Spatial magnetic field polarization below balanced double-circuit linear configured power lines for six phase arrangements

Underground and aerial metallic pipelines that run parallel to or are placed in the vicinity of high voltage power lines, are affected by inductive coupling in which voltage is induced in the pipelines due to the time varying magnetic fields produced by the power line currents. This magnetic field below the power line is made up of vertical and horizontal components which are orthogonal in space and varies with time thereby giving rise to a rotating field which traces an ellipse in a plane perpendicular to the conductors. For buried metallic pipelines along the power line, the horizontal component of the magnetic field plays a major role in the induction. We present computation and comparison in the transverse plane, of the spatial distribution of the magnetic field below, and polarization around balanced overhead AC double-circuit power transmission lines of vertical and horizontal geometries for six different phase arrangements. The computations showed that the magnetic field horizontal component profile at ground level depends among other factors, on conductors phase arrangement as well as the geometry. Also, the field is polarized with different polarization shapes at different locations. The spatial magnetic field polarization distribution below the conductors depends, among other factors, on the conductors´ phase arrangement. We concluded that in placing pipelines below AC double-circuit power lines, it is important to consider the field distribution by the phase arrangement of the line. Three-axis field measuring device is an essential tool.