Differences between triggered lightning striking to ground and distribution line inferred from measured currents and electromagnetic fields

Abstract

In 2018–2019, two types of rocket-triggered lightning tests, that is, striking to ground and distribution line, were conducted in Guangdong, China. The main focus of this paper is to compare the waveform parameters of the return strokes (RS) from the two tests. For current, the 10%–90% risetime of RS from lightning striking to distribution line is 2.4 times higher than that striking to ground, and the differences in the other parameters are small. For close magnetic field, the RS from lightning striking to distribution line have a lower peak (30% lower after considering the peak current) and a larger risetime and half-peak width time; besides, it is necessary to divide the front edge of the close magnetic field waveform into two parts: leader (BL) and return stroke (BRS). For close electric field, the close RS electric field peak (ERS) was less sensitive to distance than the leader electric field peak (EL). For far electric field, the differences in waveform parameters of RS from the two tests were not significant, but after considering the peak current, the normalised initial electric field peak (EP) of RS from lightning striking to distribution line was 14% lower than that striking to ground.