Earthing system for a small area substation having very high soil resistivity in the hilly region by multi-layer soil modeling and deep driven vertical earth electrodes - A Practical experience

Design of earthing system of a substation becomes difficult when the soil resistivity measures high and available area for laying conductor is small. Accurate measurement of soil resistivity, proper analysis of soil resistivity measurements, optimal grid spacing, proper assumption of fault currents, analysis with two or multi layers soil model play important roles in optimal, safe and economical design of earthing system of a substation.

This paper proposes a method of earthing system analysis for hilly region where soil resistivity is quite high and area available for grounding system is also limited. The impact of deep driven vertical earth electrodes has been studied for ground resistance, safe and touch potentials. An experimental analysis has been carried out at Roing substation of Arunachal Pradesh. CDEGS Autogrid pro software has been used for the experimental results of grounding system of Roing substation with multi-layer soil modeling and deep driven rods.