A Study of the Harmonic Analysis Based on the Three-Phase Impedance Matrix and the Effect of Distributed Generation on Harmonic Injection; 3상 임피던스 행렬 기반의 하모닉 해석과 분산전원의 하모닉 주입에 대한 효과에 관한 연구

초록

This paper presents a harmonic analysis methodology based on a three-phase impedance matrix under balanced system conditions, targeting voltage and current distortion caused by inverter-based distributed generation (DG). Unlike conventional single-phase approaches, the proposed algorithm constructs harmonic-specific impedance matrices to analyze individual harmonic orders. Two case studies are conducted: a 5-bus ring system and an 8-bus system with transformer connections. In the 5-bus system, a 40 MVAr DG injects harmonic current, and it is observed that reducing load capacity from 130% to 70% increases the 5th-order harmonic voltage at bus 5 from 0.801% to 0.827%. In the 8-bus system, applying IEEE Std. 519-1 shows that increasing line impedance from 90% to 110% raises voltage THD from 7.695% to 13.024%, with a Pearson correlation coefficient (r) of 0.9507 and p-value (p) of 8.33e-5. Conversely, under IEC 61000-3-6, the current THD decreases from 56.7% to 46.0%, showing a strong negative correlation (r = – 0.9987, p = 2.67e-10) due to reduced allowable harmonic current. The results verify the accuracy of the proposed method via comparison with DIgSILENT simulations and confirm that both load condition and line impedance significantly impact harmonic distortion under different regulatory standards. © © The Korean Institute of Electrical Engineers This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

키워드