Optimized pit configuration for efficient grounding of the power system in high resistivity soils using low resistivity materials

Abstract

In an electrical power system, the integrity of the grounding system is very important to maintain a reference point of potential for equipment and personnel safety, to provide a discharge point for lightning currents as well as to prevent excessive high voltages on the power system. Therefore, to maintain ground system effectiveness, proper design, installation and testing of grounding system is required. In Saudi Arabia, the weather is dry and the soil resistivity varies significantly from area to area because the geodetic terrain varies from sea shore to the arid desert and dry mountains. In most of the inland desert areas, the soil resistivity is significantly high and it is difficult to get the low earth resistance with conventional methods. Therefore to get a low value of grounding resistance, a good design of the grounding pit is necessary which can be achieved by using low resistivity materials. When such materials are used, it is important to optimize the pit design in order to have an economical and efficient grounding system. This paper presents a novel technique for finding the optimum size of grounding pits commonly used in the electrical power systems. With this technique, we can easily find out an optimized pit design that can effectively reduce the grounding resistance to an acceptable value. The obtained results can be readily used by engineers to obtain a good earth pit configuration for efficient grounding of the power system in the high resistivity soils by using low resistivity materials (LRM).