Power Systems Multiple Choice Questions on “Skin Effect and Proximity Effect”.
1. 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
Clarification: Ripple at a power converter is maximum value of instantaneous difference between average and instantaneous value.
2. 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
Clarification: Smoothening reactor is connected between the dc output and load to provide sinusoidal source current.
3. 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
Clarification: All are types of DC link.
4. (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
Clarification: Negative polarity is preferred on OH lines due to less radio interference.
5. (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
Clarification: Both the statements are correct.
6. 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
Clarification: When the two conductors in bipolar link are same then ground current is zero and they have no interaction.
7. 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
Clarification: Homopolar link reduces corona loss.
8. 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
Clarification: 50% of rated power can be supplied.
9. The overvoltage that occur mainly under converter stations are due to _________
(i) Lightening and switching overvoltage
(ii) Transients produced in conductors
(iii) Overvoltage due to fault clearing
Choose the correct option.
A. (i), (ii), (iii)
B. (ii), (iii)
C. (iii)
D. (i), (ii)
Answer: A
Clarification: All the statements are correct.
10. Insulator capacitance is does not play significant role in HVDC lines
A. True
B. False
Answer: A
Clarification: There is no capacitive current which flows in HVDC link.