Switchgear protections Archives - Page 2 of 10 - MCQ and Quiz for Exams

11. ________ relay is preferred for phase fault on short transmission line.

Induction type

Reactance

Impedance

None of the above

Detailed Solution________ relay is preferred for phase fault on short transmission line.

12. The information to the circuit breaker under fault conditions is provided by

relay

rewirable fuse

H.R.'only

all of the above

Detailed SolutionThe information to the circuit breaker under fault conditions is provided by

13. A switchgear is device used for

Interrupting an electrical circuit

Switching an electrical circuit

Switching and controlling an electrical circuit

Switching, controlling and protecting the electrical circuit and equipment

Detailed SolutionA switchgear is device used for

14. For which of the following ratings of the transformer differential protection is recommended ?

above 30 kV

equal to and above 5 MVA

equal to and above 25 MVA

none of the above

Detailed SolutionFor which of the following ratings of the transformer differential protection is recommended ?

15. Which of the following is the least expensive protection for overcurrent is low voltage system ?

Rewireable fuse

Isolator

Oil circuit breaker

Air break circuit breaker E. None of the above

Detailed SolutionWhich of the following is the least expensive protection for overcurrent is low voltage system ?

16. The power loss is an important factor for the design of

transmission line

motor

generator

feeder

Detailed SolutionThe power loss is an important factor for the design of

17. The contacts of high voltage switches used in power system are submerged in oil. The main purpose of the oil is to

lubricate the contacts

insulate the contacts from switch body

extinguish the arc

all of the above E. none of the above

Detailed SolutionThe contacts of high voltage switches used in power system are submerged in oil. The main purpose of the oil is to

18. Bus coupler is very essential in arrangement

single bus

double bus, double breaker

main and transfer bus

all of the above

Detailed SolutionBus coupler is very essential in arrangement

19. A fuse in a motor circuit provides protection against

overload

short-circuit and overload

open circuit, short-circuit and overload

none of the above

Detailed SolutionA fuse in a motor circuit provides protection against

20. To protect most of the electrical equipment handling low power, the types of relays used are

Thermocouple

Electronic and bimetallic

Both (A) and (B)

None of the above

Detailed SolutionTo protect most of the electrical equipment handling low power, the types of relays used are

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