Two Layer Soil Model For Power Station Grounding System Calculation Considering Multilayer Soil Stratification

E.MOMBELLO, O.TRAD, J.RIVERA, A.ANDREONI

ELECTRIC POWER SYSTEMS RESEARCH

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2019 vol. 37 p. 67 - 78

0378-7796

Two-layer soil models are commonly used for the design of power station grounding systems. Calculations based on such models usually give correct values for the ground resistance of grounding electrodes and for the step and touch potentials on the surface of the ground. However, the two layer soil model of rhe actual soil can give absurd resultas if incorrect values of the layer resisitivities and the first layer thickness are used. Conventional methods of fitting the apparent resistivity curve in order to obtain combinations of different layer resistivities exist. In this paper an analisis of critical cases was carried out , and a novel calculation method for the parameters of the two layer soil model is presented. The proposed method is valid for an arbitrary number of soil layers with arbitrary values of resistivity, and is applicable to simple as well as complex groundig systems. The numerical results of this method were compared with electromagnetic field calculatios carried out with a computer program based on the finite element method.