Line current balancing using unified power flow controller

The unified power flow controller (UPFC) is a typical FACTS (flexible AC transmission systems) device that is capable to instantaneous control of transmission line parameters. This paper presents a new approach for the dynamic control of UPFC. The proposed approach not only allows the fast and independent control of flowed real and reactive powers but also is capable to the compensation of unbalanced disturbances in the line current. The presented simulation results demonstrate that the presented control system acts properly for the independent controlling of real and reactive powers, regulating bus voltage and compensating unbalanced currents. The presented control system of UPFC was simulated and tested with the PSCAD/EMTDC simulation program.