KNOWN NERC EXAM QUESTIONS AND ANSWERS
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 - CORRECT 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 - CORRECT 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 - CORRECT 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 - CORRECT 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 - CORRECT 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 - CORRECT 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 - CORRECT ANSWER✅✅b) Assist with arresting
frequency deviations
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 - CORRECT 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 - CORRECT 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 - CORRECT 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 - CORRECT 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 - CORRECT 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 - CORRECT 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 - CORRECT ANSWER✅✅b) Assist with arresting
frequency deviations
