Over Voltage may be caused by condition external or internal to the electrical system. There are mainly two causes that may result to over voltage. They are:
1. Internal Causes
2. External Cause
Internal Causes
- These are mainly due to oscillations set up by sudden changes of circuit conditions or by resonance.
- These are due to
i. Switching operation of an unloaded Line
ii. Sudden Change in Load
iii. Sudden opening of loaded line, particularly under short circuit conditions.
iv. insulation failure
v. arcing grounds
vi. resonance
External Causes:
These are mainly due to atmospheric conditions that is due to lighting.
i.e. Voltage = Several Times to normal Voltage
So, external causes are neither possible nor economical to design the insulation of a transmission system.
The device used for protection of electrical equipment from surges or overvoltage are known as overvoltage protection devices and are below:
i. Ground wires
ii. Earth Screen
iii. Surge Diverters or lighting Arrestors
1. Internal Causes
2. External Cause
Internal Causes
- These are mainly due to oscillations set up by sudden changes of circuit conditions or by resonance.
- These are due to
i. Switching operation of an unloaded Line
ii. Sudden Change in Load
iii. Sudden opening of loaded line, particularly under short circuit conditions.
iv. insulation failure
v. arcing grounds
vi. resonance
External Causes:
These are mainly due to atmospheric conditions that is due to lighting.
i.e. Voltage = Several Times to normal Voltage
So, external causes are neither possible nor economical to design the insulation of a transmission system.
The device used for protection of electrical equipment from surges or overvoltage are known as overvoltage protection devices and are below:
i. Ground wires
ii. Earth Screen
iii. Surge Diverters or lighting Arrestors