Grid Interconnection of Renewable Energy Sources at the Distribution Level with Power- Quality Improvement Features

As there is increase in load demand, the Renewable Energy Resources (RES) are increasingly connected in the distribution systems which utilizes power electronic Converters or inverters. In this project, grid interfacing inverter is installed in three phase four wire distribution systems. The use of non-linear loads in the power system will lead to the generation of current harmonics which in turn deteriorates the power quality. Hence, Active Power Filters (APF) (5) are extensively used to compensate the current harmonics and load unbalance. The inverter can be controlled to perform as a multi-function device by incorporating active power filter functionality. Thus the existing inverter acts as a Shunt Active Power Filter that is capable of simultaneously compensating problems like current unbalance current harmonics and also of injecting the energy generated by renewable energy source. The inverter is controlled on the basis of hysteresis control and thus it can be utilized as a power converter injecting power generated from renewable energy resource to the grid and as a shunt active power filter to compensate the load disturbances. KEYWORD: Renewable energy resources (RES), Active power filter (APF), distributed generation (DG), distribution system, grid interconnection, power quality (PQ), renewable energy.