A unique method of predicting lightning outage rates for substations, taking into account statistics-based lightning characteristics, has been developed. The proposed method features the application of two processes in combination: a high-accuracy lightning surge analysis applying the electro-magnetic transient program (EMTP); and a statistical data analysis using general spreadsheet software. By employing an original tool applying the proposed prediction method, which is installed in a personal computer, optimal substation lightning protection can be designed. In this paper, several analysis models are proposed for lightning characteristics including lightning surge. The validity of the proposed method was achieved by comparing the transmission line outage rates derived by the models with the outage data gained during actual observations. It was found that the predicted lightning outage rates for 500 kV substations were relatively low, and this finding revealed that it is possible to decrease the impulse withstand voltage level (LIWV).