204. Air blast circuit breakers are preferred for
A. short duty
B. intermittent duty
C. repeated duty
D. none of these
205. The power factor of the arc in a circuit breaker is
A. zero leading
B. zero lagging
C. unity
D. any value from zero to unity
206. For a 400 kV system, the capacity of lightning arrester should be
A. 1 kA
B. 5 kA
C. 10 kA
D. 50 kA
207. A high speed circuit breaker can complete its operation in
A. 2 to 3 cycles
B. 3 to 8 cycles
C. 6 to 12 cycles
D. 10 to 20 cycles
208. Which of following are the desirable qualities of protective relays?
A. speed sensitivity
B. stability,. Reliability
C. selectivity, adequacy
D. none of these
209. Basic quantity measured in a distance relay is
A. impedance
B. voltage difference
C. current difference
D. none of these
210. Drop out to cutoff ratio for most relays is of the order of
A. 0.2 to 0.3
B. 0.3 to 0.4
C. 0.4 to 0.6
D. 0.6 to 1.0
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