不同运行方式下特高压直流输电线路的地面电场与离子流分布

以向家坝—上海±800 kV特高压直流输电线路工程为背景，针对特高压直流输电线路可能存在的4种运行方式，计算和分析了上述输电线路下方地面电场与离子流密度的分布情况，研究了工程投运后特高压直流输电线路产生的电磁环境问题。结果表明：在双极运行方式下，地面场强与离子流密度均满足标准要求；并联导线带有相同极性的高电压，同性排斥作用既加强了地面电场强度，又增加了离子流密度，因此单极–双导线并联大地回线运行方式下的地面场强与离子流密度最大，应在实际工程中尽量避免采取这种运行方式。

Distribution of Ground Electric Field Strength and Ionic Current Density under Different Operating Modes of UHVDC Transmission Lines

Taking ±800 kV UHVDC power transmission project from Xiangjiaba to Shanghai as subject investigated and based on four possible operating modes of UHVDC power transmission line, the distribution of ground electric field strength and ionic current density beneath the transmission line are calculated and analyzed, and the electromagnetic environment problem caused by the operation of the project is researched. Research results show that under the two-pole operating mode, both ground field strength and ionic current density conform to the standard requirements. Due to the mutual repulsion of two parallel conductors carrying high voltage with same polarity, both ground electric field strength and ionic current density are intensified, thus the ground electric field strength and ionic current density reach their highest values while the UHVDC project is operated in monopole and two parallel conductor mode with earth return, and such an operating mode should be avoided as possible in practice.