Power Systems Questions and Answers - Skin Effect and Proximity Effect Part-1

1. _______ material is used for the making of the ground wire in the transmission system.
a) Galvanised steel
b) Steel
c) Cast iron
d) Aluminium

Answer: a
Explanation: Galvanised steel is used in the ground wire.

2. In emergency cases, another wire is installed in the system, that is widely known as ________________
a) Guy wire
b) Earth wire
c) Line wire
d) Neutral wire

Answer: a
Explanation: Guy wire as the earth route in the emergency earth route.

3. Ripple of the DC-output at power converter is ____________
a) maximum value of instantaneous difference between average and instantaneous value
b) minimum value of instantaneous difference between average and instantaneous value
c) average value of output
d) maximum value of instantaneous value

Answer: a
Explanation: Ripple at a power converter is maximum value of instantaneous difference between average and instantaneous value

4. Smooth reactor is connected between _____________
a) DC output of converter and load
b) load and ground
c) source and input of converter
d) any of the mentioned

Answer: a
Explanation: Smoothening reactor is connected between the dc output and load to provide sinusoidal source current.

5.Which of the above is not a DC link?
a) Monopolar link
b) Bipolar link
c) Homopolar link
d) None of the mentioned

Answer: d
Explanation: All are types of DC link.

6. (i) Monopolar DC link has one energised conductor of positive polarity.
(ii) It was ground as return path
Opt the most appropriate.
a) (i) is False & (ii) is True
b) (i) is True & (ii) is True
c) Both are false
d) (i) is True & (ii) is False

Answer: a
Explanation: Negative polarity is preferred on OH lines due to less radio interference.

7. (i) Bipolar link has two conductors
(ii) Both conductors have same magnitude of voltage.
a) (i) is False & (ii) is True
b) (i) is True & (ii) is True
c) Both are false
d) (i) is True & (ii) is False

Answer: b
Explanation: Both the statements are correct.

8. If the currents in the two conductors of bipolar HDVC link is same, then _______
a) ground current is zero
b) two poles work independently
c) ground current zero and two poles work independently
d) none of the mentioned

Answer: b
Explanation: When the two conductors in bipolar link are same then ground current is zero and they have no interaction.

9. Homopolar link is employed instead of bipolar link to ___________
a) reduce corona loss
b) reduce radio interference
c) improve reliability
d) all of the mentioned

Answer: a
Explanation: Homopolar link reduces corona loss.

10. Which of the DC links can be operated when a fault occurs in the transmission line?
a) Bipolar link and Homopolar link
b) Monopolar link and Bipolar link
c) Monopolar link
d) Bipolar link

Answer: a
Explanation: 50% of rated power can be supplied.