Signifcance of Quality & Quantity of Gravel for Safe Designing of Grounding (Earthing) System of Substations

An electrical sub-station is an assemblage of electrical components including busbars, switchgear, power transformers, auxiliaries etc. These components are connected in a defnite sequence such that a circuit can be switched of during normal operation by manual command and also automatically during abnormal conditions such as short-circuit.

Sub-station are integral parts of a power system and form important links between the generating station, transmission systems, distribution systems and the load points.

The main objective of grounding electrical systems is to provide a suitably low resistance path for the discharge of fault current which ultimately provide safety to working personnel and costly installed equipments in the substation. The fow of heavy fault current results in rise of potential in the vicinity of point/area of fault (ground fault) with respect to remote ground. There is need to ensure that the ground potential rise, and touch and step voltages are within permissible limits.

This paper provides an overview of signifcance of quality and quantity of gravel in the substation in accurate designing of grounding system.