1. IDMT relays are used to protect the power transformers against
(a) external short-circuits.
(b) overloads.
(c) internal short-circuits.
(d) external short-circuits and overloads. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] D [/accordion-item][/accordion]
2. Which of the following relay is used to detect and protect internal fault of a transformer?
(a) Differential relay.
(b) Bucholoz relay.
(c) IDMT relay.
(d) Directional relay. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] B [/accordion-item][/accordion]
3. Which of the following relay is used for the generator phase to phase winding protection?
(a) Differential relay.
(b) Mho relay.
(c) Distance relay.
(d) Voltage balance relay. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] A [/accordion-item][/accordion]
4. Which of the following relay is used for anti-motoring Protection Scheme?
(a) Reactance relay.
(b) Reverse power relay.
(c) Differential relay.
(d) Offset mho relay. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] B [/accordion-item][/accordion]
5. Resistance switching in normally employed in
(a) bulk oil breakers.
(b) minimum oil breakers.
(c) air blast circuit breaker.
(d) SF6 circuit breaker [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] C [/accordion-item][/accordion]
6. In overhead system, the relay used for feeder protection is
(a) under-voltage relay.
(b) IDMT relay.
(c) Translay relay.
(d) thermal relay. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] C [/accordion-item][/accordion]
7. The arc voltage in a circuit breaker is
(a) in the phase with arc current..
(b) lagging the arc current by 90°.
(c) leading the arc current by 90°.
(d) lagging the arc current by 180°. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] A [/accordion-item][/accordion]
8. What is the reactive power in AC operation?
(a) Real power × sinφ.
(b) Apparent power × sinφ.
(c) Real power × cosφ.
(d) Apparent power × cosφ. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] B [/accordion-item][/accordion]
9. The purpose of using series capacitor in a transmission lines is to
(a) reduce inductance.
(b) reduce line losses.
(c) compensate voltage drop.
(d) improve power factor. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] C [/accordion-item][/accordion]
10. Which of the following circuit breaker is design for the least operating voltage?
(a) Vacuum circuit breaker.
(b) Air circuit breaker.
(c) SF6 circuit breaker.
(d) Oil circuit breaker. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] B [/accordion-item][/accordion]
11. Which of the following circuit breaker is design for the highest operating voltage?
(a) Vacuum circuit breaker.
(b) Air blast circuit breaker.
(c) SF6 circuit breaker.
(d) Oil circuit breaker. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] B [/accordion-item][/accordion]
12. Which circuit breaker has high reliability and negligible maintenance?
(a) Air blast circuit breaker.
(b) Oil circuit breaker.
(c) SF6 circuit breaker.
(d) Vacuum circuit breaker. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] C [/accordion-item][/accordion]
13. The rating of a circuit breaker is usually determine on the basis of
(a) symmetrical fault.
(b) unsymmetrical fault.
(c) line to line fault.
(d) internal fault. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] A [/accordion-item][/accordion]
14. Chimney effect occurs in air blast circuit breaker
(a) air blast circuit breaker.
(b) SF6 circuit breaker.
(c) vacuum circuit breaker.
(d) oil circuit breaker. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] A [/accordion-item][/accordion]
15. The arc voltage in an AC circuit breaker is
(a) in phase opposition with the arc current.
(b) in phase with the arc current.
(c) lag arc current by 90°.
(d) lead arc current by 90°. [accordion clicktoclose=true tag=h4][accordion-item title=”Answer” state=closed] B [/accordion-item][/accordion]