WO2021208521A1

WO2021208521A1 - Pipeline leakage position calculation method based on beam forming

Info

Publication number: WO2021208521A1
Application number: PCT/CN2020/142312
Authority: WO
Inventors: 郑晓亮; 李强; 薛生
Original assignee: 安徽理工大学
Priority date: 2020-04-13
Filing date: 2020-12-31
Publication date: 2021-10-21
Also published as: ZA202102330B; CN111350948A

Abstract

A pipeline leakage position calculation method based on beam forming. The method comprises: arranging a reference sensor on an outer wall of one end of a target pipeline, and arranging a plurality of auxiliary sensors at intervals on an outer wall of the other end of the target pipeline, wherein the plurality of auxiliary sensors and the reference sensor are arranged in a straight line to form a multi-element linear sensor array; if pipeline leakage occurs, collecting a leakage signal by means of each sensor in the multi-element linear sensor array, and sending the leakage signal to a signal processing terminal; and the signal processing terminal using an auto-spectrum-excluding cross-power spectrum beamforming algorithm to carry out joint calculation on a sound source position where the pipeline leakage occurs and the speed of a sound wave signal being propagated along the pipeline, and then outputting a positioning result.

Description

A Calculation Method of Pipeline Leakage Location Based on Beamforming

Technical field

The present invention relates to the technical field of pipeline leakage location, in particular to a method for calculating the position of pipeline leakage based on beamforming.

Background technique

In recent years, pipeline transportation, as an important means of energy transportation (100% of the world’s natural gas and 85% of crude oil are transported by pipeline), brings convenience to energy transportation and inevitably increases safety risks. In order to achieve safe and sustainable development, it is necessary to accurately locate the gas pipeline network leakage and eliminate potential safety hazards in a timely manner.

The pipeline leakage acoustic wave location method has been widely studied and applied with its better comprehensive performance. Its principle is to use the sensors at the upstream and downstream ends of the leak location to collect signals and perform delay estimation. The leak location can be calculated by combining the sensor spacing and wave velocity. . The existing acoustic wave method is a two-step positioning method, which is actually a suboptimal sound source position estimation process. The positioning error of this method is still large, and the main influencing factors are: (1) Delay estimation error, which is mainly caused by background noise interference and poor performance of the delay estimation function itself. Liu et al. Noise reduction system; (2) Theoretical wave velocity error. Due to the complicated pipeline environment and the flow of gaseous medium in the pipe, it is difficult to accurately estimate the theoretical wave velocity of the leaking sound wave propagating along the pipe. Li et al. proposed a location method based on time-frequency spectrum. The cross power spectrum of the non-dispersive guided wave mode signal is extracted, so as to realize the location of the leakage signal whose speed changes with frequency.

The existing acoustic wave method is generally based on dual sensors for delay estimation and positioning, which can be regarded as a time-of-arrival method based on a 2-element linear array. Compared with the time-of-arrival method, the high-resolution spectrum estimation method and the beamforming method have higher positioning accuracy and stronger anti-interference ability. However, the requirement of a larger number of array elements and the existence of reverberation interference limit the practical application effect of the high-resolution spectrum estimation method. However, the conventional beamforming method directly performs weighting in a delay compensation manner, without prior knowledge of the source and noise, and the practical application is simple and convenient.

Accordingly, there is an urgent need for a joint estimation method of pipeline leakage location-wave velocity based on beamforming to avoid the error of the theoretical wave velocity model, improve the anti-interference ability of the sonic method, and achieve accurate location of the leakage location.

Summary of the invention

The present invention provides a method for calculating the pipeline leakage position based on beamforming, which aims to avoid errors caused by using a theoretical velocity model to estimate the wave speed in a complicated pipeline environment, and realize accurate positioning of the pipeline leakage position.

The present invention provides a method for calculating the position of a pipeline leak based on beamforming, which includes.

A reference sensor is arranged on the outer wall of one end of the target pipeline, and a plurality of auxiliary sensors are arranged at intervals on the outer wall of the other end of the target pipeline, and the plurality of auxiliary sensors are arranged in line with the reference sensor to form a multi-element linear sensor array;

If a pipeline leak occurs, collect a leak signal through each sensor in the multi-element linear sensor array, and send the leak signal to a signal processing terminal;

The signal processing terminal uses the cross-power spectrum beamforming algorithm except for the self-spectrum to jointly calculate the sound source position generated by the pipeline leakage and the speed of the sound wave signal propagating along the pipeline and output the location result of the pipeline leakage position.

The embodiment of the present invention uses a sensor array to jointly estimate the position of the sound source generated by the pipeline leakage and the speed of the sound wave signal propagating along the pipeline, thereby avoiding the error caused by using the theoretical speed model to estimate the wave speed in the complex pipeline environment, and realizing the Accurate location of pipeline leakage.

Description of the drawings

In order to explain the technical solutions of the embodiments of the present invention more clearly, the following will briefly introduce the drawings used in the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. Ordinary technicians can obtain other drawings based on these drawings without creative work.

FIG. 1 is a schematic flow chart of a method for calculating a pipeline leakage position based on beamforming according to an embodiment of the present invention;

2 is a schematic diagram of the positioning principle of a method for calculating the position of a pipeline leakage based on beamforming according to an embodiment of the present invention;

FIG. 3 is a distribution diagram of beamforming output on the leakage position of a method for calculating a pipeline leakage position based on beamforming according to an embodiment of the present invention;

Fig. 4 is a distribution diagram of beamforming output on the wave velocity of a method for calculating a pipeline leakage position based on beamforming according to an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

It should be understood that when used in this specification and appended claims, the terms "including" and "including" indicate the existence of the described features, wholes, steps, operations, elements and/or components, but do not exclude one or The existence or addition of multiple other features, wholes, steps, operations, elements, components, and/or collections thereof.

It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

It should also be further understood that the term "and/or" used in the specification and appended claims of the present invention refers to any combination of one or more of the items listed in the associated and all possible combinations, and includes these combinations .

Please refer to FIG. 1, which is a schematic flowchart of a method for calculating a pipeline leakage position based on beamforming according to an embodiment of the present invention. The method for calculating a pipeline leakage position based on beamforming includes the following steps S101-S104.

Step S101: A reference sensor is arranged on the outer wall of one end of the target pipeline, and a plurality of auxiliary sensors are arranged at intervals on the outer wall of the other end of the target pipeline, and the plurality of auxiliary sensors are aligned with the reference sensor to form a multivariate linear sensor array.

Specifically, the sensor array is arranged on the outer wall of the pipeline along a straight line; the first step is specifically: 1 sensor is arranged on the outer wall of the pipeline at one end of the pipeline, which is recorded as the reference sensor, and M-1 sensors are arranged on the pipeline at the other end of the pipeline. The outer wall is marked as sensor m (1≤m≤M-1). Sensors 1～M-1 are arranged in order of distance from the reference sensor. Sensor 1 is the closest to the reference sensor, and sensor M-1 is the farthest from the reference sensor. The M sensors constitute an M-element linear array.

Step S102: If a pipeline leak occurs, collect a leak signal through each sensor in the multivariate linear sensor array, and send the leak signal to the signal processing terminal.

Specifically, the leakage signal propagates to each sensor along the pipe wall medium, and the time-domain waveform of the leakage signal is collected by the sensor, and sent to the signal processing PC via the collector.

Step S103: The signal processing terminal uses the cross-power spectrum beamforming algorithm except for the self-spectrum to jointly calculate the sound source position generated by the pipeline leakage and the speed of the sound wave signal propagating along the pipeline, and output the positioning result of the pipeline leakage position.

Specifically, the sensor array is used to jointly estimate the position of the sound source generated by the pipeline leakage and the speed of the sound wave signal propagating along the pipeline, so as to avoid the error caused by using the theoretical speed model to estimate the wave speed in the complex pipeline environment, and realize the pipeline Accurate location of the leak location.

In an embodiment, the signal processing terminal adopting a beamforming algorithm to analyze and process the leakage signal of the array and output the positioning result includes:

Constructing a delay vector to compensate the output signal of the auxiliary sensor for delay;

The delay vector is: τ=[τ ₁ ,τ ₂ ,...,τ _M-1 ] ^T

Where L _m is the distance between the auxiliary sensor m and the reference sensor, M-1 is the number of the auxiliary sensors, c is the wave speed, and d is the distance between the leak location and the reference sensor;

Obtaining a cross-power spectrum of the output signal of the auxiliary sensor after the delay compensation, and removing the self-spectrum element to obtain the cross-power spectrum beamforming output divided by the self-spectrum;

Search for the peak value of the beamforming output and obtain the positioning result.

In an embodiment, the obtaining the cross power spectrum of the output signal of the auxiliary sensor after the delay compensation, and removing the self-spectrum elements, to obtain the cross-power spectrum beamforming output divided by the self-spectrum includes:

Obtaining a cross power spectrum of the weighted output of each element of the multi-element linear sensor array according to a cross power spectrum calculation formula;

The cross power spectrum calculation formula is:

in,

Is the cross-power spectrum of the signal of array element m and n, p _m (ω) represents the frequency domain expression of the signal received by the array element m, exp(-jωτm) is the signal delay factor of the array element m, m,n=1, 2 ,3,...,M-1, when m=n, Cnm actually constitutes the self-power spectrum of a certain array element signal;

Obtain the cross power spectrum beamforming output divided by the self spectrum according to the calculation formula of the cross power spectrum beamforming output divided by the self spectrum;

The formula for calculating the beamforming output of the cross-power spectrum divided by the self-spectrum is:

Specifically, in the array signal processing technology, beamforming can be used for spatial filtering and direction-of-arrival estimation, and its essence is to weight the output of the array elements so as to enhance the desired signal and suppress the interference signal. Conventional beamforming uses delay compensation to weight the output of the array elements. When the focus direction coincides with the actual source direction, the maximum output can be formed. The positioning can be completed by searching for the output peak point and inverting the direction of arrival. Taking a one-dimensional M-element linear array as an example, one of the elements is used as the reference element, and the weighted summation output of the remaining M-1 elements can be expressed as:

Where pm(ω) represents the frequency domain expression of the signal received by the array element m, τ=[τ1,τ2,...,τM-1]T is the delay vector, exp(-jωτm) is the signal delay factor of the array element m . Calculate the cross power spectrum of the weighted output of each element to obtain

in

Is the cross power spectrum of the m and n signals of the array element. When m=n, Cnm actually constitutes the self-power spectrum of a certain array element signal, and removing the self-spectral elements can effectively reduce the interference of irrelevant noise. Obtain the cross-power spectrum beamforming output divided by the self-spectrum as

Search for the delay vector τ corresponding to the maximum value of the cross-power spectrum beamforming output function V'(τ,ω), which is the vector composed of the actual delay of each sensor signal relative to the reference sensor. The position of each sensor array element is known, then the delay vector τ is determined by the observable position parameter of the signal source and the signal wave speed. In the actual positioning process, the position parameters are determined by the array configuration and the source model, and the one-dimensional linear array can observe the distance of the source relative to the reference array element on the straight line where the array is located.

Applying the cross-power spectrum beamforming except for the self-spectrum to the pipeline leakage acoustic wave location is transformed into a leakage acoustic source location problem based on a one-dimensional linear array. The positioning method based on the sensor array uses the delay of the signal to reach different sensors to invert the position of the sound source. The selection of the reference sensor must satisfy the condition that the delay of all sensors and the reference sensor is related to the leakage position. Figure 2 is a schematic diagram of the positioning principle. When a linear array is used to locate the leakage position on the line where the array is located, the signal delay of the two sensors on the same side of the leakage point has nothing to do with the leakage position (only determined by the distance between the two sensors). When the two sensors are on different sides of the leak point, the delay is related to the position. Therefore, the reference sensor in Fig. 2 is arranged at the left end of the pipeline, and the sensors 1 to M-1 are arranged at the right end of the pipeline. From the geometric relationship in Figure 2, the delay τm of the sensor m relative to the reference sensor can be expressed as:

Among them, Lm is the distance between the sensor m and the reference sensor, c is the wave velocity, and d is the distance between the leak location and the reference sensor. At this time, the delay vector τ is a variable related to the leakage position d and the wave velocity c at the same time. Put it into the expression of V'(τ,ω) and search for the beamforming output peak to obtain the joint estimation result of the leakage position and wave velocity. .

In an embodiment, the leakage signal is a sound wave signal emitted from a leak location, and the sensor collects a time-domain waveform of the sound wave signal and sends the time-domain waveform information to the signal processing terminal.

In an embodiment, the frequency response range of the sensor is that the lowest frequency is not higher than 10 Hz, and the highest frequency is not lower than 10 kHz.

In the following, a 7-element linear array is taken as an example to further explain this embodiment. The 7-element linear array is arranged on the outer wall of the pipeline and the leakage signal is collected. The signal processing PC completes the signal processing and outputs the positioning result.

The 7-element linear array is composed of 7 acceleration sensors with a frequency response range of 1 Hz to 15 kHz. The reference sensor is arranged at one end of a pipeline section, and the remaining 6 auxiliary sensors are arranged at the other end of the section, and within the section A pipeline leak has occurred and the acoustic signal is generated along with the leakage. The reference sensor is 2.45m away from the leak location, that is, the actual leak location d is 2.45m, and the distance between sensors 1 to 6 and the reference sensor is 5.00m, 5.20m, 5.40m, 5.60m, respectively , 5.80m, 6.00m, that is, the distance between sensors 1 to 6 is 0.20m.

Further, will

L1=5.00m, L2=5.20m, L3=5.40m, L4=5.60m, L5=5.80m, L6=6.00m

Bring in the following formula,

have to

Further, put τ=[τ1,τ2,τ3,,τ4,τ5,τ6]T into the following formula,

Obtain the cross-power spectrum beamforming output V'(τ,ω) divided by the self-spectrum, where the distribution of the beamforming output V'(τ,ω) at the leakage position d is shown in Figure 3, and the distribution on the beam c As shown in Figure 4, from Figure 3-4, the estimated value of the leakage location d is 2.43m, and the estimated value of the wave velocity c is 1680m/s. According to this, the joint estimation result of the pipeline leakage location-wave velocity is: leak location The distance to the reference sensor is 2.43m.

In summary, the present invention applies the cross-power spectrum beamforming method except for the self-spectrum to the pipeline leakage acoustic wave positioning, so that it can jointly estimate the sound source position generated by the pipeline leakage and the speed of the acoustic signal propagating along the pipeline. It mainly includes the following steps: divide the pipeline into sections, and arrange the sensor array on the outer wall of the pipeline, where the reference sensor is arranged at one end of each section, and the remaining sensors are arranged at the other end, and the leakage signal propagates along the pipe wall medium To each sensor, the sensor collects the time-domain waveform of the leakage signal, and sends it to the signal processing PC by the acquisition instrument. Finally, the signal processing PC analyzes the sound source position and the sound source generated by the pipeline leakage based on the cross-power spectrum beamforming algorithm except the autospectrum. The speed of the acoustic signal propagating along the pipeline is jointly estimated, so as to complete the location of the leakage location of the pipeline.

The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited to this. Any person skilled in the art can easily think of various equivalents within the technical scope disclosed by the present invention. Modifications or replacements, these modifications or replacements should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

A method for calculating the position of a pipeline leak based on beamforming, which is characterized in that it includes:

A reference sensor is arranged on the outer wall of one end of the target pipeline, and a plurality of auxiliary sensors are arranged at intervals on the outer wall of the other end of the target pipeline, and the plurality of auxiliary sensors are arranged in line with the reference sensor to form a multi-element linear sensor array;

If a pipeline leak occurs, collect a leak signal through each sensor in the multi-element linear sensor array, and send the leak signal to a signal processing terminal;

The signal processing terminal uses the cross-power spectrum beamforming algorithm except for the self-spectrum to jointly calculate the sound source position generated by the pipeline leakage and the speed of the sound wave signal propagating along the pipeline and output the location result of the pipeline leakage position.
The method for calculating the location of pipeline leakage based on beamforming according to claim 1, wherein the signal processing terminal uses a beamforming algorithm to analyze and process the leakage signal of the array and output a positioning result comprises:

Constructing a delay vector to compensate the output signal of the auxiliary sensor for delay;

The delay vector is: τ=[τ 1 ,τ 2 ,...,τ M-1 ] T

Where L m is the distance between the auxiliary sensor m and the reference sensor, M-1 is the number of the auxiliary sensors, c is the wave speed, and d is the distance between the leak location and the reference sensor;

Obtaining a cross-power spectrum of the output signal of the auxiliary sensor after the delay compensation, and removing the self-spectrum element to obtain the cross-power spectrum beamforming output divided by the self-spectrum;

Search for the peak value of the beamforming output and obtain the positioning result.
The method for calculating the position of pipeline leakage based on beamforming according to claim 2, wherein said obtaining a cross power spectrum of the output signal of the auxiliary sensor after the delay compensation is performed, and removing self-spectral elements, The cross-power spectrum beamforming output obtained by dividing the autospectrum includes:

Obtaining a cross power spectrum of the weighted output of each element of the multi-element linear sensor array according to a cross power spectrum calculation formula;

The cross power spectrum calculation formula is:

in,
Is the cross power spectrum of the signal of the array element m and n, p m (ω) represents the frequency domain expression of the signal received by the array element m, exp(-jωτm) is the signal delay factor of the array element m, m,n=1, 2 ,3,...,M-1, when m=n, Cnm actually constitutes the self-power spectrum of a certain array element signal;

Obtain the cross power spectrum beamforming output divided by the self spectrum according to the calculation formula of the cross power spectrum beamforming output divided by the self spectrum;

The formula for calculating the beamforming output of the cross-power spectrum divided by the self-spectrum is:
The method for calculating the position of pipeline leakage based on beamforming according to claim 1, wherein the leakage signal is a sound wave signal emitted by the leakage position, and the sensor collects the time-domain waveform of the sound wave signal and then calculates the time domain waveform. The domain waveform information is sent to the signal processing terminal.
The method for calculating the location of pipeline leakage based on beamforming according to claim 4, wherein the frequency response range of the sensor is that the lowest frequency is not higher than 10 Hz, and the highest frequency is not lower than 10 kHz.