EPRI MAIN EXAMINATION 2026 SET QUESTIONS AND ANSWERS GRADED

EPRI MAIN EXAMINATION 2026 SET QUESTIONS AND
ANSWERS GRADED A+
✔✔Given a purely inductive load, what can be said about the MVA this load
draws from the power system?
A. The load draws only MW
B. The load draws only Mvar
C. The load magnitude cannot exceed 100 MVA
D. The load magnitude cannot exceed 1000 MVA - ✔✔B. The load draws only Mvar

✔✔A generator with spare Mvar is always a source of dynamic reactive
reserve.
A. True
B. False - ✔✔B. False

✔✔The nominal load is:
A. Equal to the rated load
B. Dependent on the actual voltage and frequency
C. Dependent on the scheduled voltage and frequency
D. Equal to the actual load - ✔✔A. Equal to the rated load

✔✔A period of voltage instability always results in a voltage collapse.
A. True
B. False - ✔✔B. False

✔✔The critical voltage and critical MW transfer are located at the:
A. Knee of the V-Q curve
B. Knee of the P-V curve
C. Origin of the V-Q curve
D. Origin of the P-V curve - ✔✔B. Knee of the P-V curve

✔✔During voltage instability prone conditions, tap changing to support
secondary voltage should generally NOT be used if the secondary load is
formed by:
A. Induction motors
B. Motor type load
C. Nominal load
D. Non-motor type load - ✔✔D. Non-motor type load

✔✔P-V curves indicate the __________ margin from voltage instability while
V-Q curves indicate the __________ margin from voltage instability.
A. Mvar / MW
B. MW/ Mvar
C. MW / current

, D. Power / Mvar - ✔✔B. MW/ Mvar

✔✔UVLS differs from UFLS in that:
A. The tripping frequencies are different
B. The tap changing points are different
C. UVLS is based on voltage while UFLS is based on frequency
D. UVLS is based on frequency while UFLS is based on voltage - ✔✔C. UVLS is based
on voltage while UFLS is based on frequency

✔✔In which type of voltage instability does a key element outage trigger the
voltage instability?
A. Oscillation Voltage Instability
B. Classical Voltage Instability
C. Transient Voltage Instability
D. Long Term Voltage Instability - ✔✔B. Classical Voltage Instability

✔✔A P-V curve relates:
A. The Mvar transferred across a system to the voltage at the
receiving end of the system
B. The MW transferred across a system to the voltage at the receiving
end of the system
C. The MW transferred across a system to the voltage at the sending
end of the system
D. The Mvar transferred across a system to the voltage at the sending
end of the system - ✔✔B. The MW transferred across a system to the voltage at the
receiving

✔✔In a radial power system, the addition of shunt capacitors at the receiving
end of the system tends to:
A. Decrease the curvature of the P-V curve
B. Flatten the P-V curve and increase the critical voltage
C. Increase the curvature of the P-V curve
D. Flatten the P-V curve and decrease the critical voltage - ✔✔B. Flatten the P-V curve
and increase the critical voltage

✔✔In which type of voltage instability does a simultaneous stalling of large
amounts of induction motor load trigger the voltage instability?
A. Oscillation Voltage Instability
B. Classical Voltage Instability
C. Transient Voltage Instability
D. Long Term Voltage Instability - ✔✔C. Transient Voltage Instability

✔✔The loss of the magnetic bonds that bind together the elements of a power
system is known as:
A. Angle stability