Preliminary Discussion on the Protection of Metro against DC Interference of Pipelines

Subway will cause DC stray current interference to adjacent or intersecting buried steel pipelines, affecting the operation of cathodic protection (CP) system, and increasing the difficulty of determining whether the cathodic protection system meets the standard. Taking an oil pipeline affected by a new subway in South China as an example, the change of the pipeline's CP potential was monitored before and after the operation of the subway. The protective measures of sacrificial anode drainage were adopted for the disturbed pipeline, which effectively improved the cathodic protection level of the pipeline in the interference section.