考虑到雷电背景、特高压线路的多分裂导线结构和高运行电压，建立分析特高压线路分裂导线表面连续上行先导起始的数值仿真模型。模型中同时考虑到流注区域空间电荷以及导线和避雷线表面感应电荷对导线和避雷线周围空间电场分布的影响。仿真中采用模拟电荷法和拉普拉斯法计算子导线和避雷线周围的电场分布，根据计算获得的电场判定关键物理过程的起始和转化。采用该模型对我国特高压试验示范工程中的ZBS2塔型线路进行仿真，并与采用已有模型的仿真结果进行对比，得到模型改进前后预测的特高压分裂导线和避雷线表面连续上行先导起始的不同特点。仿真结果表明：采用改进模型计算时，特高压交流输电线路子导线表面的连续先导的起始迟于已有的先导传播模型的预测结果；在避雷线表面则恰恰相反。这意味着已有先导传播模型对输电线路雷电屏蔽性能的预测是保守的，该研究结果可为超/特高压输电线路的防雷设计提供参考。

A numerical simulation model for analyzing the inception of continuous upward leader on the surface of ultra high voltage (UHV) AC bundle conductors under lightning background is presented. The influence of lightning, UHV bundle conductor configuration and high operating voltage were considered in the model. The impact of the space charge in streamer zone and the induced charge on phase conductor (shielding wire) surface on the space electric field distribution around the phase conductor (shielding wire) were also considered. The charge simulation method and Laplace method were adopted to calculate the electric field distribution, and the achieved electric field was used to determine the initiation and transformation of the key physical process. Applying the proposed model, the continuous upward leader inception on the conductor surface of ZBS2 type tower (used in Chinese UHV Pilot Model Project) was analyzed. The simulation results were compared with that of existed model. The different characteristics of the continuous upward leader incepted on sub-conductor and shielding wire surface were investigated. The results indicated that, on the surface of the sub-conductors, the inception of continuous leader predicted by the proposed model is occurred later than that of existed model. But for the shielding wire, the conclusion is contrary. Therefore the lightning shielding performance evaluated by the existed model of leader progression method is somewhat conservative. The research results are worth considering in the lightning protection design of EHV/UHV AC transmission lines.

上海市浦江人才计划项目(08PJ14316)；上海市科委科研计划项目(08dz0580900)。