Harmonic impedance estimation considering the correlation between harmonic sources

•This paper proposes a new approach that can suppress the effect of the correlation between non-measurable harmonic sources by the constructed and measured data.•The proposed method is more accurate when the correlation of harmonic sources on both sides is intense.•The processing the constructed bac...

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Bibliographic Details
Published inElectric power systems research Vol. 209; p. 107947
Main Authors Xu, Fangwei, Wang, Wenyu, Zheng, Hongru, Luo, Zhongyou, Guo, Kai, Wang, Chuan
Format Journal Article
LanguageEnglish
Published Amsterdam Elsevier B.V 01.08.2022
Elsevier Science Ltd
Subjects
Background harmonic
Correlation
Correlation analysis
Electric potential
Estimating techniques
Harmonic analysis
Impedance
Mathematical analysis
Power quality
Segments
Short circuits
Simulation
Utility harmonic impedance
Voltage
Background harmonic
Correlation
Utility harmonic impedance
Power quality
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Summary:•This paper proposes a new approach that can suppress the effect of the correlation between non-measurable harmonic sources by the constructed and measured data.•The proposed method is more accurate when the correlation of harmonic sources on both sides is intense.•The processing the constructed background harmonic data weakens the adverse effect of real background harmonic fluctuations. The previous utility harmonic impedance estimation methods are usually based on the assumption that harmonic sources are independent, which will cause large errors when the assumption is not met. To solve this problem, a method to weaken the negative effect of the correlation to impedance estimation is proposed. In the proposed method, the correlation between harmonic sources is reflected by that between constructed background harmonic voltage and measured harmonic current, and the effect of correlation is suppressed by obtaining the weak correlation time interval. First, construct the background harmonic voltage data based on the initial impedance, which changes in the range set according to the value of system short-circuit capacity. And then sort and divide these data into several sub-segments. Further, apply the correlation function to calculate impedance with each sub-segment. Finally, select the optimal impedance from all the initial impedances by comparing the difference between the calculated impedance and the initial impedance. The proposed method is more accurate when the correlation between harmonic sources is strong compared to other methods. Meanwhile, the processing of the background harmonic makes this method resist the significant background harmonic fluctuations. The effectiveness of the method is verified by simulation and field cases
ISSN:0378-7796
1873-2046
DOI:10.1016/j.epsr.2022.107947