Harmonic Contribution Quantification for Multiple Harmonic Sources Based on Minimum Impedance Fluctuation

Abstract

The background harmonic fluctuation has a significant impact on the results of harmonic contribution quantification. However, the existing methods, especially those applied for multiple harmonic sources scenario, usually assume that the background harmonics remain constant, which is inconsistent with the actual operation of the power grid. Thus, a method based on minimum impedance fluctuation is proposed to quantify the harmonic contribution in the multiple harmonic sources scenario. First, the harmonic impedance is roughly estimated and used to calculate the unmeasurable background harmonics; Second, the measured harmonics are sequenced according to the size of background harmonics, and divided into several segments to suppress the adverse effect of background harmonic fluctuation; Finally, the actual harmonic impedance is solved by minimizing the impedance fluctuation function with measured harmonic data in each segment, and the actual harmonic contribution of sources are quantified. Compared with the existing methods, the proposed method can reduce the adverse impact of background harmonic fluctuation and obtain more accurate results due to the preprocess of background harmonics. The effectiveness of the proposed method is verified by case studies.