Comparison of Multiple Return Strokes and Multiple Ground Strike points Characteristics of CG Lightning over Areas with Different Surface Features

Abstract:
Studies have shown that about 50% of lightning has multiple ground strike points (GSPs). Lightning with multiple GSPs poses a new challenge to the lightning protection capability of ground objects, so it is significant to explore the characteristics of lightning with multiple GSPs for lightning research and protection. In this paper, Lightning data provided by China Power Grid Lightning Location System (LLS) in four water body areas and three forest areas in 2022 and 2023 are selected to calculate characteristics of lightning with multiple GSPs. The characteristics of lightning with multiple GSPs under different surface types of water and forest are compared and analysed. The results show that 1) forest has more return strokes than water area; 2) single ground strike point is more likely to occur in the water area, which is 10% higher than that in the forest area. The average number of GSPs of the former is 2.0 per flash, and that of the latter is 1.8, it is close to what has been reported. The proportion of lightning with three or less multiple GSPs is 91.9% and 95.4%, respectively. The average number of return strokes at multiple GSPs in forest and water area is 2.5, and about 67% of the multiple GSPs contain less than or equal to 2 return strokes.