Investigations on Multilevel inverter topology for power quality improvement in distribution system

Abstract

The quality of power, supplied by the utilities, is expected to be in newlineline with the standards. In recent days, the generation of electricity from the newlinerenewable energy sector is encouraged as it helps to reduce environmental newlinepollution. However, due to the increased use of power electronics devices in newlinethe field of renewable energy, the quality of power is greatly affected. Almost newlineall the loads are non-linear in nature and this also contributes to the generation newlineof harmonics in voltage and current, along with increased reactive current newlinedeteriorating the quality of electrical power. Reduction of quality of power newlinecan result in increased power losses, abnormal and undesired behaviour of newlineequipment and interference with nearby communication lines. Various newlinecompensators are available today, which can be implemented at sending and newlinereceiving end of the line, for improving the PQ. Since most of the issues newlinerelated to PQ are with respect to the distribution side, the proposed work aims newlineat analysing the PQ issues on the distribution side. The most attractive newlinesolution, to compensate for several major PQ problems in the distribution newlineside, is the Unified Power Quality Conditioner (UPQC). UPQC is a newlinecombination of series and shunt active filters connected back to back via a newlinecommon DC-link capacitor. Shunt active filter is used for current newlinecompensation and series active filter is for voltage compensation, thereby newlineresolving all problems associated with PQ. newlineThe existing method uses a VSI for voltage regulation and it is fed newlineto the distribution system through an injection transformer. Regulated Voltage newlinefrom the inverter cannot be fed directly to the system as it has switching newlineharmonics. newline