Research on the Influence Law of Soil Layered Structure on HVDC Interference Suffered by Buried Pipeline

With the large-scale construction of HVDC transmission systems, the problems caused by HVDC interference have become increasingly prominent. Existing cases have shown that the changes in soil resistivity and layered structure in different regions will have great impact on the current quantity discharging from the grounding electrode and interference amplitude during the unipolar situation of HVDC transmission system. In this paper, a calculation model of high-voltage direct current interference electric field is built based on the parameter information of pipelines and grounding electrodes in actual projects. The influence of soil resistivity, layered soil structure, and local soil structure changes on the interference parameters of buried pipeline interfered by HVDC was investigated and obtained. The results show that the layered structure with low resistivity on upper layer/high resistivity on lower layer will generate higher interference on the pipeline compared to the uniform or high resistivity on upper layer/low resistivity on lower layer. At the same time, the change of local resistivity will only affect the change of local interference potential and current density.