an earth conductor provided on the top of the transmission line provides protection against

An earth conductor provided on the top of the transmission line provides protection against direct lightning strikes.

This earth conductor, also called a ground wire or shield wire, acts as a lightning rod for the transmission line. Here's how it works:

Lightning Attraction: The earth conductor is positioned higher than the actual transmission lines. This makes it more likely to be struck by lightning compared to the power lines themselves.

Current Path: When lightning strikes the earth conductor, the current is safely diverted away from the power lines and channeled down the conductor towards the ground.

Earthing: The earth conductor is connected to grounding rods driven deep into the earth. This allows the lightning current to dissipate harmlessly into the ground.

By intercepting lightning strikes, the earth conductor helps to prevent damage to the transmission lines and ensures a more reliable flow of electricity.