Flux-canceling effect and its application to shielding of magnetic field from power transmission lines

It is well understood that magnetic flux in opposite directions cancel each other so that the total field is weakened. It is also well known that magnetic flux tends to follow low-reluctance magnetic shunt paths. This paper describes how the two concepts can be combined to provide a technique of shielding the magnetic field emitting from a single-phase power transmission line. An analytical solution of magnetic field generated by the two wires of the power transmission line is derived. It is shown that magnetic field at any point in the space has a mirror image point. The field at the two points has the same magnitude. A technique is proposed to divert the fields at the two points to meet and cancel each other. Magnetic structures, which follow the direction of the resultant magnetic field in the space, are proposed to achieve optimal cancellation of the field.