Control system design of UPFC for optimal power flow control

Electrical power system is a large interrelated set-up, which requires a cautious design in order to supply continuous electricity to consumers without any divergence. Power electronics based Flexible Alternating Current Transmission Systems (FACTS) are devices, which are used to perk up the power system reliability and stability. Unified power flow controller (UPFC), which comes under the member of FACTS devices is used for sole purpose of active power flow control on a transmission system and recuperation of power system stability. Though, a systematic design is required to attain such a functionality of UPFC. The paper illustrates a robust design of UPFC control system using state-space equations. A complete mathematical model is presented which consists of d-q representation of Shunt and Series Voltage Source Converter (VSC) of UPFC. The validation of proposed scheme is done using MATLAB/Simulink, where a complete power system was modeled and simulated with and without UPFC in order to verify the proposed scheme. The result shows that UPFC (based on our proposed control system) can faithfully manage the real power flow on a transmission system at receiving end without affecting the system stability.