Process Analysis of Double Circuit Transmission Line Trip-out on the Same Tower Due to Lightning  

作　　者：DUAN Da-peng REN Zhi-gang WANG Peng YE Kuan CHANG Xiao-qi LI Wei 

机构地区：[1]Beijing Electric Power Research Institute, Beijing 100075, China

出　　处：《高压电器》2011年第9期31-36,43,共7页High Voltage Apparatus

摘　　要：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.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.

关 键 词：double circuit transmission lines on the same tower lightning trip-out at the same time fault recorder over-voltage calculation lightning protection 

分 类 号：TM726.1[电气工程—电力系统及自动化] TM862