Switchgear Protections - Interview Questions | Exam2Win

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81. Air blast circuit breakers for 400 kV power system are designed to operate in

A. 100 micro-second

B. 50 milli-second

C. 0.5 sec

D. 0.1 sec

Explanation:

82. If the fault occurs near the impedance relay, the VII ratio will be

A. constant for all distances

B. lower than that of if fault occurs away from the relay

C. higher than that of if fault occurs away from the relay

D. none of the above

Explanation:

83. The inductive interference between power and communication line can be minimized by

A. transposition of the power line

B. transposition of the communication line

C. both (a) and (b)

D. increasing the distance between the conductors

Explanation:

84. A fuse is never inserted in

A. neutral wire

B. negative of D.C. circuit

C. positive of D.C. circuit

D. phase dine

Explanation:

85. The torque produced in induction type relay (shaded pole structure) is

A. inversely proportional to the current

B. inversely proportional to the square of the current

C. proportional to the current

D. proportional to square of the current

Explanation: