A method of segmenting a power distribution network which comprises a plurality of AC power generating stations synchronously interconnected by AC power transmission paths is disclosed. The stations operate within associated market sectors and are subject to associated market rules. The method includes identifying all transmission paths which extend between differing ones of the sectors and, in each of said transmission paths so identified, segmenting the path by inserting a controllable DC link at a selected location in the path. Each of the sectors is then operated asynchronously. Power flow and counter-flow between the sectors is controlled by controlling the DC links. As well there is disclosed a power transmission network which comprises a plurality of AC power generating stations operable within associated market sectors subject to associated market rules; power transmission paths interconnecting the stations, at least some of the paths extending between differing ones of the sectors; and wherein each of the paths which extend between differing ones of the sectors includes a controllable DC link in the path for desynchronizing the differing sectors; and, control means operatively connectable to each of the DC links for controlling power flow between the differing sectors.