The invention relates to a DC power distribution system (1). The DC power distribution system comprises a track (2) with electrical conductors for distributing DC power for powering purposes and for position determination purposes and a position determination system (15) for determining the position of an electrical device (3, 13) like a luminaire, which is attached to the track, based on a voltage measured on the track. The DC power distribution system can therefore provide positioning information regarding the position of the electrical device along the track, which may be useful, for instance, for commissioning purposes.