高压直流输电共用接地极技术研究

Common Grounding Technique Used in the HVDC

为分析共用接地极后两直流系统受端换流站中性母线电位升的变化情况,进而研究共用接地极对直流系统稳态运行的影响,首先讨论了直流输电系统共用接地极的型式和共用接地极的特点,建立了两回直流系统共用接地极的数学模型,并结合云广特高压直流输电与贵广II回直流输电系统参数,研究分析不同运行方式下该两回直流输电系统共用接地极对直流系统运行影响大小,以及与独立接地极相比共用接地极不同运行方式对环境的影响大小,最后对共用接地极对环境的影响以及公用接地极对直流系统运行的影响方面的问题提出了解决措施。

Firstly, the types and characteristics of the common ground electrode used in HVEC system are analyzed in this paper. The effect of the common ground electrode to the HVDC transmission system and the environment are researched by modeling the common ground electrode with two High Voltage Direct Current （HVDC） transmission systems and analyzing the voltage variation （rise or down） of the neutral bus in converter station. Even more, the stability of the DC system is analyzed. Combining to the parameters of the Yunnan-Guangdong （YG） Ultra HVDC transmission system and Guizhou-Guangdong （GG） Ⅱ HVDC transmission system, a detailed analysis of the effect of the common ground electrode to the DC transmission system is given. In addition, a comparison of the environment effect of the independent ground electrode and the common ground electrode to the DC system is presented in this paper, too. In the end, solving methods and suggestions to the corresponding negative effect are presented in this paper.