A Framework for Evaluating Harmonic Losses in Distribution Planning

With the recent advent of inverter interfaced Distributed Energy Resources (DER) and end use loads employing power electronic circuits, power system harmonics are once again receiving attention as utilities integrate these resources in to their power grid. With the increased focus on DERs and new consumer electronic loads, one aspect that often gets ignored is the economic impact of harmonic emission from such energy sources and loads. This paper is part of a first attempt to bridge this gap in knowledge. Based upon previous research, a new ‘harmonic losses calculator’ was developed. This calculator quantifies losses due to the flow of harmonic currents on a distribution circuit and assigns a dollar value to them. Coupling this tool with the pre-existing ‘Harmonic Evaluation Module’, a new framework is proposed in which the economic impact of non-linear load or DER penetration can be accurately determined. The objective behind such an exercise is to enable utilities to evaluate the impact of harmonic load or savings due to DER penetration, at the planning stage. The framework is demonstrated by showing the impact of penetration of harmonic load and DER on two known distribution circuits, in the OpenDSS simulation framework. This is followed by a discussion of the change in operating costs of the feeder due to such load or generation. The paper closes with a discussion of the anticipated future research and expected capabilities to be added to this framework.