Power System - II (3150911) MCQs

MCQs of Transients in Power Systems

Showing 91 to 100 out of 106 Questions
91.
Reflection coefficient of the wave of load connected to a transmission line of surge impedance equal to that of transmission line is
(a) 1
(b) -1
(c) Zero
(d) Infinity
Answer:

Option (c)

92.
Surge voltage of 1000 kV is applied to an overhead transmission line with its receiving and open. If the surge impedance of the line is 500 Ω, then total surge power in the line is
(a) 2000 MW
(b) 500 MW
(c) 2 MW
(d) 0.5 MW
Answer:

Option (a)

93.
On an infinitely long transmission line, the attenuation coefficient α is expressed in terms of ratio K of the two voltages on km apart on the line, in bels/km.The value of this coefficient is given by
(a) α = logeK
(b) α = K2
(c) α = 2logX10K
(d) None of above
Answer:

Option (d)

94.
A surge of 260 kV traveling in a line of natural impedance of 500 Ω arrives at the junction with two lines of natural impedance of 250 Ω and 15 Ω respectively. The voltage transmitted in the branch line is
(a) 400 kV
(b) 260 kV
(c) 80 kV
(d) 40 kV
Answer:

Option (d)

95.
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 deflection at the junction, if the value of R is
(a) 100 Ω
(b) 200 Ω
(c) 400 Ω
(d) 800 Ω
Answer:

Option (c)

96.
In overhead line with surge impedance of 400 Ω is connected to a transformer by a short length of cable of surge impedance of 100 Ω. If a rectangular wave of 40 kV travels along the line towards the cable than the voltage of the wave traveling from the junction of overhead line through the cable toward the transformer will be
(a) 16 kV
(b) 24 kV
(c) 32 kV
(d) 36 kV
Answer:

Option (a)

97.
The coefficient of reflection for current for an open ended line is
(a) 1
(b) -1
(c) 0.5
(d) Zero
Answer:

Option (b)

98.
A short length of cable between the dead end tower and the power transformer
(a) Reduces the  steepness of wave under certain conditions only
(b) Always reduces the steepness of incident wave
(c) Steepness of incident wave remains unaffected
(d) None of above
Answer:

Option (b)

99.
Real part of propagation constant of a transmission line is
(a) Attenuation constant
(b) Phase constant
(c) Reliability factor
(d) None of above
Answer:

Option (a)

100.
Two transmission lines each having an impedance of 200 Ω is separated by a cable like, for zero reflection, the impedance of cable should be
(a) 100 Ω
(b) 200 Ω
(c) 400 Ω
(d) 600 Ω
Answer:

Option (b)

Showing 91 to 100 out of 106 Questions