Interference of nonlinear ferromagnetic pipeline on magnetic field produced by power lines

Recently, the investigation of the magnetic field produced by power lines has drawn a lot of attention from researchers [1,2]. Since sharing space by buried power lines and pipelines has become commonplace, it is of interest to investigate the influence of the pipeline. In this paper, we study the change of the magnetic field produced by buried cables, due to an additional steel pipe nearby. A Fourier series technique is used to calculate the magnetic field. An iterative procedure is employed to handle the non-linear characteristics of the steel pipe and to determine the varying permeability in it. The calculated results of the magnetic field are compared with those produced by buried cables without the additional pipe. The comparison shows that the steel pipe close to buried cables may significantly alter the magnetic field.