The operating voltage of extra high tension cables is upto_______________?

Constant voltage transmission entails the following disadvantage?

A. large conductor area is required for same power transmission
B. short-circuit current of the system is increased
C. either of the above
D. none of the above

The material commonly used for sheaths of underground cables is______________?

A. lead
B. rubber
C. copper
D. iron

The presence of ozone due to corona is harmful because it________________?

A. reduces power factor
B. corrodes the material
C. gives odour
D. transfer energy to the ground
E. none of the above

The voltage regulation in magnetic amplifier type voltage regulator is effected by__________?

A. electromagnetic induction
B. varying the resistance
C. varying the reactance
D. variable transformer

Which of the following relays is used on long transmission lines?

A. Impedance relay
B. Mho’s relay
C. Reactance relay
D. None of the above

The material generally used for armour of high voltage cables is_____________?

A. aluminium
B. steel
C. brass
D. copper