LA Health Check

LA Health Check

The primary function of a lightning arrestor is to absorb high energy generated by lightning or switching surges and hence to protect the equipment in substation. Lightning arrestors are exposed to stresses such as the normal operating voltage, temporary over voltages, switching over voltages, lightning over voltages and external pollution. The magnitude of over voltage could be 1.5 to 4 times of the normal operating voltage. If lightning arrestors are not healthy, it will fail to protect the equipment it is connected to in the severe over voltage condition.

Lightning arrestors drives a small amount of current under continuous operating voltage known as leakage current. This leakage current can increase over the period of time due to stresses the lightning arrestors undergo.

Measuring the Third Harmonics Leakage Current gives a fair idea of aging or weakness of the Lightning Arrestors. Also, the weak Lightning Arrestors generate a little amount of heat. Like any other equipment even a faulty or weak Lightning Arrestor produce ultrasound noise. Hence, all these parameters must be captured periodically to avoid sudden failure/blasting and outage.