NERC BGLA1 EXAM | Actual Questions and Answers Latest
Updated 2026/2027 (Graded A+)
•
A radial transmission line is overloaded. Which action must a transmission operator do to unload the
line?.
- ✔✔Shed load at the end of the radial line.Feedback:
•
A radial line carries power in one direction to serve the load demands at the end of that line. When a
radial line is overloaded, the system operator will have to shed load to relieve the overload condition.
•
A Balancing Authority's largest single contingency is a unit rated at 1,000 MW. Which of the following
disturbances would constitute a reportable disturbance for Disturbance Control Performance
evaluation based on the NERC DCS criteria?
i. - ✔✔The loss of a 950 MW generating unit at 100% output.Feedback:
ii. Reportable Disturbance (NERC Glossary) is any event that causes an ACE change greater
than or equal to 80% of a Balancing Authority's or reserve sharing group's most severe
contingency. In this question the 950-MW unit is 95% of the most severe single contingency
and therefore meets the criteria of a DCS.
•
Balancing Authority A has a peak load forecast of 5,000 MW at Hour Ending 1500 hour. Net
Interchange Schedules are -1,500 MW (imports) for Hour Ending 0400 through 2200 hour. 500 MW is
a Firm Schedule Total generation on-line is 7,500 MWs. A thunderstorm trips 3,000 MWs of generation
at 1215 with a minimum resynchronizing time of 3 hours. Generation also trips generation in the
sourcing Balancing Authority which forces the exporting BA to instantly cut a 1,000 MW schedule to
this BA to zero.
- ✔✔Notify the RC that this BA is in an EEA Level 2; start all available generation; schedule
emergency interchange purchases; prepare to reduce firm loadFeedback: Balancing
Authority A expecting a 5,000 MW peak at Hour Ending 1500 hour, when 3,000 MWs of the
7,500 MW of generation trips. That leaves 4,500 MWs of generation and 1,500 MW purchases
to meet the peak demand. When the purchases are cut by 1,000 MW to a new Net of -500
MW. Total of 5,000 MW in generation and firm schedule to meet a forecasted 5,000 MW peak
load. A factor to consider is a 5,000 MW forecast will most likely result in a higher
instantaneous load and that there is NO generation available for reserves. A Balancing
Authority in this situation would be in an Energy Emergency Alert Level 2 and will work with
the Reliability Coordinator to implement mitigating actions, such as, demand side
management.
•
A Balancing Area has separated from the Interconnection during a severe thunder storm and is in a
blackout condition. Several plants tripped off-line including a 200 MW blackstart capable unit and a
blackstart capable hydro plant located 175 miles from the load center connected by a 345 kV system.
What actions should the BA take to restore the area?
, i. - ✔✔Isolate the transmission paths into the power plants, Bring the 200 MW blackstart unit
on line to support the power plants auxiliaries, Add load in 10 MW blocks while increasing
generation, Bring on additional generation.
ii. Feedback: First Isolate the transmission paths requires a System Restoration Procedures.
Clearing (opening) breakers systematically and then closing in a transmission path. Also to
restore the area generation to support plant auxiliary must be provided by starting a
blackstart unit.
•
The hydro plant is not in a load center and is connected by high-voltage lines 175 miles away.
Energizing a 345 kV transmission lines will require the hydro plant to absorb a tremendous amount of
reactive (capacitance) power due to the Ferranti effect of the lines. It may not be possible to keep the
voltage below 380 kV under no-load conditions. Therefore the best unit to start is the 200 MW unit at
the appropriate generation value to balance any auxiliary loads.
•
In an island, what is the most appropriate AGC mode of operation?
- ✔✔Constant or Flat FrequencyNormally, the Tie Line Bias control mode, which compares
the Net Actual Interchange to the Net Scheduled Interchange plus the Balancing Authority's
frequency bias obligation, should be used. However, if a Balancing Authority is operating
asynchronously (separated from the Interconnection), it should switch to Flat Frequency
Control since its tie lines are no longer connected to the Interconnection. It is important for
the Balancing Authority to maintain 60 Hz. In the Flat Frequency control mode, ACE is
looking only at the system frequency, not the Interchange portion of the ACE equation.
•
Which of the following is Which of the following is considered to be a reliability event?
1) Low voltage
2) Loss of a small generator
3) SOL or IROL exceeded
4) Loss of Energy Management System
- ✔✔Reliability event is referred to as an event that affects or may potentially affect the
reliability of the Bulk Electric System, such as loss of generation, transmission or load or
violations or potential violations of operating limits.
•
Once a deficient Balancing Authority informs the Reliability Coordinator of future or current Capacity
and Energy Emergencies, it is the responsibility of the __________________ to mitigate the emergency
condition?
i. - ✔✔Deficient Balancing AuthorityAttachment 1 EOP-011, Energy Emergency Alerts
ii. The responsibilities for BAs and RCs are in attachment 1 to EOP-011. The RCs main
responsibility is to notify other entities of the deficiency situation. The Balancing Authority
still has responsibility of ensuring reliability by taking actions up to, and including shedding
firm load (EEA3).
•
When shall the Transmission Operator and Balancing Authority review and update its operating plan
for backup functionality?
Updated 2026/2027 (Graded A+)
•
A radial transmission line is overloaded. Which action must a transmission operator do to unload the
line?.
- ✔✔Shed load at the end of the radial line.Feedback:
•
A radial line carries power in one direction to serve the load demands at the end of that line. When a
radial line is overloaded, the system operator will have to shed load to relieve the overload condition.
•
A Balancing Authority's largest single contingency is a unit rated at 1,000 MW. Which of the following
disturbances would constitute a reportable disturbance for Disturbance Control Performance
evaluation based on the NERC DCS criteria?
i. - ✔✔The loss of a 950 MW generating unit at 100% output.Feedback:
ii. Reportable Disturbance (NERC Glossary) is any event that causes an ACE change greater
than or equal to 80% of a Balancing Authority's or reserve sharing group's most severe
contingency. In this question the 950-MW unit is 95% of the most severe single contingency
and therefore meets the criteria of a DCS.
•
Balancing Authority A has a peak load forecast of 5,000 MW at Hour Ending 1500 hour. Net
Interchange Schedules are -1,500 MW (imports) for Hour Ending 0400 through 2200 hour. 500 MW is
a Firm Schedule Total generation on-line is 7,500 MWs. A thunderstorm trips 3,000 MWs of generation
at 1215 with a minimum resynchronizing time of 3 hours. Generation also trips generation in the
sourcing Balancing Authority which forces the exporting BA to instantly cut a 1,000 MW schedule to
this BA to zero.
- ✔✔Notify the RC that this BA is in an EEA Level 2; start all available generation; schedule
emergency interchange purchases; prepare to reduce firm loadFeedback: Balancing
Authority A expecting a 5,000 MW peak at Hour Ending 1500 hour, when 3,000 MWs of the
7,500 MW of generation trips. That leaves 4,500 MWs of generation and 1,500 MW purchases
to meet the peak demand. When the purchases are cut by 1,000 MW to a new Net of -500
MW. Total of 5,000 MW in generation and firm schedule to meet a forecasted 5,000 MW peak
load. A factor to consider is a 5,000 MW forecast will most likely result in a higher
instantaneous load and that there is NO generation available for reserves. A Balancing
Authority in this situation would be in an Energy Emergency Alert Level 2 and will work with
the Reliability Coordinator to implement mitigating actions, such as, demand side
management.
•
A Balancing Area has separated from the Interconnection during a severe thunder storm and is in a
blackout condition. Several plants tripped off-line including a 200 MW blackstart capable unit and a
blackstart capable hydro plant located 175 miles from the load center connected by a 345 kV system.
What actions should the BA take to restore the area?
, i. - ✔✔Isolate the transmission paths into the power plants, Bring the 200 MW blackstart unit
on line to support the power plants auxiliaries, Add load in 10 MW blocks while increasing
generation, Bring on additional generation.
ii. Feedback: First Isolate the transmission paths requires a System Restoration Procedures.
Clearing (opening) breakers systematically and then closing in a transmission path. Also to
restore the area generation to support plant auxiliary must be provided by starting a
blackstart unit.
•
The hydro plant is not in a load center and is connected by high-voltage lines 175 miles away.
Energizing a 345 kV transmission lines will require the hydro plant to absorb a tremendous amount of
reactive (capacitance) power due to the Ferranti effect of the lines. It may not be possible to keep the
voltage below 380 kV under no-load conditions. Therefore the best unit to start is the 200 MW unit at
the appropriate generation value to balance any auxiliary loads.
•
In an island, what is the most appropriate AGC mode of operation?
- ✔✔Constant or Flat FrequencyNormally, the Tie Line Bias control mode, which compares
the Net Actual Interchange to the Net Scheduled Interchange plus the Balancing Authority's
frequency bias obligation, should be used. However, if a Balancing Authority is operating
asynchronously (separated from the Interconnection), it should switch to Flat Frequency
Control since its tie lines are no longer connected to the Interconnection. It is important for
the Balancing Authority to maintain 60 Hz. In the Flat Frequency control mode, ACE is
looking only at the system frequency, not the Interchange portion of the ACE equation.
•
Which of the following is Which of the following is considered to be a reliability event?
1) Low voltage
2) Loss of a small generator
3) SOL or IROL exceeded
4) Loss of Energy Management System
- ✔✔Reliability event is referred to as an event that affects or may potentially affect the
reliability of the Bulk Electric System, such as loss of generation, transmission or load or
violations or potential violations of operating limits.
•
Once a deficient Balancing Authority informs the Reliability Coordinator of future or current Capacity
and Energy Emergencies, it is the responsibility of the __________________ to mitigate the emergency
condition?
i. - ✔✔Deficient Balancing AuthorityAttachment 1 EOP-011, Energy Emergency Alerts
ii. The responsibilities for BAs and RCs are in attachment 1 to EOP-011. The RCs main
responsibility is to notify other entities of the deficiency situation. The Balancing Authority
still has responsibility of ensuring reliability by taking actions up to, and including shedding
firm load (EEA3).
•
When shall the Transmission Operator and Balancing Authority review and update its operating plan
for backup functionality?
