Corrosion Behavior and Evaluation Method of Pipeline Steel Under Dynamic AC Interference: A Study

Unlike the stable AC interference caused by AC transmission lines to buried pipelines, high-speed railways cause dynamic AC interference to nearby buried pipelines. The dynamic fluctuation characteristics of AC interference parameters of buried pipelines near high-speed railways with different traction power supply modes were obtained through the statistical analysis of field test data. The dynamic AC corrosion simulation experiments were conducted with different interference cycles and levels, as well as cathodic protection (CP) levels. The results show that the dynamic AC corrosion rate increases with the extension of the interference time within each interference cycle. After the J_AC ≥ 100 A/m², the dynamic AC corrosion rate shows a three-stage change with a negative shift of CP potential, that is, first decreasing, then increasing, and then decreasing again. On the basis of the experimental results, the dynamic AC corrosion risk assessment criteria were proposed, which comprehensively considers the CP level and the proportion of interference time with different AC current densities.