1. If string efficiency is 100 percent it means that ?

potential across each disc is zero

potential across each disc is same

one of the insulator discs is shorted

none of the above

Answer: potential across each disc is same

Explanation:


2. A synchronous condenser is generally installed at the of the transmission line ?

receiving end

sending end

middle

none of the above

Answer: receiving end

Explanation:


3. Power system stability is least affected by ?

reactance of generator

input torque

losses

reactance of transmission line

Answer: losses

Explanation:


4. When the load at the receiving end of a long transmission line is removed, the sending end voltage is less than the receiving end voltage. This effect is known as ?

Ferranti effect

Proximity effect

Kelvin effect

Faraday effect

Answer: Ferranti effect

Explanation:


5. Due to which of the following reasons aluminium is being favoured as busbar material ?

Low density

Low cost

Ease of fabrication

None of the above

Answer: Low cost

Explanation:


6. By using bundle conductors, the critical voltage for the formation of corona will ?

remain same

decrease

increase

not occur

Answer: increase

Explanation:


7. Solid grounding is adopted for voltages below ?

100 V

200 V

400 V

660 V

Answer: 660 V

Explanation:


8. The electrostatic stress in underground cables is ?

zero at the conductor as well as on the sheath

same at the conductor and sheath

minimum at the conductor and minimum at the sheath

maximum at the conductor and minimum at the sheath

Answer: maximum at the conductor and minimum at the sheath

Explanation:


9. System grounding is done so that ?

inductive interference between power and communication circuits can be controlled

the floating potential on the lower voltage winding for a transformer is brought down to an insignificant value

the arcing faults to earth would not set up dangerously high voltage on healthy phases

for all above reasons

Answer: for all above reasons

Explanation:


10. A lightning arrester is usually located nearer to ?

transformer

isolator

busbar

circuit breaker

Answer: transformer

Explanation: