ELECTRICAL ENGINEERING MCQ_08

Q.131 Transposition of transmission line is done to
A. reduce skin effect
B. reduce line loss
C. reduce corona
D. balance line voltage drop
Ans.: D

Q.132 Rated making capacity of a circuit breaker is equal to
A. √2 x rated symmetrical breaking capacity
B. 1.11 x rated symmetrical breaking capacity
C. 2.55 x rated symmetrical breaking capacity
D. rated symmetrical braking capacity
Ans.: C

Q.133 The bus bar zone faults are generally
A. phase to phase faults
B. double line to ground faults
C. single line to ground faults
D. three phase short circuits
Ans.: C

Q.134 The main criterion for the design of a distributor is
A. voltage drop
B. corona loss
C. temperature rise
D. radio interference
Ans.: A

Q.135 An over excited synchronous motor draws current at
A. lagging power factor
B. unity power factor
C. leading power factor
D. depends on nature of load
Ans.: C

Q.136 In the protection of transformers, harmonic restraint is used to guard against
A. magnetizing inrush current
B. switching over voltage
C. unbalanced protection
D. lighting
Ans.: A

Q.137 If a relay fails to operate inspite of a fault in it own zone of protection, it is said to
A. over reach
B. under reach
C. reach
D. pick up
Ans.: B

Q.138 Which if the following correctly represents sequence of operation if isolator, circuit breaker and earthing switch while opening a circuit?
A. close earthing switch-open circuit breaker – open isolator
B. close circuit breaker- close isolator-open earthing switch
C. open isolator-close circuit breaker- open earthing switch
D. open circuit breaker-open isolator-close earthign switch
Ans.: D

Q.139 For fast load flow calculations, the best method is
A. Gauss-Siedal
B. Newton-Raphson
B. De-coupled method
D. Approximate method
Ans.: B

Q.140 Which of the following power distribution system gives better reliability?
A. Ring main system
B. radial system
C. D.C 3-wire system
D. none of the above
Ans.: A

Q.141 Which lighting stroke is most dangerous?
A. direct stroke on tower top
B. direct stroke on ground wire
C. direct stroke on lien conductor
D. indirect stroke on conductor
Ans.: C

Q.142 Which type of back up protection is widely used for protection of transmission lines?
A. relay back up
B. remote backup
C. control backup
D. breaker backup
Ans.: B

Q.143 A fuse wire should have
A. low specific resistance and high melting point
B. low specific resistance and low melting point
C. high specific resistance and high melting point
D. high specific resistance and low melting point
Ans.: D

Q.144 Buchholz relay causes
A. tripping for major faults and alarm for minor faults
B. tripping for minor faults and alarm fir major faults
C. Tripping for both major and minor faults
D. alarm for both major and minor faults
Ans.: A
Q.145 In carrier current protection, the purpose of the wave trap is for
A. trapping power frequency
B. trapping high frequency waves entering in to generator/ transformer unit
C. trapping fault current
D. all of the above
Ans.: B

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