New transmission control systems optimize power flow

This article is a review of developments in the control of power distribution systems. Historical aspects of the problem are first noted, and then current techniques are discussed. These include: (1) STATCON---a static condenser device developed by Westinghouse for voltage support within the TVA system, (2) Unified Power Flow Controller---a device developed by EPRI and Westinghouse for American Electric Power Company, (3) Static Synchronous Series Converter---a solid-state voltage source inverter connected in series with the transmission line, and (4) Electro-Optic Voltage Transducer System---a state-of-the-art voltage sensing device developed by a team consisting of ABB, NYPA, TVA, and the Empire State Electric Energy Research Corp.