电工技术学报  2021, Vol. 36 Issue (4): 857-868    DOI: 10.19595/j.cnki.1000-6753.tces.191805
高电压与放电 |
闪电连接高度对地面电场波形的影响
周蜜, 丁文汉, 王建国, 蔡力, 樊亚东
武汉大学电气与自动化学院 武汉 430072
Effect of Lightning Junction Height on Ground Electric Field Waveform
Zhou Mi, Ding Wenhan, Wang Jianguo, Cai Li, Fan Yadong
School of Electrical Engineering and Automation Wuhan University Wuhan 430072 China
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摘要 传统回击模型认为回击从地面始发往云层发展,最新针对闪电连接过程的观测事实表明,闪电的先导连接过程发生在地面以上高度,先导连接后闪电连接高度处会产生上行回击电流和下行回击电流,并沿通道分别向云层和地面发展。该文提出考虑闪电连接高度的回击发展模型,计及在连接高度处的回击电流双向传输模式,利用该模型计算分析距闪电通道不同距离(50km、5km、50m)的地面电场。结果发现,地面电场波形受回击电流波前陡度的影响,下行回击的存在可能导致电场强度波形在上升阶段出现尖锐的初始尖峰。用电场初始尖峰过冲百分比来描述电场尖峰过冲程度,进一步分析连接高度、回击电流波前陡度和下行回击速度对电场初始尖峰过冲程度的影响,发现随着闪电连接高度的增加,电场初始尖峰过冲增大,持续时间增加;回击电流波前陡度增大,电场初始尖峰过冲增大;下行回击速度增大,电场初始尖峰过冲增大,但持续时间缩短。10m内较低闪电连接高度下,波前陡度为20~60kA/μs的电流在下行回击速度大范围变化下,电场强度波形中无明显初始尖峰。相比传统回击发展模型,考虑闪电连接高度回击发展模型的地面电场计算结果与观测事实更吻合,揭示了闪电连接高度对地面电场初始尖峰形成的影响机制。
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周蜜
丁文汉
王建国
蔡力
樊亚东
关键词 雷电流闪电连接高度电场初始尖峰传输线模型电流波前陡度回击速度    
Abstract:It was assumed by traditional return stroke models that the return stroke originates from the ground and develops towards the cloud. However, recent observation results show that, at the junction height, the lightning return stroke will generate bidirectional currents to the cloud and to the ground, respectively. Combined with the recent observation results about the lightning initiation process, an extended return stroke model incorporating bidirectional propagation of the return stroke at the junction height is proposed. Then, the ground electric field at different distances (50km, 5km, 50m) is calculated. The results show that, depending on the wavefront steepness of the current, the existence of the downward return stroke may generate a sharp initial peak in the rising portion of the electric fields. The sharp initial peak overshoot is defined to represent the extent of sharpness. The influence of junction height, current wavefront steepness and downward return stroke speed on overshoot is further analyzed. It can be seen that, as the junction height increases, the amplitude and duration of the sharp initial peak increase. Besides, a larger wavefront steepness and a larger downward return stroke speed tend to produce a larger initial field peak overshoot. The increase of downward return stroke speed results in a shorter duration of initial field peak. The electric field waveforms calculated by the proposed return stroke model are more consistent with the measured ones than the conventional models, revealing the physical mechanism of sharp initial electric field peak.
Key wordsLightning current    lightning junction height    initial sharp electric field peak    trans- mission line model    wavefront steepness of current    return stroke speed   
收稿日期: 2019-12-24     
PACS: TM865  
基金资助:国家自然科学基金(51877155,51807144,41775007)和某重大基础科研计划(2019207029)资助项目
通讯作者: 王建国 男,1968年生,教授,博士生导师,研究方向为雷电防护与接地技术、高电压绝缘与测量技术等。E-mail: wjg@whu.edu.cn   
作者简介: 周 蜜 男,1986年生,博士,副教授,研究方向为雷电防护和接地技术。E-mail: zhoumi927@whu.edu.cn
引用本文:   
周蜜, 丁文汉, 王建国, 蔡力, 樊亚东. 闪电连接高度对地面电场波形的影响[J]. 电工技术学报, 2021, 36(4): 857-868. Zhou Mi, Ding Wenhan, Wang Jianguo, Cai Li, Fan Yadong. Effect of Lightning Junction Height on Ground Electric Field Waveform. Transactions of China Electrotechnical Society, 2021, 36(4): 857-868.
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https://dgjsxb.ces-transaction.com/CN/10.19595/j.cnki.1000-6753.tces.191805          https://dgjsxb.ces-transaction.com/CN/Y2021/V36/I4/857