Improvement of Power Quality using DVR in Distribution Systems

摘要

In this paper a new three-phase, five -level inverter topology with a single dc source Multi level inverter based Dynamic Voltage Restorer (DVR) is presented to improve the Power quality in distribution system by injecting voltage in series for the protection of sensitive loads against voltage sags and voltage swells. The performance of the DVR depends on control technique involved .In this paper fuzzy logic controller is used to control the injection of voltage when the fault occurs. Among the Power quality issues voltage sags and voltage Swells are major problems which are concentrated in this paper. The DVR injects the voltage by Multi level inverter which converts dc voltage in the Energy Storage System (ESS) into ac and the amount of the injection of voltage is controlled by the fuzzy logic controller. Simulation results are presented to illustrate and understand the performances of DVR in supporting load voltage by the waveforms of load voltage without DVR and with DVR. To evaluate the quality of the load voltage during the operation of DVR, Total Harmonic Distortion (THD) is calculated.