Practice Test NERC Questions And Answers 2024
A transmission line is operating with a voltage phase angle different of 30 degrees between the sending
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Vs and the receiving bus Vr. If the receiving end load is suddenly increased, the voltage phase angle
difference will be? - ANSWER-The phase angle will increase. When load is increased phase angle will
increase.
A load has a power factor of 0.9 lagging. If the load draws 100 MVA, what is the MW draw? - ANSWER90 pf= mw/mva
The high side of a delta-wye connection transformer is connected to a power system with 199 kV L-G
high side voltage. What is the voltage across the delta winding of the transformer? - ANSWER-Vl-l=
square root of 3 times Vl-g 1.73x191= 345kV
If a transmission line is carrying 400 MW and 300 MVAR what is the MVA? - ANSWER-3-4-5 triangle 500
MVA
The prime mover is the component of the generator that creates the rotational force. In a typical coal
fired steam generator what component spins the rotor? - ANSWER-Turbine
Reactive reserve response during a disturbance is best obtained from which devise? - ANSWERSynchronous condensers
For two identically constructed transmission lines where Line A is 150 miles long and line B is 15 miles
long, if both lines are lightly loaded? - ANSWER-A produces more reactive power than B.
Lightly loaded transmission lines essentially behave like? - ANSWER-Shunt Capacitors
You receive an alarm that indicates low oil pressure on an underground transmission cable. SCADA
shows the pressure is continuing to drop. What is the first step you take to protect the line? - ANSWERIsolate the line
Computer simulations show that for a 100 MW schedule 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? - ANSWER-63%
Which statement best describes how reactive power MVAR power normally flows? - ANSWER-High
Voltage to Low Voltage
Which of the following types of data are BA and RC not required to share with one another? - ANSWERGenerator start up cost
TOP must develop, maintain, and implement formal policies and procedures to provide for transmission
reliability. Which of the following DOES NOT need to be addressed in these policies and procedures? -
ANSWER-Planned outages of generation units
A 1000 MVA rated generator that produces 800 MW and 100 MVAR is best described as? - ANSWEROperating in a lagging mode. Inductive system
Which of the following types of MW load is the most impacted by an intentional frequency reduction? -
ANSWER-Motor
Assume there are two 250 mile long transmission lines exporting an excessive amount of MW from a
generation 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? - ANSWER-Angle Instability
The phase voltage in a wye-connected load is 277 V. What is the line to line voltage? - ANSWER-480 V
A simple power system is composed of three lines 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? -
ANSWER-300 MW and No
The best prediction of system load is the load forecast tool that uses? - ANSWER-Forecasted Weather
If the phase angel at an open breaker is equal to 1/10 of a cycle, this is the the same angle as? -
ANSWER-1/10 of 360 so 36
A ___________ tool is used to ensure the power system can respond within acceptable limits of N-1 -
ANSWER-Contingency Analysis [Show Less]