Open AccessInter‐harmonics analysis and parameter estimation based on H2R6 window and constructing low‐interference zone
Author(s) -
Xu Yanchun,
Du Yufei,
Li Zhenxing,
Xi Lei,
Mi Lu
Publication year - 2020
Publication title -
iet communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.355
H-Index - 62
eISSN - 1751-8636
pISSN - 1751-8628
DOI - 10.1049/iet-com.2018.5103
Subject(s) - spectral leakage , harmonics , window function , harmonic , interference (communication) , interpolation (computer graphics) , harmonic analysis , frequency domain , mathematics , convolution (computer science) , algorithm , acoustics , computer science , mathematical analysis , fast fourier transform , physics , spectral density , telecommunications , channel (broadcasting) , frame (networking) , quantum mechanics , voltage , machine learning , artificial neural network
With a large number of renewable powers taken into the distributed grid, frequency‐irregular inter‐harmonics would cause the mainlobe interferences (MLI) in the frequency domain, which damages detection accuracy sharply. To solve MLI, a second‐order Hann and sixth‐order Rectangular convolution window (H 2 R 6 window) are constructed. It contains low sidelobes and a narrow mainlobe, which properly solves traditional harmonic problem, e.g. spectral leakage and picket‐fence effect. Moreover, by using this window, judging whether MLI exists becomes easier, and all inter‐harmonics are distinguished into three types. Different estimation strategies are applied to aim at different types of inter‐harmonics for common harmonic and the first type inter‐harmonic, a two‐point interpolation equation is calculated directly. For the second and the third type, a zone affected by MLI slightly is partitioned, then parameter can be estimated based on two spectra in this zone. The relative frequency error of the first type is about 10 −11 , and the ones corresponding to the second and the third type are at a range from 10 −3 to 10 −10 , which depends on the frequency distance of two adjacent sinusoids. Such a precision fully meets the demand for precision instruments.