Monitoring and analysis of lightning current waveform observed on transmission line and lightning tower

For better understanding lightning characteristics, we analyzed four lightning current waveforms obtained by an online lightning current monitoring system which was developed by Wuhan University. The system had 43 monitoring devices, which were distributed on transmission lines of 110, 220 and 500 kV, and some other lightning-attracting places, such as tall buildings and lightning towers. The four typical lightning current waveforms were as follows: the first one was a lightning strike on No. 51 tower of 110 kV Wangguan line in Hubei Power Grid on April 22rd, 2007, current amplitude of which was -11.8 kA; the second one was a lightning strike on a lightning tower on Fenghuang Mountain in Shenzhen, on September 17th, 2008; the third one was a lightning strike on No. 51 tower of 220 kV LuluoIline in Yunnan Power Grid, at 14:39:21 on September 8th, 2010, which had current amplitude of -10 kA, wavefront of 0.5 μs, and half wave time of 23.0 μs; the last one was a lightning strike on No. 51 tower of 220 kV LuluoIline in Yunnan Power Grid, at 23:46:49, on September 8th, 2010, which had current amplitude of -9.3 kA, wavefront of 1.0 μs, and half wave time of 22.0 μs. Time and space information of the four lightning current waveform were consistent with the data of lightning location system; all the lightning currents were oscillating. The observed lightning current waveforms can be referred in practical lightning protection.