10kV配电线路避雷器防护分析

Analysis on the Protection Characteristics of Lightning Arrester of 10 kV Overhead Power Distribution Lines

雷电是威胁配电线路安全可靠运行的关键因素,开展10 kV配电线路避雷器防护性能研究对提升避雷器安装技术经济成效具有重要意义。本文基于10 kV配电线路雷击电磁暂态EMTP模型,研究了避雷器在直击雷和感应雷下的防护性能。结果表明,雷击导线时避雷器保护范围与雷电流波头、波在线路上的传播速度等因素有关,避雷器最大吸收能量并非随着雷电流的增大而持续增大,分布在首尾安装有避雷器的杆塔之间的杆塔,其耐雷水平近似呈“U型”分布规律,安装时上相建议采用通流容量更大的避雷器;感应雷下闪络发生在未安装避雷器的杆塔,对于安装避雷器的杆塔应尽量控制接地电阻≤20Ω;配电线路每隔2基塔安装避雷器时,宜配合使用架空地线才能取得不错的雷击防护效果。

Lightning is a key factor threatening the safe and reliable operation of distribution lines,carrying out study on the protection characteristics of lightning arrester is of great importance to the technical and economic effects after installing arrester of 10 kV distribution lines.Based on the 10kV lightning electromagnetic transient EMTP model,the protective performance under direct lightning and induced lightning were studied.The results show that the protection range of arrester while lighting striking the conductor is related to the factors such as length of lightning current wavefront,propagation speed,and the maximum absorbed energy of the arrester does not increase linearly with the increase of lightning current,and as to the poles that locates between the poles with arrester installed at the head and tail,its lightning withstand level shows an“U”form distribution characteristic,It is recommended to use a surge arrester with a larger flow capacity during installation to the top phase.While under induced lighting,flashover occurs on the tower without installing arrester,the grounding resistance of pole is best to control below 20Ωafter installing arrester.As to the power distribution lines,it is feasible to install a set of arresters every two poles with installing the overhead line as well to reduce the trip rate of lightning effectively.