Improvement of the Reliability of Pipelines Buried in Soil through Real-time Monitoring and Control for Cathodic Protection and Coating Defect Detection

Abstract

Buried pipelines face corrosion risks during long-term operation in soil environments, primarily due to coating defects or degradation of cathodic protection performance. To mitigate these issues, it is crucial to accurately assess the condition of cathodic protection and promptly identify any coating defects. This study investigated the cathodic protection status at domestic power plant sites and established a mock-up facility for real-time assessments of cathodic protection and coating defect detection. This was achieved using on- off potential measurements, Close Interval Potential Survey (CIPS), and Direct Current Voltage Gradient (DCVG) techniques. The findings revealed that the cathodic protection condition at existing sites was locally inadequate. In contrast, the mock-up facility allowed for continuous monitoring of on-off potential variations, and real-time CIPS and DCVG measurements effectively identified potential changes and sig- nal reversals at the sites of intentionally introduced coating defects, aligning closely with their actual loca- tions. These results demonstrate that implementing real-time monitoring and defect detection systems for buried pipelines in soil can significantly improve the reliability of cathodic protection management.