Impact of Different Frequency-Dependent Soil Models in Transient Ground Potential Rise

The frequency dependence of soil electrical parameters must be considered for a precise computation of the electrode grounding impedance and of the transient ground potential rise (GPR) generated by an injected lightning current. This work computes the grounding impedances of conductors (rods and electrodes) seen as short transmission lines (TL) based on the Transmission Line Model (TLM). These conductors are buried into distinct types of ground, such as frequency-independent (FI) and three distinct frequency-dependent (FD) soil models. Furthermore, the transient GPR generated by a lightning strike is computed. Results indicate that FD soil models have provided distinct responses which the GPR peaks are considerably reduced when the frequency dependency of the soil electrical parameters is included in the simulations.