Evaluating the Long-Term Impact of a Continuously Increasing Harmonic Demand on Feeder-Level Voltage Distortion

The increasing implementation of nonlinear devices within residential homes may have a significant impact on feeder-level harmonic distortion. Within this paper, the long-term distortion possibilities on a distribution feeder due to a large number of residential customers producing harmonic currents near and above the IEEE Std. 519 limits are analyzed. To enhance the accuracy of the analysis, field measurements were utilized to define the relationship between the harmonic current produced by a single customer and their corresponding harmonic impedance. To evaluate how increases in harmonic demand over time will affect feeder-level harmonic voltage, the current injection method was applied to models of an actual 13.2-kV distribution feeder and an expanded version of the 4-kV IEEE 13 Node Test Feeder. Residential customers were represented by a Norton equivalent circuit with the developed harmonic impedance function. The evaluation results provide insight into future harmonic distortion levels while also establishing a structure for forecasting feeder-level harmonic distortion based upon system impedance and the existing levels of harmonic demand.