Unified voltage control to improve power transfer at controlled operating condition

This paper presents a unified voltage control to improve power transfer through a transmission line or, more generally, through an impedance of transference. Unified voltage control allows controlled operating condition for a given power transfer, avoiding either voltage sags or voltage swell. A unified voltage controller (UVC) composed of two ideal sinusoidal voltage sources is proposed. The voltage sources are series- and shunt-connected to the transmission system and work as advanced power compensators. The controllable variables for the UVC are local and remote voltage magnitudes, and transmission. Considerations on practical UVCs are introduced.