Switchgear Protections Electrical Questions Answers - Set 08 - ObjectiveBooks

Switchgear Protections Electrical Questions Answers - Set 08

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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