Practice Test: Question Set - 08
1. A switchgear is device used for
- (A) Interrupting an electrical circuit
- (B) Switching an electrical circuit 111
- (C) Switching and controlling an electrical circuit
- (D) Switching, controlling and protecting the
electrical circuit and equipment
2. Which of the following medium is employed for extinction of arc in air circuit breaker?
- (A) Water
- (B) Oil
- (C) Air
- (D) SF6
3. Circuit breakers usually operate under
- (A) Transient state of short-circuit current
- (B) Sub-transient state of short-circuit current
- (C) Steady state of short-circuit current
- (D) After D.C. component has ceased
4. In a circuit breaker the basic problem is to
- (A) Maintain the arc
- (B) Extinguish the arc
- (C) Transmit large power
- (D) Emit the ionizing electrons
5. The line insulation is the insulation level of the station equipment.
- (A) Less than
- (B) Same as
- (C) More than
- (D) Not directly related with
6. 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
7. _________ transmission line has reflection coefficient as one.
- (A) Open circuit
- (B) Short-circuit
- (C) Long
- (D) None of the above
8. The fuse blows off by
- (A) Burning
- (B) Arcing
- (C) Melting
- (D) None of the above
9. To limit short-circuit current in a power system are used.
- (A) Earth wires
- (B) Isolators
- (C) H.R.C. fuses
- (D) Reactors
10. 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
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