Mitigation of Harmonic Emissions of Distributed Energy Resources (DERS) in The Existence of Non-Linear Connected Loads

Abstract

The impact of linked distributed energy resources -employing different generation technologies- on the power quality is a significant concern for ordinary utility distribution engineers, most of whom are quite conservative in their approach to planning and operations. Power quality Issues influenced by Distributed Energy Resources (DERs) include voltage regulation, persistent interruptions, harmonics, and voltage sags. Harmonics can lead to equipment failure to perform properly, while in other circumstances, equipment may experience early failure (aging acceleration factor). This paper investigates harmonics generation from interconnected photovoltaic arrays and fixed-speed wind turbines and its propagation effects locally at the Point of Common Coupling (PCC) as well as at all the other system buses in the existence of nonlinear loads, which will be applied to the IEEE 5-bus test system. A passive filter will be constructed for effective harmonic mitigation based on the acquired results. Adding an Inductor-Capacitor-Inductor (LCL) filter has proved to be an effective solution for restoring THD to the standard limits. Results are obtained from PSCAD/EMTDC simulations and are subject to practical constraints regarding operating conditions, network modeling, and harmonic analysis depth; these limitations are explicitly discussed in the paper.