DC Current Distribution in Both AC Power Grids and Pipelines Near HVDC Grounding Electrode Considering Their Interaction

The dc current injected into the earth from the grounding electrodes of an HVdc system could flow into the ac electric power grids and gas pipelines through their grounding points. The dc current distribution either in ac power grids or in pipelines would be affected by each other. In this paper, a numerical approach to simulate the dc current distribution in ac power grids and gas pipelines considering the interaction is put forward. The approach is validated by field test. The dc current distribution in ac power grids and gas pipelines is discussed based on the calculation result in a real case. It is found that the effect of ac power grids on the current distribution in gas pipelines is greater than the effect of gas pipelines on the current distribution in ac power grids.