Avaliação da resposta de aterramentos elétricos frente a descargas atmosféricas considerando os efeitos de ionização e dependência com a frequência dos parâmetros do solo com base na aplicação do método FDTD

Abstract

This work aims to evaluate the response of electrical grounding systems to lightning, with an emphasis on soil ionization effects and the frequency dependence of soil parameters, based on results obtained from systematic computational simulations using the FDTD (Finite-Difference Time Domain) method. For this purpose, adjustments to the method were studied to represent both effects, singly. The results indicate the impact of both effects, especially in the reduction of low-frequency grounding resistance values ​and in the impulsive grounding impedance. The analyses indicate that ionization and frequency dependence influence the impulsive grounding impedance differently. The grounding resistance at low frequency decreases as the electrode length increases, while the impulse impedance reduces until it reaches the value corresponding to the effective electrode length. Frequency dependence exerts greater influence in more resistive soils and longer electrodes. To ensure the reliability of both studies, the results incorporating the effect of soil ionization were compared with Weck's formulation. Additionally, the results obtained through FDTD, which consider the frequency dependence of soil parameters, were compared with the HEM (Hybrid Electromagnetic) electromagnetic model.