electrical

Transmission and Distribution MCQ Objective Questions and Answers Page - 2

1.

The maximum tension in a section of overhead line conductor between two supports of unequal height occurs at

Answer/ Hint      

Answer : A

Explanation :

2.

Stringing chart is useful

Answer/ Hint      

Answer : A

Explanation :

3.

Hot template curves are plots of

Answer/ Hint      

Answer : B

Explanation :

4.

The effect of wind pressure is more predominant on

Answer/ Hint      

Answer : C

Explanation :

5.

Galloping in transmission line conductors arises due to

Answer/ Hint      

Answer : A

Explanation :

6.

Which of the following is reduced by using stock bridge dampers on power overhead transmission lines  ?

Answer/ Hint      

Answer : B

Explanation :

7.

The sag of the conductors of a transmission line is 2.5 m when the span is  250 m. now if the height of supporting tower is increased by  25%, the sag will

Answer/ Hint      

Answer : D

Explanation :

8.

For a 400 kV line, the spacing between phase conductors is around

Answer/ Hint      

Answer : A

Explanation :

9.

Stranded conductors usually have a central wire around which there are successive layers of  6,12,18,24  wires.  For  n-layers, the total number of individual wires is

Answer/ Hint      

Answer : C

Explanation :

10.

The diameter of each strand is  d  then the diameter of  n-layer  stranded conductor will be

Answer/ Hint      

Answer : A

Explanation :

11.

Strain type insulators are used

Answer/ Hint      

Answer : D

Explanation :

12.

Wavy structure of pin insulator increases its

Answer/ Hint      

Answer : C

Explanation :

13.

Which type of insulators are used on  132 kV  transmission lines  ?

Answer/ Hint      

Answer : B

Explanation :

14.

Whenever the conductors are dead-ended or there is a change in the direction of transmission line, the insulators used are of the

Answer/ Hint      

Answer : C

Explanation :

15.

The number of discs in a string of insulators for  400 kV  ac overhead transmission line lies in the range of

Answer/ Hint      

Answer : B

Explanation :

16.

100 per cent string efficiency means

Answer/ Hint      

Answer : C

Explanation :

17.

If the frequency of a transmission system is changed from  50 Hz to 100 Hz, the string efficiency

Answer/ Hint      

Answer : C

Explanation :

18.

The string efficiency of a high-voltage line is around

Answer/ Hint      

Answer : B

Explanation :

19.

In three-unit insulator string, voltage across the lowest unit is  17.5 kV and string efficiency is 84.28%. the total voltage across the string will be equal to

Answer/ Hint      

Answer : B

Explanation :

20.

Two-insulator discs of identical capacitance value  C  makes up a string for a  22 kV , 50 Hz, single-phase overhead line insulation system. If the pin to earth capacitance is also  C, then the string efficiency is

Answer/ Hint      

Answer : B

Explanation :

21.

In a cable the sheath radius is  R and conductor radius is  r. as  r changes from  0.5 R  to  0.25 R  the maximum voltage gradient in the dielectric

Answer/ Hint      

Answer : B

Explanation :

22.

The insulators may fail due to

Answer/ Hint      

Answer : D

Explanation :

23.

The purpose of guard ring in transmission lines is to

Answer/ Hint      

Answer : A

Explanation :

24.

Which of the following statements is true regarding corona  ?

Answer/ Hint      

Answer : A

Explanation :

25.

Corona is accompanied by

Answer/ Hint      

Answer : D

Explanation :

26.

Ozone effect can be detected by

Answer/ Hint      

Answer : D

Explanation :

27.

Corona loss increases with

Answer/ Hint      

Answer : A

Explanation :

28.

The good effect of corona on overhead lines is to

Answer/ Hint      

Answer : D

Explanation :

29.

Compared with a solid conductor of the same radius, corona appears on a stranded conductor at a lower voltage, because stranding

Answer/ Hint      

Answer : D

Explanation :

30.

Corona loss can be reduced by using

Answer/ Hint      

Answer : D

Explanation :

31.

Corona loss can be reduced by the use of hollow conductors because

Answer/ Hint      

Answer : C

Explanation :

32.

Corona occurs between two transmission conductors when they

Answer/ Hint      

Answer : D

Explanation :

33.

In humid weather, the corona occurs at a voltage

Answer/ Hint      

Answer : A

Explanation :

34.

The effect of corona is

Answer/ Hint      

Answer : A

Explanation :

35.

The charging current in a transmission line increases due to corona effect because corona increases

Answer/ Hint      

Answer : D

Explanation :

36.

The chances of occurrence of corona are maximum during

Answer/ Hint      

Answer : A

Explanation :

37.

Corona is likely to occur maximum in case of

Answer/ Hint      

Answer : B

Explanation :

38.

The only advantage of corona is that it

Answer/ Hint      

Answer : C

Explanation :

39.

Presence of ozone owing to corona

Answer/ Hint      

Answer : C

Explanation :

40.

What is the approximate breakdown strength of atmospheric air at N.T.P.  ?

Answer/ Hint      

Answer : D

Explanation :

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