NERC RC Exam Questions & Answer key
(NIa - NIs) - 10β(fa - fs) - Ime
Calculated every 6 seconds
What is ACE? Uses Tie line Frequency Bias
Largest offset to ACE
What is Tie line deviation?
What is NIA? Net Interchange Actual (sum of all tie-line values)
Net Interchange Scheduled (sum of all interchange
What is NIS? schedules)
What is the multiplier for 10
frequency bias?
Frequency bias - represented as negative number in
ACE calculation - reflects area natural response to
frequency changes (Inertia, Governor, Load) - atleast
1% of annual peak load for areas with native load -
What is β? 1% of peak generation output for area with no load
What is FA? Frequency Actual
Frequency Schedule - normally 60.00 HZ except for
What is FS? time corrections - +/- .02 Hz
Meter error
fudge factor
What is IME? used for inadvertent bilateral payback
Negligible
Contact RC
What should be done if
unable to calculate ACE
for 30 minutes?
Annually
How often should time
error and frequency
devices be
checked/calibrated?
Negative Ace The BA is Undergenerating
Positve ACE The BA is Overgenerating
, NERC RC Exam Questions & Answer key
Frequency and ACE increase.
What happens during
Internal Loss of Load?
Frequency increases, no change in ACE.
What happens during
External Loss of Load?
Monthly average >= 1% of estimated yearly peak
What is the Frequency
Bias Setting? demand per 0.1 Hz
By January 1 of each year
When should the
Balancing Authority
recalculate its Frequency
Bias Setting?
Frequency and ACE drop, tie-line flows increase into
What happens when there the system
is internal generation
loss?
Frequency drops, no change in ACE, net tie-line flows
What happens when there increase out of the system
is external generation
loss?
ACE will be positive causing the AGC to lower
What happens when generation
Frequency bias setting is
lower than frequency
response?
1% - 2% change in load
What is the percentage
change in load required
for a 1% change in
frequency?
Load will reduce by 3%
What is the load reduction
when Transmission
Customer Voltage is
reduced by 5%?
, NERC RC Exam Questions & Answer key
ACE will be a negative value and AGC will increase
generation
What happens to ACE and
AGC when 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?
ACE will be a positive value and AGC will lower
generation
What happens to ACE and
AGC when 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 is the normal 60.00 Hz
schedule frequency?
59.98 Hz
What is the frequency
correction for fast clock
schedule?
60.02 Hz
What is the frequency
corrections for a slow
clock schedule?
When does frequency Generation increases or load decreases
increase?
Generation decreases or load increases
When does frequency
decrease?
Can only be RC
Who is the Time Monitor? one per Interconnection
(NIa - NIs) - 10β(fa - fs) - Ime
Calculated every 6 seconds
What is ACE? Uses Tie line Frequency Bias
Largest offset to ACE
What is Tie line deviation?
What is NIA? Net Interchange Actual (sum of all tie-line values)
Net Interchange Scheduled (sum of all interchange
What is NIS? schedules)
What is the multiplier for 10
frequency bias?
Frequency bias - represented as negative number in
ACE calculation - reflects area natural response to
frequency changes (Inertia, Governor, Load) - atleast
1% of annual peak load for areas with native load -
What is β? 1% of peak generation output for area with no load
What is FA? Frequency Actual
Frequency Schedule - normally 60.00 HZ except for
What is FS? time corrections - +/- .02 Hz
Meter error
fudge factor
What is IME? used for inadvertent bilateral payback
Negligible
Contact RC
What should be done if
unable to calculate ACE
for 30 minutes?
Annually
How often should time
error and frequency
devices be
checked/calibrated?
Negative Ace The BA is Undergenerating
Positve ACE The BA is Overgenerating
, NERC RC Exam Questions & Answer key
Frequency and ACE increase.
What happens during
Internal Loss of Load?
Frequency increases, no change in ACE.
What happens during
External Loss of Load?
Monthly average >= 1% of estimated yearly peak
What is the Frequency
Bias Setting? demand per 0.1 Hz
By January 1 of each year
When should the
Balancing Authority
recalculate its Frequency
Bias Setting?
Frequency and ACE drop, tie-line flows increase into
What happens when there the system
is internal generation
loss?
Frequency drops, no change in ACE, net tie-line flows
What happens when there increase out of the system
is external generation
loss?
ACE will be positive causing the AGC to lower
What happens when generation
Frequency bias setting is
lower than frequency
response?
1% - 2% change in load
What is the percentage
change in load required
for a 1% change in
frequency?
Load will reduce by 3%
What is the load reduction
when Transmission
Customer Voltage is
reduced by 5%?
, NERC RC Exam Questions & Answer key
ACE will be a negative value and AGC will increase
generation
What happens to ACE and
AGC when 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?
ACE will be a positive value and AGC will lower
generation
What happens to ACE and
AGC when 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 is the normal 60.00 Hz
schedule frequency?
59.98 Hz
What is the frequency
correction for fast clock
schedule?
60.02 Hz
What is the frequency
corrections for a slow
clock schedule?
When does frequency Generation increases or load decreases
increase?
Generation decreases or load increases
When does frequency
decrease?
Can only be RC
Who is the Time Monitor? one per Interconnection
