农村电网防雷保护的分析与讨论

通过对农村电网在实际运行中的雷害事故情况和典型事例的分析,认为线路绝缘水平低,缺少防直击雷的措施,避雷器的使用不当和接地不良,雷电过电压与内过电压的联合作用是目前农村电网雷击跳闸率居高不下的主要原因。提出了规范避雷器的安装维护,改善避雷器和杆塔接地,使用塔顶避雷针和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,降低配电网建弧率等防雷措施,可提高配电网的耐雷水平。

Analysis on Lightning Protection of Rural Distribution Networks

Through studying on practical cases of lightning damage and typical accidents in operation of rural distribution networks, the network structure, insulation level and anti-lightning measures are analyzed. The high lightning trip rate at rural distribution line is attributed to low insulation level of lines,llack of direct lightning stroke protection measures,improper use and imperfect earthing of lightning arrester and combinative action of lightning over-voltage and internal over-voltage.jBased on it, combinative lightning protective measures such as improvement of lightning arrester and tower grounding, installation of lightning rod on the top of tower,using automatic arc extinction devices for reducing the arcing rate and limiting the arc grounding over-voltage and the ferroresonant over-voltages caused by lightning surge current are proposed to improve lightning protection level and reliability of power supply in distribution networks.