低气压对直流正极性导线地面合成电场特性影响的实验研究

Experimental Study on Influence of Low Atmospheric Pressure on Total Ground Electric Fields of DC Positive Conductors

输电线路电磁环境与环境保护和工程投资密切相关,尤其在高海拔地区,直流线路地面合成电场已成为决定导线选择和线路结构参数的关键技术指标。为研究海拔和气压对直流线路地面合成电场的影响,在特高压直流试验基地人工气候环境实验室架设了单根正极性导线,对不同气压下地面合成电场和离子流密度进行了测量和分析,同时基于Deutsch假设的离子流场计算方法对地面合成电场和离子流密度进行了仿真,通过实测和计算结果的分析,获得了海拔和气压对正极导线起晕电压及离子迁移率的影响规律。研究结果表明：海拔每增加1000 m,正极导线起晕电压近似下降8.2%;随着气压的降低,离子的迁移率会逐渐增加,在分析海拔和气压对地面合成电场的影响时,还需要关注离子迁移率的影响。

Electromagnetic environment of transmission line is closely related to environment protection and project cost. Especially at high altitude area, total DC electric field becomes the key technical factor deciding conductor type and transmission line structure. In order to investigate influence of altitude and atmospheric pressure on total electric field, a single positive electrode was set up in artificial climate environment laboratory of the UHVDC test base of SGCC. In the experiment, the total electric field and ion current density on ground were measured and analyzed under different atmospheric pressures. In addition, on the basis of Deutsch hypothesis calculation method for ionized fields, the total electric field and ion current density were calculated and compared with the measurement results. Influence of altitude and atmospheric pressure on corona inception voltage and ion mobility was obtained. Results show that the positive corona inception voltage in the experiment decreases by nearly 8.2% as the altitude rises 1000 m. In addition, the ion mobility will increase with decrease of atmospheric pressure. This should be carefully considered when analyzing influence of altitude and atmospheric pressure on total DC electric fields.