NERC System Operator Exam Preparation (SOS/HSI) | Actual
Questions and Answers Latest Updated 2026/2027 (Graded A+)
•
Power equation
- ✔✔P=IV; power (watts)=current (amps) x voltage (volts)
•
Power equation three phase
- ✔✔Power=Voltage (v) x Current (I) x 1.73 x Power Factor (PF)
•
If operating reserve gradually decreases throughout the hour, it's because ___.
- ✔✔Incorrect load forecast
•
Operating reserves are made up of ___ and ___.
- ✔✔Regulating Reserves and Contingency Reserve
•
What type of reserves are used for AGC?
- ✔✔Regulating
•
A BA's MSSC is usually its ___.
- ✔✔Largest Generator
•
Equation to determine speed in RPM of a Generator?
- ✔✔7200/# of poles
•
At what frequency will a generator trip on underfrequency?
- ✔✔57.5 Hz
•
Why do we have underfrequency tripping?
- ✔✔Protect turbines from damage
•
Why does frequency drop faster/is harder to correct, when we have a disturbance when we have
increased wind generation?
- ✔✔Less inertia/governor response to correct frequency
•
Frequency above 60 Hz means ___.
,- ✔✔Overgenerating
•
Frequency below 60 Hz means ___.
- ✔✔Undergenerating
•
Frequency decrease is usually caused by ___.
- ✔✔Loss of generation
•
A 1% drop in frequency results in ___.
- ✔✔2% drop in total load; 3% drop in motor load
•
Formula for ACE?
- ✔✔NIa-NIs -10B(Fa-Fs)
•
Governor response is based on its ___ characteristic.
- ✔✔Droop
•
5% of 60 Hz=
- ✔✔3 Hz; most Governor's have 5% droop characteristic
•
Droop setting is the % required for a generator to run at ___ capacity.
- ✔✔Full
•
What is the purpose of a governor deadband?
- ✔✔Minimize wear on equipment
•
What % for governor deadband?
- ✔✔+/- .036 Hz
•
An isochrynous generator setting has ___ droop.
- ✔✔0%
•
When are isochryonous generators used?
- ✔✔one unit, during islanding
, •
Is 10% droop or 5% droop more responsive?
- ✔✔5%
•
On a classic disturbance chart, what brings frequency from point c to d?
- ✔✔Contingency Reserve
•
On a classic disturbance chart, what causes a 'step' change?
- ✔✔Fast-start generator
•
What's the primary response to frequency drop?
- ✔✔Governor response
•
Examples of asynchronous generation?
- ✔✔Solar, wind
•
What happens to load with increased behind-the-meter generation?
- ✔✔Peaks later in the day; duck curve
•
MWs flowing into a BA are - or +?
- ✔✔Negative
•
If you lose a 500 MW generator in your BA, your ACE ___.
- ✔✔Decreases by 500 MW
•
What part of the ACE equation is always negative?
- ✔✔Frequency Bias
•
CPS1 says BA has to be ___ for 12 month period, which is evaluated ___.
- ✔✔≥100%, monthly
•
BAAL is a long-term measurement of ___.
- ✔✔ACE
•
BAAL says Reporting ACE can't exceed the BA's BAAL for more than ___ consecutive minutes.
- ✔✔30
Questions and Answers Latest Updated 2026/2027 (Graded A+)
•
Power equation
- ✔✔P=IV; power (watts)=current (amps) x voltage (volts)
•
Power equation three phase
- ✔✔Power=Voltage (v) x Current (I) x 1.73 x Power Factor (PF)
•
If operating reserve gradually decreases throughout the hour, it's because ___.
- ✔✔Incorrect load forecast
•
Operating reserves are made up of ___ and ___.
- ✔✔Regulating Reserves and Contingency Reserve
•
What type of reserves are used for AGC?
- ✔✔Regulating
•
A BA's MSSC is usually its ___.
- ✔✔Largest Generator
•
Equation to determine speed in RPM of a Generator?
- ✔✔7200/# of poles
•
At what frequency will a generator trip on underfrequency?
- ✔✔57.5 Hz
•
Why do we have underfrequency tripping?
- ✔✔Protect turbines from damage
•
Why does frequency drop faster/is harder to correct, when we have a disturbance when we have
increased wind generation?
- ✔✔Less inertia/governor response to correct frequency
•
Frequency above 60 Hz means ___.
,- ✔✔Overgenerating
•
Frequency below 60 Hz means ___.
- ✔✔Undergenerating
•
Frequency decrease is usually caused by ___.
- ✔✔Loss of generation
•
A 1% drop in frequency results in ___.
- ✔✔2% drop in total load; 3% drop in motor load
•
Formula for ACE?
- ✔✔NIa-NIs -10B(Fa-Fs)
•
Governor response is based on its ___ characteristic.
- ✔✔Droop
•
5% of 60 Hz=
- ✔✔3 Hz; most Governor's have 5% droop characteristic
•
Droop setting is the % required for a generator to run at ___ capacity.
- ✔✔Full
•
What is the purpose of a governor deadband?
- ✔✔Minimize wear on equipment
•
What % for governor deadband?
- ✔✔+/- .036 Hz
•
An isochrynous generator setting has ___ droop.
- ✔✔0%
•
When are isochryonous generators used?
- ✔✔one unit, during islanding
, •
Is 10% droop or 5% droop more responsive?
- ✔✔5%
•
On a classic disturbance chart, what brings frequency from point c to d?
- ✔✔Contingency Reserve
•
On a classic disturbance chart, what causes a 'step' change?
- ✔✔Fast-start generator
•
What's the primary response to frequency drop?
- ✔✔Governor response
•
Examples of asynchronous generation?
- ✔✔Solar, wind
•
What happens to load with increased behind-the-meter generation?
- ✔✔Peaks later in the day; duck curve
•
MWs flowing into a BA are - or +?
- ✔✔Negative
•
If you lose a 500 MW generator in your BA, your ACE ___.
- ✔✔Decreases by 500 MW
•
What part of the ACE equation is always negative?
- ✔✔Frequency Bias
•
CPS1 says BA has to be ___ for 12 month period, which is evaluated ___.
- ✔✔≥100%, monthly
•
BAAL is a long-term measurement of ___.
- ✔✔ACE
•
BAAL says Reporting ACE can't exceed the BA's BAAL for more than ___ consecutive minutes.
- ✔✔30
