Intelligent control of Unified Power Flow Controller for stability enhancement of transmission systems

To control the power flow, for increasing the transmission capacity and optimizing the stability of the power system, FACTS devices are used. One of the most widely used FACTS devices is Unified Power Flow Controller (UPFC). The controller used in the operation of UPFC has significant effect on power flow control and stability enhancement. Conventional PI regulators are generally used in the control of UPFC. This paper investigates control method, using fuzzy logic, for the unified power flow controller in order to improve the stability of a power system. FLC was developed by taking into consideration Mamdani inference system in the decision process and Mamdani´s Centroid method in the defuzzification process. Studies with different operating conditions are simulated to prove the ability of UPFC in controlling the power flow and the effectiveness of fuzzy controller in the performance of UPFC. MATLAB / Simulink is used to simulate the FLC and UPFC models.