Abstract:
The problem of power quality is highly pressing in this era. The rise in the use of new generation loads based on microprocessors and power electronic equipment has increased concerns about quality of supplied power. The study of different power quality phenomena including frequency variation, overvoltage, under voltage, voltage sag, voltage swell, transient, waveform distortions and voltage fluctuation along with poor power factor at point of common coupling (PCC) was done in order to have a thorough understanding of these events. 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 in the power system.
This thesis includes study of power quality issues and use of UPQC to mitigate voltage and current harmonics. UPQC is analysed for three phase three 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. Thus, the proposed control strategy can be used to operate UPQC and eliminate variations in voltage at PCC thereby preventing mal-operation of sensitive loads.
