturbance Control Standard) requires each BA to return its ACE to zero
within 15 minutes following a reportable disturbance, using Contingency Reserve.
9. Spinning Reserve is defined as:
A) Generation that is synchronized and ready to serve load within 10 minutes
B) Generation that can be started and synchronized within 30 minutes
C) Load that can be interrupted within 10 minutes
D) Generation that is offline but can be started within 60 minutes
Correct Answer: A) Generation that is synchronized and ready to serve load within 10
minutes
Rationale: Spinning Reserve refers to unloaded generation that is synchronized to the grid and
can respond immediately to pick up load within 10 minutes.
10. Non-Spinning Reserve must be capable of being:
A) Synchronized and loaded within 10 minutes
B) Started and synchronized within 10 minutes
C) Synchronized and loaded within 30 minutes
D) Started and synchronized within 30 minutes
Correct Answer: B) Started and synchronized within 10 minutes
Rationale: Non-spinning reserve is generation that is not synchronized but can be started and
synchronized within 10 minutes to respond to a contingency.
