Low-frequency oscillation analysis method based on SURE wavelet denoising and improved HHT

A technology of low-frequency oscillation and wavelet denoising, applied in the direction of reducing/preventing power oscillation

Active Publication Date: 2019-08-09
FUZHOU UNIVERSITY
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Problems solved by technology

[0006] In view of this, the object of the present invention is to provide a low-frequency oscillation analysis method based on SURE wavelet denoising and improved HHT to solve the problem of accurate identification of low-frequency oscillation signals under the influence of noise in the power system wide-area measurement system, and to ensure that the power grid adopts reasonable Effective suppression measures to improve the stable operation of the power grid

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  • Low-frequency oscillation analysis method based on SURE wavelet denoising and improved HHT
  • Low-frequency oscillation analysis method based on SURE wavelet denoising and improved HHT
  • Low-frequency oscillation analysis method based on SURE wavelet denoising and improved HHT

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Embodiment Construction

[0058] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0059] Please refer to figure 1 , the present invention provides the process based on SURE wavelet denoising and the low-frequency oscillation analysis method of improving HHT, it is characterized in that comprising the following steps:

[0060] Step S1: extracting the WAMS low-frequency oscillation signal.

[0061] Step S2: Perform SURE wavelet denoising preprocessing on the low-frequency oscillation signal. In this embodiment, the test signal x(n)=x is adopted 1 (n)+x 2 (n)+x 3 (n) is analyzed, where The number of sampling points is N=1000, and the sampling interval is T s = 0.01. Set the signal y(n)=x(n)+w(n), where y(n) is the low-frequency oscillation WAMS measurement signal, x(n) is the low-frequency oscillation signal, and w(n) is the noise signal. After SURE wavelet denoising preprocessing, in is the signal of y(n) preprocessed ...

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Abstract

The invention relates to the technical field of low-frequency oscillation modal identification in a wide-area measurement system, and provides a low-frequency oscillation analysis method based on SUREwavelet denoising and improved HHT. The method comprises the steps: carrying out the preprocessing of an oscillation signal through employing the SURE wavelet denoising, and carrying out the modal identification through employing an improved HHT method. The method comprises the following steps: firstly, for a power grid containing stronger noise, measuring a low-frequency oscillation signal, andcarrying out SURE wavelet denoising to realize signal preprocessing; secondly, performing CEEMD on the preprocessed low-frequency oscillation signal, screening all IMF components through a permutationentropy method, and improving the empirical mode decomposition, thereby improving the HHT analysis of low-frequency oscillation. According to the invention, the method effectively inhibits the phenomena of modal aliasing and pseudo components in empirical mode decomposition, does not need the order determination, is accurate in identification, and has a good application value in low-frequency oscillation identification of a power system.

Description

technical field [0001] The invention relates to the technical field of grid stability analysis of a power system wide-area measurement system, in particular to a low-frequency oscillation analysis method based on SURE wavelet denoising and improved HHT. Background technique [0002] The scale of modern power grids is getting larger and larger, and the transmission network presents the characteristics of cross-regional, long-distance, and large-region interconnection. It is important to identify the low-frequency oscillation mode of the power system, and then warn and suppress the oscillation of the power system to ensure the safe and stable operation of the power system. significance. [0003] Wide Area Measurement Systems (WAMS) use Phase Measurement Units (PMU) as the low-level measurement unit, which can directly measure generator power angle, angular velocity, bus voltage, etc., which are closely related to the electromechanical transient process of generators The physi...

Claims

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Application Information

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IPC IPC(8): H02J3/24
CPCH02J3/24H02J2203/20
Inventor 金涛陈坚沈学宇张可
Owner FUZHOU UNIVERSITY
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