Grid Grounding Calculations for a 132-KV Substation Using Soil Backfilling

Abstract

Safe and reliable grid design is complicated by the compact design of gas insulated substations (GIS). This paper discusses the complete grounding design procedure for a 132-KV substation in the city of Al Kharj based on the IEEE-80 specifications and local standard practices in the Kingdom of Saudi Arabia. To ensure a safely grounded grid design, local Saudi Electricity Company (SEC) standard design constraints were used. The current distribution electromagnetic interference, grounding, and soil structure (CDEGS) software was used to compare the test results for soils with and without backfilling. Due to the high resistivity of the plot, soil with a low resistivity should be used as backfill. The calculated results were compared to the standard values of ground potential rise, step voltage, touch voltage, and soil resistance. This paper contributes to an understanding of effective grounding techniques for soil with high resistivity and optimizes the increase in cost due to backfilling.