Influence of a Multilayer Soil Model on Calculation Accuracy of Lightning-Induced Currents on a Buried Cable

Abstract

To test theoretical methods proposed or adopted by researchers for the assessment of lightning-induced currents on buried cables, three sets of experimental data available in the literature are frequently used. The published tests results consist of the comparison of computed currents with the measured ones (of each set). For one set, a reasonably good agreement has been obtained by the assumption of a finitely conducting homogeneous ground (one-layer soil model). Recently, a reasonably good agreement has been obtained for the second set of data by more accurate modeling of the soil using a two-layer soil model. While for the third set, an important disagreement is still observed. In this paper, we propose an analysis which allows inspecting possible reasons of the latterly observed disagreement. It is shown that, the average accuracy of the calculated currents for a one-layer soil model can be improved from 6 to 15 % by the assumption of a two-layer soil model. Furthermore, the average accuracy obtained for a two-layer soil model can be improved from 0.3 to 51 % by the assumption of a three-layer soil model and for which the waveshapes of the measured and calculated currents are in a reasonably good agreement.