Power system simple harmonic detection method and system

Abstract

The invention relates to a power system simple harmonic detection method and system, and the method comprises the steps: carrying out the short-time Fourier transform of a power signal, and obtaininga spectrogram; constructing a distribution operator by detecting a local maximum value in the frequency direction of the spectrogram, and constructing a local maximum synchronous compression transformation model; denoising the power signal based on a synchronous extraction operator in combination with a ridge detection method; separating the denoised power signal based on the local maximum synchronous compression transformation model to obtain a plurality of non-noise signals; and calculating the instantaneous frequency and the instantaneous amplitude of each non-noise signal based on Hilbert,and identifying a harmonic signal according to the instantaneous frequency and the instantaneous amplitude of each non-noise signal. According to the method, good frequency band division and modal separation are carried out on multi-component signals, good anti-noise capability is achieved, detection deviation caused by noise is overcome, and real-time accurate detection is carried out on steady-state and transient-state harmonic parameters.

Description

technical field [0001] The invention relates to the field of simple harmonic detection, in particular to a method and system for simple harmonic detection of a power system. Background technique [0002] With the rapid development of power electronics technology, a large number of nonlinear power electronic devices have been put into use, the harmonic pollution in the power system is becoming more and more serious, and the influence of harmonics on power quality has attracted more and more attention; The frequency is an integer multiple of the power frequency, and there are a large number of non-integer and fractional harmonics; the existence of these harmonics seriously affects the safe operation of the power system, so these harmonics must be controlled and accurately The detection of inter-harmonics is the premise of harmonic control. How to accurately obtain the instantaneous frequency and amplitude of inter-harmonics is the key to harmonic detection [0003] Existing ...

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Problems solved by technology

However, SST still has certain deficiencies: first, when the frequency of each component of the signal is relatively close, due to the lack of focus of SST in the spectrum domain, the spectrum of the signal will be blurred, which seriously affects the analysis of the instantaneous frequency; second, when the signal When the noise interference is serious, due to the lack of a screening mechanism for the noise coefficient in the reconstruction process of the SST modal component, the extraction of the modal component is greatly affected by the noise, thereby affecting the analysis accuracy of the modal component parameters

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