Theoretical analyses of a substation grounding system

The paper deals with grounding systems used in the substations and by the HV towers. The aim of the work was to verify the possibility of numerical simulations of these systems by standard FEM software and to analyse the influence of different disturbances on the grounding system. A simplified model of a substation grounding system was prepared in several different sizes. To cover the problem, it was necessary to solve the electric current field with the current injected into a grounding system point. Different values of the ground resistivity were considered and the problem was also solved with defined disturbances: disconnected chosen branches of the grounding system etc. Performed simulations confirmed the possibility of simulations of the grounding systems by standard FEM software packages and they give us an idea about the grounding system behaviour in the case of different failures. The paper describes the problem, used geometrical models, applied boundary conditions and the results under different system and ground configurations. Some results are presented. The results summary and conclusions are at the end of the paper.