Planar magnetic field distribution underneath two-circuit linear configured power lines in various phase arrangements

Inductive coupling affects both aerial and underground metallic pipelines that run parallel to or in the vicinity of AC high voltage power lines, whereby voltage is induced in to the pipelines due to the time varying magnetic fields produced by the transmission line currents. We present computation of the planar magnetic field distribution on the ground below balanced AC double circuit power transmission lines of vertical and horizontal geometries for six different phase arrangements. The computations showed that the magnetic field distribution depends, among other factors, on the conductors´ phase sequence arrangement. Some arrangements show symmetrical lateral profile while some exhibit asymmetrical lateral profile. The field is also polarized with different polarization shapes at different locations which depend on the phase arrangements as well as other factors. We concluded that in placing pipelines in the vicinity of AC double circuit HVTLs, it is essential to consider the field distribution by the phase arrangement of the line. If possible, pipelines should be placed in a region of minimum field intensity within the allowable servitude of the line, in order to have minimal induction on the pipeline from the HVTL in normal operating conditions.