KNOWN NERC EXAM QUESTIONS complete solution
with Questions and Answers 2023
A Balancing Authority notices that Operating Reserve has steadily declined throughout
the hour. What is the most likely cause?
a) Loss of a large generator in the area
b) An inaccurate load forecast
c) Loss of a major transmission line
d) A malfunction of EMS - ANSWER b) An inaccurate load forecast
Balancing Area A notices that the Interconnection frequency is 59.94 Hz and their ACE
is 0. Which of the following could be the cause of this reading?
a) A net under-generation in Balancing Area A
b) A net under-generation in the Interconnection
c) A loss of load in Balancing Area A
d) A loss of load in the Interconnection - ANSWER b) A net under-generation in the
Interconnection
What is the penalty for a Balancing Authority violating the Disturbance Control
Standard?
a) Must carry additional Contingency Reserve
b) Must develop a correction action plan
c) Must re-evaluate and change its Frequency Bias Setting
d) Must increase its Regulating Reserve - ANSWER a) Must carry additional
Contingency Reserve
Your ACE is a large negative value and system frequency is 59.80 Hz. Your AGC
system is pulsing your units down. What should you do?
a) Place AGC in flat frequency control
b) Place AGC in flat tie line control
c) Suspend AGC and investigate
d) Do nothing as this is normal - ANSWER c) Suspend AGC and investigate
When two identical generating units are operated in parallel on governor control, and on
machine has a 5% droop and the other has a 10% droop, the unit with the greater
(10%) governor droop will:
a) Respond less to frequency deviations
b) Respond more to frequency deviations
, c) Respond the same to frequency deviations
d) Not adjust for frequency changes - ANSWER a) Respond less to frequency
deviations
On a radial transmission system a generator has a capacity of 600 MWs. The Droop
characteristic is at 5% and the generator is currently loaded at 300 MWs. If frequency
suddenly drops to 59.3 Hz, what would be the total generator output?
a) 350
b) 400
c) 440
d) 600 - ANSWER c) 440
What is the main purpose of the Frequency Bias Setting in the ACE equation?
a) Control frequency to 60 Hz for the entire Interconnection
b) Assist with arresting frequency deviations
c) Restore frequency to 60 Hz after a disturbance
d) maintains frequency between 59.95 and 60.05 Hz - ANSWER b) Assist with arresting
frequency deviations
A Balancing Authority has a Frequency Bias Setting of -200 MW/.1Hz. What is the
Balancing Authority's Frequency Response for a frequency of 59.95 Hz?
a) 10 MWs
b) 50 MWs
c) 100 MWs
d) 200 MWs - ANSWER c) 100 MWs
Scheduled Interchange is 250 MWs and Actual Interchange is 285 MWs. The Bias
Setting is 35 MW/.1Hz and frequency is 60.00 Hz with no time error correction in effect.
Frequency suddenly drops to 59.80 Hz. What does ACE indicate after the disturbance?
a) 70 MW under-generating
b) 70 MW over-generating
c) 35 MW under-generating
d) 35 MW over-generating - ANSWER d) 35 MW over-generating
Inadvertent energy accumulation occurs due to a difference in Net Actual Interchange
and Net Interchange Schedule over time. This energy accumulation can be paid back
unilaterally by adjusting delivery of power:
a) During off-peak periods
b) During periods corresponding to those in which the inadvertent energy was
accumulated
c) On weekends
with Questions and Answers 2023
A Balancing Authority notices that Operating Reserve has steadily declined throughout
the hour. What is the most likely cause?
a) Loss of a large generator in the area
b) An inaccurate load forecast
c) Loss of a major transmission line
d) A malfunction of EMS - ANSWER b) An inaccurate load forecast
Balancing Area A notices that the Interconnection frequency is 59.94 Hz and their ACE
is 0. Which of the following could be the cause of this reading?
a) A net under-generation in Balancing Area A
b) A net under-generation in the Interconnection
c) A loss of load in Balancing Area A
d) A loss of load in the Interconnection - ANSWER b) A net under-generation in the
Interconnection
What is the penalty for a Balancing Authority violating the Disturbance Control
Standard?
a) Must carry additional Contingency Reserve
b) Must develop a correction action plan
c) Must re-evaluate and change its Frequency Bias Setting
d) Must increase its Regulating Reserve - ANSWER a) Must carry additional
Contingency Reserve
Your ACE is a large negative value and system frequency is 59.80 Hz. Your AGC
system is pulsing your units down. What should you do?
a) Place AGC in flat frequency control
b) Place AGC in flat tie line control
c) Suspend AGC and investigate
d) Do nothing as this is normal - ANSWER c) Suspend AGC and investigate
When two identical generating units are operated in parallel on governor control, and on
machine has a 5% droop and the other has a 10% droop, the unit with the greater
(10%) governor droop will:
a) Respond less to frequency deviations
b) Respond more to frequency deviations
, c) Respond the same to frequency deviations
d) Not adjust for frequency changes - ANSWER a) Respond less to frequency
deviations
On a radial transmission system a generator has a capacity of 600 MWs. The Droop
characteristic is at 5% and the generator is currently loaded at 300 MWs. If frequency
suddenly drops to 59.3 Hz, what would be the total generator output?
a) 350
b) 400
c) 440
d) 600 - ANSWER c) 440
What is the main purpose of the Frequency Bias Setting in the ACE equation?
a) Control frequency to 60 Hz for the entire Interconnection
b) Assist with arresting frequency deviations
c) Restore frequency to 60 Hz after a disturbance
d) maintains frequency between 59.95 and 60.05 Hz - ANSWER b) Assist with arresting
frequency deviations
A Balancing Authority has a Frequency Bias Setting of -200 MW/.1Hz. What is the
Balancing Authority's Frequency Response for a frequency of 59.95 Hz?
a) 10 MWs
b) 50 MWs
c) 100 MWs
d) 200 MWs - ANSWER c) 100 MWs
Scheduled Interchange is 250 MWs and Actual Interchange is 285 MWs. The Bias
Setting is 35 MW/.1Hz and frequency is 60.00 Hz with no time error correction in effect.
Frequency suddenly drops to 59.80 Hz. What does ACE indicate after the disturbance?
a) 70 MW under-generating
b) 70 MW over-generating
c) 35 MW under-generating
d) 35 MW over-generating - ANSWER d) 35 MW over-generating
Inadvertent energy accumulation occurs due to a difference in Net Actual Interchange
and Net Interchange Schedule over time. This energy accumulation can be paid back
unilaterally by adjusting delivery of power:
a) During off-peak periods
b) During periods corresponding to those in which the inadvertent energy was
accumulated
c) On weekends
