A Detailed Study of AC Interference on Metal Pipelines due to Double Circuit Power Lines

The electromagnetic interference between Electrical Power Lines (EPL) and nearby Metallic Pipelines (MP) has been an important research subject over the last decades. The proximity between various types of EPLs and MPs is unavoidable nowadays. This interference may result in currents and voltages on MPs that may pose a serious threat to operating personnel and equipment. In addition, the integrity of the MPs may be threatened due to corrosion. In this paper, based on the transmission line model of pipeline-earth circuit, the analytic expressions of inductive coupling voltage generated by the normally operating Ac transmission line were obtained for different terminal loads of the oil/gas pipeline. Then, the influence of some important parameters, such as the phase sequence, parallel length, soil resistivity, separation distance and the different loading between the two circuits were revealed by the proposed method. The manuscript provides detailed graphs and numerical data that may be useful for engineers and researchers for evaluation of the interference level or in selecting and applying proper protection measures.