Research on Scope of Environmental Influence of DC Grounding Electrode Rated ±800kV

The reasons of environmental influence caused by DC electrode is analyzed. By analyzing the earth parameters of those DC projects which have been in operation, it presented that 1) when the current injected into the earth is 4000A, the boundary of influence caused by electrodes of ±800 kV UHVDC project is at least 20 km; 2) As for the converter station or the AC transforming plants rated HOkV or above, the site where they are located should be chosen between 20 km and 60 km off the electrode. Combining with the preparatory site Dongyang of UHVDC project from Xiluodu to Zhexi, earth parameters such as distribution of potential, step voltage in the range of 20 km have been calculated. From the results, it can be concluded that the electrode site will meet the requirement of the DC system under the condition in existence, and causes less influence to the environment.