PERFORMANCE INVESTIGATION OF UNIFIED POWER QUALITY CONDITIONER (UPQC)

Abstract

Precipitous rise in digital electronics, microprocessors and power electronics based devices has increased the concerns of quality the transmission and distribution systems. Different power quality phenomena are frequency variation, overvoltage, undervoltage, voltage sag, voltage swell, transient, waveform distortions and voltage fluctuation along with poor power factor at point of common coupling (PCC). To improve the power quality at PCC, passive filters along with several power electronics based devices (active filters) such as Dynamic voltage regulator (DVR), dynamic static compensator (DSTATCOM), unified power quality controller (UPQC) are used. Unified power quality conditioner (UPQC) is the most effective device to improve the power quality at PCC. UPQC is the integration of shunt and series active filters that compensate for almost all kind of voltage and current problems manifested in the power system. This thesis includes study of power quality issues and use of UPQC to mitigate voltage and current problems. UPQC is analyzed for three phase three wires and three phase four wires system with two control strategies to generate reference generation. The whole system was simulated in MATLAB/Simulink environment. A prototype of UPQC for three phase three wires system is developed for the validation of the simulation results.