Or relating to power transmission networks

A network interconnection, for interconnecting a power supply network with a plurality of power distribution networks, comprising:

• a power converter station arranged to be connected to an end of a power supply network and controllable to provide an alternating voltage source;
• an interconnection bus extending from the power converter station towards each of a primary point of interconnection connected in use with a primary power distribution network and at least one secondary point of interconnection each of which is connected in use with a corresponding secondary power distribution network;
• a power regulator electrically connected between the interconnection bus and each secondary point of interconnection, each power regulator being operable to control a flow of power from the interconnection bus to the corresponding secondary point of interconnection, wherein at least one power regulator is or includes a phase shifter;
• and
• a power flow controller arranged in operative communication with the power converter station and each power regulator and programmed to adjust the alternating voltage source provided by the power converter station to control the power delivered to the primary point of interconnection and alter as needed the influence of each power regulator to control the power delivered to each corresponding secondary point of interconnection,
• wherein the power flow controller is programmed to alter as needed the influence of each phase shifter by sending a respective shift angle reference to each phase shifter to manipulate the voltage angle of the alternating voltage source presented by the respective phase shifter to the corresponding secondary point of interconnection.