Interference monitoring and influence rule of HVDC grounding electrode to buried pipelines

In order to understand the influence rule of the grounding electrode of HVDC transmission engineering on the stray current of buried pipeline, the remote potential monitoring system was equipped for 12 pipelines near the 17 grounding electrodes of HVDC transmission engineering for continuous monitoring of pipeline potential in long time. The interference frequency and time of grounding electrodes, as well as the interference degree and range of pipeline, were analyzed based on the variation of pipeline potential. According to the monitoring results, the interference influence of grounding electrode to pipeline can be judged accurately through the long-time continuous monitoring of pipeline potential. In 2017, the interference frequency of 17 grounding electrodes was 201 times, and the total interference time was 657.31 h, which was slightly shorter than that in 2016. Interference of grounding electrode was monitored on 1 987 km pipelines, and particularly, the interference of grounding electrode to pipeline in South China was greater than that in East China, Central China and Northwest China. By analysis on the distribution rule of interference potential, it is found that the shorter the vertical distance from grounding electrode to pipeline, the shorter the pipeline section with stray current flowing in the end close to the grounding electrode, the greater the interference to the pipeline far away from the grounding electrode, and the larger the interference range is.