An arrangement to control an electrical property of a medium or high voltage AC system including a number n of phases with n being at least two includes a number n of phases, each phase including a series connection of at least two electrical elements with an intermediate connection point between each pair of the at least two electrical elements, where each of the n phases of the arrangement is connected on one side to an original common neutral point and on the other side to one of the n phases of the AC system. The arrangement further includes a number of first switchable interconnections, where the first switchable interconnections are each arranged between two intermediate connection points of two of the n phases of the arrangement, and at least one control unit arranged to control the first switchable interconnections.