多个特高压直流系统共用接地极的研究

Study on Sharing Earth Electrode by Rectifiers or Inverters of Some UHVDC Systems

根据向家坝-南汇±800kV直流输电工程的具体参数,利用电磁暂态计算软件EMTP-RV对3个特高压直流输电系统送端及受端分别采用共用接地极方案进行详细的仿真研究,从系统稳态运行角度进行了深入透彻地分析,对该方案的优缺点进行了详细总结,并对该方案下各直流输电控制系统的协调控制提出了可行性建议。仿真结果表明,多个直流共用接地极的方案是可行的,但应该限制接地极接地电阻和引线电阻在一定范围,另外对接地极址的选择和共用接地极本体设计也有较高要求。

Sharing earth electrode by three UHVDC system rectifiers or inverters are studied respectively by electromagnetic transient analysis software EMTP-RV based on the main parameters of ±800kV HVDC project from Xiangjiaba to Nanhui. This paper analyzes the different operation modes of the UHVDC system sharing earth electrode from the aspect of power system stable operation. The merits and demerits of sharing earth electrode are summarized in detail The feasible suggestions for the corresponding control and protection of UHVDC system sharing earth electrode are put forward. The simulation results show that the scheme of sharing earth electrode is feasible. However, the resistors of both the earth electrode and earth electrode line should be restricted within a certain range. In addition, there are very strict requirements for choosing the position to bury the earth electrode and designing the shared earth electrode itself.