模拟试验是研究超/特高压输电线路绕击特性的一个重要手段，针对直流线路标称电场对线路雷电绕击特性的影响问题开展模拟试验研究，首先从模拟试验比例尺的确定、地闪先导过程近区电场的模拟和模型线路标称电场模拟三方面论证了试验的物理等价性；在计及直流电压的条件下，通过放电试验得出了±500kV输电线路G4–40型杆塔绕击空间分布；试验中观测到主放电击中导线(或避雷线)的同时，避雷线(或导线)上残存的迎面流注。依据试验现象，定性分析了标称电场对绕击特性的影响机理；对试验结果定量分析表明，计及直流电压后G4–40型杆塔正极绕击率为不考虑直流电压时的1.79倍。

Simulation experiment is one of the important techniques for the lightning shielding performance study of EHV/UHV transmission line. A simulation experiment was carried out in this paper for studying the impact of nominal field on the lightning shielding performance of HVDC transmission line, the test equivalency was verified in following aspects: the determination of test scale, the simulation of near field during the descend leader process and the simulation of nominal field in the vicinity of model lines. The exposure space of G4-40 is received both when the polar conductor is applied with DC voltage and without DC voltage. The residue upward streamer incepted from the surface of conductors which is fail to hit and the primary discharge can be observed at the same time. According to observed phenomenon, the influence mechanism of DC voltage was analyzed qualitatively, and the shielding failure rate of positive polar with DC voltage is 1.79 times of which without DC voltage.