EARTHING WIRE and SURGE ARRESTER

Q.Why we are using both earthing wire on top of tower and again surge arrester in substation?

A.              Generally there are two types of lightning one is direct lightning and indirect lightning. Direct ligtining can be diverted to earth by using earth wire on top of power line so that power line was in safe condition. But there is another type of lightning called indirect lightning which cannot  be arrested by using earth wire or top earth poles because it will form on power line directly as clouds are moving on top of power line. It can be diverted only through surge arrester or lightning arrester.

                     

Preparing earth pit for system earthing by using GI pipe and coal,salt mixture (India).