Switchgear Protections Multiple Choice Questions and Answers pdf free download | Electrical Engineering Questions

1.    The main function of a fuse is to _______.
2.    On which of the following routine tests are conducted ?
3.    SF6 gas _______.
4.    The arcing contacts in a circuit breaker are made of _____.
5.    Which  of the following  medium is employed for extinction of arc in air circuit breaker ?
6.    With which of the following, a circuit breaker must be equipped for remote operation ?
7.    Fault diverters are basically
8.    A thermal protection switch can protect against
9.    Arc in a circuit behaves as
10.    Thermal circuit breaker has
11.    Relays can be designed to respond to changes in
12.    Overload relays are of ______ type.
13.    Thermal overload relays are used to protect the motor against over current due to
14.    Magnetic circuit breaker has ______ trip action.
15.    D.C. shunt relays are made of _____.
16.    The relay operating speed depends upon _____.
17.    In order that current should flow without causing excessive heating or voltage drop, the relay contacts should
18.    Circuit breakers usually operate under _____.
19.    Circuit breakers are essentially ______.
20.    The current zero interruption, in oil and air blast circuit breakers, is achieved by
21.    Air blast circuit breaker is used for ______.
22.    An efficient and a well designed protective relaying should have
23.    Burden of a protective relay is the power
24.    Directional relays are based on flow of
25.    A differential relay measures the vector difference between
26.    A transmission line is protected by _____.
27.    Large internal faults are protected by _____.
28.    When a transmission line is energized, the wave that propagates on it is
29.    Protective relays are devices that detect abnormal conditions in electrical circuits by measuring
30.    The voltage appearing across the contacts after opening of the circuit breaker is called______voltage.
31.    Ionization in circuit breaker is facilitated by _____.
32.    In a circuit breaker the basic problem is to ____.
33.    Overheating of relay contacts or contact born out is due to
34.    Interruption of large currents by relay requires
35.    Shunt capacitance is neglected while considering
36.    The arc voltage produced in A.C. circuit breaker is always
37.    The time of closing the cycle, in modern circuit breakers is
38.    Insulation resistance of high voltage circuit breakers is more than
39.    H.R.C. fuses provide best protection against ______.
40.     The ground wire should not be smaller than No ______ copper.
41.    The delay fuses are used for the protection of ________ .
42.    Which of the following is the least expensive protection for overcurrent is low voltage system ?
43.    Resistance grounding is used for voltage between
44.    The contacts of high voltage switches used in power system are submerged in oil. The main purpose of the oil is to
45.    In Railway applications ______ circuit breaker is used.
46.    To protect most of the electrical equipment handling low power, the types of relays used are
47.    Wave trap is used to trap waves of _____.
48.    Ungrounded neutral transmission system is not recommended because of system
49.    The reflection co-efficient at the open circuited end of a transmission line.
50.    For the protection of power station buildings against direct strokes the requirements are
51.    The line insulation is _____ the insulation level of the station equipment.
52.    The interaction between a transmission line and communication line is minimized by
53.    When a wave propagates on a transmission line, it suffers reflection several times at
54.    Which of the following statements is incorrect?
55.    Discrimination between main and back up protection is provided by the use of relays which are
56.    Induction cup relay is operated due to changes in
57.    A.C. network analyser is used to solve problems of
58.    Which of the following statements is incorrect ?
59.    Short-circuit currents are due to ______.
60.    To reduce short circuit fault currents are used.
61.    Bus coupler is very essential in arrangement
62.    For cost and safety, the outdoor substations are installed for voltages above
63.    The short circuit in any winding of the transformer is the result of
64      ______ relays are used for phase faults on long line.
65.   For which of the following protection from  negative  sequence  currents  is provided ?
66    ______ relay is preferred for phase fault on short transmission line.
67.    Distance relays are generally ______.
68.    For which of the following ratings of the transformer differential protection is recommended ?
69.    A _______ is used to measure the stator % winding temperature of the generator.
70.    The under voltage relay can be used for _____.
71.    The relay with inverse time characteristic will operate within
72.    The single phasing relays are used for the protection of _____.
73.    Which of the following devices will receive voltage surge first traveling on the transmission line ?
74.    Which of the following parameter can be neglected for a short line ?
75.    Series reactors should have _____.
76.    Which of the following circuit breakers has high reliability and minimum maintenance ?
77.    Arc in a circuit breaker is interrupted at ______.
78     _______ transmission line has reflection coefficient as one.
79.    What will be the reflection co-efficient of the wave of load connected to transmission line if surge impedance of the line is equal to load ?
80.    The inverse definite mean time relays are used for over current and earth fault protection of transformer against
81.    Over voltage protection is recommended for
82.    Air blast circuit breakers for 400 kV power system are designed to operate in
83.    Overfluxing protection is recommended for
84.    Series capacitors are used to ______.
85.    Admittance relay is _______ relay.
86.    The material used for fuse must have
87.    If the fault occurs near the impedance relay, the VII ratio will be
88.    The torque produced in induction type relay (shaded pole structure) is
89.    The steady state stability of the power system can be increased by
90.    The inductive interference between power and communication line can be minimized by
91.    The power loss is an important factor for the design of
92.    A fuse is connected ______.
93.    H.R.C. fuse, as compared to a rewirable fuse, has
94.    The fuse rating is expressed in terms of ______.
95.    The fuse blows off by ______.
96.    On which of the following effects of electric current a fuse operates ?
97.    An isolator is installed ______.
98.    A fuse in a motor circuit provides protection against
99.    Protection by fuses is generally not used beyond
100.    A fuse is never inserted in ______.