Numerical Technique to the Evaluation of Multiple Grounding Electrodes Coupled by the Soil in High Voltage Substations

This paper shows one way to calculate grounding potentials in adjacent electrodes presented in high voltage substation coupled by soil to the main grounding grid in a two- layer soil. This problem is of special concern due to the presence of passers-by near metallic fences, whose potentials usually have not been evaluated, not directly connected to the grounding grid. In this context, the paper presents a general analytical formulation aiming to estimate the possible risk to human beings close to the substation. In order to do that, the generated potentials originating from a short-circuit in the electric power system are calculated considering the coupling by soil between the main grounding system and the adjacent electrode (the metallic fence).