Combined methods for solving inductive coupling problems

The problem of induced AC voltages on pipelines has always been with us, and the interference caused by power transmission lines to buried gas pipelines is under investigation for many years. Situations where a pipeline is influenced by power lines in a right-of-way are more frequent nowadays. Even under normal operating conditions, voltages and currents are induced on the pipeline that may pose danger to working personnel or may accelerate the corrosion of the pipeline´s metal. The aim of the paper is to evaluate the induced voltages and currents in case of an underground gas pipeline, which shares a same right of way with a high voltage transmission line, in order to detect the possibility of the AC corrosion in occurring of the pipeline. We choose to combine the electromagnetic field method and the conventional circuit method. Because the electrical equivalent circuit involves a high number of circuit elements that must be defined, a software code that generates this automatically was created. The considered complex problem is studied for different operating conditions of the power transmission line and different values of the coupling coefficient.