Electrical Engineering XYZ MCQ on Power Transmission lines
Which of the following factor decides the insulation level of 400 kV, EHV line:
- Radio interference
- Skin effect
- Lighting voltage
- Switching over voltage
Correct answer: 4. Switching over voltage
Explanation: In case of transmission line voltages up to 230 kV the insulation level is decided by the requirement of protection against lightning.
In case of EHV, switching surges cause higher over voltages than lightning and therefore mainly responsible for insulation level decision.