Study On Modeling And Simulation Of UPFC

As the most representative and multiplex device of Flexible A.C. TransmissionSystem (FACTS), the Unified Power Flow Controller (UPFC) is one of the researchfocuses in FACTS recently. UPFC has the characteristic functions as follows: fast anddynamical adjusting the parameters of electricity transmission system, such asvoltage, impedance, phase angle, real power and reactive power, expanding thecapacity of electricity transmission, improving the stability of power system and optimizing the operation of power system.This paper analyses the basic principle of UPFC and its controlling function and completes its mathematical modeling by considering the dynamic effect of capacitor. The model of UPFC in this paper uses a PID controller and its control system adopts a d-q decoupled strategy. With MATLAB, this paper realizes the power flow analysis and power system voltage stability computation. The simulation results of the power flow indicate that UPFC has strong control capability of power flow and voltage. The computation of the latter proves that UPFC can improve the system stability.