Method for extracting lightning strike signals and transient harmonic signals in power system

A power system and harmonic signal technology, which is applied in the field of extraction of lightning strike signals and transient harmonic signals in power systems, can solve the problems of inaccurate extraction, achieve small calculation, wide application range, wavelet aliasing suppression Effect

Inactive Publication Date: 2010-02-24
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to solve the problem of inaccurate extraction existing in the extraction method of the lightning strike signal and transient harmonic signal in the current power system, and to provide a method for extracting the lightning strike signal and transient harmonic signal in the power system

Method used

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  • Method for extracting lightning strike signals and transient harmonic signals in power system
  • Method for extracting lightning strike signals and transient harmonic signals in power system
  • Method for extracting lightning strike signals and transient harmonic signals in power system

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specific Embodiment approach 1

[0020] Specific implementation mode one: the method for extracting the lightning strike signal and the transient harmonic signal in the power system of the present specific implementation mode, its specific process is as follows:

[0021] 1. Collect the grid current signal in the power system, and convert the current signal into a 12-bit digital signal;

[0022] 2. Carry out fast Fourier transform to the obtained 12-bit digital signal, and select the sampling frequency and decomposition scale of wavelet decomposition according to the results of fast Fourier transform;

[0023] 3. Perform wavelet decomposition on the 12-bit digital signal, so that the different frequency components of the 12-bit digital signal are correspondingly distributed in different wavelet scales, and then carry out characteristic information on the wavelet coefficients obtained by wavelet decomposition or the single wavelet reconstruction signal Evaluation, the specific process of the feature information...

specific Embodiment approach 2

[0027] Embodiment 2: This embodiment is a further description of the method for extracting lightning strike signals and transient harmonic signals in power systems described in Embodiment 1. The generalized wavelet entropy described in step 32 in step 3 The operation includes Tsallis wavelet time entropy operation and Tsallis wavelet energy entropy operation. The specific process of performing generalized wavelet entropy operation on the wavelet coefficient with abnormal singularity or single wavelet reconstruction signal is as follows:

[0028] The discrete wavelet coefficients of multiresolution analysis or single-branch wavelet reconstruction signal matrix is ​​D={d(k), k=1, 2,..., N}, wherein, d(k) is the kth discrete wavelet coefficient or single branch Branch wavelet reconstructed signal, k is discrete wavelet coefficient or element position variable in single branch wavelet reconstructed signal matrix, N is data length;

[0029] A sliding data window is defined on the w...

specific Embodiment approach 3

[0047] Specific implementation mode three: this specific implementation mode is a further description of the method for extracting lightning strike signals and transient harmonic signals in power systems described in specific implementation mode two:

[0048] In the operation process of Tsallis wavelet time entropy, the selection range of non-extensive parameter q is

[0049] (0,1)∪(1,2);

[0050] In the operation process of Tsallis wavelet energy entropy, the selection range of non-extensive parameter q is

[0051] [0.05, 0.2].

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Abstract

The invention relates to a method for extracting lightning strike signals and transient harmonic signals in a power system, which overcomes the problem of inaccurate extraction of the method for extracting the lightning strike signals and the transient harmonic signals in the power system in the prior art. The method comprises the steps of firstly converting the collected current signals to digital signals, further carrying out fast Fourier transform on the digital signals, determining the sampling frequency and the decomposition scale of wavelet decomposition according to the transform result, then carrying out wavelet decomposition on the digital signals, sequentially carrying out modulus maxima extraction, singularity detection and generalized wavelet entropy calculation on wavelet coefficients or single-branch wavelet reconstruction signals after the decomposition, and finally extracting the lightning strike signals and the transient harmonic signals according to the calculation result. The method can overcome the deficiencies of the prior art and be applicable to representing information features of the lightning signals and the transient harmonic signals in the time-frequencydomain.

Description

technical field [0001] The invention relates to a method for extracting lightning strike signals and transient harmonic signals in a power system. Background technique [0002] Lightning strike signal and transient harmonic signal belong to the transient signal of power system, which is a typical short-term non-stationary random process, which cannot be correctly represented by traditional signal analysis methods such as Fourier transform. Because the wavelet transform can transform the signal at multiple scales in the time-frequency domain at the same time, it has the characteristics of multi-resolution analysis. In recent years, the wavelet transform has been widely used in the detection and classification of transient signals in power systems. However, studies have shown that the actually collected power system transient signal has the characteristics of complex noise components, strong data correlation and high spatial dimension. There are many post-wavelet coefficients...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R19/25G01R23/16
Inventor 陈继开李浩昱寇宝泉
Owner HARBIN INST OF TECH
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