Designing Earthing Grid/Mat for 33/11 KV Substation using GI Earth Flats and Pipes Maintaining Tolerable Step and Touch Potential
Dealing with high voltage could be a dangerous situation, unless the designing parameters (resistivity, selection of conductor, sizing) are met with effective performance to maintain the power quality, safety and reliability . In order to maintain a healthy system the design of earthing system should be such that, even in worst conditions of electrical faults which increase the step and touch potentials, all the equipment’s in the substation operates safe. An effective earthing grid helps to achieve this by selecting an effective grid area, conductor sizing, reduced soil resistivity with backfill component, creating a low impedance path to earth . This paper presents a brief calculation on designing an earthing grid/mat with GI flats and pipes rather than going for copper rods(being cost effective) for 33/11 KV substation, with a reference to IS 3043 of earthing a substation.
Keywords - Earthing, Earthing Grid, Step Potential, Touch Potential, Step Voltage, Mesh Voltage, Split Factor, GI Earthing, HV Substation, IEEE std 80, IS 3043.