AC mitigation

Current events survey. Pipelines that travel across country, though utility right-of-ways (ROWs) under high-tension electric power lines, may pick up induced AC. NACE International standards say that a safety hazard exists when the induced voltage exceeds 15 volts as measured against a copper-copper sulfate reference electrode. At these locations efforts to mitigate the induced AC must be implemented.

CPM performed an AC survey for a major petroleum customer on a 15-mile segment of a cross-country pipeline. AC structure-to-electrolyte (S/E) potential measurements were obtained at all cathodic protection test stations located along the pipeline as well as at aboveground locations where the pipeline could be accessed directly. Concurrently, we documented the presence and magnitude of impact of the high-tension power lines on the client’s pipeline. In particular, we highlighted locations where voltages on the pipeline exceeded NACE criteria.