考虑先导发展随机性的输电线路雷击仿真模型

随着电压等级的升高,由雷电绕击而引起的线路跳闸事故所占比例越来越大。为准确评价线路的绕击耐雷性能,考虑先导发展随机性,运用模拟电荷法,建立了输电线路雷屏蔽性能的雷击仿真模型。仿真结果表明:随着下行先导随机发展的方向由靠近输电线路变为远离输电线路,雷击目的物也由地线逐渐转变为导线,并最终变为大地;相比地线,导线上的上行先导较难产生。算得的对地击距与IEEE推荐的击距公式一致,绕击概率与雷击模拟实验结果相符,证实了模型的可信性。

Simulation Model of Lightning Stroke to a Transmission Line Considering the Leader Propagation Randomness

With the increase of voltage level of transmission line,the proportion of outages because of shielding failure increases,therefore,exactly evaluating lightning-withstanding level of transmission line is especially important for system service and stable operation.Considering the randomness of leader propagation,a lightning stroke simulation model on lightning shielding performance of transmission line was presented,in which the simulation charge method was applied.Simulation results of this model reflected the general rules of lightning stroke:with the direction of downward leader changing from close to the transmission line to far away from it,the lightning strike spot changed gradually from ground wire to conducting wire,finally the earth.Shielding failure probability and stroke distance to earth,which were calculated by the simulation model,were in accordance with the results of lightning simulation experiment and the stroke distance equation recommended by IEEE.So,the simulation model is reasonable.