The design of 110kV substation grounding grid with high resistivity soil

This paper presents the design of 110kV substation grounding grid with high resistivity soil. A horizontal two layer soil model is built by means of the MALT program of the Software (CDEGS). The purpose of this paper is to minimize the touch and step voltages when the resistivity soil is high, in urban substation during a direct lightning stroke. The touch and step voltages in surface of the ground was calculated based on its soil resistivity in top and bottom layers. The calculated results are compared with the standard values that formulated in IEEE Guide for Safety in AC Substation Grounding.