An Automatic Recognition Method of Residual Current Waveform Based on Sparse Representation

A residual current, sparse representation technology, applied in character and pattern recognition, instrument, calculation, etc., can solve problems such as waveform misrecognition, refusal to operate, and protector malfunction.

CN107578016BActive Publication Date: 2021-05-11CHONGQING UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2021-05-11

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Abstract

The invention discloses an automatic identification method of residual current waveform based on sparse representation. The method is: use the residual current transformer (RCD) to collect the residual current signals of leakage faults of N kinds of different equipment, perform denoising preprocessing to obtain N kinds of preprocessed signals, and use them as sample sets; extract the time-frequency domain characteristics of the signals in the sample sets respectively , get the eigenvectors, and perform normalization processing; the normalized eigenvectors form the eigenmatrix of all signals, as an over-complete dictionary of N kinds of residual current signals; use RCD to collect the residual current signals when the leakage fault is to be tested, and denoise The test sample is obtained by preprocessing, and its feature vector is extracted; the extracted feature vector is sparsely represented by an over-complete dictionary; the sparse representation of each signal is input into the sparse representation classifier, and the recognition result of the residual current signal type to be tested can be obtained. The invention can improve the validity and accuracy of residual current waveform identification.
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Description

technical field

[0001] The invention relates to the technical field of pattern recognition of residual current signals in power systems, in particular to an automatic recognition method for residual current waveforms based on sparse representation. Background technique

[0002] With the advancement of science and technology and the continuous development of smart grids, the types of power electronic equipment in urban and rural low-voltage power grids are increasing. When a leakage fault occurs on a line, the residual current generated is no longer a single power frequency sinusoidal current, but has a pulsating DC component and high frequency AC. components, even complex waveforms such as smooth DC components. In this case, the traditional AC-type residual current-operated protector has been unable to effectively protect this complex AC-DC residual current, so A-type and B-type residual current-operated protectors have become a research hotspot in leakage protection. [00...

Examples

specific Embodiment approach

[0018] 1. Use the residual current transformer (RCD) to collect residual current data as a sample data set for constructing a dictionary. The specific implementation is as follows:

[0019] Use the residual current transformer (RCD) to collect the residual current signals of N different types of equipment loads when leakage faults occur, including sine AC, half-wave, 90° wave, 135° wave, half-wave superimposed 6mA smooth DC wave, half-wave Superimpose N types of 10mA smooth DC wave and high-frequency AC residual current, etc., filter out the noise signal through a filter, and then select the same residual current signal to discretize it to obtain a sub-sample data set:

[0020]

[0021] Among them, i=1,2,...,N represent different residual current signal types, M represents the number of sample points after discretization of each residual current, and the selected residual current samples contain data of multiple periods of the residual current signal as much as possible, t...