Power cable field partial discharge signal noise reduction method

A technology for discharging signals and power cables, applied in the direction of measuring electricity, measuring electrical variables, testing dielectric strength, etc., can solve the problems of low signal-to-noise ratio, low restoration accuracy, large waveform distortion rate, etc. ratio, suppressing periodic narrow-band noise, and reducing the effect of waveform distortion rate

Inactive Publication Date: 2018-02-23
STATE GRID ZHEJIANG ELECTRIC POWER CO LTD SHAOXING POWER SUPPLY CO +2
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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a noise reduction method for on-site partial discharge signals of power cables to solve the problems of low signal-to-noise ratio, large waveform distortion rate and low restoration accuracy in the traditional wavelet analysis algorithm

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  • Power cable field partial discharge signal noise reduction method
  • Power cable field partial discharge signal noise reduction method
  • Power cable field partial discharge signal noise reduction method

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Embodiment Construction

[0029] The present invention aims at the problems that the traditional wavelet analysis denoising algorithm will lead to waveform distortion or incomplete denoising, as well as low signal-to-noise ratio, high waveform distortion rate, and low restoration accuracy, and proposes a more advanced denoising algorithm. Noise reduction processing for on-site noise.

[0030] like figure 1 As shown, a method for reducing noise of partial discharge signals of power cables comprises the following steps,

[0031] S1: The power cable partial discharge signal is collected on site, and after digital processing, the time domain signal f(t) of the site partial discharge signal including periodic narrowband noise and white noise is formed.

[0032] S2: Let the fast Fourier transform of the signal f(t) be F(ω), namely Its FFT power spectrum is

[0033] S3: Proportionally sample from the global data set to obtain a subset of the global data set, and then perform hierarchical clustering by s...

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Abstract

The invention discloses a power cable field partial discharge signal noise reduction method. The method comprises the steps that S1 a field power cable partial discharge signal is collected, and digital processing is carried out to form the time domain signal f (t) of the field partial discharge signal; S2 the time domain signal f (t) is converted to a corresponding frequency domain function F (omega) through fast Fourier transform, and mathematical processing is carried out on the frequency domain function F (omega) to acquire a fast Fourier power spectrum described in the description; S3 anAGFCM algorithm is used to classify noisy signal power spectrum data into two categories; S4 narrow band interference peak is positioned; the positioned narrow band interference peak is compressed; inverse fast Fourier transform is carried out on P (omega) after narrow band interference peak filtering to acquire a narrow band noise filtered signal g (t); and S5 wavelet transform analysis is carried out on g (t); mother wavelet is selected; a threshold is determined; white noise is filtered out to acquire a final denoised signal. According to the invention, periodic narrow-band noise can be suppressed; the waveform distortion rate is reduced; and the signal-to-noise ratio of the denoising result is improved.

Description

technical field [0001] The invention relates to the technical field of electric power detection, in particular to a noise reduction method for on-site partial discharge signals of power cables. Background technique [0002] Partial discharge (PD) is a common fault in the safe operation of power cables. If the partial discharge signal cannot be detected in time, it will cause potential safety hazards, and may cause power accidents in severe cases. PD detection is one of the effective methods for evaluating the insulation state at present. However, due to the influence of the operating environment, in the actual on-site PD signal collection process, the PD signal collected by the transformer will contain a large amount of interference and noise. For example, white noise caused by thermal noise of electrical equipment, periodic narrow-band interference caused by system carrier communication or high-order harmonics, random pulse interference caused by switching devices such as t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/12
CPCG01R31/1272
Inventor 任广振郑月忠许海峰曹俊平林祖荣黄晓光韦爱平刘安文周永伟王鹏丁克松
Owner STATE GRID ZHEJIANG ELECTRIC POWER CO LTD SHAOXING POWER SUPPLY CO
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