Analysis of twisted cable options for reducing low frequency magnetic fields due to traction currents in vehicles with electric powertrains

Low frequency magnetic field distributions around twisted and un-twisted three-phase power cables of finite length have been calculated using analytical models, quasi-static Biot-Savart calculations, and 3D finite element simulations. For cable geometries that could be used in electric vehicles, the models suggest that the expected enhanced field decay rate due to cable twisting is not maintained at large distances for cables of finite length. Nonetheless, twisting could still be beneficial in electric vehicle applications. Magnetic fields from cables with lengths of 1-5 m could be reduced at distances of around 5-30 cm, where field levels are in any case higher than at more distant points.