Observation of Attachment processes of Lightning Flashes Striking 500 kV Transmission lines with High-speed Video Cameras

Abstract:
Natural lightning has been observed by high-speed video cameras since 2010. From 2010 to 2020, we observed nine lightning flashes striking 500 kV transmission lines. These observation results show the attachment processes of lightning flashes striking 500 kV transmission lines. When the downward leader approach the transmission line, many upward leaders initiate from the ground wire. The range of the ground wire from which upward leaders initiate is wide. Finally, one of them connects the downward leader. We estimated 2D striking distances of the 500 kV transmission line from the observation results using two definitions of striking distance. Furthermore, the relationships between the peak of lightning current and the striking distance are evaluated.