Effect of compression ratio on touch voltage in layered soil

This paper presents analysis of substation grounding grid using exponentially spaced grid. We have mainly focussed on safety touch voltage criterion for various compression ratios of grid. The grids are analysed for single layer soil model with and without ground rods. Further, the effect of compression ratio on touch voltage for two layer soil model at different soil resistivity reflection factors and top layer thickness are analysed. Moreover, the impact of compression ratio on various multilayer soil models is analysed. The analysis revels that once the area of substation grid and soil model are defined, with same number of grid conductors, when exponentially spaced enhances the safety by decreasing touch voltage as compared to equally spaced grid. With use of ground rods, optimal compression ratio increases, and makes grid more uniform.