输电线路雷电先导发展三维仿真模型

On the 3-Dimentional Leader Progression Model for the Lightning Shielding Failure Performance Estimation of Overhead Transmission Lines

超、特高压线路雷电屏蔽性能的科学评估方法是电力系统防雷研究的前沿课题之一。现有输电线路雷电先导发展模型中上行先导起始未考虑流注空间电荷影响、假设发展速度为恒值,且未考虑杆塔、线路实际三维结构对雷电屏蔽性能的影响。针对上述不足,该文研究建立了考虑流注空间电荷屏蔽作用的输电线路上行先导起始和发展全过程的动态仿真模型,开展了3m棒-板间隙正极性操作冲击放电流注先导转化过程实验观测,对所建立模型进行了验证;基于模拟电荷法建立了雷击输电线路下行先导过程附近空间三维电场并行计算方法。应用文中模型定量计算了典型的特高压同塔双回输电线路雷电上行先导放电特征参数,得出Rizk判据和临界电晕判据不考虑空间电荷的屏蔽作用,将夸大工作电压对上行先导起始的促进作用;现有的雷电先导发展模型假设上行先导与下行先导的速度比为恒值,既不能准确反映上行先导间的竞争关系,也有可能夸大上行先导的引雷能力。

The study of numerical estimation method of lightning shielding performance for extra and ultra high voltage transmission lines is a frontier issue. In the existing leader progression model（LPM）, the inhibition effect of streamer discharge space charge on the upward leader initiation was not considered and the velocity of upward leader was assumed to be a constant. Moreover, the impact of the actual three dimensional structure of towers and transmission lines was not considered in those models. In response to these deficiencies, the upward leader inception and continuous propagation model was proposed,which could take into account of the inhibition effect of streamer discharge space charge. The 3m rod-plane gap discharge experiment subjected to positive switching impulse was carried out. Base on the observation data in the streamer to leader transition, the proposed upward leader model was validated. A three dimensional electric field parallel computing method for the transmission lines under thunder cloud and negative downward stepped leader was presented. Combining the upward leader model and three dimensional electric field compute method, a revised three dimensional LPM was established. The characteristics parameters of upward leader initiated from the UHV double circuit transmission line were derived by using this model. It is concluded that the promotion effect of operation voltage on the upward leader inception will be over-estimated by using Rizk criterion and critical corona radius method. The competition effect between upward leaders initiated from difference target can not be considered if the velocity of upward leader is assumed to be constant which may magnify the attraction capability of the upward leader.