Top 250+ Solved Testing and Commissioning of Electrical Equipment’s MCQ Questions Answer
Q. For which of the following ratings of the transformer differential protection is recommended ?
a. above 30 kVA.
b. equal to and above 5 MVA
c. equal to and above 25 MVA
d. none of the above
Q. A _______ is used to measure the stator % winding temperature of the generator.
a. thermocouple
b. pyrometer
c. resistance thermometer
d. thermometer
Q. The relay with inverse time characteristic will operate within
a. 1.5 sec
b. 5 to 10 sec
c. 5 to 20 sec
d. 20 to 30 sec
Q. The single phasing relays are used for the protection of
a. single phase motors only
b. two phase motors only
c. two single phase motors running in parallel
d. three phase motors
Q. Which of the following devices will receive voltage surge first travelling on thetransmission line ?
a. Lightning arresters
b. Relays
c. Step-down transformer
d. Switchgear
Q. Which of the following parameter can be neglected for a short line ?
a. Inductance
b. Capacitance
c. Resistance
d. Reactance
Q. Series reactors should have
a. low resistance
b. high resistance
c. low impedance
d. high impedance
Q. Which of the following circuit breakers has high reliability and minimummaintenance ?
a. Air blast circuit breakers
b. Circuit breaker with SF6 gas
c. Vacuum circuit breakers
d. Oil circuit breakers
Q. Arc in a circuit breaker is interrupted at
a. zero current
b. maximum current
c. minimum voltage
d. maximum voltage
Q. transmission line has reflection coefficient as one.
a. Open circuit
b. Short-circuit
c. Long
d. None of the above
Q. What will be the reflection co-efficient of the wave of load connected to transmission line if surge impedance of the line is equal to load ?
a. Zero
b. Unity
c. Infinity
d. None of the above
Q. The inverse definite mean time relays are used for over current and earth fault protection of transformer against
a. heavy loads
b. internal short-circuits
c. external short-circuits
d. all of the above
Q. Over voltage protection is recommended for
a. hydro-electric generators
b. steam turbine generators
c. gas turbine generators
d. all of the above
Q. Air blast circuit breakers for 400 kV power system are designed to operate in
a. 100 microsecond
b. 50 millisecond
c. 0.5 sec
d. 0.1 sec
Q. Overfluxing protection is recommended for
a. distribution transformer
b. generator transformer of the power plant
c. auto-transformer of the power plant
d. station transformer of the power plant