Power Systems Questions and Answers

1. Which of the following has least effect on corona ?

(a) Atmospheric temperature
(b) Number of ions
(c)Site and charge per ion
(d) Mean free path

2. In context of corona, if the conductors are polished and smooth, which of the following statements is correct ?

(a) Hissing sound will be more intense
(b) Power loss will be least
(c) Corona glow will be uniform along the length of the conductor
(d) Corona glow will not occur.

3. Power loss due to corona is not directly proportional to

(a) spacing between conductors
(b) supply voltage frequency
(c) phase to neutral voltage
(d) all of the above.

4. The effect of ice on transmission line conductors is to increase the

(a) transmission losses
(b) weight of the conductor
(c) tendency for corona
(d) resistance to flow of current

5. If the height of transmission tower is increased

(a) the line capacitance will decrease but line inductance will remain unchanged
(b) the line capacitance and inductance will not change
(c) the line capacitance will increase but line inductance will decrease
(d) the line capacitance will decrease and line inductance will increase

6. If string efficiency is 100 percent it means that

(a) potential across each disc is zero
(b) potential across each disc is same
(c) one of the insulator discs is shorted
(d) none of the above.

7. In a 70/6 A.C.S.R conductor there are

(a) 35 aluminum conductors and 3 steel conductors
(b) 70 aluminum conductors and 6 steel conductors
(c) 70 steel conductors and 6 aluminum conductors
(d) none of the above.

8. On which of the following does the size of a feeder depend ?

(a) Voltage drop
(b) Voltage
(c) Frequency
(d) Current carrying capacity

9. Which of the following are connected by the service mains ?

(a) Transformer and earth
(b) Distributor and relay system
(c) Distributor and consumer terminals
(d) Distributor and transformer.

10. In the design of a distributor which of the following is the major consideration ?

(a) Voltage drop
(b) Current carrying capacity
(c) Frequency
(d) kVA of system

11. In a distribution system major cost is that of

(a) earthing system
(b) distribution transformer
(c) conductors
(d) meters.

12. A booster is connected in

(a) parallel with earth connection
(b) parallel with the feeder
(c) series with the feeder
(d) series with earth connection.

13. With which of the following are step-up substations associated ?

(a) Concentrated load
(b) Consumer location
(c) Distributors
(d) Generating stations.

14. Which of the following equipment should be installed by the consumers having low power factor?

(a) Synchronous condensers
(b) Capacitor bank
(c) Tap changing transformer
(d) Any of the above

15. Which of the following equipment is used to limit short-circuit current level in a substation ?

(a) Isolator
(b) Lightning switch
(c) Coupling capacitor
(d) Series reactor

16. Steepness of the travelling waves is altered by ……….. of line.

(a) capacitance
(b) inductance
(c) resistance
(d) all of the above

17. The limit of distance of transmission line may be increased by the use of

(a) series resistances
(b) shunt capacitors and series reactance
(c) series capacitors and shunt reactors
(d) synchronous condensers.

18. The voltage drop, for constant voltage transmission, is compensated by installing

(a) inductors
(b) capacitors
(c) synchronous motors
(d) all of above.

19. By which of the following factors is the sag of a transmission line least affected?

(a) Current through the conductor
(b) Ice deposited on the conductor
(c) Self weight of conductor
(d) Temperature of surrounding air
(e) None of the above

20. Which of the following causes transient disturbances?

(a) Faults
(b) Load variations
(c) Switching operations
(d) Any of the above

21. A gay wire

(a) protects conductors against short-circuiting
(b) provides emergency earth route
(c) provides protection against surges
(d) support the pole

22. Which of the following is neglected in the analysis of short transmission lines?

(a) Series impedance
(b) Shunt admittance
(c) None of the above
(d) All of the above

23. Basically the boosters are

(a) synchronous motors
(b) capacitors
(c) inductors
(d) transformers

24. Which of the following is a static exciter ?

(a) Rectifier
(b) Rotorol
(c) Amplidyne
(d) D.C. separately excited generator

25. For exact compensation of voltage drop in the feeder the booster

(a) must be earthed
(b) must work on line voltage
(c) must work on linear portion of its V-I characteristics
(d) must work on nonlinear portion of its V-I characteristics.

26. The purpose of using a booster is to

(a) increase current
(b) reduce current
(c) reduce voltage drop
(d) compensate for voltage drop

27. Induction regulators are used for voltage control in

(a) alternators
(b) primary distribution
(c) secondary distribution
(d) none of the above.

28. A synchronous condenser is generally installed at the ………..of the transmission line.

(a) receiving end
(b) sending end
(c) middle
(d) none of the above

29. The area of cross-section of the neutral in a 3-wire D.C. system is generally ………….. the area of cross-section of main conductor

() same as
(a) one-fourth
(b) one half
(c) double

30. For which of the following, the excitation control method is satisfactory?

(a) Low voltage lines
(b) High voltage lines
(c) Short lines
(d) Long lines

1. Power System MCQ With Answers
2. Power System Multiple Choice Questions
3. MCQ on Power System
4. Power Systems Questions and Answers
5. Power System Question Bank
6. Power System MCQ Part – 1
7. Power System MCQ Part – 2
8. Power System MCQ Part – 3

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