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
Based on the idea of risk evaluation, the existing lightning damage risk assessment methods are reviewed and summarized in this paper. And the power grid lightning damage risk assessment system is established on the b...Based on the idea of risk evaluation, the existing lightning damage risk assessment methods are reviewed and summarized in this paper. And the power grid lightning damage risk assessment system is established on the basis of lightning flashover risk evaluation methodology for transmission lines, and adopts the improved Analytic Hierarchy Process as the core algorithm. It can comprehensively evaluate the risk for transmission lines of regional grid, various sections of a line and each tower of the section, considering much more impact factors, including the running time of line, importance of grades, equipment damage, and the success rate of lightning stroke reclosing and so on. According to the calculation results of the risk assessment of the analytic hierarchy process and lightning flashover risk evaluation, the principles and methods of grade classification for power grid lightning damage risk map are studied, and give typical examples in the paper. It can describe the lightning withstanding ability much more scientifically and provide important references for the manage department of power system.展开更多
统计分析了包头地区雷电地闪次数、雷电流幅值累积概率分布特征及配电线路雷击跳闸故障的时空分布特征;在电磁暂态程序(EMTP)中建立10 k V同塔四回线路雷击闪络模型,在考虑系统工作电压的情况下,研究了同塔四回线路雷击同跳闪络特性及...统计分析了包头地区雷电地闪次数、雷电流幅值累积概率分布特征及配电线路雷击跳闸故障的时空分布特征;在电磁暂态程序(EMTP)中建立10 k V同塔四回线路雷击闪络模型,在考虑系统工作电压的情况下,研究了同塔四回线路雷击同跳闪络特性及避雷器的不同配置方式对线路耐雷性能的影响;根据研究结果,提出了改善同塔四回线路耐雷性能的最优方案:对多雷区的杆塔,宜采用在I回AC相、III回C相、IV回BC相加装避雷器;对中雷区的杆塔,建议在I回AC相、IV回BC相加装避雷器;对少雷区的杆塔,只需将避雷器加装在I回A相和IV回B相。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Based on the idea of risk evaluation, the existing lightning damage risk assessment methods are reviewed and summarized in this paper. And the power grid lightning damage risk assessment system is established on the basis of lightning flashover risk evaluation methodology for transmission lines, and adopts the improved Analytic Hierarchy Process as the core algorithm. It can comprehensively evaluate the risk for transmission lines of regional grid, various sections of a line and each tower of the section, considering much more impact factors, including the running time of line, importance of grades, equipment damage, and the success rate of lightning stroke reclosing and so on. According to the calculation results of the risk assessment of the analytic hierarchy process and lightning flashover risk evaluation, the principles and methods of grade classification for power grid lightning damage risk map are studied, and give typical examples in the paper. It can describe the lightning withstanding ability much more scientifically and provide important references for the manage department of power system.
文摘统计分析了包头地区雷电地闪次数、雷电流幅值累积概率分布特征及配电线路雷击跳闸故障的时空分布特征;在电磁暂态程序(EMTP)中建立10 k V同塔四回线路雷击闪络模型,在考虑系统工作电压的情况下,研究了同塔四回线路雷击同跳闪络特性及避雷器的不同配置方式对线路耐雷性能的影响;根据研究结果,提出了改善同塔四回线路耐雷性能的最优方案:对多雷区的杆塔,宜采用在I回AC相、III回C相、IV回BC相加装避雷器;对中雷区的杆塔,建议在I回AC相、IV回BC相加装避雷器;对少雷区的杆塔,只需将避雷器加装在I回A相和IV回B相。
