The unified power flow controller-a concept becomes reality

The unified power flow controller (UPFC) is the first member of an emerging family of advanced flexible AC transmission system (FACTS) controllers that use multiple synchronous voltage sources (SVS) operated conjunctively to optimize the use of electric power transmission networks. This paper gives an overview of the practical aspects of UPFC design and operation, and illustrates the implementation of the equipment and the achievable performance with particular reference to the Inez installation in Kentucky, USA.