Effect of Output of Cathodic Protection Power Supply on Potential Distribution of Pipeline under DC Grounding Electrode Current Interference

The existing protective measures on pipeline were used to weaken the influence of DC grounding electrode current on the pipeline. During the commissioning of Changji-Guquan ±1 100 kV ultra-high voltage direct current (UHVDC) transmission project, the potentials of nearby Sichuan-East pipeline were tested. The output currents from cathodic protection power supplies were adjusted actively to obtain the effect law of output current from cathodic protection power supply on the potential distribution of the pipeline under the interference of DC grounding electrode current. The results show that the ON potentials reduced as a whole with the increase of output currents from cathodic protection power supplies. The closer to the adjusted cathodic protection power supply, the greater the decrease of ON potential of the pipeline, and vice versa. Adjusting the output current from cathodic protection power supply at the right position could greatly reduce the interference of DC grounding electrode current to pipelines, which might also accumulate the original data for adjusting the configuration of protective measures on the pipeline and controlling the interference of DC grounding electrode current to pipelines.