Analysis of Electrical Interference from Power Lines to Gas Pipelines Part I: Computation Methods

Analysis of electrical interference effects of transmission lines upon nearby pipelines has been a topic of growing interest due to the proliferation of rights-of-way which must be shared by transmission lines and pipelines. This paper describes the results of a recent joint EPRI/A.G.A. research project whose objectives were to develop an effective tool for simulating complex realistic right-ofway problems accurately and to investigate the effects of various system parameters. The ECCAPP computer program, which resulted from the EPRI/A.G.A. research program, combines a powerful input data preprocessor with a computation algorithm which accurately evaluates the effects of both conductive and inductive interference for arbitrarily positioned above-ground and buried conductors which could occur in typical rights-of-way. This paper discusses, in a detailed manner, the computation methods used by ECCAPP. A companion paper summarizes some of the results of an extensive parametric analysis which was conducted using ECCAPP and which illustrates some of the capabilities of the computer program and provides insight on how to control both conductive and inductive interference effects. Computer Program ECCAPP analyzes the effects of power transmission lines on neighbouring gas pipelines and determines the influence of mitigation measures, if any, on interference levels. A distinguishing feature of this computer program is its ability to analyze the combined effects of inductive (electromagnetic) and conductive (galvanic, through earth) coupling. These effects may develop simultaneously during power faults at transmission lines structures which are near gas pipelines, or during normal conditions.