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

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.

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...

AI Technical Summary

Problems solved by technology

[0004] At present, the residual current waveform identification method is limited to the judgment of a single feature of the signal, which is easily affected by environmental noise and the difference of the residual current transformer, which leads to misidentification of the waveform, causing the protector to malfunction or refuse to operate.

Images