Download PDF
Free download in PDF Switchgear and Protection Short Questions and 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.
41
The main function of a fuse is to
[A]
protect the line
[B]
open the circuit
[C]
protect the appliance
[D]
prevent excessive currents
Answer: prevent excessive currents
42
Arc in a circuit behaves as
[A]
a capacitive reactance
[B]
an inductive reactance
[C]
a resistance increasing with voltage rise across the arc
[D]
a resistance decreasing with voltage rise across the arc
Answer: a resistance decreasing with voltage rise across the arc
43
The time of closing the cycle, in modern circuit breakers is
[A]
0.003 sec
[B]
0.001 sec
[C]
0.01 sec
[D]
0.10 sec
44
Wave trap is used to trap waves of
[A]
power frequencies
[B]
higher frequencies entering generator or transformer units
[C]
either of the above
[D]
none of the above
Answer: higher frequencies entering generator or transformer units
45
Bus coupler is very essential in arrangement
[A]
single bus
[B]
double bus, double breaker
[C]
main and transfer bus
[D]
None Of The Above
Answer: main and transfer bus
46
The relay with inverse time characteristic will operate within
[A]
1.5 sec
[B]
5 to 10 sec
[C]
5 to 20 sec
[D]
20 to 30 sec
47
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
48
In a circuit breaker the basic problem is to
[A]
maintain the arc
[B]
extinguish the arc
[C]
transmit large power
[D]
emit the ionizing electrons
Answer: transmit large power
49
Interruption of large currents by relay requires
[A]
arc suppressing blow out coils
[B]
wide separation of the opened contacts
[C]
high speed opening of contacts
[D]
All Of The Above
50
Overheating of relay contacts or contact born out is due to
[A]
slow making and breaking of load circuit contacts
[B]
foreign matter on the contact surface
[C]
too low contact pressure
[D]
all of the above
51
The arc voltage produced in A.C. circuit breaker is always
[A]
in phase with the arc current
[B]
lagging the arc current by 90″
[C]
leading the arc current by 90°
[D]
None of the above
Answer: in phase with the arc current
52
Insulation resistance of high voltage circuit breakers is more than
[A]
1 mega ohms
[B]
10 mega ohms
[C]
100 mega ohms
[D]
500 mega ohms
53
H.R.C. fuses provide best protection against
[A]
overload
[B]
reverse current
[C]
open-circuits
[D]
short-circuits
54
The delay fuses are used for the protection of ________ .
[A]
motors
[B]
power outlet circuits
[C]
fluorescent lamps
[D]
None Of The Above
55
Resistance grounding is used for voltage between
[A]
33kVto66kV
[B]
HkVto33kV
[C]
3.3kVandllkV
[D]
none of the above
56
Wave trap is used to trap waves of
[A]
power frequencies
[B]
higher frequencies entering generator or transformer units
[C]
either of the above
[D]
all of the above
Answer: higher frequencies entering generator or transformer units
57
Ungrounded neutral transmission system is not recommended because of system
[A]
insulation being overstressed due to over voltages
[B]
insulation overstress may lead to failure and subsequent phase to phase faults
[C]
being inadequately protected against ground fault
[D]
all of the above
58
For the protection of power station buildings against direct strokes the requirements are
[A]
interception
[B]
interception and conduction
[C]
interception, conduction and dissipation
[D]
interception, conduction, dissipation and reflection
Answer: interception, conduction and dissipation
59
The interaction between a transmission line and communication line is minimized by
[A]
transposing transmission as well as communication lines
[B]
increasing the height of the trans-mission line tower
[C]
increasing the distance between the two lines
[D]
all of the above
60
Which of the following statements is incorrect?
[A]
Station batteries are used to operate relay only
[B]
The lightning arresters are basically surge diverters
[C]
An impedance relay has maximum fault current when fault occurs near the relay
[D]
A high speed relay has an operation of 1 to 2 cycles
Answer: Station batteries are used to operate relay only
Please share this page