[amp_mcq option1=”Square conductors” option2=”Circular conductors” option3=”Rectangular conductors” option4=”None of the above” correct=”option2″]
Transmission and distribution
22. Corona usually occurs when the electrostatic stress in air around the conductor exceeds
[amp_mcq option1=”6.6 kV (r.m.s. value)/cm” option2=”11 kV (r.m.s. value)/cm” option3=”22 kV (maximum value)/cm” option4=”30 kV (maximum value)/cm” correct=”option3″]
23. Galvanized steel wire is generally used as
[amp_mcq option1=”Stay wire” option2=”Earth wire” option3=”Structural components” option4=”All of the above” correct=”option4″]
24. When a live conductor of public electric supply breaks down and touches the earth which of the following will happen?
[amp_mcq option1=”Current will flow to earth” option2=”Supply voltage will drop” option3=”Supply voltage will increase” option4=”No current will flow in the conductor” correct=”option1″]
25. By which of the following methods string efficiency can be improved?
[amp_mcq option1=”Using a guard ring” option2=”Grading the insulator” option3=”Using long cross arm” option4=”Any of the above” correct=”option1″]
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
[amp_mcq option1=”Electromagnetic induction” option2=”Varying the resistance” option3=”Varying the reactance” option4=”Variable transformer” correct=”option1″]
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’ ?
[amp_mcq option1=”Increase of short-circuit current of the system” option2=”Availability of steady voltage at all loads at the line terminals” option3=”Possibility of better protection for the line due to possible use of higher terminal reactants” option4=”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” correct=”option1″]
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?
[amp_mcq option1=”Circuit breakers” option2=”Isolators” option3=”Load break switch” option4=”Circuit breakers and load break switches” correct=”option3″]
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
[amp_mcq option1=”150 to 220 kV” option2=”100 to 120 kV” option3=”60 to 100 kV” option4=”20 to 50 kV” correct=”option1″]
30. Which of the following materials is not used for transmission and distribution of electrical power?
[amp_mcq option1=”Copper” option2=”Aluminium” option3=”Steel” option4=”Tungsten” correct=”option4″]