Testing Methods and Evaluation Criteria for AC Stray Current on Buried Steel Pipelines

With the rapid development of the national energy industry and railway industry, it is becoming more and more common that buried steel pipelines share the same corridor with high-voltage wire or AC electrified railway, which may easily lead to AC stray current on buried steel pipelines. If the coatings on buried steel pipelines are damaged, AC stray current on buried steel pipelines can cause AC corrosion and destroy the cathodic protection(CP) system. When AC voltage on the buried steel pipeline reaches a certain value, it would be a great threatening to pipeline maintenance personnel. This paper presents the corrosion mechanism of AC stray current, detection methods, signal processing methods and evaluation criteria, in order to attract the attention from pipeline laying personnel, inspectors and maintenance personnel.