Numerical Simulation of Transferred Potentials in Earthing Grids Considering Layered Soil Models

Computing the potential distribution on the earth surface when a fault condition occurs is essential to assure the security of the grounding systems in electrical substations. This paper presents a numerical formulation for the analysis of transferred earth potentials in a grounding installation due to metallic structures or conductors in the surroundings of the grounding grid when a layered soil model is considered . This transference of potentials between the grounding area to distant points by buried conductors, such as communication or signal circuits, neutral wires, pipes, rails, or metallic fences, may produce serious safety problems. The authors have recently developed a numerical technique based on the Boundary Element Method for the analysis of transferred earth potentials in the case of uniform soil models . In this work, it is presented its generalization for a two layer soil model. Thus, the main highlights of the numerical approach are summarized and some examples by using the geometry of real grounding systems in different cases of transferred potentials considering different soil models are presented.