Observation of lightning flashes to transmission lines using a high speed camera system

The observation of lightning flashes striking transmission lines in a mountainous area has been conducted using the Automatic Lightning Progressing feature Observation System for the improvement of the lightning protection of the electric power systems [1]. The observation system is a high-speed digital camera for measurement of progressing features in lightning discharges. In the observation, we obtained three flashes to transmission lines and seven flashes to the ground. From the results, we estimated the striking distance. The value of the striking distance was about 80 m at a current of 23 kA and about 150 m at a current of 88 kA. We evaluated the return stroke velocity. On the basis of the analysis, we discussed the lightning shielding model.