Assessing the impact of subsequent strokes on the lightning performance of transmission lines of 138 kV

The Hybrid Electromagnetic Model was used systematically to determine lightning overvoltages across insulator strings due to direct strikes to the tower top in order to assess the importance of subsequent strokes on backflashovers for 138-kV transmission lines. It was found that for some specific conditions, especially for lines with high towers and low tower-footing grounding resistances, subsequent strokes may be a relevant source of lightning outages.