On the optimization of Grounding Design of Rods Covered by Low Resistivity Materials

Reducing the grounding resistance using low resistivity materials (LRM) is a widely used technique to improve the grounding system performance, especially under high resistivity conditions. In this light, the present paper deals with cost-effective design of a typical configuration of grounding systems with LRM coverings. Indeed, optimization problems are proposed and resolved using particle swarm optimisation. Considering vertical ground electrodes partially and fully covered by LRM, the objective is devoted to obtain the geometrical configuration that gives simultaneously an economical and safe grounding design. Each step in the optimization is discussed to help generalise the technique for more complex grounding designs. The results show that soil treatment can significantly reduce the grounding resistance by more than 50% compared to identical systems without LRM coverings. Moreover, the optimal geometrical parameters are senssitive to the variation of the soil resistivity as well as the maximum tolerable limits.