The State of Art in the Field of AC Interference caused by Transmission Power-Lines affecting buried Metallic Pipelines

This paper outlines the state of the art in the field of AC interference assessment on buried metallic pipelines. In particular, the attention is on pipelines that are located close to high voltage transmission-lines. Due to both the complexity and hazard of AC interference caused by overhead power-lines on metallic buried pipelines, there is an industrial need for reliable simulation software able to provide capabilities for predicting and possibly mitigating coupled voltages on these structures. This electromagnetic interference is present during both normal operating conditions and faults, and it generally consists of an inductive, a conductive, and a capacitive contribution. In particular, the focus of this paper is on the inductive coupling mechanism, but the other two are still discussed. Furthermore, the main risks for equipment and personnel are highlighted, in order to clarify the pivotal importance of performing an accurate analysis of these effects. The two main methods that were used over the course of the years to investigate this topic are described, starting from the circuital analysis. Afterwards, the main physical assumptions are discussed and the field theory is introduced, reporting the main pros and cons compared to the previous approach.