Abstract :
Electromagnetic interference effects of transmission lines upon near by metallic pipelines are real problems especially in faulty cases. Electromagnetic can be induced on a pipeline from overhead power lines in close proximity by (1) capacitance, (2) conductance, (3) and induction [1]. The electrical influence exerted by power line on a pipeline varies with the electrical characteristics and geometry on the individual system. Electromagnetic induced on pipeline poses a shock hazard rather than a corrosion concern. One of the greatest causes of voltage induction on pipelines is line current flow[2]. Current flow in an AC conductor creates an electromagnetic field of force which always lies at right angles to the current that produces it. With alternating current, the field expands away from the conductor and then collapses towards the conductor at a rate which is a function of the system frequency[3]. The magnitude of the induced voltage on the pipeline is a function of the following: separation between AC conductors and pipeline, the magnitude of electric system current flow (especially in short circuit cases), resistivity of the soil, and the screening factors[3]. Many formulas are used to calculate the mutual impedances and the pipeline induced voltages between the power lines and pipeline such as Carson and Pollaczek formula [2–4]. Carson-Clem formula [5–7] and Haber-Lands formula [5]. In this paper the induced voltage due to mutual inductance between power lines and pipelines especially in short circuit conditions of high voltage over head transmission lines is investigated under different short circuit cases, the effect of ground conductors on reducing the mutual interface between the power lines and pipelines is discussed also. The soil resistivity variation is taken into consideration. New technique by using EMTP and design Matlab M-file program by the author are used to calculate the pipeline induced voltage.
