A Review on Power Quality Improvement by UPQC

The current power sector is dealing with the poor power quality issues and the reason behind this poor power quality is voltage fluctuations, harmonics, transients and reactive power demands and these problems arises due to changing trend of our demand. Nowadays in our demand the share of power from power electronic devices has increase a lot and also coupling of grids to wind farms and solar farms has raised the problem of poor power quality.[25] No doubt series and shunt compensations are effective but if they are used simultaneously as a unified unit, this enhances the effectiveness of the device and becomes more beneficiary for power sector and they are used together as UPQC. So the main task of UPQC is to improve the power quality and it proves out to be quite good at that by compensating the above mentioned problems. Hence UPQC is considered as the efficient solution of the power quality problems. As the UPQC serves purpose of both series and shunt compensators, hence to provide this it contains two inverters, which are voltage source inverters with common DC link. These are called series and shunt converters. These controllers can be controlled by various techniques such as PI controllers, FUZZY controllers, Neural Networks etc .Shunt converter compensates the distortion in load current and the series converter is responsible for smoothening of voltage.