Dynamic SVD controller design of UPFC for power flow control considering interactions

Unified power flow controller (UPFC) is a multifunction flexible AC transmission system (FACTS) device with capability of performing such several functions as active and reactive power flow, voltage and stability control in a power system. It is well-known that strong interactions exist between active and reactive power flow control functions of a UPFC. From another point of view, there are also interactions within internal parts of UPFC and also between UPFC and power system. In this paper, considering power system and UPFC´s model as a unit including series and shunt converters, common DC link and thevenin equivalent circuits of power system on either sides of UPFC, in addition to interaction analysis, a singular value decomposition (SVD) controller will be designed for active and reactive power flow control. In order to evaluate the performance of the proposed controller, computer simulation using MATLAB/SIMULINK software has been provided comparing performance of the proposed controller with decoupling matrix (DM) and proportional-integral (PI) controllers. Simulation results have clearly confirmed the competence of SVD over DM and PI.