Single-node water leakage position positioning method based on distance parameter inversion

Abstract

The invention discloses a single-node water leakage position positioning method based on distance parameter inversion, and the method comprises the steps: firstly installing a noise sensor in an experiment pipeline, and repeatedly collecting signal data through changing the flow of fluid in the pipeline and simulating the position parameters of a leakage point from the noise sensor in a to-be-detected experiment pipeline operation state; decomposing and reconstructing a sound signal acquired by the sensor by using a self-adaptive variational mode decomposition method; analyzing the reconstructed collected sound data, constructing a low-frequency dispersion equation based on an elastic constitutive relation and a global matrix method, solving group velocity and phase velocity of modal waves in a low-frequency band range, namely waveguide invariants, and constructing a relation between a frequency wave number relation and a distance by utilizing the waveguide invariants; a distance parameter # imgabs0 # and a frequency dispersion parameter # imgabs1 # are introduced, frequency dispersion elimination transformation is established, the distance of a leakage point is calculated, and the defect that the detection range is small due to the fact that medium-high frequency signals are collected in acoustic emission detection is overcome.

Description

Technical Field

[0001] The invention discloses a method for locating a water leakage position by a single node based on distance parameter inversion, and belongs to the technical field of pipeline leakage diagnosis. Background Art

[0002] Pipeline transportation is an efficient, safe and environmentally friendly way to transport liquid and gas materials over long distances. Through underground closed pipelines, oil, natural gas, chemicals and other fluids can be transported stably, reducing the risk of leakage and saving energy, making it the preferred way to transport energy materials. However, with the use of pipelines, leakage caused by pipeline damage has become a major hidden danger threatening safety, and the detection and location of pipeline leakage has become the top priority of pipeline maintenance.

[0003] At present, the main means of locating pipeline leakage include hardware-based infrared temperature sensor positioning, ultrasonic sensor positioning, and software-based analysis and positioning based on the collection of pipeline pressure, flow, temperature and other data. However, these methods may affect the normal use of the pipeline or fail to detect in real time, and are less practical in locating pipeline leakage. Acoustic emission detection technology generally focuses on the medium and high frequency bands, and rarely involves the frequency band below 1kHz. It has severe attenuation over long distances, resulting in high sensor costs and a small monitoring range. Therefore, it is of great significance to explore accurate low-frequency leakage signal positioning methods. Summary of the invention

[0004] The technical problem to be solved by the present invention is to address the above shortcomings and provide a method for locating the leakage position of a single node based on distance parameter inversion. Based on the dispersion theory, the leakage signal collected in the field is subjected to distance parameter inversion analysis and processing. The error between the leakage point position calculated using low-frequency data and the actual pipeline leakage source position is small, which solves the deficiency of a small detection range caused by the collection of medium and high-frequency signals in acoustic emission detection.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A method for locating a water leakage position by a single node based on distance parameter inversion comprises the following steps: Step 1: a noise sensor is installed in the experimental pipeline. When the experimental pipeline to be tested is in operation, signal data is repeatedly collected by changing the fluid flow rate in the pipeline and the position parameters of the simulated leakage point from the noise sensor; Step 2, using an adaptive variational mode decomposition method to decompose the acoustic signal collected by the sensor; Step 3, analyze the reconstructed collected sound data, construct a low-frequency dispersion equation based on the elastic constitutive relationship and the global matrix method, perform a grid search on the frequency to obtain the frequency-wave number correspondence, and thus calculate the group velocity and phase velocity of the modal wave in the low-frequency range. At this time, the waveguide invariant is used to construct the relationship between the frequency-wave number relationship and the distance; Step 4: Introduce distance parameter Sum dispersion parameters , establish the de-dispersion transformation and calculate the distance of the leakage point.

[0006] Furthermore, the specific process in step 2 is as follows: Assume the collected signal is: ; in To collect signals The envelope amplitude of is the instantaneous phase, satisfying the non-decreasing phase function and non-negative envelope function, and then the signal is translated to the baseband through Hilbert transform, and finally Gaussian smoothing is applied to estimate the bandwidth of the decomposed signal, and the modal function with the minimum sum of the bandwidth of the center frequency of each modal component is calculated. and center frequency ,Right now: ; ; The main components of the collected signal are selected according to the Wasserstein distance to reconstruct the leakage signal, and the frequency distribution of the reconstructed signal is calculated to determine the main frequency of the leakage signal.

[0007] Furthermore, in step 3, when analyzing the reconstructed collected sound data, only the waves on the plane perpendicular to the radial direction of the pipeline are considered, and the field formula formed by the propagation of sound waves is: .

[0008] Furthermore, in step 3, the low-frequency dispersion equation is constructed based on the elastic constitutive relation and the global matrix method as follows: ; in is the stress matrix, is the medium matrix determined by the wave speed, frequency and material properties of sound propagating in the pipe, AMP is the wave intensity matrix, the stress matrix is ​​a 0 matrix and there is no 0 element in the wave intensity matrix AMP, that is: .

[0009] Furthermore, in step 3, the frequency-wave number correspondence relationship is obtained by performing a grid search on the frequency to obtain the root as follows: The frequency grid is divided into 0,n,2n,…, , fixed frequency , along the wave number Search, if , then a set of corresponding frequencies and wave numbers is found , the frequency-wave number correspondence can be obtained by performing a grid search on the frequency to find the root.

[0010] Furthermore, the specific process of using the waveguide invariant in step 3 to construct the relationship between the frequency wavenumber relationship and the distance is as follows: The group velocity is calculated using the following formula: and phase velocity : ; ; Thus, the group velocity and phase velocity of the modal wave in the low frequency range are obtained. At this time, the waveguide invariant is used to construct the relationship between the frequency wavenumber relationship and the distance: .

[0011] Furthermore, the specific process of step 4 is as follows: Introducing distance parameters Sum dispersion parameters , establish the de-dispersion transform: ; ; in is a constant, is the leakage signal spectrum, is the modal wave number, so when , the exponential terms cancel each other out, and the energy of the modal waveguide is maximum. This is the distance to the leak point.

[0012] The present invention adopts the above technical solution, and has the following technical effects compared with the prior art: Based on the dispersion theory, the leakage signal collected in the field is processed by distance parameter inversion analysis. The leakage signal is collected with the help of a high-sensitivity sensor. The low-frequency modal waveguide of the leakage signal is extracted using the dispersion theory and adaptive variational mode decomposition method. The leakage signal is analyzed and processed in combination with the distance parameter to obtain the maximum energy of the modal waveguide. The distance dispersion inversion parameter value at this energy value is the distance to the leakage point, thereby achieving the purpose of effectively discovering the pipeline leakage point and accurately locating it. The error between the leakage point position calculated using the low-frequency data and the actual pipeline leakage source position is small, which solves the problem of a small detection range caused by the collection of medium and high-frequency signals in acoustic emission detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0014] Figure 1 It is a schematic diagram of the structure of a pipeline leakage location device based on low-frequency modal waves; Figure 2 It is a schematic diagram of the wave number-frequency relationship; Figure 3 It is a schematic diagram of the amplitude and frequency of the adaptive variational mode decomposition components IMFs; Figure 4 It is a schematic diagram of the leakage signal energy spectrum. DETAILED DESCRIPTION

[0015] Embodiment, a method for locating a water leakage position by a single node based on distance parameter inversion, comprising the following steps: Step 1, such as Figure 1 As shown, a noise sensor is installed in the experimental pipeline. When the experimental pipeline to be tested is in operation, signal data is repeatedly collected by changing parameters such as the fluid flow rate in the pipeline and the position L of the simulated leakage point from the noise sensor; Step 2: Use the adaptive variational mode decomposition method to decompose the acoustic signal collected by the sensor, such as Figure 3 As shown, assume that the collected signal is: ; in To collect signals The envelope amplitude of is the instantaneous phase, satisfying the non-decreasing phase function and non-negative envelope function, and then the signal is translated to the baseband through Hilbert transform, and finally H1 Gaussian smoothing is applied to estimate the bandwidth of the decomposed signal, and the modal function with the minimum sum of the bandwidth of the center frequency of each modal component is calculated. and center frequency ,Right now: ; ; in is the partial derivative with respect to t, It's Dirac Function, j is an imaginary unit, satisfies , k is the number of decomposed modes, f is the original signal, is the center frequency and e is a natural constant.

[0016] The main components of the collected signal are selected according to the Wasserstein distance to reconstruct the leakage signal, and the frequency distribution of the reconstructed signal is calculated to determine the main frequency of the leakage signal.

[0017] Step 3: Analyze the reconstructed collected sound data. Due to the design of the sensor, the circumferential displacement and radial displacement of the pipeline are basically not reflected in the collected data. Only the waves on the plane perpendicular to the radial direction of the pipeline are considered. The field formula formed by the propagation of sound waves is: ; in is the acoustic wave field function, is the Fourier transform of the original signal, i is the imaginary unit, The wave number is related to the frequency, x is the distance, is the frequency, t is the time, is the frequency differential.

[0018] The low-frequency dispersion equation is constructed based on the elastic constitutive relation (i.e. the relationship between the mechanical and kinematic quantities of the material) and the global matrix method: ; in is the stress matrix, is the medium matrix determined by the wave velocity, frequency and material properties of sound propagation in the pipeline, AMP is the wave intensity matrix, and the stress between the media at the coupling surface of the media inside and outside the pipeline should be balanced and each wave exists fixedly in the medium. It can be seen that the stress matrix is ​​a 0 matrix and there is no 0 element in the wave intensity matrix AMP, that is: ; The frequency grid is divided into 0,n,2n,…, , fixed frequency , along the wave number Search, if ,in is the dielectric matrix with wave number K, is a medium matrix with wave number K+1, then a set of corresponding frequencies and wave numbers is found. , the frequency-wave number correspondence can be obtained by grid search for the frequency root, such as Figure 2 As shown, the group velocity is calculated using the following formula and phase velocity : ; ; Thus, the group velocity and phase velocity of the modal wave in the low frequency range are obtained. At this time, the waveguide invariant is used to construct the relationship between the frequency wavenumber relationship and the distance: .

[0019] Step 4: Introduce distance parameter Sum dispersion parameters , establish the de-dispersion transform, such as Figure 4 As shown: Dispersion-free transform ; ; in To find the distance, The speed of sound in a medium, Dispersion parameters, is a constant, is the leakage signal spectrum, is the modal wave number, so when , the exponential terms cancel each other out, and the energy of the modal waveguide is maximum. This is the distance to the leak point.

[0020] Because the energy of the modal waveguide is maximum when fixed, To find the distance, is the dispersion parameter to be determined, and It is an artificially introduced variable. When the computer traverses the set solution space to obtain the maximum energy, .

[0021] With the help of high-sensitivity sensors, leakage signals are collected. First, noise is reduced and the leakage signals are extracted. Then, the relevant physical quantities in the environment are obtained according to relevant theories. The low-frequency modal waveguide of the leakage signal is extracted using dispersion theory and adaptive variational mode decomposition method. The leakage signal is analyzed and processed in combination with the distance parameter to obtain the maximum energy of the modal waveguide. The distance dispersion inversion parameter value at this energy value is the distance to the leakage point. The distance is obtained according to the de-dispersion transformation of the leakage signal, thereby achieving the purpose of effectively discovering the pipeline leakage point and accurately locating it.

[0022] The description of the present invention is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the invention to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for particular uses.

Claims

1. A method for locating a water leakage position by a single node based on distance parameter inversion, characterized in that: The following steps are involved: Step 1: a noise sensor is installed in the experimental pipeline. When the experimental pipeline to be tested is in operation, signal data is repeatedly collected by changing the fluid flow rate in the pipeline and the position parameters of the simulated leakage point from the noise sensor; Step 2, using an adaptive variational mode decomposition method to decompose and reconstruct the acoustic signal collected by the sensor; Step 3, analyze the reconstructed collected sound data, construct a low-frequency dispersion equation based on the elastic constitutive relationship and the global matrix method, perform a grid search on the frequency to obtain the frequency-wave number correspondence, and thus calculate the group velocity and phase velocity of the modal wave in the low-frequency range. At this time, the waveguide invariant is used to construct the relationship between the frequency-wave number relationship and the distance; Step 4: Introduce distance parameter Sum dispersion parameters , establish the de-dispersion transformation and calculate the distance of the leakage point.

2. A method for locating a water leakage position by a single node based on distance parameter inversion as claimed in claim 1, characterized in that: The specific process in step 2 is as follows: Assume the collected signal is: ; in To collect signals The envelope amplitude of is the instantaneous phase, satisfying the non-decreasing phase function and non-negative envelope function, and then the signal is translated to the baseband through Hilbert transform, and finally Gaussian smoothing is applied to estimate the bandwidth of the decomposed signal, and the modal function with the minimum sum of the bandwidth of the center frequency of each modal component is calculated. and center frequency ,Right now: ; ; The main components of the collected signal are selected according to the Wasserstein distance to reconstruct the leakage signal, and the frequency distribution of the reconstructed signal is calculated to determine the main frequency of the leakage signal.

3. The method for locating a water leakage position by a single node based on distance parameter inversion according to claim 1, characterized in that: In step 3, when analyzing the reconstructed collected sound data, only the waves on the plane perpendicular to the radial direction of the pipeline are considered, and the field formula formed by the propagation of sound waves is: 。 4. The method for locating a water leakage position by a single node based on distance parameter inversion according to claim 1, characterized in that: In step 3, the low-frequency dispersion equation is constructed based on the elastic constitutive relation and the global matrix method as follows: ； in is the stress matrix, is the medium matrix determined by the wave speed, frequency and material properties of sound propagating in the pipe, AMP is the wave intensity matrix, the stress matrix is ​​a 0 matrix and there is no 0 element in the wave intensity matrix AMP, that is: 。 5. The method for locating a water leakage position by a single node based on distance parameter inversion according to claim 1, characterized in that: In step 3, the frequency-wave number correspondence relationship is obtained by performing a grid search on the frequency to obtain the root as follows: The frequency grid is divided into 0,n,2n,…, , fixed frequency , along the wave number Search, if , then a set of corresponding frequencies and wave numbers is found , the frequency-wave number correspondence can be obtained by performing a grid search on the frequency to find the root.

6. The method for locating a water leakage position by a single node based on distance parameter inversion according to claim 1, characterized in that: The specific process of using the waveguide invariant in step 3 to construct the connection between the frequency wavenumber relationship and the distance is as follows: The group velocity is calculated using the following formula: and phase velocity : ； ； Thus, the group velocity and phase velocity of the modal wave in the low frequency range are obtained. At this time, the waveguide invariant is used to construct the relationship between the frequency wavenumber relationship and the distance: 。 7. A method for locating a water leakage position by a single node based on distance parameter inversion as claimed in claim 1, characterized in that: The specific process of step 4 is as follows: Introducing distance parameters Sum dispersion parameters , establish the de-dispersion transform: ； ； in is a constant, is the leakage signal spectrum, is the modal wave number, so when , the exponential terms cancel each other out, and the energy of the modal waveguide is maximum. This is the distance to the leak point.

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