Investigation of the magnetic field produced by unbalanced phase current in an underground three-phase pipe-type cable

摘要

This paper presents a numerical technique for investigating the magnetic field produced by an underground three-phase pipe-type cable, which may carry unbalanced phase current. The numerical technique is based on finite element method and the equivalence principle. To validate the numerical technique, numerical results of the magnetic field generated by a pipe-type cable carrying balanced phase current are compared with the existing measurement data first. Then, the numerical results of the magnetic field generated by unbalanced phase current in a pipe-type cable are presented and analyzed. Through the analysis of the data, we observe that the zero-sequence current returning in the pipe, resulting from the unbalanced phase current, may significantly alter the magnetic field above the pipe.