A transformer acoustic and vibration signal fusion detection method and system

Abstract

The present invention discloses a transformer acoustic-vibration signal fusion detection method and system. The technical scheme adopted by the method of the present invention is: short-time Fourier transform is performed on the collected original vibration signal and the original acoustic signal respectively, and the one-dimensional signal is transformed into a vibration power spectrum signal and an acoustic power spectrum signal; A-weighted calculation is performed on the acoustic power spectrum signal to obtain an acoustic A-weighted power spectrum signal; the amplitude ratio of each frequency point of the vibration power spectrum signal and the acoustic A-weighted power spectrum signal is calculated respectively, and the amplitude ratio is fused based on the additivity principle of information entropy to obtain the fused acoustic amplitude information parameter, that is, the amplitude spectrum of the acoustic-vibration fusion signal; the phase information of the vibration power spectrum signal is used as the phase information of the fusion signal, and then the inverse Fourier transform is performed in combination with the amplitude spectrum of the acoustic-vibration fusion signal, and the fusion signal is converted from the frequency domain to the time domain to obtain the final acoustic-vibration fusion time domain data. The present invention takes into account the sensitive characteristics of the acoustic signal to high frequencies and the recognition reliability of the vibration signal to low frequencies, obtains rich information parameters of the test equipment, and thus can realize reliable detection of the state of the test equipment.

Description

Technical Field

[0001] The invention belongs to the field of transformer signal detection, and in particular to a transformer acoustic and vibration signal fusion detection method and system. Background Art

[0002] As an important power equipment for long-distance transmission and distribution of electric energy, the safe and reliable operation of power transformers is the key to ensuring the normal production and life of users. Due to the complex working environment and long operation cycle of power transformers, the probability of failure will be greatly increased. If the failure is not handled in time, the power outage area of ​​the power system will be expanded, resulting in economic losses. Therefore, timely detection of potential faults of power transformers and improving the safety of transformer operation are of great significance to enhancing the reliability of power system operation and reducing equipment inspection and maintenance costs.

[0003] Since the vibration state of the power transformer can characterize its working condition under the corresponding state, the transformer equipment state can be identified by detecting the transformer vibration signal. However, in order to obtain a complete measurement target vibration signal, a large number of sensors need to be deployed, and it is usually difficult to deploy sensors in certain special parts. Therefore, the conventional power equipment fault diagnosis method based on vibration signal analysis can only measure local vibration signals, and it is difficult to obtain good identification results.

[0004] When a device fails, its internal components or structures will undergo mechanical deformation, which will produce abnormal sounds that are different from normal operation, and can be used as important characteristic parameters for diagnosing defects and faults. At the same time, the measurement method based on acoustic signals does not require contact with the test equipment, is low-cost and easy to implement, so it is gradually being used in the detection of power equipment. However, for some weak vibration signals, the measurement method based on acoustic signals is usually difficult to measure its complete signal parameters, which also limits the development of this method to a certain extent.

[0005] Most conventional single-type signal detection methods have the problem of incomplete state information provided, which may lead to large errors. Therefore, it is difficult to obtain good detection results in many cases, which in turn affects the reliable operation of the power system. Since the acoustic signal has the global characteristics of the entire sound field, and the vibration signal is more sensitive to the local characteristics of the specified test point, it is necessary to provide a detection method that effectively integrates the acoustic and vibration measurement information, so that it can not only obtain rich detection information parameters of the test equipment, but also significantly improve the recognition of the detection state. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the above-mentioned prior art and provide a transformer acoustic and vibration signal fusion detection method and system, which takes into account the sensitive characteristics of acoustic signals to high frequencies and the recognition reliability of vibration signals to low frequencies, and utilizes highly integrated algorithms such as Fourier transform to obtain rich information parameters of the test equipment, thereby realizing reliable detection of the test equipment status.

[0007] To this end, a technical solution adopted by the present invention is: a transformer acoustic vibration signal fusion detection method, which includes:

[0008] Step 1), performing short-time Fourier transform on the collected original vibration signal and original acoustic signal respectively, and transforming the one-dimensional signal into a vibration power spectrum signal and an acoustic power spectrum signal;

[0009] Step 2), performing A-weighted calculation on the acoustic power spectrum signal to obtain an acoustic A-weighted power spectrum signal;

[0010] Step 3), respectively calculating the amplitude ratio of each frequency point of the vibration power spectrum signal and the acoustic A-weighted power spectrum signal, and fusing the amplitude ratio based on the additivity principle of information entropy to obtain the fused acoustic vibration amplitude information parameter, that is, the amplitude spectrum of the acoustic vibration fusion signal;

[0011] Step 4), use the phase information of the vibration power spectrum signal as the phase information of the fusion signal, and then combine it with the amplitude spectrum of the acoustic vibration fusion signal to perform inverse Fourier transform, convert the fusion signal from the frequency domain to the time domain, and obtain the final acoustic vibration fusion time domain data.

[0012] Furthermore, in step 1), the formula of short-time Fourier transform is as follows:

[0013]

[0014] Where V s STFT , P s STFT Represent the original vibration signal V s , the original acoustic signal P s The vibration power spectrum signal and acoustic power spectrum signal after short-time Fourier transform are two-dimensional functions of time t and acoustic signal frequency f; g(t-τ) represents the time window function centered at a certain time τ, where τ is a constant; represents the imaginary unit, and ω=2πf represents the angular frequency.

[0015] Furthermore, in step 2), when the A-weighted calculation is performed on the acoustic power spectrum signal, the A-weighted calculation is about the time domain L A The calculation formula of (t) and frequency domain A(f) is as follows:

[0016]

[0017] Where f is the frequency of the sound signal, f i , i=1,2,3,4 are constant terms, A 1000 represents the normalized constant term, τ represents a certain moment and is a constant; ξ represents the time integral variable from a certain moment to the observation moment; p A (ξ) represents the A-weighted sound pressure at time ξ; p 0 is the reference sound pressure.

[0018] Further, in step 3), the amplitude proportion ψ of each frequency point of the vibration power spectrum signal and the acoustic A-weighted power spectrum signal is calculated respectively, and the calculation formula is as follows:

[0019]

[0020] In the formula, f current Indicates the amplitude of the current calculation frequency, f total Indicates the overall amplitude under the calculation frequency band;

[0021] Based on the additive property of information entropy, the amplitude ratio of the vibration power spectrum signal is organically combined with the amplitude ratio of the acoustic power spectrum signal to obtain the fused acoustic amplitude information parameter:

[0022]

[0023] In the formula, σ i represents the amplitude spectrum of the vibroacoustic fusion signal at the i-th frequency, Respectively represent the amplitude proportion of the vibration power spectrum signal and the acoustic power spectrum signal at the i-th frequency, N + Represents a positive integer.

[0024] Furthermore, in step 4), the phase information of the vibration power spectrum signal is used as the phase information of the fusion signal to perform inverse Fourier transform, and the transformation formula is as follows:

[0025]

[0026] Where a is the final acoustic-vibration fusion time domain data, ifft represents the inverse Fourier transform, represents the phase information of the vibration power spectrum signal, and σ represents the amplitude spectrum of the acoustic vibration fusion signal.

[0027] Another technical solution adopted by the present invention is: a transformer acoustic and vibration signal fusion detection system, which includes:

[0028] The short-time Fourier transform unit performs short-time Fourier transform on the collected original vibration signal and the original acoustic signal respectively, and transforms the one-dimensional signal into a vibration power spectrum signal and an acoustic power spectrum signal;

[0029] An A-weighted calculation unit performs A-weighted calculation on the acoustic power spectrum signal to obtain an acoustic A-weighted power spectrum signal;

[0030] The amplitude ratio fusion unit calculates the amplitude ratio of each frequency point of the vibration power spectrum signal and the acoustic A-weighted power spectrum signal respectively, and performs amplitude ratio fusion based on the additivity principle of information entropy to obtain the fused acoustic vibration amplitude information parameter, that is, the amplitude spectrum of the acoustic vibration fusion signal;

[0031] The inverse Fourier transform unit uses the phase information of the vibration power spectrum signal as the phase information of the fusion signal, and then combines it with the amplitude spectrum of the acoustic-vibration fusion signal to perform an inverse Fourier transform, converting the fusion signal from the frequency domain to the time domain to obtain the final acoustic-vibration fusion time domain data.

[0032] The present invention overcomes the deficiency that it is difficult to obtain comprehensive status information based on conventional single signal detection methods, takes into account the sensitive characteristics of acoustic signals for high frequencies and the recognition reliability of vibration signals for low frequencies, and utilizes highly integrated algorithms such as Fourier transform to achieve simple and efficient calculations, thereby obtaining rich information parameters of the test equipment, thereby realizing reliable detection of the test equipment status.

[0033] The present invention is simple, efficient and accurate, and the obtained acoustic-vibration fusion data contains rich transformer status information, thus providing an accurate and reliable data source for transformer fault diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a flow chart of the transformer acoustic and vibration signal fusion detection method of the present invention;

[0035] Figure 2 (a) is a time domain schematic diagram of the original vibration signal used when the method of the present invention is applied;

[0036] Figure 2 (b) is a frequency domain schematic diagram of the original vibration signal used when the method of the present invention is applied;

[0037] Figure 2 (c) is a time domain schematic diagram of the original acoustic signal used when the method of the present invention is applied;

[0038] Figure 2 (d) is a frequency domain schematic diagram of the original acoustic signal used when the method of the present invention is applied;

[0039] Figure 2 (e) is a time domain schematic diagram of the fused signal after the method of the present invention is applied;

[0040] Figure 2 (f) is a frequency domain schematic diagram of the fused signal after the method of the present invention is applied;

[0041] Figure 3 It is a structural block diagram of the transformer acoustic and vibration signal fusion detection system of the present invention. DETAILED DESCRIPTION

[0042] The technical solution of the present invention is described more clearly and completely below in conjunction with the embodiments and the accompanying drawings.

[0043] Example 1

[0044] This embodiment provides a transformer acoustic vibration signal fusion detection method, such as Figure 1 As shown, it includes:

[0045] Step 1), performing short-time Fourier transform on the collected original vibration signal and original acoustic signal respectively, and transforming the one-dimensional signal into a vibration power spectrum signal and an acoustic power spectrum signal;

[0046] Step 2), performing A-weighted calculation on the acoustic power spectrum signal to obtain an acoustic A-weighted power spectrum signal;

[0047] Step 3), respectively calculating the amplitude ratio of each frequency point of the vibration power spectrum signal and the acoustic A-weighted power spectrum signal, and fusing the amplitude ratio based on the additivity principle of information entropy to obtain the fused acoustic vibration amplitude information parameter, that is, the amplitude spectrum of the acoustic vibration fusion signal;

[0048] Step 4), use the phase information of the vibration power spectrum signal as the phase information of the fusion signal, and then combine it with the amplitude spectrum of the acoustic vibration fusion signal to perform inverse Fourier transform, convert the fusion signal from the frequency domain to the time domain, and obtain the final acoustic vibration fusion time domain data.

[0049] Specifically, in step 1), the formula of short-time Fourier transform is as follows:

[0050]

[0051] Where V s STFT , P s STFT Represent the original vibration signal V s , the original acoustic signal P s The vibration power spectrum signal and acoustic power spectrum signal after short-time Fourier transform are two-dimensional functions of time t and acoustic signal frequency f; g(t-τ) represents the time window function centered at a certain time τ, where τ is a constant; represents the imaginary unit, and ω=2πf represents the angular frequency.

[0052] Specifically, in step 2), when the A-weighted calculation is performed on the acoustic power spectrum signal, the A-weighted calculation is about the time domain L A The calculation formula of (t) and frequency domain A(f) is as follows:

[0053]

[0054] Where f is the frequency of the sound signal, f i , i=1,2,3,4 are constant terms; A 1000 represents the normalized constant term; τ represents a certain moment, which is a constant; ξ represents the time integral variable from a certain moment to the observation moment; p A (ξ) represents the A-weighted sound pressure at time ξ; p 0 is the reference sound pressure.

[0055] Specifically, in step 3), the amplitude proportion ψ of each frequency point of the vibration power spectrum signal and the acoustic A-weighted power spectrum signal is calculated respectively, and the calculation formula is as follows:

[0056]

[0057] In the formula, f current Indicates the amplitude of the current calculation frequency, f total Indicates the overall amplitude under the calculation frequency band;

[0058] Based on the additive property of information entropy, the amplitude ratio of the vibration power spectrum signal is organically combined with the amplitude ratio of the acoustic power spectrum signal to obtain the fused acoustic amplitude information parameter:

[0059]

[0060] In the formula, σ i represents the amplitude spectrum of the vibroacoustic fusion signal at the i-th frequency, Respectively represent the amplitude proportion of the vibration power spectrum signal and the acoustic power spectrum signal at the i-th frequency, N + Represents a positive integer.

[0061] Specifically, in step 4), the phase information of the vibration power spectrum signal is used as the phase information of the fusion signal to perform inverse Fourier transform, and the transformation formula is as follows:

[0062]

[0063] Where a is the final acoustic-vibration fusion time domain data, ifft represents the inverse Fourier transform, represents the phase information of the vibration power spectrum signal, and σ represents the amplitude spectrum of the acoustic vibration fusion signal.

[0064] In order to highlight the superiority of the method of the present invention, the method of the present invention is used to perform acoustic vibration fusion calculation on a certain measured data, and the calculation results are as follows: Figure 2 shown.

[0065] It can be seen from the above table that the characteristics of the acoustic vibration fusion signal obtained by the method of the present invention in the full frequency band are more prominent. Figure 2 (b) It can be seen that the amplitude of the vibration signal is low when the frequency f = 300 Hz, while Figure 2 In (d), the amplitude of the acoustic signal at 300 Hz is more obvious; Figure 2 (f) It can be seen that the amplitude of the fusion signal at 300 Hz is more obvious, which shows that the acoustic signal can be a good supplement to the vibration signal. In summary, compared with a single signal detection method, the method of the present invention can obtain more abundant state information parameters of the device under test.

[0066] Example 2

[0067] This embodiment provides a transformer acoustic and vibration signal fusion detection system. Figure 3 As shown, it includes:

[0068] The short-time Fourier transform unit performs short-time Fourier transform on the collected original vibration signal and the original acoustic signal respectively, and transforms the one-dimensional signal into a vibration power spectrum signal and an acoustic power spectrum signal;

[0069] An A-weighted calculation unit performs A-weighted calculation on the acoustic power spectrum signal to obtain an acoustic A-weighted power spectrum signal;

[0070] The amplitude ratio fusion unit calculates the amplitude ratio of each frequency point of the vibration power spectrum signal and the acoustic A-weighted power spectrum signal respectively, and performs amplitude ratio fusion based on the additivity principle of information entropy to obtain the fused acoustic vibration amplitude information parameter, that is, the amplitude spectrum of the acoustic vibration fusion signal;

[0071] The inverse Fourier transform unit uses the phase information of the vibration power spectrum signal as the phase information of the fusion signal, and then combines it with the amplitude spectrum of the acoustic-vibration fusion signal to perform an inverse Fourier transform, converting the fusion signal from the frequency domain to the time domain to obtain the final acoustic-vibration fusion time domain data.

[0072] In the short-time Fourier transform unit, the formula of short-time Fourier transform is as follows:

[0073]

[0074] Where V s STFT , P s STFT Represent the original vibration signal V s , the original acoustic signal Ps The vibration power spectrum signal and acoustic power spectrum signal after short-time Fourier transform are two-dimensional functions of time t and acoustic signal frequency f; g(t-τ) represents the time window function centered at a certain time τ, where τ is a constant; represents the imaginary unit, and ω=2πf represents the angular frequency.

[0075] In the A-weighted calculation unit, when performing A-weighted calculation on the acoustic power spectrum signal, the A-weighted calculation is performed on the time domain L A The calculation formula of (t) and frequency domain A(f) is as follows:

[0076]

[0077] Where f is the frequency of the sound signal, f i , i=1,2,3,4 are constant terms; A 1000 represents the normalized constant term; τ represents a certain moment, which is a constant; ξ represents the time integral variable from a certain moment to the observation moment; p A (ξ) represents the A-weighted sound pressure at time ξ; p 0 is the reference sound pressure.

[0078] In the amplitude ratio fusion unit, the amplitude ratio ψ of each frequency point of the vibration power spectrum signal and the acoustic A-weighted power spectrum signal is calculated respectively, and the calculation formula is as follows:

[0079]

[0080] In the formula, f current Indicates the amplitude of the current calculation frequency, f total Indicates the overall amplitude under the calculation frequency band;

[0081] Based on the additive property of information entropy, the amplitude ratio of the vibration power spectrum signal is organically combined with the amplitude ratio of the acoustic power spectrum signal to obtain the fused acoustic amplitude information parameter:

[0082]

[0083] In the formula, σ i represents the amplitude spectrum of the vibroacoustic fusion signal at the i-th frequency, Respectively represent the amplitude proportion of the vibration power spectrum signal and the acoustic power spectrum signal at the i-th frequency, N + Represents a positive integer.

[0084] In the inverse Fourier transform unit, the phase information of the vibration power spectrum signal is used as the phase information of the fusion signal to perform inverse Fourier transform, and the transformation formula is as follows:

[0085]

[0086] Where a is the final acoustic-vibration fusion time domain data, ifft represents the inverse Fourier transform, represents the phase information of the vibration power spectrum signal, and σ represents the amplitude spectrum of the acoustic vibration fusion signal.

[0087] The above embodiments are only preferred embodiments of the present invention. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention fall within the protection scope of the present invention.

Claims

1. A transformer acoustic and vibration signal fusion detection method, It is characterized in that include: Step 1), performing short-time Fourier transform on the collected original vibration signal and original acoustic signal respectively, and transforming the one-dimensional signal into a vibration power spectrum signal and an acoustic power spectrum signal; Step 2), performing A-weighted calculation on the acoustic power spectrum signal to obtain an acoustic A-weighted power spectrum signal; Step 3), respectively calculating the amplitude ratio of each frequency point of the vibration power spectrum signal and the acoustic A-weighted power spectrum signal, and fusing the amplitude ratio based on the additivity principle of information entropy to obtain the fused acoustic vibration amplitude information parameter, that is, the amplitude spectrum of the acoustic vibration fusion signal; Step 4), using the phase information of the vibration power spectrum signal as the phase information of the fusion signal, and then combining it with the amplitude spectrum of the acoustic vibration fusion signal to perform inverse Fourier transform, converting the fusion signal from the frequency domain to the time domain, and obtaining the final acoustic vibration fusion time domain data; In step 3), the amplitude ratio ψ of each frequency point of the vibration power spectrum signal and the acoustic A-weighted power spectrum signal is calculated respectively, and the calculation formula is as follows: In the formula, f current Indicates the amplitude of the current calculation frequency, f total Indicates the overall amplitude under the calculation frequency band; Based on the additive property of information entropy, the amplitude ratio of the vibration power spectrum signal is organically combined with the amplitude ratio of the acoustic power spectrum signal to obtain the fused acoustic amplitude information parameter: In the formula, σ i represents the amplitude spectrum of the acoustic vibration fusion signal at the i-th frequency, Respectively represent the amplitude proportion of the vibration power spectrum signal and the acoustic power spectrum signal at the i-th frequency, N + Represents a positive integer.

2. According to the transformer acoustic vibration signal fusion detection method of claim 1, It is characterized in that In step 1), the formula for short-time Fourier transform is as follows: In the formula, Represent the original vibration signal V s , original acoustic signal P s The vibration power spectrum signal and acoustic power spectrum signal after short-time Fourier transform are two-dimensional functions of time t and acoustic signal frequency f; g(t-τ) represents the time window function centered at a certain time τ, where τ is a constant; represents the imaginary unit, and ω=2πf represents the angular frequency.

3. According to the transformer acoustic vibration signal fusion detection method of claim 1, It is characterized in that In step 2), when the A-weighted calculation is performed on the acoustic power spectrum signal, the A-weighted calculation is about the time domain L A The calculation formula of (t) and frequency domain A(f) is as follows: Where f is the frequency of the sound signal, f i , i=1,2,3,4 are constant terms; A 1000 represents the normalized constant term; τ represents a certain moment, which is a constant; ξ represents the time integral variable from a certain moment to the observation moment; p A (ξ) represents the A-weighted sound pressure at time ξ; p 0 is the reference sound pressure.

4. According to claim 1, a transformer acoustic vibration signal fusion detection method, It is characterized in that In step 4), the phase information of the vibration power spectrum signal is used as the phase information of the fusion signal to perform inverse Fourier transform. The transformation formula is as follows: Where a is the final acoustic-vibration fusion time domain data, ifft represents the inverse Fourier transform, represents the phase information of the vibration power spectrum signal, and σ represents the amplitude spectrum of the acoustic vibration fusion signal.

5. A transformer acoustic and vibration signal fusion detection system, It is characterized in that include: The short-time Fourier transform unit performs short-time Fourier transform on the collected original vibration signal and the original acoustic signal respectively, and transforms the one-dimensional signal into a vibration power spectrum signal and an acoustic power spectrum signal; An A-weighted calculation unit performs A-weighted calculation on the acoustic power spectrum signal to obtain an acoustic A-weighted power spectrum signal; The amplitude ratio fusion unit calculates the amplitude ratio of each frequency point of the vibration power spectrum signal and the acoustic A-weighted power spectrum signal respectively, and performs amplitude ratio fusion based on the additivity principle of information entropy to obtain the fused acoustic vibration amplitude information parameter, that is, the amplitude spectrum of the acoustic vibration fusion signal; The inverse Fourier transform unit uses the phase information of the vibration power spectrum signal as the phase information of the fusion signal, and then combines it with the amplitude spectrum of the acoustic-vibration fusion signal to perform inverse Fourier transform, converting the fusion signal from the frequency domain to the time domain to obtain the final acoustic-vibration fusion time domain data; In the amplitude ratio fusion unit, the amplitude ratio ψ of each frequency point of the vibration power spectrum signal and the acoustic A-weighted power spectrum signal is calculated respectively, and the calculation formula is as follows: In the formula, f current Indicates the amplitude of the current calculation frequency, f total Indicates the overall amplitude under the calculation frequency band; Based on the additive property of information entropy, the amplitude ratio of the vibration power spectrum signal is organically combined with the amplitude ratio of the acoustic power spectrum signal to obtain the fused acoustic amplitude information parameter: In the formula, σ i represents the amplitude spectrum of the acoustic vibration fusion signal at the i-th frequency, Respectively represent the amplitude proportion of the vibration power spectrum signal and the acoustic power spectrum signal at the i-th frequency, N + Represents a positive integer.

6. A transformer acoustic and vibration signal fusion detection system according to claim 5, It is characterized in that In the short-time Fourier transform unit, the formula of short-time Fourier transform is as follows: In the formula, Represent the original vibration signal V s , original acoustic signal P s The vibration power spectrum signal and acoustic power spectrum signal after short-time Fourier transform are two-dimensional functions of time t and acoustic signal frequency f; g(t-τ) represents the time window function centered at a certain time τ, where τ is a constant; represents the imaginary unit; ω=2πf represents the angular frequency.

7. A transformer acoustic and vibration signal fusion detection system according to claim 5, It is characterized in that In the A-weighted calculation unit, when performing A-weighted calculation on the acoustic power spectrum signal, the A-weighted calculation is performed on the time domain L A The calculation formula of (t) and frequency domain A(f) is as follows: Where f is the frequency of the sound signal, f i , i=1,2,3,4 are constant terms, A 1000 represents the normalized constant term; τ represents a certain moment, which is a constant; ξ represents the time integral variable from a certain moment to the observation moment, p A (ξ) represents the A-weighted sound pressure at time ξ; p 0 is the reference sound pressure.

8. The transformer acoustic and vibration signal fusion detection system according to claim 5, It is characterized in that In the inverse Fourier transform unit, the phase information of the vibration power spectrum signal is used as the phase information of the fusion signal to perform inverse Fourier transform, and the transformation formula is as follows: Where a is the final acoustic-vibration fusion time domain data, ifft represents the inverse Fourier transform, represents the phase information of the vibration power spectrum signal, and σ represents the amplitude spectrum of the acoustic vibration fusion signal.

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