Power System - II (3150911) MCQs

MCQs of Transients in Power Systems

Showing 1 to 10 out of 106 Questions
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1.
An overhead line with surge impedance 400 Ω is terminated through a resistance R. A surge traveling over the line does not suffer any reflection at the junction if the value of R is
(a) 20 Ω
(b) 200 Ω
(c) 800 Ω
(d) None of the above
Answer:

Option (d)

2.
The coefficient of reflection for current for an open ended line is
(a) 1
(b) 0.5
(c) – 1.0
(d) Zero
Answer:

Option (c)

3.
A short length of cable between the dead end tower and the power transformer
(a) Always reduces the steepness of the incident wave
(b) Reduces the steepness of the wave under certain conditions only
(c) It does not change the steepness
(d) None of above
Answer:

Option (a)

4.
The coefficient of reflection of voltage for a short circuited line is
(a) 1
(b) – 1.0
(c) Zero
(d) 2
Answer:

Option (b)

5.
The sending end voltage of a feeder with reactance 0.2 pu is 1.2 pu. If the reactive power supplied at the receiving end of the feeder is 0.3 pu, the approximate drop of volts in the feeder is
(a) 0.2 pu
(b) 0.06 pu
(c) 0.05 pu
(d) 0.072 pu
Answer:

Option (c)

6.
The reflection coefficient of a short-circuited line for voltage is
(a) – 1
(b) 1
(c) 0.5
(d) Zero
Answer:

Option (a)

7.
Consider the following expression: v = f1 (x – rt) + f2 (x + rt) where f1 and f2 represent two traveling waves on a transmission line. In this case
(a) Both waves travel in the positive direction of x
(b) Both waves travel in the negative direction of x
(c) Wave f2 travels in the positive direction of x but wave f1 travels in the negative direction of x
(d) Wave f1 travels in the positive direction of x but wave f2 travels in the negative direction of x
Answer:

Option (d)

8.
An overhead line with a surge impedance of 400 Ω is connected to a transformer by a short length of cable of surge impedance 100 Ω. If a rectangular surge wave of 40 kV travels along the line towards the cable, then the voltage of the wave traveling from the junction of the overhead line through the cable towards the transformer would be
(a) 16 kV
(b) 32 kV
(c) 30 kV
(d) 36 kV
Answer:

Option (a)

9.
An overhead line with surge impedance of 400 Ω is terminated through a resistance R. A surge traveling over the line will not suffer any reflection at the junction, if the value of R is
(a) 100 Ω
(b) 200 Ω
(c) 400 Ω
(d) 800 Ω
Answer:

Option (c)

10.
If a traveling-wave travels along a loss-free overhead line does not result in any reflection after it has reached the far end, then the far end of the line is
(a) Open circuited
(b) Short circuited
(c) Terminated into a resistance equal to surge impedance of the line
(d) Terminated into a capacitor
Answer:

Option (c)

Showing 1 to 10 out of 106 Questions
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