NERC Practice Exam Questions – Power Systems Operator
Certification Prep
1. A transmission line is operating with a voltage phase The phase angle will in-
angle different of 30 degrees between the sending Vs crease. When load is in-
and the receiving bus Vr. If the receiving end load is creased phase angle will
suddenly increased, the voltage phase angle differ- increase.
ence will be?
2. A load has a power factor of 0.9 lagging. If the load 90 pf= mw/mva
draws 100 MVA, what is the MW draw?
3. The high side of a delta-wye connection transformer is Vl-l= square root of 3 times
connected to a power system with 199 kV L-G high side Vl-g 1.73x191= 345kV
voltage. What is the voltage across the delta winding
of the transformer?
4. If a transmission line is carrying 400 MW and 300 3-4-5 triangle 500 MVA
MVAR what is the MVA?
5. The prime mover is the component of the generator Turbine
that creates the rotational force. In a typical coal fired
steam generator what component spins the rotor?
6. Reactive reserve response during a disturbance is Synchronous condensers
best obtained from which devise?
7. For two identically constructed transmission lines A produces more reactive
where Line A is 150 miles long and line B is 15 miles power than B.
long, if both lines are lightly loaded?
8. Lightly loaded transmission lines essentially behave Shunt Capacitors
like?
9. You receive an alarm that indicates low oil pressure Isolate the line
on an underground transmission cable. SCADA shows
, NERC Practice Exam Questions
the pressure is continuing to drop. What is the first
step you take to protect the line?
10. Computer simulations show that for a 100 MW sched- 63%
ule from Bus A to Bus B, 63% of the schedule will flow
on the scheduled path and the remainder will flow on
other parallel paths. What is the distribution factor for
the scheduled path?
11. Which statement best describes how reactive power High Voltage to Low Volt-
MVAR power normally flows? age
12. Which of the following types of data are BA and RC not Generator start up cost
required to share with one another?
13. TOP must develop, maintain, and implement formal Planned outages of gen-
policies and procedures to provide for transmission eration units
reliability. Which of the following DOES NOT need to
be addressed in these policies and procedures?
14. A 1000 MVA rated generator that produces 800 MW Operating in a lagging
and 100 MVAR is best described as? mode. Inductive system
15. Which of the following types of MW load is the most Motor
impacted by an intentional frequency reduction?
16. Assume there are two 250 mile long transmission lines Angle Instability
exporting an excessive amount of MW from a gener-
ation area to a load area. One of the lines suddenly
trips and the area power system collapses within a few
seconds. The most likely cause of the collapse?
17. The phase voltage in a wye-connected load is 277 V. 480 V
What is the line to line voltage?
, NERC Practice Exam Questions
18. A simple power system is composed of three lines 300 MW and No
connecting generation to load. Each lines the same
impedance, is initially loaded at 200 MW, and has a
thermal limit of 400 MW. If one line trips, what the
loading on the shortest remaining line be and will the
thermal limit either remaining line be violated?
19. The best prediction of system load is the load forecast Forecasted Weather
tool that uses?
20. If the phase angel at an open breaker is equal to 1/10 1/10 of 360 so 36
of a cycle, this is the the same angle as?
21. A ___________ tool is used to ensure the power system Contingency Analysis
can respond within acceptable limits of N-1
22. Which of the following activities would not be included Ancillary service pricing
in the procedures for transmission reliability?
23. The transmission Operator and BA shall provide doc- Proper NERC Certification
umentation that operating personnel have ______ to Credential
implement real time actions to ensure the stable and
reliable operation of the BES.
24. A utility distribution bus has the following customer 20 mw and Inductive
loads attached. What is the total customer MW load
and is the total customer load capacitive or inductive?
5 MW 1 MVAR & 3 MW 1 MVAR & 2 MW -2 MVAR & 10
MW 3 MVAR
25. How many MVARs does a 230 kV, 50 MVAR capacitor Actual MW/ Rated MW ^2
bank provide when the voltage id 207 kV x Capacitor Rating
40
, NERC Practice Exam Questions
26. You are a system operator and the load forecast is for 735 kV shunt reactor
an all time summer peak load day, generations and maintenance.
reactive resources will be tight. Which scheduled job
would you allow to proceed?
27. A contingency results in the exceedance of an IROL. Interruption of power to a
What could be the result if the IROL is allowed to be large part of the BES
exceeded longer than T sub v
28. Generators have the ability to be used as voltage con- Increase
trol devices. If a generator raises its VAR output, the
system orator should expect system stage to?
29. The actual voltage is 362kV on a 345 bus. What is the 1.05
p.u. voltage?
30. In the initial stages of a system restoration condition Because of excessive
high transmission system voltage problems are more MVAR supply from the en-
likely than low transmission system voltage problems ergization of transmission
why? lines
31. All transmission operators shall operate so that insta- Most severe single contin-
bility uncontrolled separation or cascading outages gency MSSC
will not occur in result of?
32. A 230kV transmission line is energized at 230kV and is 30MVAR
100 miles long. What is the approximate line charging
contribution?
33. When the system is on the verge of a voltage collapse Shed Load
and nothing else can be done to alleviate the problem,
operating personnel should?
Certification Prep
1. A transmission line is operating with a voltage phase The phase angle will in-
angle different of 30 degrees between the sending Vs crease. When load is in-
and the receiving bus Vr. If the receiving end load is creased phase angle will
suddenly increased, the voltage phase angle differ- increase.
ence will be?
2. A load has a power factor of 0.9 lagging. If the load 90 pf= mw/mva
draws 100 MVA, what is the MW draw?
3. The high side of a delta-wye connection transformer is Vl-l= square root of 3 times
connected to a power system with 199 kV L-G high side Vl-g 1.73x191= 345kV
voltage. What is the voltage across the delta winding
of the transformer?
4. If a transmission line is carrying 400 MW and 300 3-4-5 triangle 500 MVA
MVAR what is the MVA?
5. The prime mover is the component of the generator Turbine
that creates the rotational force. In a typical coal fired
steam generator what component spins the rotor?
6. Reactive reserve response during a disturbance is Synchronous condensers
best obtained from which devise?
7. For two identically constructed transmission lines A produces more reactive
where Line A is 150 miles long and line B is 15 miles power than B.
long, if both lines are lightly loaded?
8. Lightly loaded transmission lines essentially behave Shunt Capacitors
like?
9. You receive an alarm that indicates low oil pressure Isolate the line
on an underground transmission cable. SCADA shows
, NERC Practice Exam Questions
the pressure is continuing to drop. What is the first
step you take to protect the line?
10. Computer simulations show that for a 100 MW sched- 63%
ule from Bus A to Bus B, 63% of the schedule will flow
on the scheduled path and the remainder will flow on
other parallel paths. What is the distribution factor for
the scheduled path?
11. Which statement best describes how reactive power High Voltage to Low Volt-
MVAR power normally flows? age
12. Which of the following types of data are BA and RC not Generator start up cost
required to share with one another?
13. TOP must develop, maintain, and implement formal Planned outages of gen-
policies and procedures to provide for transmission eration units
reliability. Which of the following DOES NOT need to
be addressed in these policies and procedures?
14. A 1000 MVA rated generator that produces 800 MW Operating in a lagging
and 100 MVAR is best described as? mode. Inductive system
15. Which of the following types of MW load is the most Motor
impacted by an intentional frequency reduction?
16. Assume there are two 250 mile long transmission lines Angle Instability
exporting an excessive amount of MW from a gener-
ation area to a load area. One of the lines suddenly
trips and the area power system collapses within a few
seconds. The most likely cause of the collapse?
17. The phase voltage in a wye-connected load is 277 V. 480 V
What is the line to line voltage?
, NERC Practice Exam Questions
18. A simple power system is composed of three lines 300 MW and No
connecting generation to load. Each lines the same
impedance, is initially loaded at 200 MW, and has a
thermal limit of 400 MW. If one line trips, what the
loading on the shortest remaining line be and will the
thermal limit either remaining line be violated?
19. The best prediction of system load is the load forecast Forecasted Weather
tool that uses?
20. If the phase angel at an open breaker is equal to 1/10 1/10 of 360 so 36
of a cycle, this is the the same angle as?
21. A ___________ tool is used to ensure the power system Contingency Analysis
can respond within acceptable limits of N-1
22. Which of the following activities would not be included Ancillary service pricing
in the procedures for transmission reliability?
23. The transmission Operator and BA shall provide doc- Proper NERC Certification
umentation that operating personnel have ______ to Credential
implement real time actions to ensure the stable and
reliable operation of the BES.
24. A utility distribution bus has the following customer 20 mw and Inductive
loads attached. What is the total customer MW load
and is the total customer load capacitive or inductive?
5 MW 1 MVAR & 3 MW 1 MVAR & 2 MW -2 MVAR & 10
MW 3 MVAR
25. How many MVARs does a 230 kV, 50 MVAR capacitor Actual MW/ Rated MW ^2
bank provide when the voltage id 207 kV x Capacitor Rating
40
, NERC Practice Exam Questions
26. You are a system operator and the load forecast is for 735 kV shunt reactor
an all time summer peak load day, generations and maintenance.
reactive resources will be tight. Which scheduled job
would you allow to proceed?
27. A contingency results in the exceedance of an IROL. Interruption of power to a
What could be the result if the IROL is allowed to be large part of the BES
exceeded longer than T sub v
28. Generators have the ability to be used as voltage con- Increase
trol devices. If a generator raises its VAR output, the
system orator should expect system stage to?
29. The actual voltage is 362kV on a 345 bus. What is the 1.05
p.u. voltage?
30. In the initial stages of a system restoration condition Because of excessive
high transmission system voltage problems are more MVAR supply from the en-
likely than low transmission system voltage problems ergization of transmission
why? lines
31. All transmission operators shall operate so that insta- Most severe single contin-
bility uncontrolled separation or cascading outages gency MSSC
will not occur in result of?
32. A 230kV transmission line is energized at 230kV and is 30MVAR
100 miles long. What is the approximate line charging
contribution?
33. When the system is on the verge of a voltage collapse Shed Load
and nothing else can be done to alleviate the problem,
operating personnel should?
