Multiple Choice Questions on Power Systems - 6

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Important Multiple Choice Questions On Power Systems


1.       Plug-setting of a relay can be altered by varying
A)     Number of ampere-turns
B)      Air gap of magnetic path
C)      Adjustable back up stop
D)     None of these
2.       If the time of operation of a relay for unity TMS is 10 sec, the time of operation of 0.5 TMS will be
A)     20 Sec
B)      5 Sec
C)      10 Sec
D)     None of these
3.       Where the voltages are high and current to be interrupted is low, the breaker proffered is
A)     Air blast CB
B)      Oil CB
C)      Vacuum CB
D)     Any of these
4.       Resistance switching is normally employed in
A)     All breakers
B)      Bulk oil breakers
C)      Minimum oil breakers
D)     Air blast circuit breakers
5.       For protection of rotating machines against lightning surges a combination of
A)     Lighting conductor and capacitors are used
B)      Lighting conductor and lighting arrestors are used
C)      Lighting arrestors and capacitors are used
D)     Lighting arrestors alone is used
6.       The rate of rise of  restricting voltage depends upon the
A)     Type of circuit breaker
B)      Inductance of the system only
C)      Capacitance of the system only
D)     Inductance and capacitance of the system
7.       The insulation of modern EHV lines is designed based on
A)     The lighting voltage
B)      The switching voltage
C)      Corona
D)     RI
8.       A large-size alternator is protected against over loads by providing
A)     Over current relays
B)      Temperature sensitive relays
C)      Thermal relays
D)     A combination of (A) and (B)
9.       The most suitable circuit breaker for short line fault without switching resistor is
A)     Air blast circuit breaker
B)      Minimum oil circuit breaker
C)      Sulphur hexafluoride circuit breaker
D)     None of these
10.   The capacitor switching is easily done with
A)     Air blast circuit breaker
B)      Oil circuit breaker
C)      Vacuum circuit breaker

D)     Any one of these

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