Particular grounding systems analysis using FEM models

The aim of this work is to study the actual behavior of grounding systems using the Finite Element Method (FEM) in the Ansys Maxwell environment. Given the importance of grounding resistance to ensuring the proper functioning of all electrical systems and even more so for people's safety, it is nevertheless advisable to verify and validate this method for its application during the design stage. The validation of the model has been carried out through the hemispheric electrode, whose mathematical expression for the grounding resistance is well known. However, for other type of electrodes, as grounding rods, the equations usually adopted to design grounding systems provide only approximated values for their grounding resistance. Besides, these equations are able to estimate the grounding resistance only for homogeneous resistivity of the earth. Consequently, traditional methods can give values for the grounding resistance that can differ from the actual behavior due to these uncertainties. In this paper, the use of finite element analysis has been investigated to determine a better estimation of the grounding resistance in different scenarios and to find the distribution of the grounding potential for step and touch voltages calculation on particular critical conditions.

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