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       Comment On Question

Answer : B

Explanation :

Hot template curves are used to show the relationships between Conductor sag and span lengths.

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       Comment On Question

Answer : B

Explanation :

The insulators are used on  132 kV transmission lines is Disc type.

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       Comment On Question

Answer : A

Explanation :

The purpose of guard ring in transmission lines is to reduce the earth capacitance of the lowest unit.

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       Comment On Question

Answer : A

Explanation :

The chances of occurrence of corona are maximum during Humid weather.

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 :

41.

Which of the following are the constants of the transmission lines?

Answer/ Hint      

Answer : D

Explanation :

42.

The phenomenon of rise in voltage at the receiving end of the open-circuited or lightly loaded line is called the

Answer/ Hint      

Answer : B

Explanation :

43.

The square root of the ratio of line impedance and shunt admittance is called the

Answer/ Hint       Comment On Question

Answer : A

Explanation :

The square root of the ratio of line impedance and shunt admittance is called the Surge impedance of the line.

44.

Low voltage cables are meant for use up to

Answer/ Hint      

Answer : C

Explanation :

45.

The operating voltage of high voltage cables is up to

Answer/ Hint      

Answer : D

Explanation :

46.

The operating voltage of super-tension cables is up to

Answer/ Hint      

Answer : D

Explanation :

47.

The operating voltage of extra high-tension cables is up to

Answer/ Hint      

Answer : D

Explanation :

48.

Which of the following methods is used for laying of underground cables?

Answer/ Hint      

Answer : D

Explanation :

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