基于先导发展模型的输电线路绕击跳闸率计算

Calculation of Shielding Failure Flashover Rate of Transmission Line Using Leader Progression Model

雷电绕击是影响电力系统安全稳定运行的关键因素之一,现有输电线路雷电绕击分析模型对先导起始和发展过程的描述较为简化。为此,根据正极性上行先导起始和发展机理,提出了用于单根导线和分裂导线的上行先导起始判据,并提出了1种考虑背景电位变化贡献的流注空间电荷计算方法,在此基础上建立了绕击跳闸率计算模型和自适应算法,最后对我国典型的500 kV线路的绕击特性开展了仿真研究。计算结果表明,低电压等级时该模型得到的先导起始时刻与Rizk判据和临界半径判据基本一致,500 kV输电线路绕击跳闸率平原地区为0.012次/(100 km·a),山地地区为0.211次/(100 km·a),与我国运行经验相符。绕击跳闸率自适应算法与原有方法相比,在同样精度下所需计算时间更短。

Lightning shielding failure is the key problem for safety and stability of power system. Current models for analysis of lightning shielding failure are simplified in the description of the leader process. Consequently, using the mechanism of positive upward leader inception and propagation, we proposed a criterion of upward leader inception for single and bundle conductors, and proposed a method for calculating streamer space charge considering the variation of background potential. Thereby, we put forward an algorithm and adaptive strategies for calculation of transmission line shielding failure flashover rate using the proposed model, by which the shielding failure characteristics of 500 kV trans- mission line are analyzed. The result of leader inception agrees with that of Rizk model and critical radius model for low voltage cases. The calculated shielding failure flashover rate of 500 kV transmission line in plain area is 0.012 strokes/（100 km＇a）, and the value is 0.211 strokes/（100 kin.a） for mountainous region, which is consistent with the opera- tion data. The adaptive method is faster than theoriginal method in the same precision.