A device for reducing a magnetic unidirectional flux component in the core of a three-phase transformer includes at least one compensation winding, which is magnetically coupled to the core of the three-phase transformer, a switch arranged electrically in a current path in series with the at least one compensation winding to feed current into the winding, where the effect of the current is directed opposite to the unidirectional flux component, and an apparatus for limiting current arranged electrically in a current path in series with the at least one compensation winding, and where two compensation windings are provided on different legs of the core of the three-phase transformer such that a greater reduction of the magnetic unidirectional flux component is achieved.