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