Performance dos modelos do solo com parâmetros elétricos variáveis com a frequência e o teor de umidade

Walter Luiz Manzi de Azevedo; Anderson Ricardo Justo de Araújo; José Pissolato Filho

doi:10.20906/sbse.v2i1.2877

Walter Luiz Manzi de Azevedo School of Electrical and Computer Engineering, University of Campinas, Campinas, São Paulo
Anderson Ricardo Justo de Araújo School of Electrical and Computer Engineering, University of Campinas, Campinas, São Paulo
José Pissolato Filho School of Electrical and Computer Engineering, University of Campinas, Campinas, São Paulo

DOI: https://doi.org/10.20906/sbse.v2i1.2877

Keywords: Electromagnetic transients, Lightning performance, Grounding system, Frequency dependence of soil parameters, Water content

Abstract

This article investigates the performance of three soil models with electrical parameters dependent on the frequency and the moisture content proposed by Smith-Longmire, Scott, and Messier. Firstly, the grounding harmonic impedance is calculated for these soil models using the electromagnetic software FEKO for a frequency range between 100 Hz and 5 MHz. Three different cases are analyzed: homogeneous soil and stratified soils (2 and 3 layers). Then, the ground potential rise (GPR) is computed for two typical lightning impulse currents. All results are compared with those computed assuming a soil model with frequency-constant electrical parameters. Results show a variation in grounding harmonic impedances for the different soil models, being the most expressive for the Smith-Longmire model. The GPR presents a significant reduction in the peak values obtained, especially for the frequency-dependent homogeneous soil. However, there is a small impact on the potential elevation for soil with 3 layers due to the lowest equivalent resistivity, concerning a soil computed with the same soil topology using the frequency-constant parameters.