Effect of dimension on ground grid design in MEA's power distribution substation

Abstract

This paper proposes characteristic of uniform (homogeneous) soil and grounding performance assessment which consist of ground potential rise (GPR), touch voltage and step voltage of ground grid buried in 0.5 m depth of uniform and two-layer soil. The study is separated in 2 parts. Part 1 involves characteristic of uniform soil. If the upper layer of two-layer soil is greater than 16 m, the characteristic of the soil can be regarded of homogeneous condition. Part 2 deals with the grounding performance between square and rectangle grids of the same coverage area. It is found that the less the ratio of a grid's width to its length, the better its grounding performance. By comparison the performance between square and rectangle of the same coverage area, rectangle ground grid possesses better grounding performance than square one. Modeling and simulation done throughout the paper is by the Current Distribution Electromagnetic interference Grounding and Soil structure (CDEGS) program. The simulation results exhibit the design and analysis of power system grounding and perhaps could be set as a standard in grounding system design and modification in distribution substations.