SIMULATION, MODELING AND PERFORMANCE- INVESTIGATION OF UNIFIED POWER QUALITY CONDITIONER (UPQC

Abstract

Nonlinear devices, such as power electronics converters, inject harmonic currents in the AC system and increase overall reactive power demanded by the equivalent load. Also, the number of sensitive loads that require ideal sinusoidal supply voltages for their proper operation has increased. In order to keep power quality under limits proposed by standards, it is necessary to include some sort of compensation. Different types of power quality compensators of higher or lower complexity have been reported. This dissertation thesis deals with the shunt APF, series APF and the unified power quality conditioner (UPQC) which aims at the integration of series and shunt active filters. The main purpose of a UPQC is to compensate for voltage flicker/imbalance, reactive power, negative sequence current and harmonics. In other words, the UPQC has the capability of improving power quality at the point of installation on power. distribution systems or industrial power systems. In this dissertation work the modeling of shunt APF, series APF and the UPQC has been carried out and different topologies of shunt APF, series APF and the UPQC have been discussed briefly. The shunt APF is suitable for compensation against source current harmonics and the series APF is suitable against load voltage harmonics while the UPQC can compensate for source current and load voltage simultaneously and hence more suitable for improving the power quality. The shunt APF, series APF, and the UPQC have been simulated for different loads using the SIMPOWERSYSTEM (SPS) of MATLAB/SIMULINK models in this dissertation work. The simulation results show that these filters are good choice for improving the power quality of an electrical power system. Key words- Active Power Filter (APF), UPQC, Harmonics, Power Quality, SPS MATLAB / SIMULINK.