Self-adaptation independent component analysis method for harmonic wave impedance estimation

Abstract

The invention discloses a self-adaptation independent component analysis method for harmonic wave impedance estimation, relates to the field of power systems and aims to solve the problems that in theprior art a conventional power system harmonic wave impedance estimation method is low in precision, a novel rapid independent component analysis algorithm is low in convergence performance and source signals cannot be all recovered with an optimal effect. The method comprises the following steps: firstly, sampling a harmonic wave voltage and harmonic wave current at a public coupling point; secondly, carrying out centralization and whitening processing on a harmonic wave voltage sampling value and a harmonic wave current sampling value as known mixed signals; thirdly, with the criterion of negentropy maximization, carrying out iteration so as to obtain a primary separation matrix; finally carrying out self-adaptation selection on nonlinear functions, and carry outing progressivity analysis till an optimal nonlinear function, and calculating a harmonic wave impedance matrix, thereby finally obtaining harmonic wave impedance. By adopting the method, limits of conventional methods are overcome, meanwhile defects of rapid independent component analysis are made up, and the harmonic wave impedance estimation precision can be improved.

Description

technical field [0001] The invention relates to the field of power systems, in particular to an adaptive independent component analysis method for harmonic impedance estimation. Background technique [0002] As more and more nonlinear loads are connected to the distribution network in large quantities, a large number of applications of power electronic devices have been spawned, and a large number of harmonics have been injected into the power grid, resulting in harmonic pollution. Therefore, it is urgent to divide the responsibility of each harmonic source and carry out corresponding punishment. Harmonic impedance is a key parameter for the division of harmonic responsibilities, and the correct estimation of harmonic impedance is an important prerequisite for the division of harmonic responsibilities. [0003] At present, the harmonic impedance estimation of power system is mainly based on the linear regression method and the fluctuation quantity method. The former uses th...

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Problems solved by technology

[0005] The purpose of the present invention is: in order to solve the problem that the traditional method for estimating the harmonic impedance of the power system in the prior art has low accuracy, the emerging fast independent quantity analysis algorithm has low convergence performance, and cannot recover all source signals with the optimal effect, the present invention provides a An adaptive independent component analysis method for harmonic impedance estimation, first sampling the harmonic voltage and harmonic current at the common coupling point; then taking the sampled values ​​of harmonic voltage and harmonic current as known mixed signals, It performs centralization and whitening processing; then uses the maximization of negentropy as a criterion to obtain the initial separation matrix through iteration; finally, adaptively selects the nonlinear function for progressive analysis until the optimal nonlinear function is found to obtain the harmonic impedance matrix, and finally get the harmonic impedance, which overcomes the limitations of the traditional method and at the same time makes up for the deficiency of fast independent component analysis and improves the estimation accuracy of harmonic impedance

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