Question

5. Overvoltage protection of power transmission lines.

Answer 1

OVERVOLTAGE PROTECTION:

over voltage protection is a power supply feature which shuts down the supply, or clamps the output, when the voltage exceeds a pressure level. Most the power supplies use an over voltage protection circuit to prevent damage to the electronic components.

over voltage protection is required in case of hydro electric or gas turbine generators but not in case of turbo generators transmission line.

Over voltage may be caused due to

1.the transient over voltage in the transmission line due to lighrening.

2. Defective operation of the voltage regulator.

3.Sudden loss of load due to line tripping

The protection is provided with an overvoltage relay.

It is usually of induction pattern with an IDMT ccharacteristic