Magnetic field reduction of twisted three-phase power cables of finite length by specific phase mixing

The subject of investigation is the magnetic induction of twisted three-phase power cables of finite length and the reduction of their fields by utilizing compensation effects. After deriving integral expressions for the induction of such cables we propose a simple model consisting of twist-free elements which requires no integration. The lengths of the cable elements as well as their displacement angles with respect to a referring axis depend on the element numbers. By comparing the magnetic induction of cables with 3 and 6 wires we show that for the phase sequence L1-L2-L3-L1-L2-L3 the 6-wire cable causes a drastically reduced field. An attenuation factor between 125 for the near field and greater than 1000 for the far field is achieved.