A power plant earthing system is built around a site-wide earth mat (grid) that every structure, machine and the system neutral connect to. It handles very high fault currents, keeps step and touch voltages safe across the switchyard, and ties in lightning protection - designed to IEEE 80 and IS 3043.
The parts of the system
- Earth mat - buried copper or GI grid with perimeter and corner rods.
- Equipment earthing - every machine, structure and panel bonded to the mat.
- Neutral and system earthing - generator and transformer neutrals to a dedicated earth.
- Lightning protection - masts over the switchyard and tall structures.
- Instrument / clean earth - a reference for control and protection systems.
Design drivers
The fault level sets the conductor size; the soil resistivity sets the grid length and rod count; the step-and-touch limits set the mesh spacing. High-fault switchyards use heavy copper; poor soil uses compound or conductive-concrete electrodes to reach the resistance target.
