Contribution of the UPFC in Improving the Quality of Electrical Power

Unified Power Flow Controller (UPFC) is used to control the power flow in the transmission systems by controlling the impedance, voltage magnitude and phase angle. This controller offers advantages in terms of static and dynamic operation of the power system. It also brings in new challenges in power electronics and power system design. The basic structure of the UPFC consists of two voltage source inverter (VSI); where one converter is connected in parallel to the transmission line (STATCOM) while the other is in series with the transmission line (SSSC). We present in this paper a theoretical description of the UPFC system, its modeling and a case study by simulation by Matlab/Simulink. We investigate so, the effect of UPFC on the voltage of the related bus, it’s also considers the effect on the amount active and reactive power flowing through the transmission system. The aim of the paper is the modeling, the identification of the references and control of UPFC and studying its influence on the electrical network. Finally the simulation results have been presented to indicate the improvement in the performance of the UPFC to control voltage in power systems.