Earthing has to be provided for
- Safety of personnel,
- Prevention of and minimizing damage to equipment as a result of flow of heavy fault currents, and
- Improved reliability of power supply.
The primary grounding system is in the form of an earth mat with risers. Risers of MS flat are commonly provided. Earth mat is provided inside the substation area. The earth rods are linked to the station earth mat. The earthing must be designed so as to remain the earth resistance as low as possible.