electrical

Transmission and Distribution MCQ Objective Questions and Answers Page - 3

1.

Disruptive corona begins in smooth cylindrical conductors in air at  NTP  if the electric field intensity at the conductor surface goes up to

Answer/ Hint      

Answer : A

Explanation :

2.

The dielectric strength of air is

Answer/ Hint      

Answer : A

Explanation :

3.

Visual critical voltage is

Answer/ Hint      

Answer : B

Explanation :

4.

Critical voltage limit of a transmission line is increased by

Answer/ Hint      

Answer : A

Explanation :

5.

Corona losses are minimised when

Answer/ Hint      

Answer : B

Explanation :

6.

The corona loss on a particular system at  50 Hz  is  1kW/km per phase. What is the corona loss at  60 Hz in kW/km per phase  ?

Answer/ Hint      

Answer : C

Explanation :

7.

In a transmission line the distributed constants are

Answer/ Hint      

Answer : D

Explanation :

8.

Skin effect depends upon

Answer/ Hint      

Answer : D

Explanation :

9.

Skin effect in transmission line is due to

Answer/ Hint      

Answer : D

Explanation :

10.

Increasing the frequency of transmission line will

Answer/ Hint      

Answer : C

Explanation :

11.

Skin effect exists in

Answer/ Hint      

Answer : C

Explanation :

12.

Skin effect

Answer/ Hint      

Answer : C

Explanation :

13.

The skin effect of a conductor reduces with the increase in

Answer/ Hint      

Answer : B

Explanation :

14.

Skin effect in conductor is proportional to

Answer/ Hint      

Answer : C

Explanation :

15.

In order to reduce the skin effect at  UHF

Answer/ Hint      

Answer : A

Explanation :

16.

A  100 km  long transmission line is loaded at  110 kV . if the loss of line is  15 MW  and the load is  150 MVA, the resistance of the line is

Answer/ Hint      

Answer : A

Explanation :

17.

Consider a long, two-wire line composed of solid round conductors. The radius of both conductors is  0.25 cm  and the distance between their centres is  1 m. if this distance is doubled, then the inductance per unit length.

Answer/ Hint      

Answer : C

Explanation :

18.

The inductance of single-phase two-wire power transmission line per  km  gets doubled when the

Answer/ Hint      

Answer : C

Explanation :

19.

For  11 kV line, the inductance per  km  per phase will be of the order of

Answer/ Hint      

Answer : C

Explanation :

20.

A 3-phase transmission line has its conductors at the corners of an equilateral triangle with side  3 m. the diameter of each conductor is  1.63 cm. the inductance of the line per phase per  km  is

Answer/ Hint      

Answer : A

Explanation :

21.

The conductors of a  10 km  long, single-phase, 2-wire line are separated by a distance of  1.5 m. the diameter of each conductor is  1 cm. if the conductors are of coper, the inductance of the circuit is

Answer/ Hint      

Answer : C

Explanation :

22.

The inductance of a power transmission line increases with

Answer/ Hint      

Answer : C

Explanation :

23.

The inductance of a transmission line minimum when

Answer/ Hint      

Answer : D

Explanation :

24.

Hollow conductors are used in transmission lines to

Answer/ Hint      

Answer : C

Explanation :

25.

In  hv  transmission, the spacing between sub-conductors of a bundle is approximately

Answer/ Hint      

Answer : B

Explanation :

26.

For a stranded conductor, the ratio of GMR to actual radius is

Answer/ Hint      

Answer : D

Explanation :

27.

Bundled conductors in EHV transmission system provide

Answer/ Hint      

Answer : B

Explanation :

28.

Which one of the following statements is not correct for use of bundled conductors in transmission lines  ?

Answer/ Hint      

Answer : D

Explanation :

29.

Bundled conductors are mainly used in high voltage overhead transmission lines to

Answer/ Hint      

Answer : C

Explanation :

30.

Proximity effect

Answer/ Hint      

Answer : D

Explanation :

31.

Capacitance in equivalent circuit of transmission line is due to

Answer/ Hint      

Answer : A

Explanation :

32.

If the separation between the three phases of transmission line in increased then

Answer/ Hint      

Answer : C

Explanation :

33.

The recharging reactance of  50 km  length of the line is  1500 Ω. What is the charging reactance for  100 km  length of the line  ?

Answer/ Hint      

Answer : C

Explanation :

34.

Bundled conductors are used to

Answer/ Hint      

Answer : D

Explanation :

35.

If the effect of earth is taken into account, the capacitance of line to ground

Answer/ Hint      

Answer : B

Explanation :

36.

For equilateral spacing of conductors of an untransposed  3-phase line, we have

Answer/ Hint      

Answer : A

Explanation :

37.

Transmission lines are transposed to

Answer/ Hint      

Answer : C

Explanation :

38.

Transposition of Transmission line is done to

Answer/ Hint      

Answer : C

Explanation :

39.

High voltage Transmission lines are transposed because then

Answer/ Hint      

Answer : D

Explanation :

40.

The concept of an electrically short, medium and long line is primarily based on the

Answer/ Hint      

Answer : B

Explanation :

41.

Equivalent    model is quite suitable for analysing the performance of transmission line of

Answer/ Hint      

Answer : C

Explanation :

42.

Which of the following is the source of heat generation in the cables?

Answer/ Hint      

Answer : D

Explanation :

43.

Which of the following D.C distribution system is the simplest and lowest in first cost?

Answer/ Hint      

Answer : A

Explanation :

44.

A booster is a

Answer/ Hint      

Answer : A

Explanation :

45.

Besides a method of trial and error, which of the following methods is employed for solution of network problems in interconnected system?

Answer/ Hint      

Answer : D

Explanation :

46.

Which of the following faults is most likely to occur in cable?

Answer/ Hint      

Answer : D

Explanation :

47.

The cause of damage to the lead sheath of a cable is

Answer/ Hint      

Answer : D

Explanation :

48.

The voltage of the single-phase supply to residential consumers is

Answer/ Hint      

Answer : C

Explanation :

49.

Most of the high voltage transmission lines in India are

Answer/ Hint      

Answer : B

Explanation :

50.

The distributor for residential areas are

Answer/ Hint      

Answer : C

Explanation :

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