Switchgear and protection. Part – 2

11. What type of back up protection is used for alternators?

A. IDMT relay

B. Buchholz relay

C. Mho relay

D. Impedance relay

12. Current chopping mainly occurs in

A. Air blast circuit breaker

B. Vacuum circuit breaker

C. SF₆ circuit breaker

D. Oil circuit breaker

13. Peterson coil is used in case of transmission line for

A. Reduce ferranti effect

B. Compensating of arcing grounds

C. Improve power factor

D. Increase the voltage level

14. In routine tests, the cable is tested by applying an ac voltage of

A. 2 times the rated value

B. 2.5 times the rated value

C. 3 times the rated value

D. 3.5 times the rated value

15. What is the actuating quantity for the relays?

A. Magnitude

B. Frequency                     

C. Phase angle

D. All of these

16. Plug setting of a relay can be altered by varying

A. Air gap of magnetic path

B. No. Of ampere-turns

C. Adjustable back up stop

D. None of these

17. For load flow studies, what are the quantities specified at load bus are

A. P and V

B. P and Q

C. V and δ

D. δ and Q

18. The unit protection scheme provides

A. Simultaneous protection

B. Back up protection

C. Remote protection

D. Primary protection

19. For a fault at the terminals of a synchronous generator, the fault current is maximum for

A. Line to line fault

B. Line to ground fault

C. 3 phase to ground fault

D. 3 phase fault

20. A circuit breaker, under normal conditions, should be inspected

A. every day

B. every week

C. every month

D. once in 6 months or 12 months