Power System - I (3140914) MCQs

MCQs of Neutral Grounding

Showing 11 to 20 out of 31 Questions
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11.
3-phase, 50 Hz, transmission line has the following constants ( line to neutral) R = 10 Ω, X = 20 Ω and S = 4×10–4 ℧. The inductance of arc suppression coil to be used in the system is
(a) 0.063 H
(b) 0.127 H
(c) 1.127 H
(d) 2.654 H
Answer:

Option (d)

12.
Which of the following grounding methods is used to reduce the tower footing resistance where earth resistance is low?
(a) Single driven rod
(b) Multiple rod
(c) Counterpoise
(d) Plates
Answer:

Option (a)

13.
The method of neutral grounding affects the
(a) Positive sequence network
(b) Negative sequence network
(c) Zero sequence network
(d) None of above
Answer:

Option (c)

14.
The earthing transformer is used to
(a) To avoid harmonics in the transformer
(b) Provide artificial neutral earthing where neutral point is not accessible
(c) Improve stability of the system
(d) Measure the voltage
Answer:

Option (b)

15.
Grounding transformer in a system is usually connected in
(a) Delta/delta
(b) Star/delta
(c) Zigzag/delta
(d) Star/star
Answer:

Option (b)

16.
The positive, negative and zero sequence impedance of a solidly grounded system under steady state condition always follow the relation
(a) Z0 < Z1 < Z2
(b) Z1 < Z2 < Z0
(c) Z1 < Z0 < Z2
(d) Z0 > Z1> Z2
Answer:

Option (b)

17.
Arcing on transmission line is prevented by connecting
(a) Inductor in neutral
(b) Resistor in neutral
(c) Capacitor in neutral
(d) None of above
Answer:

Option (a)

18.
In an isolated neutral system, when a single line to ground fault occurs
(a) Persistent arcing ground will be developed
(b) Voltage in the healthy phase rise to full line value causing insulator breakdown
(c) Capacitive current in a faulty phase rises to three times its normal value
(d) All of above
Answer:

Option (d)

19.
During arcing ground conditions, phase voltage of the system rises to
(a) 20 times normal value
(b) 15 times normal value
(c) 5 to 6 times normal value
(d) √3 times normal value
Answer:

Option (c)

20.
Earthing of electrical equipment is necessary for the protection against
(a) Overloading
(b) Voltage fluctuation
(c) Danger of electric shock
(d) High conductor temperature
Answer:

Option (c)

Showing 11 to 20 out of 31 Questions
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