Transmission and distribution

21. Multi-core cables generally use

Square conductors
Circular conductors
Rectangular conductors
None of the above

Detailed SolutionMulti-core cables generally use

22. Corona usually occurs when the electrostatic stress in air around the conductor exceeds

6.6 kV (r.m.s. value)/cm
11 kV (r.m.s. value)/cm
22 kV (maximum value)/cm
30 kV (maximum value)/cm

Detailed SolutionCorona usually occurs when the electrostatic stress in air around the conductor exceeds

23. Galvanized steel wire is generally used as

Stay wire
Earth wire
Structural components
All of the above

Detailed SolutionGalvanized steel wire is generally used as

24. When a live conductor of public electric supply breaks down and touches the earth which of the following will happen?

Current will flow to earth
Supply voltage will drop
Supply voltage will increase
No current will flow in the conductor

Detailed SolutionWhen a live conductor of public electric supply breaks down and touches the earth which of the following will happen?

25. By which of the following methods string efficiency can be improved?

Using a guard ring
Grading the insulator
Using long cross arm
Any of the above

Detailed SolutionBy which of the following methods string efficiency can be improved?

26. The voltage regulation in magnetic amplifier type voltage regulator is effected by

Electromagnetic induction
Varying the resistance
Varying the reactance
Variable transformer

Detailed SolutionThe voltage regulation in magnetic amplifier type voltage regulator is effected by

27. Which of the following is the demerit of a ‘constant voltage transmission system’ ?

Increase of short-circuit current of the system
Availability of steady voltage at all loads at the line terminals
Possibility of better protection for the line due to possible use of higher terminal reactants
Improvement of power factor at times of moderate and heavy loads E. Possibility of carrying increased power for a given conductor size in case of long-distance heavy power transmission

Detailed SolutionWhich of the following is the demerit of a ‘constant voltage transmission system’ ?

28. For which of the following equipment current rating is not necessary?

Circuit breakers
Isolators
Load break switch
Circuit breakers and load break switches

Detailed SolutionFor which of the following equipment current rating is not necessary?

29. For transmission of power over a distance of 500 km, the transmission voltage should be in the range

150 to 220 kV
100 to 120 kV
60 to 100 kV
20 to 50 kV

Detailed SolutionFor transmission of power over a distance of 500 km, the transmission voltage should be in the range

30. Which of the following materials is not used for transmission and distribution of electrical power?

Copper
Aluminium
Steel
Tungsten

Detailed SolutionWhich of the following materials is not used for transmission and distribution of electrical power?

Page 1Page 2Page 3Page 4Page 5
Test 1Test 2