Power System MCQ With Answers

1. ……………. are the conductors, which connect the consumer’s

(a) terminals to the distribution
(b) Distributors
(c) Service mains
(d) Feeders
(e) None of the above


Answer: (c) Service mains
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2. The underground system cannot be operated above

(a) 440 V
(b) 11 kV
(c) 33 kV
(d) 66 kV


Answer: (d) 66 kV
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3. The usual spans with R.C.C. poles are

(a) 40 – 60 metres
(b) 80 – 100 metres
(c) 80 – 100 metres
(d) 300 – 500 metres


Answer: (c) 80 – 100 metres
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4. The corona is considerably affected by which of the following?

(a) Size of the conductor
(b) Shape of the conductor
(c) Surface condition of the conductor
(d) All of the above


Answer: (d) All of the above
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5. Which of the following are the constants of the transmission lines ?

(a) Resistance
(b) Inductance
(c) Capacitance
(d) All of the above.


Answer: (d) All of the above
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6. The phenomenon of rise in voltage at the receiving end of the open-circuited or lightly loaded line is called the

(a) Seeback effect
(b) Ferranti effect
(c) Raman effect
(d) none of the above.


Answer: (b) Ferranti effect
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7. The square root of the ratio of line impedance and shunt admittance is called

(a) surge impedance of the line
(b) conductance of the line
(c) regulation of the line
(d) none of the above.


Answer: (a) surge impedance of the line
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8. Which of the following is the demerit of a ‘constant voltage transmission system’?

(a) Increase of short-circuit current of the system
(b) Availability of steady voltage at all loads at the line terminals
(c) Improvement of power factor at times of moderate and heavy loads
(d) Possibility of carrying increased power for a given conductor size in case of long distance heavy power transmission.


Answer: (a) Increase of short-circuit current of the system
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9. Which of the following is the source of heat generation in the cables ?

(a) Dielectric losses in cable insulation
(b) I2R losses in the conductor
(c) Losses in the metallic sheathings and armouring
(d) all of the above.


Answer: (d) all of the above.
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10. Due to which of the following reasons, the cables should not be operated too hot?

(a) the oil may loose its viscosity and it may start drawing off from higher levels
(b) expansion of the oil may cause the sheath to burst
(c) unequal expansion may create voids in the insulation which will lead to ionization
(d) the thermal instability may rise due to the rapid increase of dielectric losses with temperature
(d) all of the above.


Answer: (d) all of the above.
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11. A booster is a

(a) series wound generator
(b) shunt wound generator
(c) synchronous generator
(d) none of the above.


Answer: (a) series wound generator
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12. Besides a method of trial and error, which of the following methods is employed for solution of network problems in interconnected system ?

(a) Circulating current method
(b) Thevenin’s theorem
(c) Superposition of currents
(d) Direct application of Kirchhoff’s laws
(d) All of the above.


Answer: (d) All of the above.
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13. Which of the following faults is most likely to occur in cables ?

(a) Cross or short-circuit fault
(b) Open circuit fault
(c) Breakdown of cable insulation
(d) All of the above.


Answer: (c) Breakdown of cable insulation
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14. The cause of damage to the lead sheath of a cable is

(a) crystallization of the lead through vibration
(b) chemical action on the lead when buried in the earth
(c) mechanical damage
(d) all of the above.


Answer: (d) all of the above.
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15. The distributors for residential areas are

(a) single phase
(b) three phase three wire
(c) three phase four wire
(d) none of the above.


Answer: (c) three phase four wire
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16. The conductors of the overhead lines are

(a) solid
(b) stranded
(c) both solid and stranded
(d) none of the above.


Answer: (b) stranded
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17. High voltage transmission lines use

(a) suspension insulators
(b) pin insulators
(c) both
(d) none of the above.


Answer: (a) suspension insulators
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18. Multi-core cables generally use

(a) square conductors
(b) circular conductors
(c) rectangular conductors
(d) sector shaped conductors.


Answer: (d) sector shaped conductors
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19. The material commonly used for insulation in high voltage cables is

(a) lead
(b) paper
(c) rubber
(d) none of the above.


Answer: (b) paper
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20. The loads on distributors are generally

(a) balanced
(b) unbalanced
(c) either of the above.


Answer: (b) unbalanced
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21. The material generally used for armour of high voltage cables is

(a) aluminium
(b) steel
(c) brass
(d) copper.


Answer: (b) steel
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22. Transmission line insulators are made of

(a) glass
(b) porcelain
(c) iron
(d) P.V.C.


Answer: (b) porcelain
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23. The material commonly used for sheaths of underground cables is

(a) lead
(b) rubber
(c) copper
(d) iron.


Answer: (a) lead
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24. The spacing between phase conductors of a 220 kV line is approximately equal to

(a) 2 m
(b) 3.5 m
(c) 6 m
(d) 8.6 m


Answer: (c) 6 m
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25. In a D.C. 3-wire distribution system, balancer fields are cross-connected in order to

(a) boost the generated voltage
(b) balance loads on both sides of the neutral
(c) make both machines run as unloaded motors
(d) equalize voltages on the positive and negative outer.


Answer: (d) equalize voltages on the positive and negative outer.
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26. In a D.C. 3-wire distributor using balancers and having unequal loads on the two sides

(a) both balancers run as generators
(b) both balancers run as motors
(c) balancer connected to lightly loaded side runs as a motor
(d) balancer connected to heavily-loaded side runs as a motor.


Answer: (c) balancer connected to lightly loaded side runs as a motor
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27. Transmitted power remaining the same, if supply voltage of a D.C. 2-wire feeder is increased 100 percent, saving in copper is

(a) 25 percent
(b) 50 percent
(c) 75 percent
(d) 100 percent


Answer: (b) 50 percent
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28. A uniformly-loaded D.C. distributor is fed at both ends with equal voltages. As compared to a similar distributor fed at One end only, the drop at the middle point is

(a) one-fourth
(b) one-third
(c) one-half
(d) twice
(e) none of the above.


Answer: (a) one-fourth
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29. As compared to a 2 – wire D.C. distributor, in 3 – wire distributor with same maximum voltage to earth uses only

(a) 31.25 percent of copper
(b) 33.3 percent of copper
(c) 66.7 percent of copper
(d) 125 percent of copper


Answer: (a) 31.25 percent of copper
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30. Which of the following is usually not the generating voltage ?

(a) 6.6 kV
(b) 8.8 kV
(c) 11 kV
(d) 13.2 kV


Answer: (b) 8.8 kV
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31. Which of the following D.C. distribution system is the simplest and lowest in cost?

(a) Radial system
(b) Ring system
(c) Inter-connected system
(d) None of the above


Answer: (a) Radial system
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Power System MCQ With Answers

 

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