交流线路对平行架设特高压直流线路的影响及限制措施

随着电力需求的不断增长以及输电线路走廊资源的紧缺，在一些地区可能出现特高压直流线路与交流线路平行架设或同走廊的情况。根据向家坝—上海南汇±800kV特高压直流主回路参数和规划的1 000 kV交流线路数据，采用EMTDC程序建立了特高压交/直流输电系统的仿真模型。计算了交/直流线路不同平行架设长度、不同接近距离下特高压直流线路上感应的工频电压、电流。研究了换流变阀侧直流偏磁电流与直流线路工频感应电流的关系，给出了换流变阀侧直流偏磁电流的计算结果。最后对交/直流线路的平行长度，它们之间的接近距离以及抑制换流变压器阀侧直流偏磁电流的措施提出了建议。

Influence of AC Transmission Lines on Parallelly Erected UHVDC Transmission Lines and Suppression Measures

With unceasingly increasing of electric power requirement and the shortage of corridor resource for transmission lines, in some regions the situation that the UHVDC lines are parallelly erected with UHVAC lines or the corridor is common-used.According to the main circuit parameters of UHVDC project from Xiangjiaba to Nanhui and the data of 1000kV AC transmission line being planned, the model for simulation of UHVAC/UHVDC transmission lines is built by Electro-Magnetic Transient in DC System (EMTDC) program.The power frequency voltages and currents induced in UHVDC lines under different parallel erection lengths and different adjacent distances are calculated.The relation between DC bias current at valve side of converter transformer and power frequency induced current in UHVDC lines is researched;and the corresponding calculation results are given.Several suggestions on the parallel length between UHVAC and UHVDC lines, their adjacent distance and the measure to suppress the DC bias current at valve side of converter transformer are put forward.