In recent years,several failures of double circuit transmission line on the same tower due to lightning were happened in Beijing power grid.Although it can be reclosed successful,the lightning strike caused a grave th...In recent years,several failures of double circuit transmission line on the same tower due to lightning were happened in Beijing power grid.Although it can be reclosed successful,the lightning strike caused a grave threat to the power grid security.The cause of the accident and the accident process were studied for the sake of further understanding of the impact of lightning on power grid.As an example,110 kV double circuit transmission line(Xilong-line) was analyzed.At first,the system topology was given.Through the analysis on relay protection actions and the fault recorder data,over voltage on the insulator strings was calculated.Based on the analysis and the calculation,accident cause and the process were presented respectively.Secondly,it comes to the conclusion that the lightning failure was caused by counterattack.The wave of the lightning over voltage would spread to the not grounded neutral point of the transformers,and make the neutral protective gap breakdown,then cause freewheeling with the frequency of 50 Hz.As results of the relay protection,the double circuit transmission line all tripped out.Finally,the causes of the accident were proposed that included terrain features,large corner towers,strong thunderstorm weather and poor grounded contact of the tower.展开更多
电网雷电监测网已积累了大量雷电数据,为研究和获取雷电特征,采用统计分析、数据挖掘并结合近年来大数据分析方法,对2005—2014年10年雷电监测数据进行了分析。分析结果表明：全国10年合计落雷1.28亿次,正极性比率呈现总体上升趋势,平均...电网雷电监测网已积累了大量雷电数据,为研究和获取雷电特征,采用统计分析、数据挖掘并结合近年来大数据分析方法,对2005—2014年10年雷电监测数据进行了分析。分析结果表明：全国10年合计落雷1.28亿次,正极性比率呈现总体上升趋势,平均为7.50%;各区域雷电活动差异较大,总数南方最高,地闪密度华东最高,全国平均地闪密度为1.33次/（km2·a）;雷电流幅值10年分布规律比较接近,累积概率分布拟合曲线a、b值为31.33 k A和2.76,与国际上IEEE和CIGRE推荐取值非常接近。对武汉和杭州两城雷电与降水量相关性分析表明：2者高峰期大体一致,月分布除个别年份外呈现中强相关性;两城雷电正极性比率与降水量相关性一致,除个别年份外呈现弱相关性;平均电流与降水量武汉为弱相关性、杭州除个别年份外也为弱相关性。基于雷电监测数据,融入大气电场、卫星云图、气象雷达数据,采用数据挖掘技术预测雷暴团运动趋势实现雷电预警。具体实例表明,预警提前时间为10～30 min,预警平均空间误差为5～15 km,预警有效率达75%～85%。展开更多
我国学者尝试在雷电活动强烈、污秽严重地区的110 k V架空线路应用复合材料绝缘杆,以提高相对地空气间隙距离和爬电距离。然而绝缘水平的提高,复合材料杆还是否需要架设避雷线以及避雷线接地引下线,是防雷面临的关键技术问题之一。针对...我国学者尝试在雷电活动强烈、污秽严重地区的110 k V架空线路应用复合材料绝缘杆,以提高相对地空气间隙距离和爬电距离。然而绝缘水平的提高,复合材料杆还是否需要架设避雷线以及避雷线接地引下线,是防雷面临的关键技术问题之一。针对典型110 k V复合材料杆,对比研究未架设避雷线的复合材料杆与架设避雷线的同电压等级、相同导线高度铁塔线路的雷电性能,考虑2种杆塔线路引雷能力、雷电冲击绝缘强度以及建弧率等因素的差异,发现:2种杆塔线路引雷能力间的差异可以忽略;未架设避雷线的复合材料杆雷电冲击绝缘强度是铁塔的3.5倍,建弧率为铁塔的53%,但是反击耐雷水平仅为24.5 k A,雷击跳闸率高达1.13次/(100 km?a),均明显劣于铁塔。据此,推荐110 k V复合材料杆架设避雷线。然后,对比估算避雷线不同接地方案下雷电性能的差异发现:避雷线若不经引下线接地,则复合材料杆雷电性能明显劣于铁塔,但若经引下线逐杆接地,则雷电性能显著优于铁塔。因此,提出避雷线应逐杆接地。综上所述,110 k V复合材料杆线路防雷接地方案应当采用架设避雷线,且通过金属引下线逐杆接地的设计。展开更多
文摘In recent years,several failures of double circuit transmission line on the same tower due to lightning were happened in Beijing power grid.Although it can be reclosed successful,the lightning strike caused a grave threat to the power grid security.The cause of the accident and the accident process were studied for the sake of further understanding of the impact of lightning on power grid.As an example,110 kV double circuit transmission line(Xilong-line) was analyzed.At first,the system topology was given.Through the analysis on relay protection actions and the fault recorder data,over voltage on the insulator strings was calculated.Based on the analysis and the calculation,accident cause and the process were presented respectively.Secondly,it comes to the conclusion that the lightning failure was caused by counterattack.The wave of the lightning over voltage would spread to the not grounded neutral point of the transformers,and make the neutral protective gap breakdown,then cause freewheeling with the frequency of 50 Hz.As results of the relay protection,the double circuit transmission line all tripped out.Finally,the causes of the accident were proposed that included terrain features,large corner towers,strong thunderstorm weather and poor grounded contact of the tower.
文摘电网雷电监测网已积累了大量雷电数据,为研究和获取雷电特征,采用统计分析、数据挖掘并结合近年来大数据分析方法,对2005—2014年10年雷电监测数据进行了分析。分析结果表明：全国10年合计落雷1.28亿次,正极性比率呈现总体上升趋势,平均为7.50%;各区域雷电活动差异较大,总数南方最高,地闪密度华东最高,全国平均地闪密度为1.33次/（km2·a）;雷电流幅值10年分布规律比较接近,累积概率分布拟合曲线a、b值为31.33 k A和2.76,与国际上IEEE和CIGRE推荐取值非常接近。对武汉和杭州两城雷电与降水量相关性分析表明：2者高峰期大体一致,月分布除个别年份外呈现中强相关性;两城雷电正极性比率与降水量相关性一致,除个别年份外呈现弱相关性;平均电流与降水量武汉为弱相关性、杭州除个别年份外也为弱相关性。基于雷电监测数据,融入大气电场、卫星云图、气象雷达数据,采用数据挖掘技术预测雷暴团运动趋势实现雷电预警。具体实例表明,预警提前时间为10～30 min,预警平均空间误差为5～15 km,预警有效率达75%～85%。
文摘我国学者尝试在雷电活动强烈、污秽严重地区的110 k V架空线路应用复合材料绝缘杆,以提高相对地空气间隙距离和爬电距离。然而绝缘水平的提高,复合材料杆还是否需要架设避雷线以及避雷线接地引下线,是防雷面临的关键技术问题之一。针对典型110 k V复合材料杆,对比研究未架设避雷线的复合材料杆与架设避雷线的同电压等级、相同导线高度铁塔线路的雷电性能,考虑2种杆塔线路引雷能力、雷电冲击绝缘强度以及建弧率等因素的差异,发现:2种杆塔线路引雷能力间的差异可以忽略;未架设避雷线的复合材料杆雷电冲击绝缘强度是铁塔的3.5倍,建弧率为铁塔的53%,但是反击耐雷水平仅为24.5 k A,雷击跳闸率高达1.13次/(100 km?a),均明显劣于铁塔。据此,推荐110 k V复合材料杆架设避雷线。然后,对比估算避雷线不同接地方案下雷电性能的差异发现:避雷线若不经引下线接地,则复合材料杆雷电性能明显劣于铁塔,但若经引下线逐杆接地,则雷电性能显著优于铁塔。因此,提出避雷线应逐杆接地。综上所述,110 k V复合材料杆线路防雷接地方案应当采用架设避雷线,且通过金属引下线逐杆接地的设计。
