Optimal Design in Distribution Substation’s Grounding System for Decreasing Touch Voltage

This paper presents a technique for grounding system design in a small area distribution substation. Compression ratio adjustment in order to decrease touch voltage is hard to design with this situation due to the limitation of area. Furthermore, this condition can’t use the ground rod length increasing method since the length doesn’t reach bottom layer of the ground. So this paper will show a method for solve this problem by using apparent resistivity from field, then analyze and estimate the resistivity with steepest descent method, after that simulate grounding system with two layers of soil by using CDEGS software base on IEEE 80-2000. The results show that touch voltage decrease 47.48 percent when increase ground grid and ground rod in square type at the edge of substation although bottom layer has more soil resistivity than top layer.