配电网防雷保护的分析与研究

结合配电网实际运行中的雷害情况和典型事例 ,全面分析了配电网的防护现状和雷害原因 ,认为配电网目前在网络结构、绝缘水平、防雷措施等防雷保护方面存在许多问题 (特别是线路绝缘水平低、防直击雷措施少、避雷器使用不当和接地不良、雷电过电压与内过电压联合作用 ,这些是目前配电网雷击跳闸率居高不下的主要原因 )。在此基础上提出了综合防雷措施 (包括规范避雷器的安装维护、改善避雷器和杆塔接地、使用塔顶避雷针、使用自动消弧装置降低配电网建弧率、限制雷电流过后的弧光接地过电压和铁磁谐振过电压等 ) ,以提高配电网耐雷水平和供电可靠性。

ANALYSIS OF LIGHTNING PROTECTION OF DISTRIBUTION NETWORKS

Through studying actual cases of lightning damage and representative accidents in the operation of distribution networks, the network structure, insulation level and lightning protection measure of distribution networks are analyzed. The status of lightning protection and problems, especially low insulation level of lines, lack of direct lightning protection measures, misemploy of lightning arrester and imperfect earth are discussed. Associative action of lightning overvoltage may be considered as the main reason of high lightning trip-out rate in distribution networks. Based on it, synthesis lightning protective measures including the perfect lightning arrester installation and operation, improvement of lightning arrester and tower grounding, taking use of lightning arrester on the top of tower, reducing the rate of arc generation in distribution networks using automatic tracing arc extinction devices, and limiting the arc over-voltage and the ferroresonant overvoltage caused by lightning, are proposed to improve lighting protection level and reliability of power supply in distribution networks.