Switchgear protections

21. D.C. shunt relays are made of

few turns of thin wire
few turns of thick wire
shunt relays are made of A. few turns of thin wire B. few turns of thick wire C. many turns of thin wire
many turns of thick wire

Detailed SolutionD.C. shunt relays are made of

22. Ungrounded neutral transmission system is not recommended because of system

insulation being overstressed due to over voltages
insulation overstress may lead to failure and subsequent phase to phase faults
being inadequately protected against ground fault
all of the above

Detailed SolutionUngrounded neutral transmission system is not recommended because of system

23. When a wave propagates on a transmission line, it suffers reflection several times at

tapping
load end
sending end
sending and other end E. all of the above

Detailed SolutionWhen a wave propagates on a transmission line, it suffers reflection several times at

24. Series capacitors are used to

compensate for line inductive reactance
compensate for line capacitive reactance
improve line voltage
none of the above

Detailed SolutionSeries capacitors are used to

25. Admittance relay is _______ relay.

impedance
directional
non-directional
none of the above

Detailed SolutionAdmittance relay is _______ relay.

26. Resistance grounding is used for voltage between

33kV to 66kV
22kV to 33kV
3.3kV and 11kV
none of the above

Detailed SolutionResistance grounding is used for voltage between

27. A _______ is used to measure the stator % winding temperature of the generator.

thermocouple
pyrometer
resistance thermometer
thermometer

Detailed SolutionA _______ is used to measure the stator % winding temperature of the generator.

28. The relay operating speed depends upon

the spring tension
the rate of flux built up
armature core air gap
all of the above

Detailed SolutionThe relay operating speed depends upon

29. Which of the following medium is employed for extinction of arc in air circuit breaker ?

Water
Oil
Air
SF6

Detailed SolutionWhich of the following medium is employed for extinction of arc in air circuit breaker ?

30. In a single bus-bar system there will be complete shut down when

fault occurs on the bus itself
fault occurs on neutral line
two or more faults occur simultaneously
fault occurs with respect to earthing

Detailed SolutionIn a single bus-bar system there will be complete shut down when

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