Operational experience of HVDC LightTM

HVDC Light^TM is an electric power transmission technology based on voltage source converters with pulse width modulation and modern HVDC cables. This type of converter with modern power electronics has interesting characteristics based on separate and fast-acting controls of active and reactive powers. The technology is well suited for connection of networks that otherwise are difficult or impossible to interconnect. It´s suitability is based on accurate control of the transmitted active power and independent control of the reactive power in the connected AC networks. HVDC Light^TM is designed at standard units between 10 and 300 MW and are built in transportable housings. This together with the above technical, characteristics make them suitable for various applications of power transmission, such as exchange of power between networks, infeed of wind power to a network or as a feeder to an isolated load. There are four HVDC Light^TM transmissions in operation in the world: one each in the countries of Sweden, Denmark, Australia and US. The HVDC Light^TM links so far in operation or under construction have been justified for network interconnection or infeed of windpower. The speed and accuracy of both active and reactive controls have been used in customised ways in each of the above projects and is a key to success for HVDC Light^TM projects. As the first project, the Gotland Light in Sweden started operation in November 1999 and the others came along during 2000. The operational experiences for the Gotland Light, Tjaereborg, Directlink and Eagle Pass projects regarding the use of the controllability of HVDC Light^TM projects is presented.