A novel method for Hysteresis based control of UPFC

Appropriate design and use of Unified Power Flow Controller (UPFC), which has the ability of controlling the bus voltage level and transmission line power flow simultaneously, provides suitable conditions to improve restructured power systems operation. In this paper, a novel control method is proposed for Hysteresis based UPFC, which uses four degrees of freedom to control bus voltage, DC link voltage, and active and reactive transmission line power flows independently. Results obtained by simulations with PSCAD/EMTDC show that proposed control method is more effective than the reported methods in achieving better power quality indices and more stability i.e. less overshoots and settling times.