Power System - II (3150911) MCQs

MCQs of Transients in Power Systems

Showing 21 to 30 out of 106 Questions
1 2 3 4 5 6
21.
During faults in a power system severe over voltages are produced with neutral
(a) Solidly earthed
(b) Isolated
(c) Earthed through an inductive coil
(d) Earthed through low resistance
Answer:

Option (b)

22.
Considering the following statement about ground wires
1. Ground wire helps to increase the effective capacitance between the line conductor and ground
2. It shields the main conductor against direct stroke
3. It is placed higher than the main conductors and supported on the same tower
4. It helps to reduce the risk of back flash over in case of direct strokes
(a) 1 and 2 are correct
(b) 2 and 3 are correct
(c) 1, 2 and 4 are correct
(d) 1, 2, 3 and 4 are correct
Answer:

Option (d)

23.
Switching over voltages may be caused by
1. Sustained earth fault on phase conductor
2. Energisation or reclosure of long lines
3. Load rejection at the receiving lines
4. Fault initiation
(a) 1 and 2
(b) 2 and 3
(c) 1, 2 and 3
(d) 1, 2, 3 and 4
Answer:

Option (d)

24.
The velocity of traveling wave through a cable of relative permittivity 9 is
(a) 9×108 m/s
(b) 3×108 m/s
(c) 108 m/s
(d) 2×108 m/s
Answer:

Option (c)

25.
The propagation constant of a transmission line is 0.15×10–3 + j1.5×10–3. The wavelength of the traveling wave is
(a) (15×10–3)/2π
(b) 2π/(15×10–3)
(c) (15×10–3)/π
(d) π/(15×10–3)
Answer:

Option (b)

26.
The velocity of traveling wave through a cable of relative permittivity 9 is
(a) 9×108 m/s
(b) 3×108 m/s
(c) 2×108 m/s
(d) 108 m/s
Answer:

Option (d)

27.
The velocity of propagation of electromagnetic waves on overhead line is
(a) 3×108 m/s
(b) 3×108 km/s
(c) 3×1010 m/s
(d) 3×108 km/hr
Answer:

Option (a)

28.
A cable has following characteristics, L = 0.2 μH/m and C=196.2 pF/m. The velocity of wave propagation through  cable is
(a) 32 m/s
(b) 159.24 m/μs
(c) 0.0312 m/s
(d) 159.24 m/s
Answer:

Option (b)

29.
The square root of the ratio of line impedance and shunt admittance is known as the line
(a) Surge impedance
(b) Conductance
(c) Susceptance
(d) Admittance
Answer:

Option (a)

30.
Which of the following statements is correct?
(a) Surge impedance is the impedance at the time of breakdown of voltage
(b) Surge impedance and characteristic impedance for a transmission line are the same
(c) Surge impedance is the impedance of transmission line when corona takes place
(d) None of above
Answer:

Option (b)

Showing 21 to 30 out of 106 Questions
1 2 3 4 5 6