The Indirect-Lightning Performance of Overhead Distribution Line Considering the Mixed Ocean-Land Propagation Path

This article investigated the indirect lightning performance of an overhead line versus critical flashover voltage in the ground with two vertical layers, ocean and land. A novel method based on Monte Carlo and 3-D finite element method is provided to evaluate the annual number of line insulator flashovers. The proposed procedure reduced the computational efforts of the accurate induced voltage calculation and then the estimation of the line lightning performance. Using the proposed Monte Carlo method, the effect of the line distance from the ocean-land line interface, overhead line poles distance, land conductivity, and different ways for calculating the striking distance on the prediction of the yearly lightning flashover was analyzed. The obtained statistical results show that considering the mixed ocean-land propagation path ground strongly impacted the predicted number of the line flashovers caused by indirect lightning.