Simulation of initial electric field distribution for prediction of lightning-caused breakdown paths to underground cables

Information about the initial electric field distribution in soil is fundamental to the prediction of lightning-caused breakdown paths and performance of struck underground cables. Field calculations in existing models assume homogeneous soils and ignore presence of cables. In this paper, the initial electric field distribution is calculated using a 2-dimensional model which recognizes the presence of cables and soil inhomogeneity. The effects of artificial boundary placement, lightning strike location and cable configuration have also been considered. The results are used to explain the effect of the presence of the cable on the tendency of formation of breakdown paths in soil. The proposed model is useful in assessing the impact of direct lightning strikes on underground cables.