A current injection UPFC model for enhancing power system dynamic performance

This paper presents a current injection model of unified power flow controller (UPFC) that is suitable for use in power system stability studies. To use the current injection model, a proper control method is necessary. It is proposed that the shunt compensation of UPFC is controlled to maintain the system bus voltage and the two components of UPFC series voltage, which are in phase and quadrature with the line current, are controlled in coordination by the strip eigenvalue assignment method. The eigenvalue analysis and nonlinear simulation results show that the proposed UPFC model and control method can significantly improve the dynamic performance of the power system