Contents of large current flashes among all the lightnings measured on transmission lines

“ I (amplitude of lightning current” vs “P(1) (probability of s t r o k e c u r r e n t amplitude exceeding I ) ” characteristics are published in many papers. These are given by a single curve or by a functional formula of “I” regardless of t h e i s o k e r a u n i c level in the d i s t r i c t s where the transmission lines are passing. The author analized the results of lightning current measurement in Japan, and found that the I vs P(1) characteristic curves vary depending on the intensity of lightnings in the district concerned. In other words, the content (%) of large current lightnings (such as larger than 80kA) is very larger in heavy lightning districts than in mild lightning districts.