Observed Induced Overvoltage on the Test Overhead Distribution initiated from Natural Lightning Activities

A new rocket-triggered lightning experiment site has been established by us in Zhanjiang, Guangdong Province, China since the summer of 2022, for the aim of the direct or indirect coupling effect research on industrial systems such as wind turbine, overhead distribution line system, small-scale steel building structure, and buried cables due to both the natural and rocket-triggered lightning flash. This paper reports the lightning-induced overvoltage observed on a test overhead distribution line, caused by 24 natural lightning return-stroke events during 2 consecutive days of afternoon thunderstorms. Comparing with the results of the rocket-triggered LIV reported by Wang et al. and Cai et al., and the natural LIV observations by Yang et al., the general characteristics of the recorded pulse waveforms are similar, while there is a significant difference in the 10%-90% rising time of the first positive wave peak of the LIVs. Considering the recorded much lower amplitude of the waveforms, the phenomenon can be reasonably illustrated by the fact that lightning activity occurs farther away from the observation site and the high-frequency attenuation of EM propagation is more significant. Meanwhile, three LIVs waveforms were recorded to have the initial reverse polarity wave before the return-stroke-induced first positive waves, which are regarded to be leader-process response and are impacted by the location of the lightning relative to the line. The report is an important guide for the research and practice techniques of lightning activity monitoring, localization, and overvoltage surge identification based on the line monitoring devices in real operation.