Effects of Electromagnetic Interference on Underground Pipelines Caused by the Operation of High Voltage AC Traction Systems: The Impact of Harmonics

When evaluating the risks resulting from the effects of electromagnetic interference (EMI) on buried pipelines running near ac electrified traction systems, the harmonic distortion in railway systems should be considered. This is because the tractive units enforce current harmonics on the interference source, in addition to the fundamental frequency. The presence of harmonics may exacerbate voltages accumulating on buried pipelines running in close vicinity to traction systems. Such voltages may cause danger to persons or may cause damage to the pipelines, in the long term. However, the technical standards on pipelines-traction systems' separation disregard the impact of harmonics. They are based on the fundamental frequency induction. This paper uses state-of-the-art modeling techniques to holistically assess EMI on underground pipelines near ac traction systems. This is achieved through a realistic modeling of the infrastructure associated with a traction system and by accounting for the presence of harmonics in the contact line system (i.e., interference source).