阅读说明：本技术 一种基于传声器阵列的gis声学信号提取方法及系统 (GIS acoustic signal extraction method and system based on microphone array ) 是由 高山 赵科 刘咏飞 杨景刚 张量 陈少波 胡成博 李洪涛 腾云 李玉杰 张照辉 于 2021-07-14 设计创作，主要内容包括：本发明公开了一种基于传声器阵列的GIS声学信号提取方法及系统,包括采集模块,用于获取GIS辐射出的声信号；降噪模块,用于对所述采集模块获取的GIS声信号进行降噪处理；PC模块,对处理后的信号进行显示和储存。本发明中,通过传声器阵列可以获取声源多方位的角度信息,提高了空间分辨率,通过构建指向性的空间滤波器对声信号加权滤波,接着对空间滤波后的声信号进一步的小波包阈值降噪,具有良好的GIS声信号提取效果。(The invention discloses a method and a system for extracting GIS acoustic signals based on a microphone array, which comprises an acquisition module, a processing module and a processing module, wherein the acquisition module is used for acquiring acoustic signals radiated by a GIS; the noise reduction module is used for carrying out noise reduction processing on the GIS acoustic signal acquired by the acquisition module; and the PC module is used for displaying and storing the processed signals. In the invention, the multidirectional angle information of the sound source can be acquired through the microphone array, the spatial resolution is improved, the sound signal is subjected to weighted filtering through constructing the directional spatial filter, and then the wavelet packet threshold value of the sound signal subjected to spatial filtering is subjected to noise reduction, so that the good GIS sound signal extraction effect is achieved.)

1. A GIS acoustic signal extraction method based on a microphone array is characterized by comprising the following steps:

s1, acquiring GIS operation sound signals in multiple azimuth angles by using the microphone array (11), and performing spatial filtering to obtain noise-containing signals;

s2, recording the obtained noise-containing signals and carrying out digital processing to obtain noise-containing signal data;

s3, carrying out wavelet packet decomposition processing on the obtained noise-containing signal data;

s4, carrying out threshold noise reduction processing on the signal subjected to wavelet packet decomposition, separating a GIS expected signal and interference noise, and obtaining a noise reduction signal;

and S5, visually projecting the obtained noise reduction signal.

2. The method for extracting the GIS acoustic signal based on the microphone array as claimed in claim 1, wherein the step of acquiring the GIS operation acoustic signal by the microphone array in S1 adopts a far-field acoustic source signal model, wherein: s is a far-field sound source, L₁…L_MThe method is characterized in that M array elements in a microphone array are shown, d is the distance between two adjacent microphones, theta is the incident angle of a far-field sound source, signals received by the array elements at different positions have certain time delay according to different distribution positions of the microphones, and the time delay of the sound signals reaching other microphones is relative to the time delay of the first microphone by taking the first array element as a reference:

τ_m＝dcosθ/c，m＝1,2,…,M

the output of the beamforming is:

by weighting w_mSetting the spatially filtered pitch angle is performed, focusing the signal in the desired direction.

3. The system for GIS acoustic signal extraction based on microphone array as claimed in claims 1-2, characterized by comprising:

the acquisition module (1) is used for acquiring acoustic signals radiated by the GIS;

the noise reduction module (2) is used for carrying out noise reduction processing on the GIS acoustic signals acquired by the acquisition module (1);

and the PC module (3) is used for displaying and storing the processed signals.

4. A system for microphone array based GIS acoustic signal extraction according to claim 3, characterized by the acquisition module (1) comprising a microphone array (11) and a data acquisition instrument (12);

the microphone array (11) is used for acquiring operation acoustic signals of the GIS at multiple azimuth angles;

and the data acquisition instrument (12) is used for recording the acquired CIS running acoustic signals and carrying out digital processing on the recorded CIS running acoustic signals.

5. A system for microphone array based GIS acoustic signal extraction according to claim 3, characterized by that, the noise reduction module (2) comprises a front end array processing module (21) and a back end wavelet packet noise reduction module (22);

the front-end array processing module (21) is used for focusing acoustic signals in a desired direction and nulling interference noise;

and the rear-end wavelet packet denoising module (22) is used for setting a threshold value and filtering a frequency band with wavelet packet energy smaller than the threshold value.

6. A system for microphone array based GIS acoustic signal extraction as claimed in claim 3, characterized by that the PC module (3) comprises a display screen (31) and a memory (32);

the display screen (31) is used for displaying the signal data processed by the noise reduction module (2);

the memory (32) is used for storing signal data.

Technical Field

The invention relates to the technical field of noise vibration signal acquisition and analysis in the power industry, in particular to a method and a system for extracting a GIS acoustic signal based on a microphone array.

Background

At present, the fault diagnosis of the GIS is generally judged by adopting a vibration measurement mode, and the method is not interfered by an electric field and a magnetic field. Because sound comes from vibration, GIS fault information contained in the vibration signal can also be reserved in the sound signal, and compared with vibration signal collection, the sound signal collection can be independent of a detection object in a non-contact mode. However, in the actual acoustic signal collection process of the GIS, the amplitude of noise radiated by other devices such as the peripheral transformer and the reactor is much higher than the amplitude of the operating acoustic signal of the GIS, the expected GIS signal is submerged in the interference noise, and the expected signal and the interference signal are coupled with each other and are not easy to separate.

At present, acoustic signals radiated by the GIS need to be collected firstly when the acoustic signals are generally adopted for carrying out the fault diagnosis of the GIS, and the traditional method based on a single sound transmitter has certain limitation in the GIS acoustic fault detection, and the specific expression is the interference of strong noise. In an actual acquisition environment, background noise is very large, especially operation noise of other equipment around the GIS, and signals acquired by a single sound transmitter are coupling of expected equipment and interference equipment radiation signals, which is not beneficial to extraction of fault characteristic sound signals of the GIS.

In addition, the traditional noise reduction method usually only performs filtering at the back end of signal processing, but because the signal-to-noise ratio is often low in the acoustic diagnosis process, a single noise reduction method cannot achieve the desired noise reduction effect.

Therefore, a method and a system for extracting a GIS acoustic signal based on a microphone array are provided to solve the above problems.

Disclosure of Invention

The invention aims to provide a method and a system for extracting a GIS acoustic signal based on a microphone array, which can reduce noise of an acquired signal from the front end and the rear end of signal processing and extract an acoustic signal radiated by expected equipment.

In order to achieve the purpose, the invention adopts the following technical scheme:

a GIS acoustic signal extraction method based on a microphone array comprises the following steps:

s1, acquiring the running sound signals of the GIS at multiple azimuth angles by using the microphone array, and performing spatial filtering to obtain noise-containing signals;

s2, recording the obtained noise-containing signals and carrying out digital processing to obtain noise-containing signal data;

s3, carrying out wavelet packet decomposition processing on the obtained noise-containing signal data;

s4, carrying out threshold noise reduction processing on the signal subjected to wavelet packet decomposition, separating a GIS expected signal and interference noise, and obtaining a noise reduction signal;

and S5, visually projecting the obtained noise reduction signal.

Preferably, the microphone array acquiring the GIS operation acoustic signal in S1 adopts a far-field acoustic source signal model, where: s is a far-field sound source, L₁…L_MThe method is characterized in that M array elements in a microphone array are shown, d is the distance between two adjacent microphones, theta is the incident angle of a far-field sound source, signals received by the array elements at different positions have certain time delay according to different distribution positions of the microphones, and the time delay of the sound signals reaching other microphones is relative to the time delay of the first microphone by taking the first array element as a reference:

τ_m＝dcosθ/c，m＝1,2,…,M

the output of the beamforming is:

by weighting w_mSetting the spatially filtered pitch angle is performed, focusing the signal in the desired direction.

A system for GIS acoustic signal extraction based on microphone arrays, comprising:

the acquisition module is used for acquiring acoustic signals radiated by the GIS;

the noise reduction module is used for carrying out noise reduction processing on the GIS acoustic signal acquired by the acquisition module;

and the PC module is used for displaying and storing the processed signals.

Preferably, the acquisition module comprises a microphone array and a data acquisition instrument;

the microphone array is used for acquiring operation acoustic signals of the GIS at multiple azimuth angles;

and the data acquisition instrument is used for recording the acquired CIS running acoustic signals and carrying out digital processing on the recorded CIS running acoustic signals.

Preferably, the noise reduction module comprises a front-end array processing module and a rear-end wavelet packet noise reduction module;

the front-end array processing module is used for focusing acoustic signals in a desired direction and nulling interference noise;

and the rear-end wavelet packet denoising module is used for setting a threshold value and filtering a frequency band with wavelet packet energy smaller than the threshold value.

Preferably, the PC module includes a display screen and a memory;

the display screen is used for displaying the signal data processed by the noise reduction module;

the memory is used for storing signal data.

The technical scheme provided by the embodiment of the invention has the following beneficial effects:

according to the method and the system for extracting the GIS acoustic signal based on the microphone array, the microphone array can be used for acquiring the multi-directional angle information of a sound source, the spatial resolution is improved, the directional spatial filter is constructed for carrying out weighted filtering on the sound signal, then the wavelet packet threshold value noise reduction is further carried out on the sound signal after the spatial filtering, the good GIS acoustic signal extraction effect is achieved, and the signal to noise ratio in the acoustic diagnosis process is improved.

Drawings

Fig. 1 is a schematic flow chart of a method for extracting a GIS acoustic signal based on a microphone array according to the present invention;

fig. 2 is a schematic structural diagram of a system for extracting GIS acoustic signals based on a microphone array according to the present invention.

In the figure: 1. an acquisition module; 11. a microphone array; 12. a data acquisition instrument; 2. a noise reduction module; 21. a front end array processing module; 22. a rear-end wavelet packet noise reduction module; 3. a PC module; 31. a display screen; 32. a memory.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

Referring to fig. 1-2, a method for extracting a GIS acoustic signal based on a microphone array includes the following steps:

s1, acquiring GIS operation sound signals at multiple azimuth angles by using the microphone array 11, and performing spatial filtering to obtain noise-containing signals;

s2, recording the obtained noise-containing signals and carrying out digital processing to obtain noise-containing signal data;

s3, carrying out wavelet packet decomposition processing on the obtained noise-containing signal data;

s4, carrying out threshold noise reduction processing on the signal subjected to wavelet packet decomposition, separating a GIS expected signal and interference noise, and obtaining a noise reduction signal;

and S5, visually projecting the obtained noise reduction signal.

In this application, microphone array 11 adopts the acoustics microphone of certain figure to arrange for the sound field of radiation carries out the spatial characteristics collection when moving GIS, can acquire the diversified angle information of sound source through microphone array, and with traditional adoption list microphone to gather the acoustic signal that GIS radiates out and compare, improved spatial resolution, the limitation is littleer, is favorable to the extraction to the acoustic signal of GIS's fault signature.

Furthermore, the sound source radiated when the microphone array 11 operates the GIS is subjected to multi-directional angle information acquisition and spatial filtering processing, then is subjected to digital processing by the data acquisition instrument 12 and then is subjected to wavelet packet decomposition processing, and then is subjected to threshold denoising processing, so that a GIS desired signal and interference noise are separated, a denoising signal is obtained, compared with the traditional method in which filtering processing is only performed at the rear end of signal processing, the obtained signal-to-noise ratio is higher, and the desired denoising effect achieved by the multi-denoising method can reach a desired state.

Specifically, because the acoustic signal collected by the microphone array 11 contains background noise, the wavelet packet threshold noise reduction can effectively remove the influence of the background noise. The principle of wavelet packet threshold noise reduction is to compare the amplitude coefficient after wavelet packet transformation with a set threshold, set the component smaller than the threshold as 0, retain the coefficient larger than or equal to the threshold, and finally reconstruct the residual wavelet packet coefficient.

In S1, a far-field sound source signal model is used for acquiring the GIS operating sound signal by the microphone array, wherein: s is a far-field sound source, L₁…L_MThe method is characterized in that M array elements in a microphone array are shown, d is the distance between two adjacent microphones, theta is the incident angle of a far-field sound source, signals received by the array elements at different positions have certain time delay according to different distribution positions of the microphones, and the time delay of the sound signals reaching other microphones is relative to the time delay of the first microphone by taking the first array element as a reference:

τ_m＝dcosθ/c，m＝1,2,…,M

the output of the beamforming is:

by weighting w_mSetting the spatially filtered pitch angle is performed, focusing the signal in the desired direction.

In the invention, wavelet packet threshold noise reduction is applied to actual GIS acoustic signal noise reduction.

Let { theta }_j(t-2/n)}_n∈ZIs a space U_jThe orthogonal basis, the orthogonal scale function and the wavelet function of (1) form a two-scale equation:

i.e. let signal W₁(t) by h_k、g_kThe two high and low pass combined quadrature mirror filters are combined for two samples. The essence of the wavelet packet decomposition is to decompose the signal into different frequency bands, the frequency band width Deltaf of the wavelet packet decomposition, the decomposition layer number j and the sampling frequency f_sSatisfy the requirement of

The required frequency band width and the start and stop frequency bands of each frequency band can be obtained by properly selecting the number of decomposition layers

. Decomposing the wavelet packet to obtain a wavelet coefficient relation between two scales:

the signal is decomposed into:

wherein u is_nAnd (t) a subspace generated by the wavelet packet corresponding function set. And performing threshold processing on the decomposed wavelet coefficients of each scale, setting the wavelet coefficients lower than the threshold value as zero, and reconstructing residual coefficients of each scale to obtain the noise-reduced signals. And considering the relation among the sampling frequency, the wavelet packet decomposition sub-band frequency and the GIS body noise frequency range, and performing noise reduction processing on the collected GIS original noise signal by adopting a 3-layer wavelet packet decomposition algorithm.

The invention also discloses a system for extracting the GIS acoustic signal based on the microphone array, which comprises the following steps:

the acquisition module 1 comprises a microphone array 11 and a data acquisition instrument 12, and is used for acquiring acoustic signals radiated by the GIS. The microphone array 11 is configured to acquire operating acoustic signals of the GIS at multiple azimuth angles, acquire angle information of a sound source at multiple azimuth angles, and improve resolution of the acquired acoustic signals. The data collector 12 is used for recording the acquired CIS operation acoustic signals and performing digital processing on the recorded CIS operation acoustic signals.

The noise reduction module 2 comprises a front-end array processing module 21 and a rear-end wavelet packet noise reduction module 22, and is configured to perform noise reduction processing on the GIS acoustic signals acquired by the acquisition module 1. Wherein, the front-end array processing module 21 is disposed on the microphone array 11 for focusing the acoustic signal in the desired direction, and nulling the interference noise. And the rear-end wavelet packet denoising module 22 is configured to set a threshold, and filter a frequency band in which the energy of the wavelet packet is smaller than the threshold, so as to perform threshold denoising processing.

The PC module 3, the PC module 3 includes a display screen 31 and a memory 32, and displays and stores the processed signal. And the display screen 31 is used for displaying the signal data processed by the noise reduction module 2. A memory 32 for storing signal data.

According to the invention, the multidirectional angle information of a sound source can be obtained through the microphone array, the spatial resolution is improved, the sound signal is subjected to weighted filtering through the directional spatial filter, and then the wavelet packet threshold value of the sound signal after the spatial filtering is subjected to noise reduction, so that the effect of improving the GIS sound signal extraction effect is achieved, and the signal-to-noise ratio in the acoustic diagnosis process is improved.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.