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Free download in PDF Switchgear and Protection Multiple Choice Questions with Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams. These short solved questions or quizzes are provided by Gkseries.
61
A.C. network analyser is used to solve problems of
[A]
load flow
[B]
load flow and short-circuit
[C]
load flow and stability
[D]
load flow, short-circuit and stability
Answer: load flow, short-circuit and stability
62
Short-circuit currents are due to
[A]
single phase to ground faults
[B]
phase to phase faults
[C]
two phase to ground faults
[D]
any of these
63
The short circuit in any winding of the transformer is the result of
[A]
mechanical vibration
[B]
insulation failure
[C]
loose connection
[D]
impulse voltage
64
For which of the following protection from negative sequence currents is provided ?
[A]
Generators
[B]
Motors
[C]
Transmission line
[D]
Transformers
65
Relay is preferred for phase fault on short transmission line.
[A]
Induction type
[B]
Reactance
[C]
Impedance
[D]
None Of The Above
66
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
Answer: equal to and above 5 MVA
67
The under voltage relay can be used for
[A]
generators
[B]
busbars
[C]
transformers
[D]
all of the above
68
The single phasing relays are used for the protection of
[A]
single phase motors only
[B]
two phase motors only
[C]
two single phase motors running in parallel
[D]
three phase motors
Answer: three phase motors
69
Which of the following parameter can be neglected for a short line ?
[A]
Inductance
[B]
Capacitance
[C]
Resistance
[D]
All Of The Above
70
Which of the following circuit breakers has high reliability and minimum maintenance ?
[A]
Air blast circuit breakers
[B]
Circuit breaker with SF6 gas
[C]
Vacuum circuit breakers
[D]
Oil circuit breakers
Answer: Circuit breaker with SF6 gas
71
Transmission line has reflection coefficient as one.
[A]
Open circuit
[B]
Short-circuit
[C]
Long
[D]
None of the above
72
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
Answer: internal short-circuits
73
Air blast circuit breakers for 400 kV power system are designed to operate in
[A]
100 microsecond
[B]
50 millisecond
[C]
0.5 sec
[D]
0.1 sec
74
Series capacitors are used to
[A]
compensate for line inductive reactance
[B]
compensate for line capacitive reactance
[C]
improve line voltage
[D]
None Of The Above
Answer: compensate for line inductive reactance
75
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
Answer: lower than that of if fault occurs away from the relay
76
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]
all of the above
Answer: inversely proportional to the square of the current
77
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
78
The power loss is an important factor for the design of
[A]
transmission line
[B]
motor
[C]
generator
[D]
feeder
Answer: transmission line
79
H.R.C. fuse, as compared to a rewirable fuse, has
[A]
no ageing effect
[B]
high speed of operation
[C]
high rupturing capacity
[D]
all of the above
80
The fuse rating is expressed in terms of
[A]
current
[B]
voltage
[C]
VAR
[D]
kVA
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