(in lingua inglese)
In this paper, the dynamic model of UPFC, which consist of two shunt converters and a series capacitor, has been obtained. Simulation results operated by MATLAB/SIMULINK show that response of system without using the controller is unstable. For dynamic stability improvement, lead-lag controller has been used. SVD has been employed to evaluate the EM mode controllability to PSS and the four UPFC control signals. It has been shown that the EM mode is most strongly controlled via dB for a wide range of loading conditions. Classical and intelligent techniques have been used to enhance the dynamic stability.