Evaluation of Lightning-Induced Currents on Cables Buried in a Lossy Dispersive Ground
The paper discusses the effect of frequency dependence of soil electrical parameters (also called soil dispersion) on lightning currents induced on the shield of buried cables. To this aim, a full-wave approach based on the finite element method is used in which soil dispersion is incorporated into the model using available analytical formulae obtained from experimental data. It is shown that the soil dispersion can affect the induced currents only for soils with very low conductivities (<= 0.003 S/m). It is also shown that, depending on the burial depth of the cable, for poorly conducting soils with conductivities lower than 0.0005 S/m or so, the soil dispersion can result either in an increase or in a decrease of the induced current peak.