Partial discharge detection positioning method and system

Abstract

The present application relates to the technical field of partial discharge detection, and particularly relates to a partial discharge detection positioning method and system. The present application uses a detection sensor installed in the interior of a device under test to collect an acoustic emission signal generated by a partial discharge acoustic emission source; extracts an envelope of the acoustic emission signal collected by each detection sensor; takes a time corresponding to a first peak in the envelope of the acoustic emission signal collected by each detection sensor as a time at which the acoustic emission signal reaches each detection sensor; converts the time at which the acoustic emission signal reaches each detection sensor into a distance between the partial discharge acoustic emission source and each detection sensor using a propagation speed of the acoustic emission signal in a medium corresponding to the device under test; and obtains a position of the partial discharge acoustic emission source based on a position coordinate of each detection sensor and the distance between the partial discharge acoustic emission source and each detection sensor. The present application improves the accuracy of partial discharge detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of partial discharge detection, and in particular to a partial discharge detection positioning method and system. BACKGROUND

[0002] Power equipment defect detection is one of the important work of power equipment operation and maintenance. When there is a local defect in the power equipment, partial discharge phenomenon (PD) often occurs. As a key indicator for evaluating the insulation state of electrical equipment in a substation, the accurate positioning of partial discharge has always been the core topic of industry research, especially in the distribution substation scene, the equipment layout is scattered, the structure is highly integrated, and the on-site monitoring conditions are complex, making the positioning of the partial discharge source face unprecedented challenges.

[0003] At present, the partial discharge detection methods are mainly optical detection method, ultra-high frequency positioning method and ultrasonic positioning method, all of which have certain limitations. The optical detection method relies on capturing the light signal generated by discharge, but the complex structure inside the substation equipment seriously limits the propagation of the light signal, not only the penetration ability is insufficient, but also it is easily disturbed by environmental stray light, resulting in a big discount in positioning accuracy. Although the ultra-high frequency positioning method uses electromagnetic wave signals, in a complex electromagnetic environment, high-frequency signals are prone to reflection, scattering and diffraction, and the propagation path is difficult to estimate, at the same time, the electromagnetic interference generated by the equipment in the station and the effective signal are mixed, making it extremely difficult to identify and process the signal. Although the ultrasonic positioning method overcomes some of the defects of the above two methods to some extent, it relies on complex hyperbolic positioning equation iterative solution, which requires high hardware performance and algorithm; and the sensor installation needs to follow strict geometric layout specifications, which is difficult to implement in a space-limited substation. In addition, the refraction, reflection and scattering of ultrasonic waves caused by uneven medium further aggravate the complexity of the practical application of the ultra-high frequency positioning method. SUMMARY

[0004] Therefore, the technical problem to be solved by the present application is to overcome the defects that the existing partial discharge detection methods all have certain limitations, the optical detection method is easily disturbed by equipment blockage and stray light, the ultra-high frequency positioning method has difficulty in signal processing in a complex electromagnetic environment, and the ultrasonic positioning method has strict requirements for hardware and sensor layout and is greatly affected by medium, resulting in poor positioning accuracy of partial discharge.

[0005] To solve the above technical problems, the present application provides a partial discharge detection positioning method, comprising:

[0006] Using a plurality of detection sensors installed at different positions inside the measured equipment, respectively collecting the acoustic emission signals generated by the acoustic emission source of the partial discharge; extracting the envelope lines of the acoustic emission signals collected by each detection sensor;

[0007] The first peak value in the envelope of the acoustic emission signal collected by each detection sensor corresponds to the time when the acoustic emission signal reaches each detection sensor.

[0008] The detection sensor with the shortest time corresponding to the first peak value in the envelope of the acoustic emission signal is taken as the reference detection sensor.

[0009] The time corresponding to the first peak value in the envelope of the acoustic emission signal of the reference detection sensor is taken as the reference time, and the difference between the time corresponding to the first peak value in the envelope of the acoustic emission signal of each detection sensor and the reference time is taken as the normalized time sequence.

[0010] The normalized time sequence is converted into the difference between the distance from each detection sensor to the acoustic emission source of the partial discharge and the distance from the reference detection sensor to the acoustic emission source of the partial discharge by using the propagation speed of the acoustic emission signal in the medium corresponding to the device under test.

[0011] The position of the acoustic emission source of the partial discharge is obtained based on the position of each detection sensor, the difference between the distance from each detection sensor to the acoustic emission source of the partial discharge and the distance from the reference detection sensor to the acoustic emission source of the partial discharge.

[0012] Preferably, the position of the acoustic emission source of the partial discharge is obtained based on the position of each detection sensor, the difference between the distance from each detection sensor to the acoustic emission source of the partial discharge and the distance from the reference detection sensor to the acoustic emission source of the partial discharge, including:

[0013] The orthogonal coordinate system of the device under test is discretized into a plurality of three-dimensional pixel units.

[0014] For each detection sensor, it is determined whether the difference between the distance from each three-dimensional pixel unit to the current detection sensor and the distance to the reference sensor is equal to the difference between the distance from the current detection sensor to the acoustic emission source of the partial discharge and the distance from the reference detection sensor to the acoustic emission source of the partial discharge. If it is equal, the three-dimensional pixel unit is marked as 1, otherwise it is marked as 0, and a spatial binary pixel matrix of each detection sensor is obtained.

[0015] The values of the same three-dimensional pixel unit in the spatial binary pixel matrix of each detection sensor are added to obtain a total spatial binary pixel matrix, and the three-dimensional pixel unit with the maximum value in the total spatial binary pixel matrix is taken as the position of the acoustic emission source of the partial discharge.

[0016] Preferably, the device under test is divided into a plurality of detection surfaces, and a plurality of detection sensors are installed at different positions on each detection surface in turn to obtain the position of the acoustic emission source of the partial discharge.

[0017] Preferably, for each detection surface, the total plane binary pixel matrix of the detection surface is constructed based on the position of each detection sensor in the detection surface, the distance from each detection sensor to the local discharge acoustic emission source and the difference between the distance from the reference detection sensor to the local discharge acoustic emission source; the maximum value in the total plane binary pixel matrix of the detection surface is obtained;

[0018] The two-dimensional pixel unit corresponding to the maximum value in the total plane binary pixel matrix of all detection surfaces is taken as the position of the local discharge acoustic emission source.

[0019] Preferably, the total plane binary pixel matrix of the current detection surface is constructed based on the position coordinates of each detection sensor in the current detection surface, the distance from each detection sensor to the local discharge acoustic emission source and the difference between the distance from the reference detection sensor to the local discharge acoustic emission source, including:

[0020] Discretize the plane rectangular coordinate system of the current detection surface into a plurality of two-dimensional pixel units;

[0021] For each detection sensor on the detection surface, it is judged whether the difference between the distance from each two-dimensional pixel unit to the current detection sensor and the distance to the reference sensor is equal to the difference between the distance from the current detection sensor to the local discharge acoustic emission source and the distance from the reference detection sensor to the local discharge acoustic emission source, if equal, the two-dimensional pixel unit is marked as 1, otherwise marked as 0, to obtain the plane binary pixel matrix of each detection sensor in the current detection surface;

[0022] The values of the same two-dimensional pixel unit in the plane binary pixel matrix of all detection sensors on the detection surface are added to obtain the total plane binary pixel matrix of the current detection surface.

[0023] Preferably, the detection sensor is any one of an acoustic emission sensor and an ultrasonic sensor.

[0024] Preferably, the envelope of the acoustic emission signal collected by each detection sensor is extracted through envelope detection.

[0025] Preferably, the envelope detection is any one of Hilbert transform and wavelet transform.

[0026] Preferably, after collecting the acoustic emission signal generated by the local discharge acoustic emission source, the acoustic emission signal is filtered to obtain the target acoustic emission signal collected by each detection sensor.

[0027] The application also provides a local discharge detection and positioning system, comprising:

[0028] A plurality of detection sensors are installed at different positions in the measured equipment for collecting acoustic emission signals generated by the local discharge acoustic emission source.

[0029] The detection sensor arrangement position recording module is in communication connection with the plurality of detection sensors, and is used for acquiring the positions of the detection sensors;

[0030] The signal conditioning module is in communication connection with the plurality of detection sensors, and is used for receiving the acoustic emission signals output by the detection sensors and extracting the envelope lines of the acoustic emission signals collected by the detection sensors;

[0031] The discharge detection module is in communication connection with the detection sensor arrangement position recording module and the signal conditioning module, and is used for receiving the positions of the detection sensors and the envelope lines of the acoustic emission signals collected by the detection sensors;

[0032] The first peak value corresponding time in the envelope line of the acoustic emission signal collected by each detection sensor is taken as the time of arrival of the acoustic emission signal at each detection sensor;

[0033] The detection sensor with the shortest first peak value corresponding time in the envelope line of the acoustic emission signal is taken as the reference detection sensor;

[0034] The first peak value corresponding time in the envelope line of the acoustic emission signal corresponding to the reference detection sensor is taken as the reference time, and the difference between the first peak value corresponding time in the envelope line of the acoustic emission signal corresponding to each detection sensor and the reference time is taken as the normalized time sequence;

[0035] The normalized time sequence is converted into the difference between the distance of each detection sensor to the local discharge acoustic emission source and the distance of the reference detection sensor to the local discharge acoustic emission source by using the propagation speed of the acoustic emission signal in the medium corresponding to the device under test;

[0036] The position of the local discharge acoustic emission source is acquired based on the position of each detection sensor and the difference between the distance of each detection sensor to the local discharge acoustic emission source and the distance of the reference detection sensor to the local discharge acoustic emission source.

[0037] The above technical solution of the present application has the following beneficial effects compared with the prior art:

[0038] The partial discharge detection positioning method and system provided by the application, by deploying multiple detection sensors at different positions in the measured equipment, real-time capture the acoustic emission signals generated by the partial discharge, extract the envelope line of the acoustic emission signals collected by each detection sensor, and take the time corresponding to the first peak in the envelope line as the time reference of the arrival of the acoustic emission signals at each sensor. This time capture method based on signal characteristics reduces the time error caused by hardware differences and environmental noise. Considering that the emission time of the acoustic emission signal is unknown, if the time corresponding to the first peak in the envelope line is directly multiplied by the propagation speed in the medium to calculate the distance between the partial discharge acoustic emission source and each detection sensor, the positioning error will significantly increase due to the lack of emission time. The application converts the time of the arrival of the acoustic emission signal at each detection sensor into the difference between the distance from each detection sensor to the partial discharge acoustic emission source and the distance from the reference detection sensor to the partial discharge acoustic emission source, through the propagation speed of the acoustic emission signal in the medium corresponding to the measured equipment and the normalized time sequence. By judging whether the difference between the distance from each three-dimensional pixel unit to the current detection sensor and the distance to the reference sensor is equal to the difference between the distance from the current detection sensor to the partial discharge acoustic emission source and the distance from the reference detection sensor to the partial discharge acoustic emission source, the spatial binary pixel matrix of each detection sensor is obtained. The values of the same three-dimensional pixel unit in the spatial binary pixel matrix of each detection sensor are added to obtain the total spatial binary pixel matrix. The three-dimensional pixel unit with the maximum value in the total spatial binary pixel matrix is taken as the position of the partial discharge acoustic emission source. The matrix value is marked by judging whether the distance difference matches the actual distance difference pixel by pixel, which realizes the grid accurate search of the position of the partial discharge acoustic emission source. Without determining the emission time of the acoustic emission signal, the positioning accuracy of the partial discharge detection is improved.

[0039] In the actual engineering application scene of partial discharge detection, three-dimensional positioning can provide accurate spatial coordinate information, but the distance parameters of three dimensions of space X, Y and Z need to be considered at the same time in the calculation process, which not only greatly increases the complexity of the calculation model, but also puts higher requirements on the performance and resources of the calculation device, leading to significant increase in calculation time and rise in system operation cost. At the same time, in many actual working conditions, the specific plane range of the partial discharge source can be preliminarily judged according to the structural characteristics and running state of the equipment. Therefore, the present application divides the detection surface of the measured equipment, installs a plurality of detection sensors on each detection surface in turn, for each detection surface, constructs the total plane binary pixel matrix of the detection surface based on the position of each detection sensor in the detection surface, the distance between each detection sensor and the partial discharge acoustic emission source and the distance between the reference detection sensor of the detection surface and the partial discharge acoustic emission source. By comparing the maximum value of the total plane binary pixel matrix of each detection surface, the final position of the partial discharge acoustic emission source is determined, the focusing positioning on the two-dimensional plane is realized, the calculation difficulty is significantly reduced, the calculation resource consumption is reduced, and the two-dimensional positioning accuracy of partial discharge detection is improved. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to make the content of the present application easier to be clearly understood, the present application will be further described in detail below according to the specific embodiments of the present application and in combination with the drawings, in which:

[0041] Figure 1 is a three-dimensional positioning flowchart of a partial discharge detection positioning method of the present application.

[0042] Figure 2 is a two-dimensional positioning flowchart of a partial discharge detection positioning method of the present application.

[0043] Figure 3 is a schematic diagram of the installation positions of a plurality of detection sensors when the measured equipment is an oil-immersed transformer.

[0044] Description of the drawing marks of the specification: 1, partial discharge acoustic emission source; 2, oil-immersed area of the oil-immersed transformer; 3, detection sensor. DETAILED DESCRIPTION

[0045] The present application will be further described below in combination with the drawings and specific embodiments, so that those skilled in the art can better understand the present application and implement it, but the embodiments are not limiting to the present application.

[0046] The partial discharge detection positioning method provided in the application can flexibly select three-dimensional or two-dimensional positioning modes according to the actual structure characteristics and detection requirements of the measured equipment in actual application. When the internal structure of the measured equipment is complex (such as an oil-immersed transformer), three-dimensional positioning can be adopted. The advantage is that the installation position of the detection sensor 3 is flexible, and there is no strict layout restriction. The position of the partial discharge acoustic emission source 1 can be accurately locked through three-dimensional space coordinates, but the X, Y and Z three-dimensional distance parameters need to be processed synchronously during calculation, which leads to high model complexity and high requirements for the performance of the calculation equipment. There are disadvantages of long calculation time and increased system operation cost.

[0047] The two-dimensional positioning needs to install multiple detection sensors 3 on the same detection surface of the measured equipment. It is suitable for scenarios that can be based on the structure characteristics of the equipment (such as transformer tank wall, switch cabinet panel, etc. regular plane) or can preliminarily judge the plane range of the partial discharge source. The focusing positioning is realized through the sensor array in a single plane, and only two-dimensional calculation is required, which significantly reduces the calculation complexity and resource consumption.

[0048] Referring to Figure 1 The three-dimensional positioning process of the partial discharge detection positioning method provided in the embodiment I includes the following steps.

[0049] Step S11: Use multiple detection sensors 3 installed at different positions inside the measured equipment to respectively collect the acoustic emission signals generated by the partial discharge acoustic emission source 1; and extract the envelope lines of the acoustic emission signals collected by each detection sensor 3.

[0050] In the embodiment, when used for three-dimensional positioning, the multiple detection sensors 3 are arranged on one side inside the measured equipment. The arrangement mode of the detection sensors 3 can be spiral arrangement, or cross array, ring array, or any other shape of random array arrangement, such as 4x4 array, etc.

[0051] Step S12: The time corresponding to the first peak value in the envelope line of the acoustic emission signal collected by each detection sensor 3 is taken as the time when the acoustic emission signal reaches each detection sensor 3.

[0052] Step S13: The detection sensor 3 with the shortest time corresponding to the first peak value in the envelope line of the acoustic emission signal is taken as the reference detection sensor.

[0053] Step S14: The time corresponding to the first peak value in the envelope line of the acoustic emission signal corresponding to the reference detection sensor is taken as the reference time; and the difference between the time corresponding to the first peak value in the envelope line of the acoustic emission signal of each detection sensor 3 and the reference time is taken as the normalized time sequence.

[0054] Step S15: using the propagation speed of the acoustic emission signal in the medium corresponding to the device under test, convert the normalized time series into the difference between the distance between each detection sensor 3 and the partial discharge acoustic emission source 1 and the distance between the reference detection sensor and the partial discharge acoustic emission source 1;

[0055] When the device under test is an oil-immersed transformer, in order to detect the position of a partial discharge acoustic emission source 1 inside the oil-immersed transformer, this embodiment deploys five detection sensors 3 at different positions on a side wall inside the oil-immersed transformer. The five detection sensors 3 are numbered A1, A2, A3, A4 and A5, respectively. After the acoustic emission signal received by each detection sensor 3 is subjected to envelope detection, the corresponding time of the first peak is extracted as shown in Table 1. Table 1 is a schematic diagram of the corresponding time of the first peak of the five detection sensors 3.

[0056] Table 1

[0057] Detection sensor 3 number First peak corresponding time (microseconds) A1 10 A2 11 A3 12 A4 15 A5 16

[0058] The normalized time series constructed is , To detect the total number of sensors 3, To detect sensor 3 index, For the The time corresponding to the first peak in the envelope of the acoustic emission signal of the detection sensor 3 With the base time The difference, that is , For the The time corresponding to the first peak in the envelope of the acoustic emission signal corresponding to each detection sensor 3, is the base time;

[0059] Then A1 is the reference detection sensor, and the reference time is , the normalized time series is {0,1,2,5,6}.

[0060] The propagation speed of the acoustic emission signal in the medium corresponding to the device under test is used , convert the normalized time series into the difference between the distance from each detection sensor 3 to the local discharge acoustic emission source 1 and the distance from the reference detection sensor to the local discharge acoustic emission source 1, and use it as the space-position series ; For the The difference between the distance from the detection sensor 3 to the partial discharge acoustic emission source 1 and the distance from the reference detection sensor to the partial discharge acoustic emission source 1, that is, , It is the propagation speed of the acoustic emission signal in the medium corresponding to the device under test.

[0061] At this time, the propagation speed of the acoustic emission signal in the medium corresponding to the device under test is the propagation speed of the acoustic emission signal in the transformer oil-immersed medium , then the space-position sequence is {0mm,1.42mm,2.84mm,7.1mm,8.52mm}.

[0062] Step S16: obtaining the position of the partial discharge acoustic emission source 1 based on the position of each detection sensor 3 and the difference between the distance from each detection sensor 3 to the partial discharge acoustic emission source 1 and the distance from the reference detection sensor to the partial discharge acoustic emission source 1 .

[0063] In this embodiment, preferably, the position of the partial discharge acoustic emission source 1 is obtained based on the position of each detection sensor 3, the difference between the distance between each detection sensor 3 and the partial discharge acoustic emission source 1, and the distance between the reference detection sensor and the partial discharge acoustic emission source 1:

[0064] Step S161: discretizing the spatial rectangular coordinate system of the device under test into a plurality of three-dimensional pixel units;

[0065] Step S162: For each detection sensor 3, determine whether the difference between the distance from each 3D pixel unit to the current detection sensor 3 and the distance to the reference sensor is equal to the difference between the distance from the current detection sensor 3 to the partial discharge acoustic emission source 1 and the distance from the reference detection sensor to the partial discharge acoustic emission source 1. If so, mark the 3D pixel unit as 1; otherwise, mark it as 0, thereby obtaining a spatial binary pixel matrix for each detection sensor 3.

[0066] Step S163: Add the values ​​of the same three-dimensional pixel unit in the spatial binary pixel matrix of each detection sensor 3 to obtain a total spatial binary pixel matrix; and use the three-dimensional pixel unit with the largest value in the total spatial binary pixel matrix as the position of the partial discharge acoustic emission source 1.

[0067] This application takes into account the unknown emission time of the acoustic emission signal. Simply multiplying the time corresponding to the first peak in the envelope by the propagation speed of the acoustic emission signal in the corresponding medium of the device under test to calculate the distance between the PD AE source 1 and each detection sensor 3 would significantly increase the positioning error due to the missing emission time. The present invention, by introducing the difference between the distance from each detection sensor 3 to the PD AE source 1 and the distance from a reference detection sensor to the PD AE source 1, circumvents the problem of unknown emission time and can still accurately locate the position of the PD AE source 1 even when the emission time is unknown.

[0068] By deploying multiple detection sensors 3 at different positions inside the device under test, the acoustic emission signals generated by partial discharge are captured in real time, and the envelope lines of the signals collected by each detection sensor 3 are extracted, and the time corresponding to the first peak in the envelope line is accurately locked as the time reference of the arrival of the signal at each detection sensor 3. Based on this, the time of arrival of the acoustic emission signal at each detection sensor 3 is converted into the difference between the distance from each detection sensor 3 to the partial discharge acoustic emission source 1 and the distance from the reference detection sensor to the partial discharge acoustic emission source 1, and the relative relationship between the multiple detection sensors 3 is used to effectively eliminate the error caused by the non-uniformity of the medium, the difference in the propagation path, and to reduce the time error caused by hardware differences and environmental noise. In the positioning calculation link, a three-dimensional pixel unit is formed by discretizing the spatial rectangular coordinate system of the device under test, a spatial binary pixel matrix is constructed, and whether the difference between the distance from each three-dimensional pixel unit to the current detection sensor 3 and the distance from the reference sensor is equal to the difference between the distance from the current detection sensor 3 to the partial discharge acoustic emission source 1 and the distance from the reference detection sensor to the partial discharge acoustic emission source 1 is judged to mark the matrix value, realizing the grid-based accurate search of the position of the partial discharge acoustic emission source 1, effectively eliminating the interference of environmental factors, and effectively improving the three-dimensional positioning accuracy of partial discharge detection.

[0069] Reference Figure 2 The second embodiment provides a two-dimensional positioning process of a partial discharge detection positioning method, which comprises:

[0070] Step S21: dividing the device under test into a plurality of detection surfaces, installing a plurality of detection sensors 3 on the first detection surface, and initializing ;

[0071] Step S22: using the plurality of detection sensors 3 installed at different positions on the first detection surface to respectively collect the acoustic emission signals generated by the partial discharge acoustic emission source 1; and extracting the envelope lines of the acoustic emission signals collected by each detection sensor 3 on the first detection surface;

[0072] Step S23: taking the time corresponding to the first peak in the envelope line of the acoustic emission signal collected by each detection sensor 3 in the first detection surface as the time of arrival of the acoustic emission signal at each detection sensor 3 in the first detection surface;

[0073] Step S24: taking the detection sensor 3 in the first detection surface with the shortest time corresponding to the first peak in the envelope line of the acoustic emission signal as the reference detection sensor of the first detection surface;

[0074] Step S25: The time corresponding to the first peak in the envelope of the acoustic emission signal corresponding to the reference detection sensor of the detection surface is taken as the first The benchmark time of each detection surface; The difference between the time corresponding to the first peak in the envelope of the acoustic emission signal of each detection sensor 3 in the detection surface and the reference time is used as the first Normalized time series of detection surfaces;

[0075] Step S26: Using the propagation speed of the acoustic emission signal in the medium corresponding to the device under test, The normalized time series of the detection faces is converted into The difference between the distance from each detection sensor 3 to the partial discharge acoustic emission source 1 and the distance from the reference detection sensor to the partial discharge acoustic emission source 1 within the detection surface;

[0076] Step S27: Based on The position of each detection sensor 3 within the detection surface, the distance between each detection sensor 3 and the local discharge acoustic emission source 1 and the The difference between the distances of the reference detection sensor of the detection surface and the local discharge acoustic emission source 1 is used to construct the The total plane binary pixel matrix of the detection surface includes:

[0077] Step 271: The plane rectangular coordinate system of the detection surface is discretized into multiple two-dimensional pixel units;

[0078] Step 272: For Each detection sensor 3 on the detection surface determines the The distance between each two-dimensional pixel unit in the detection surface and the current detection sensor 3 is the same as the distance between the first and second detection sensors. Is the difference between the distances of the reference sensors of the detection surface equal to the difference between the distance of the current detection sensor 3 to the partial discharge acoustic emission source 1 and the distance of the first detection sensor 3 to the reference sensor 1? The difference between the distances between the reference detection sensor of each detection surface and the local discharge acoustic emission source 1 is equal to, if so, the two-dimensional pixel unit is marked as 1, otherwise it is marked as 0, and the distance between each detection sensor 3 and the local discharge acoustic emission source 1 is obtained. A planar binary pixel matrix of a detection surface;

[0079] Step S273: The values ​​of the same two-dimensional pixel unit in the plane binary pixel matrix of all detection sensors 3 on the detection surface are added to obtain the first The total plane binary pixel matrix of the detection surface; get the The maximum value in the total plane binary pixel matrix of the detection surface;

[0080] Step S28: judging whether or not , if not, returning to step S22; if yes, taking the two-dimensional pixel unit corresponding to the maximum value in the total planar binary pixel matrix of the detection surface as the position of the partial discharge acoustic emission source 1. When the device structure is simple (such as the side plate of a switch cabinet or the wall of a box transformer) and the range where the partial discharge acoustic emission source 1 is located is clear, the two-dimensional positioning only needs to calculate the distance difference in the plane to lock the position of the partial discharge acoustic emission source 1, without processing the X, Y and Z three-dimensional parameters, avoiding the complex calculation of three-dimensional positioning, greatly reducing the dependence on high-performance computing devices, and further reducing the system operation energy consumption and maintenance cost. For example, in the detection of devices such as switch cabinets and box transformers with relatively simple structures, if it is known that the partial discharge may be concentrated on a certain side plate or internal plane, the two-dimensional positioning can quickly lock the plane where the discharge source is located through a single-plane sensor array, simplifying the complex calculation of three-dimensional space traversal to focused analysis of a two-dimensional plane, shortening the detection time and avoiding the waste of resources caused by excessive calculation in three-dimensional positioning.

[0081] In the embodiments one and two, the essence is to judge, for each detection sensor 3, whether the difference between the distance of each pixel unit to the current detection sensor 3 and the distance to the reference sensor is equal to the difference between the distance of the current detection sensor 3 to the partial discharge acoustic emission source 1 and the distance of the reference detection sensor to the partial discharge acoustic emission source 1, and if yes, mark the pixel unit as 1, considering that the pixel unit may be the position of the partial discharge acoustic emission source 1, to obtain the binary pixel matrix of each detection sensor 3; based on the total binary pixel matrix, the position of the partial discharge acoustic emission source 1 is confirmed, so as to realize the positioning of the partial discharge acoustic emission source 1 without determining the emission time of the acoustic emission signal.

[0082] In the embodiments one and two, the essence is to judge, for each detection sensor 3, whether the difference between the distance of each pixel unit to the current detection sensor 3 and the distance to the reference sensor is equal to the difference between the distance of the current detection sensor 3 to the partial discharge acoustic emission source 1 and the distance of the reference detection sensor to the partial discharge acoustic emission source 1, and if yes, mark the pixel unit as 1, considering that the pixel unit may be the position of the partial discharge acoustic emission source 1, to obtain the binary pixel matrix of each detection sensor 3; based on the total binary pixel matrix, the position of the partial discharge acoustic emission source 1 is confirmed, so as to realize the positioning of the partial discharge acoustic emission source 1 without determining the emission time of the acoustic emission signal.

[0083] In the embodiments one and two, the essence is to judge, for each detection sensor 3, whether the difference between the distance of each pixel unit to the current detection sensor 3 and the distance to the reference sensor is equal to the difference between the distance of the current detection sensor 3 to the partial discharge acoustic emission source 1 and the distance of the reference detection sensor to the partial discharge acoustic emission source 1, and if yes, mark the pixel unit as 1, considering that the pixel unit may be the position of the partial discharge acoustic emission source 1, to obtain the binary pixel matrix of each detection sensor 3; based on the total binary pixel matrix, the position of the partial discharge acoustic emission source 1 is confirmed, so as to realize the positioning of the partial discharge acoustic emission source 1 without determining the emission time of the acoustic emission signal.

[0084] In the embodiments one and two, the essence is to judge, for each detection sensor 3, whether the difference between the distance of each pixel unit to the current detection sensor 3 and the distance to the reference sensor is equal to the difference between the distance of the current detection sensor 3 to the partial discharge acoustic emission source 1 and the distance of the reference detection sensor to the partial discharge acoustic emission source 1, and if yes, mark the pixel unit as 1, considering that the pixel unit may be the position of the partial discharge acoustic emission source 1, to obtain the binary pixel matrix of each detection sensor 3; based on the total binary pixel matrix, the position of the partial discharge acoustic emission source 1 is confirmed, so as to realize the positioning of the partial discharge acoustic emission source 1 without determining the emission time of the acoustic emission signal.

[0085] In the embodiments one and two, the essence is to judge, for each detection sensor 3, whether the difference between the distance of each pixel unit to the current detection sensor 3 and the distance to the reference sensor is equal to the difference between the distance of the current detection sensor 3 to the partial discharge acoustic emission source 1 and the distance of the reference detection sensor to the partial discharge acoustic emission source 1, and if yes, mark the pixel unit as 1, considering that the pixel unit may be the position of the partial discharge acoustic emission source 1, to obtain the binary pixel matrix of each detection sensor 3; based on the total binary pixel matrix, the position of the partial discharge acoustic emission source 1 is confirmed, so as to realize the positioning of the partial discharge acoustic emission source 1 without determining the emission time of the acoustic emission signal.

[0086] In the embodiments one and two, the essence is to judge, for each detection sensor 3, whether the difference between the distance of each pixel unit to the current detection sensor 3 and the distance to the reference sensor is equal to the difference between the distance of the current detection sensor 3 to the partial discharge acoustic emission source 1 and the distance of the reference detection sensor to the partial discharge acoustic emission source 1, and if yes, mark the pixel unit as 1, considering that the pixel unit may be the position of the partial discharge acoustic emission source 1, to obtain the binary pixel matrix of each detection sensor 3; based on the total binary pixel matrix, the position of the partial discharge acoustic emission source 1 is confirmed, so as to realize the positioning of the partial discharge acoustic emission source 1 without determining the emission time of the acoustic emission signal. In the embodiments one and two, the essence is to judge, for each detection sensor 3, whether the difference between the distance of each pixel unit to the current detection sensor 3 and the distance to the reference sensor is equal to the difference between the distance of the current detection sensor 3 to the partial discharge acoustic emission source 1 and the distance of the reference detection sensor to the partial discharge acoustic emission source 1, and if yes, mark the pixel unit as 1, considering that the pixel unit may be the position of the partial discharge acoustic emission source 1, to obtain the binary pixel matrix of each detection sensor 3; based on the total binary pixel matrix, the position of the partial discharge acoustic emission source 1 is confirmed, so as to realize the positioning of the partial discharge acoustic emission source 1 without determining the emission time of the acoustic emission signal. ​​​The amplitude time function of the acoustic emission signal collected by the detection sensor 3, The central frequency of the acoustic emission signal collected by the detection sensor 3, The phase time function of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3,

[0087] The envelope of the acoustic emission signal collected by the detection sensor 3,

[0088] ,

[0089] ,

[0090] The envelope of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3, The envelope of the acoustic emission signal collected by the detection sensor 3, The square of the envelope of the acoustic emission signal collected by the detection sensor 3, The square of the envelope of the acoustic emission signal collected by the detection sensor 3. In the embodiment, preferably, after collecting the acoustic emission signal generated by the partial discharge acoustic emission source 1, the acoustic emission signal is filtered to obtain the target acoustic emission signal collected by each detection sensor 3, and the filtering algorithm is used to remove the low-frequency and direct-current components in the detection signal and suppress noise, so that the partial discharge detection precision is effectively improved.

[0091] The partial discharge detection system based on acoustic imaging provided by the application can not only detect the internal partial discharge source of the oil-immersed transformer, but also detect other partial discharge sources and locate the acoustic source, so that the application prospect is wide and the potential application value is high.

[0092] The partial discharge detection system based on acoustic imaging provided by the application can not only detect the internal partial discharge source of the oil-immersed transformer, but also detect other partial discharge sources and locate the acoustic source, so that the application prospect is wide and the potential application value is high. Figure 3 Figure 3 ​​Figure 2 shows the installation positions of the plurality of detection sensors 3 when the device under test is an oil-immersed transformer. When detecting the partial discharge source inside the oil-immersed transformer, the detection sensor 3 needs to be an oil-immersed detection sensor.

[0093] The third embodiment provides a partial discharge detection positioning system, which comprises:

[0094] A plurality of detection sensors 3 are installed at different positions inside the device under test to collect the acoustic emission signals generated by the partial discharge acoustic emission source 1.

[0095] A detection sensor 3 arrangement position recording module is in communication connection with the plurality of detection sensors 3 to obtain the positions of the detection sensors 3.

[0096] A signal conditioning module is in communication connection with the plurality of detection sensors 3 to receive the acoustic emission signals output by the detection sensors 3 and extract the envelope lines of the acoustic emission signals collected by the detection sensors 3.

[0097] A discharge detection module is in communication connection with the detection sensor 3 arrangement position recording module and the signal conditioning module to receive the positions of the detection sensors 3 and the envelope lines of the acoustic emission signals collected by the detection sensors 3.

[0098] The time corresponding to the first peak in the envelope line of the acoustic emission signal collected by each detection sensor 3 is taken as the time when the acoustic emission signal reaches each detection sensor 3.

[0099] The detection sensor 3 with the shortest time corresponding to the first peak in the envelope line of the acoustic emission signal is taken as the reference detection sensor.

[0100] The time corresponding to the first peak in the envelope line of the acoustic emission signal corresponding to the reference detection sensor is taken as the reference time, and the difference between the time corresponding to the first peak in the envelope line of the acoustic emission signal corresponding to each detection sensor 3 and the reference time is taken as the normalized time sequence.

[0101] The normalized time sequence is converted into the difference between the distance from each detection sensor 3 to the partial discharge acoustic emission source 1 and the distance from the reference detection sensor to the partial discharge acoustic emission source 1 by using the propagation speed of the acoustic emission signal in the medium corresponding to the device under test.

[0102] The position of the partial discharge acoustic emission source 1 is obtained based on the position of each detection sensor 3, the distance from each detection sensor 3 to the partial discharge acoustic emission source 1, and the difference between the distance from the reference detection sensor to the partial discharge acoustic emission source 1.

[0103] Those skilled in the art will appreciate that embodiments of the application can be devised for a method, a system, or a computer program product. Accordingly, the present application can be embodied in the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) embodying computer readable program code.

[0104] The present application is described in reference to the flowchart illustrations and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams.

[0105] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams.

[0106] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams.

[0107] Obviously, the above-described embodiments are only examples and are not intended to limit the present application. Based on the above description, those skilled in the art can make other variations and modifications of the present application without deviating from the scope of the present application. Therefore, the present application should not be limited by the above embodiments.

Claims

1. A method for detecting and locating partial discharge, characterized in that: include: Utilize multiple detection sensors installed at different locations inside the device under test to collect the acoustic emission signals generated by the partial discharge acoustic emission source; Extracting the envelope of the acoustic emission signal collected by each detection sensor; The time corresponding to the first peak in the envelope of the acoustic emission signal collected by each detection sensor is taken as the time when the acoustic emission signal arrives at each detection sensor; The detection sensor with the shortest corresponding time of the first peak in the acoustic emission signal envelope is used as the reference detection sensor; The time corresponding to the first peak in the envelope of the acoustic emission signal of the reference detection sensor is used as the reference time; The difference between the time corresponding to the first peak in the envelope of the acoustic emission signal corresponding to each detection sensor and the reference time is used as the normalized time series; Using the propagation speed of the acoustic emission signal in the medium corresponding to the device under test, the normalized time series is converted into the difference between the distance from each detection sensor to the partial discharge acoustic emission source and the distance from the reference detection sensor to the partial discharge acoustic emission source; Obtaining the position of the partial discharge acoustic emission source based on the position of each detection sensor, the difference between the distance between each detection sensor and the partial discharge acoustic emission source and the distance between the reference detection sensor and the partial discharge acoustic emission source, including: Discrete the spatial rectangular coordinate system of the device under test into multiple three-dimensional pixel units; For each detection sensor, determine whether the difference between the distance from each 3D pixel unit to the current detection sensor and the distance to the reference sensor is equal to the difference between the distance from the current detection sensor to the partial discharge acoustic emission source and the distance from the reference detection sensor to the partial discharge acoustic emission source. If so, mark the 3D pixel unit as 1; otherwise, mark it as 0, to obtain a spatial binary pixel matrix for each detection sensor; The values ​​of the same three-dimensional pixel unit in the spatial binary pixel matrix of each detection sensor are added together to obtain a total spatial binary pixel matrix; the three-dimensional pixel unit with the largest value in the total spatial binary pixel matrix is ​​used as the location of the partial discharge acoustic emission source.

2. A partial discharge detection and positioning method according to claim 1, characterized in that: The device under test is divided into multiple detection surfaces, and multiple detection sensors are installed in sequence at different positions on each detection surface.

3. A partial discharge detection and positioning method according to claim 2, characterized in that: For each detection surface, construct a total planar binary pixel matrix for the detection surface based on the position of each detection sensor within the detection surface, the difference between the distance between each detection sensor and the partial discharge acoustic emission source, and the distance between a reference detection sensor of the detection surface and the partial discharge acoustic emission source; and obtain the maximum value in the total planar binary pixel matrix for the detection surface; The two-dimensional pixel unit corresponding to the maximum value in the total plane binary pixel matrix of all detection surfaces is used as the position of the partial discharge acoustic emission source.

4. A partial discharge detection and positioning method according to claim 3, characterized in that: Based on the position coordinates of each detection sensor in the current detection surface, the difference between the distance between each detection sensor and the partial discharge acoustic emission source and the distance between the reference detection sensor and the partial discharge acoustic emission source, a total plane binary pixel matrix of the current detection surface is constructed, including: Discretize the plane rectangular coordinate system of the current detection surface into multiple two-dimensional pixel units; For each detection sensor on the detection surface, determine whether the difference between the distance from each two-dimensional pixel unit to the current detection sensor and the distance to the reference sensor is equal to the difference between the distance from the current detection sensor to the partial discharge acoustic emission source and the distance from the reference detection sensor to the partial discharge acoustic emission source; if so, mark the two-dimensional pixel unit as 1; otherwise, mark it as 0, to obtain a planar binary pixel matrix for each detection sensor on the current detection surface; The values ​​of the same two-dimensional pixel unit in the planar binary pixel matrix of all detection sensors on the detection surface are added together to obtain the total planar binary pixel matrix of the current detection surface.

5. A partial discharge detection and positioning method according to claim 1, characterized in that: The detection sensor is any one of an acoustic emission sensor and an ultrasonic sensor.

6. A partial discharge detection and positioning method according to claim 1, characterized in that: Through envelope detection, the envelope of the acoustic emission signal collected by each detection sensor is extracted.

7. A partial discharge detection and positioning method according to claim 6, characterized in that: The envelope detection can be any one of Hilbert transform and wavelet transform.

8. A partial discharge detection and positioning method according to claim 1, characterized in that: After collecting the acoustic emission signal generated by the partial discharge acoustic emission source, the acoustic emission signal is filtered to obtain the target acoustic emission signal collected by each detection sensor.

9. A partial discharge detection and positioning system, characterized in that: include: Multiple detection sensors are installed at different locations inside the device under test to collect the acoustic emission signals generated by the partial discharge acoustic emission source; A detection sensor arrangement position recording module is connected to the plurality of detection sensors for obtaining the position of each detection sensor; A signal conditioning module is communicatively connected to the plurality of detection sensors, and is used to receive the acoustic emission signals output by each detection sensor and extract the envelope of the acoustic emission signals collected by each detection sensor; A discharge detection module, which is in communication with the detection sensor arrangement position recording module and the signal conditioning module, and is used to receive the position of each detection sensor and the envelope of the collected acoustic emission signal; The time corresponding to the first peak in the envelope of the acoustic emission signal collected by each detection sensor is taken as the time when the acoustic emission signal arrives at each detection sensor; The detection sensor with the shortest corresponding time of the first peak in the acoustic emission signal envelope is used as the reference detection sensor; The time corresponding to the first peak in the envelope of the acoustic emission signal of the reference detection sensor is used as the reference time; The difference between the time corresponding to the first peak in the envelope of the acoustic emission signal corresponding to each detection sensor and the reference time is used as the normalized time series; Using the propagation speed of the acoustic emission signal in the medium corresponding to the device under test, the normalized time series is converted into the difference between the distance from each detection sensor to the partial discharge acoustic emission source and the distance from the reference detection sensor to the partial discharge acoustic emission source; Obtaining the position of the partial discharge acoustic emission source based on the position of each detection sensor, the difference between the distance between each detection sensor and the partial discharge acoustic emission source and the distance between the reference detection sensor and the partial discharge acoustic emission source, including: Discrete the spatial rectangular coordinate system of the device under test into multiple three-dimensional pixel units; For each detection sensor, determine whether the difference between the distance from each 3D pixel unit to the current detection sensor and the distance to the reference sensor is equal to the difference between the distance from the current detection sensor to the partial discharge acoustic emission source and the distance from the reference detection sensor to the partial discharge acoustic emission source. If so, mark the 3D pixel unit as 1; otherwise, mark it as 0, to obtain a spatial binary pixel matrix for each detection sensor; The values ​​of the same three-dimensional pixel unit in the spatial binary pixel matrix of each detection sensor are added together to obtain a total spatial binary pixel matrix; the three-dimensional pixel unit with the largest value in the total spatial binary pixel matrix is ​​used as the location of the partial discharge acoustic emission source.

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