中文摘要：

交、直流线路同走廊架设将会产生不同于单独交流或单独直流线路的电场效应问题。为有效预测这种线路的电场，基于上流有限元法和向后Euler方法，提出了一种交、直流混合电场的计算方法，可以在计算过程中考虑交流线路电压瞬时变化对直流导线电晕活动及空间电荷运动的影响。测量试验线段验证了该方法的有效性。对交、直流混合离子流场中离子的运动进行了模拟，并计算了不同交流电压等级、不同交、直流线路接近距离下的地面电场和离子流密度。结果表明：交、直流线路同走廊架设时，地面混合电场交流分量、直流分量和离子流密度均有所减小，并且接近距离越小、交流电压等级越高，混合电场直流分量和离子流密度越小；交流电场的扰动使直流线路下方空间电荷的分布向线路两侧更加分散，是导致直流分量和离子流密度减小的重要原因。

英文摘要：

Erecting HVAC and HVDC transmission lines in the same corridor will induces electric field in quite different forms from single AC lines or single DC lines. In order to predict this electric field, i.e. to calculate the AC-DC hybrid electric field, we proposed a time-domain algorithm based on the upstream finite-element method and the backward Euler approach by taking into account that the effects of the instantaneous change of AC voltage on the corona of DC lines and on the movement of space charges. The proposed method was then verified by experiments on some test lines. In addition, we simulated the movement of space charge in AC-DC hybrid ion field, and calculated the ground electric field and ion current density under different AC voltages and different approaching distances between AC and DC lines. The results show that, with HVAC and HVDC transmission lines in the same corridor, the AC component, DC component, and ion current density in the AC-DC hybrid electric field on the ground will decrease, while the DC component and ion current density become smaller with AC voltage increasing or approaching distance decreasing. An important factor that induces this decrease of DC component and ion current density is that the disturbance of AC electric field escalates the dispersion of space charge distribution under DC lines.