NERC Prep Test 2 Questions with
Complete Solutions
A transaction of 100 MWs is scheduled out of your area at the top of the hour with a 10-minute
ramp. You have the following generation available: What combination of generation would need
to be used?
Generator Capacity Current MWs Ramp Capability
1 100 MW 50 MW 5 MW/min
2 100 MW 40 MW 3 MW/min
3 100 MW 50 MW 1 MW/min
4 100 MW 60 MW 2 MW/min - ANSWERS-Generators 1, 2, 4
The Balancing Authority selling power to an end user entered the wrong schedule for the
upcoming hour. Which part of the ACE equation [ACE = (NIA - NIS) - 10B (FA - FS) - IME], will
cause Inadvertent Interchange to occur as the result of the incorrect schedule? - ANSWERS-Both
the Interchange portion and frequency portion of the Ace Equation will contribute
What is the most common cause of frequency fluctuations? - ANSWERS-System generation and
load imbalance
A Balancing Authority's inadvertent accumulation reflects over-generation during on-peak
hours. When system load is decreasing, what actions could a Balancing Authority system
operator take to limit additional on peak inadvertent accumulation? - ANSWERS-Decrease
transactions into their system
Decrease generation
, Balancing Authority A is currently reading a system frequency of 59.98 Hz. Its Net Actual
Interchange is +100 MW and its Net Scheduled Interchange is +100 MW. If Balancing Authority
A's frequency bias setting is 100 MW/0.1 HZ, what is ACE? - ANSWERS--20
Governor droop is expressed as: - ANSWERS-A percentage of the frequency change required for
a governor to move a unit from no load to full load, or full load to no load
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? - ANSWERS-The ACE will be positive value and AGC will
lower generation
Which of the following combinations would represent the best generation control performance
(in terms of helping the Interconnection's frequency) by a Balancing Area? - ANSWERS-ACE is
positive while frequency is below 60
If a Balancing Authority has an ACE of -175 MW and Frequency is 59.85 Hz. Which real-time
Control Performance Standard maybe outside of its low limit? - ANSWERS-BAAL
For the ACE equation to work properly, dynamic schedules, pseudo ties, frequency, and all
________________ must be metered. - ANSWERS-Tie lines
Balancing Authority A is scheduled to import 300 MW but is only importing 260 MW.
Interconnection frequency is 59.94 and Balancing Authority A's Frequency Bias Setting is -120
MW/0.1 Hz. What is Balancing Authority A's ACE reading? - ANSWERS--32 MW
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? - ANSWERS-25 MWs in
Complete Solutions
A transaction of 100 MWs is scheduled out of your area at the top of the hour with a 10-minute
ramp. You have the following generation available: What combination of generation would need
to be used?
Generator Capacity Current MWs Ramp Capability
1 100 MW 50 MW 5 MW/min
2 100 MW 40 MW 3 MW/min
3 100 MW 50 MW 1 MW/min
4 100 MW 60 MW 2 MW/min - ANSWERS-Generators 1, 2, 4
The Balancing Authority selling power to an end user entered the wrong schedule for the
upcoming hour. Which part of the ACE equation [ACE = (NIA - NIS) - 10B (FA - FS) - IME], will
cause Inadvertent Interchange to occur as the result of the incorrect schedule? - ANSWERS-Both
the Interchange portion and frequency portion of the Ace Equation will contribute
What is the most common cause of frequency fluctuations? - ANSWERS-System generation and
load imbalance
A Balancing Authority's inadvertent accumulation reflects over-generation during on-peak
hours. When system load is decreasing, what actions could a Balancing Authority system
operator take to limit additional on peak inadvertent accumulation? - ANSWERS-Decrease
transactions into their system
Decrease generation
, Balancing Authority A is currently reading a system frequency of 59.98 Hz. Its Net Actual
Interchange is +100 MW and its Net Scheduled Interchange is +100 MW. If Balancing Authority
A's frequency bias setting is 100 MW/0.1 HZ, what is ACE? - ANSWERS--20
Governor droop is expressed as: - ANSWERS-A percentage of the frequency change required for
a governor to move a unit from no load to full load, or full load to no load
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? - ANSWERS-The ACE will be positive value and AGC will
lower generation
Which of the following combinations would represent the best generation control performance
(in terms of helping the Interconnection's frequency) by a Balancing Area? - ANSWERS-ACE is
positive while frequency is below 60
If a Balancing Authority has an ACE of -175 MW and Frequency is 59.85 Hz. Which real-time
Control Performance Standard maybe outside of its low limit? - ANSWERS-BAAL
For the ACE equation to work properly, dynamic schedules, pseudo ties, frequency, and all
________________ must be metered. - ANSWERS-Tie lines
Balancing Authority A is scheduled to import 300 MW but is only importing 260 MW.
Interconnection frequency is 59.94 and Balancing Authority A's Frequency Bias Setting is -120
MW/0.1 Hz. What is Balancing Authority A's ACE reading? - ANSWERS--32 MW
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? - ANSWERS-25 MWs in
