Measurements of Induced Voltages on Overhead Distribution Line Due to Altitude-Triggered Lightning

Abstract

This article presents the measurements of induced voltages at the terminal of an overhead distribution line caused by three altitude-triggered lightning events, consisting of three mini-return strokes and 16 subsequent return strokes. The results indicate that even mini-return strokes can generate significant induced voltages on the overhead line, as one of the mini-return strokes occurring at a distance of 20 m produces a peak value of 37.1 kV. The voltage waveforms predominantly exhibit positive polarity, with a noticeable negative polarity rebound at the end of the descending edge. However, the polarity of the voltage waveform induced by a subsequent return stroke exhibits either bipolar or unipolar characteristics, depending on the location of the lightning relative to the overhead line. During a lightning event, the average 10%–90% rise time of the induced voltage waveforms caused by the subsequent return strokes is slightly less than that of the mini-return stroke. Moreover, compared with the simulation results, the induced voltages are notably influenced by the tortuosity of the lightning channel.