A Class of Hazardous Subsequent Lightning Strokes in Terms of Insulation Stress

Events of a class, consisting of the subsequent strokes of multiple-stroke flashes presenting the largest peak current, have features that make their effects very severe in terms of insulation stress, notably the combination of a relatively intense peak current and a very short front time. According to instrumented-tower measurements, their median peak current 27.2 kA is around 55% higher than that of the whole set of subsequent strokes and their median front time is around 0.7 μs. The frequency of such events is relatively significant since around 80% of lightning flashes are multiple-stroke flashes.