A transformer partial discharge detection method and system based on multiple sensors

Abstract

Multiple embodiments of this specification relate to the technical field of power equipment detection, and specifically to a transformer partial discharge detection method and system based on multiple sensors. The method includes the following steps: an inspection drone carries an ultrasonic acquisition device and couples it to a predetermined position on the target transformer casing; after waiting for a preset period of time, the ultrasonic acquisition device is removed to obtain sound data; the features of the sound data are extracted and compared with the reference sound features. If the comparison matches, it is determined that there is no partial discharge; when the comparison does not match, the ultrasonic acquisition device is carried one by one and coupled to multiple marked points on the target transformer casing; sound data is obtained; a delay vector is obtained; and according to the delay vector and the delay positioning reference table, a partial discharge position identification result is obtained. The transformer partial discharge detection method and system provided in this specification improves the accuracy and efficiency of partial discharge detection by carrying an ultrasonic acquisition device on an inspection drone.

Description

Technical Field

[0001] Multiple embodiments of this specification relate to the technical field of power equipment detection, and specifically to a transformer partial discharge detection method and system based on multiple sensors. Background Art

[0002] Online monitoring and localization of partial discharge (PD) within transformers is crucial for maintaining transformer health. This monitoring is accomplished by capturing the electrical pulses generated by PD using Rogowski coils installed on the high-voltage bushing down conductor and neutral grounding conductor, while simultaneously collecting ultrasonic signals using an ultrasonic sensor fixed to the transformer's oil tank casing. Given the stochastic nature of PD and the resulting ultrasonic signals, the spectrum of each recorded PD ultrasonic signal varies, primarily in the peak frequency. However, the overall frequency distribution remains relatively stable. Based on their generation mechanism, PD-related ultrasonic waves can be divided into two categories. The first category is discharges occurring within bubbles or air gaps, characterized by uniform and dense acoustic sound, similar to discharges in oil between metal plate electrodes. Bubble sizes range from a few microns to several hundred microns, and the acoustic frequency at breakdown ranges from a few kilohertz to several hundred kilohertz. The second category is free-flowing breakdown of dielectrics under high field strength, characterized by intermittent and large pulses, such as needle-plate discharges. The acoustic emission spectrum is broader, approaching a typical D-function distribution, with energy concentrated primarily in the 50 to 300 kHz frequency range. Summary of the Invention

[0003] Multiple embodiments of this specification describe a transformer partial discharge detection method and system based on multiple sensors.

[0004] In a first aspect, the embodiments of this specification provide a transformer partial discharge detection method based on multiple sensors, comprising the steps of:

[0005] The inspection drone carries an ultrasonic acquisition device, and based on the wireless communication connection established between the inspection drone and the ultrasonic acquisition device, after setting time synchronization, acquisition duration and acquisition frequency, the ultrasonic acquisition device is coupled to a predetermined position of the target transformer housing;

[0006] After waiting for a preset time, the ultrasonic acquisition device is removed, and the sound data collected by the ultrasonic acquisition device is obtained through the wireless communication connection;

[0007] Extracting features from the sound data and comparing them with reference sound features stored in the inspection drone, and determining that there is no partial discharge if the comparison matches;

[0008] When the comparison does not match, the inspection drone is controlled to carry the ultrasonic acquisition device one by one from the designated location, set time synchronization, acquisition duration and acquisition frequency, and couple to multiple pre-marked points on the target transformer housing;

[0009] After waiting for a preset period of time, the plurality of ultrasonic collection devices are removed one by one, and the sound data collected by the plurality of ultrasonic collection devices are obtained through the wireless communication connection;

[0010] After aligning the plurality of sound data along the time axis, selecting the sound data corresponding to the designated marked point to calibrate a discharge pulse, and obtaining the sound propagation delay generated by the discharge pulse at the remaining calibrated points based on the remaining sound data to obtain a delay vector;

[0011] The position recognition result of the partial discharge is obtained according to the delay vector and the delay positioning reference table pre-stored in the inspection drone. The delay positioning reference table is an association table of the position recognition results and delay vectors of the same model and the same marked points obtained under laboratory conditions.

[0012] In a second aspect, the embodiments of this specification provide a transformer partial discharge detection system based on multiple sensors, including a patrol drone and multiple ultrasonic acquisition devices, wherein the patrol drone performs the following steps:

[0013] The inspection drone carries an ultrasonic acquisition device, and based on the wireless communication connection established between the inspection drone and the ultrasonic acquisition device, after setting time synchronization, acquisition duration and acquisition frequency, the ultrasonic acquisition device is coupled to a predetermined position of the target transformer housing;

[0014] After waiting for a preset time, the ultrasonic acquisition device is removed, and the sound data collected by the ultrasonic acquisition device is obtained through the wireless communication connection;

[0015] Extracting features from the sound data and comparing them with reference sound features stored in the inspection drone, and determining that there is no partial discharge if the comparison matches;

[0016] When the comparison does not match, the inspection drone is controlled to carry the ultrasonic acquisition device one by one from the designated location, set time synchronization, acquisition duration and acquisition frequency, and couple to multiple pre-marked points on the target transformer housing;

[0017] After waiting for a preset period of time, the plurality of ultrasonic collection devices are removed one by one, and the sound data collected by the plurality of ultrasonic collection devices are obtained through the wireless communication connection;

[0018] After aligning the plurality of sound data along the time axis, selecting the sound data corresponding to the designated marked point to calibrate a discharge pulse, and obtaining the sound propagation delay generated by the discharge pulse at the remaining calibrated points based on the remaining sound data to obtain a delay vector;

[0019] The position recognition result of the partial discharge is obtained according to the delay vector and the delay positioning reference table pre-stored in the inspection drone. The delay positioning reference table is an association table of the position recognition results and delay vectors of the same model and the same marked points obtained under laboratory conditions.

[0020] In a third aspect, embodiments of this specification provide an electronic device, including a processor and a memory;

[0021] The processor is connected to the memory;

[0022] The memory is used to store executable program code;

[0023] The processor reads the executable program code stored in the memory to run a program corresponding to the executable program code, so as to execute the method described in any one of the above aspects.

[0024] In a fourth aspect, an embodiment of this specification provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method described in any one of the above aspects is implemented.

[0025] In a fifth aspect, embodiments of this specification provide a computer program product, including a computer program, which implements the method described in any of the above aspects when executed by a processor.

[0026] The beneficial effects of the technical solutions provided by some embodiments of this specification include at least:

[0027] The transformer partial discharge detection method and system provided in this specification uses an ultrasonic acquisition device carried by an inspection drone to flexibly and efficiently collect sound data at a predetermined location. Combined with time synchronization, acquisition duration and frequency settings, it can more accurately capture the partial discharge signal inside the transformer, improve the accuracy and efficiency of partial discharge detection, and adapt to the growth of the distribution network scale. By using the sound data of multiple marked points, aligning the time axis and analyzing the sound propagation delay vector, and combining it with a pre-stored delay positioning reference table, the location of the partial discharge can be quickly determined, avoiding the large amount of calculation and error problems that may occur in existing calculation methods. The changes in sound data under different load conditions are divided into load intervals and the amplitude ratio comparison method is used to improve the accuracy of the comparison, so that the partial discharge phenomenon can be effectively identified even under different working conditions.

[0028] Other features and advantages of the various embodiments of this specification will be further disclosed in the following detailed description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of this specification, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0030] Figure 1 This is a flow chart of a transformer partial discharge detection method provided in an embodiment of this specification.

[0031] Figure 2 This is a schematic diagram of the marking points provided in the embodiments of this specification.

[0032] Figure 3 Schematic diagram of the inspection drone provided in the embodiments of this specification.

[0033] Figure 4 This is a schematic diagram of the ultrasonic acquisition device provided in the embodiments of this specification.

[0034] Figure 5 This is a schematic diagram of the back structure of the ultrasonic acquisition device provided in the embodiments of this specification.

[0035] Figure 6 This is a schematic diagram of the designated location provided in the embodiments of this specification.

[0036] Figure 7 A flowchart of a method for comparing sound features with a reference sound provided in an embodiment of this specification.

[0037] Figure 8 This is a flow chart of a method for obtaining a delayed positioning reference table provided in an embodiment of this specification.

[0038] Figure 9 This is a schematic diagram of an electronic device provided in an embodiment of this specification.

[0039] Among them: 11. Shell, 12. Marking point, 21. Inspection drone, 22. Support rod, 23. Magnetic head, 30. Designated position, 31. Shell, 32. Electromagnet, 33. Magnet, 34. Sound collector, 35. Elastic bracket, 36. Back magnet, 1100. Electronic device, 1101. Processor, 1102. Communication bus, 1103. User interface, 1104. Network interface, 1105. Memory. DETAILED DESCRIPTION

[0040] The following is an explanation and description of the technical solutions of the embodiments of this specification in conjunction with the drawings of the embodiments of this specification. However, the following embodiments are only preferred embodiments of this specification and are not exhaustive. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without making any creative work are all within the scope of protection of this specification.

[0041] Throughout this specification, the claims, and the accompanying drawings, the terms "first," "second," "third," and the like are used to distinguish between different items, not to describe a particular order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may include other steps or elements inherent to the process, method, product, or apparatus.

[0042] In the following description, terms such as "inside", "outside", "up", "down", "left", "right", etc. that indicate directions or positional relationships are only used to facilitate the description of the embodiments and simplify the description. They do not indicate or imply that the devices or elements referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, they should not be understood as limitations on this specification.

[0043] The data involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection of relevant data complies with the relevant laws, regulations and standards of relevant countries and regions.

[0044] Before introducing the technical solution in this specification, the application scenarios and related technologies of the technical solution are introduced.

[0045] Partial discharge (PD) in transformers refers to a localized electrical breakdown phenomenon within a transformer's insulation system caused by the electric field strength exceeding the withstand voltage of the insulation material in a certain area. It typically occurs within or on the surface of the insulation material, as well as in air gaps between conductors. Although the energy released by a single PD is relatively small, frequent occurrences can cause gradual deterioration and damage to the insulation material, ultimately leading to failure of the entire insulation system and compromising the safe operation of the transformer. To effectively monitor and prevent PD-induced failures, modern power systems employ a variety of monitoring technologies to detect PD within transformers in real time. These technologies include, but are not limited to, Rogowski coils for acquiring electrical pulse signals generated by PD and ultrasonic sensors for capturing ultrasonic signals generated by the discharge.

[0046] As a type of inspection drone 21, the quadcopter inspection drone 21 features a simple structure, flexible control, and vertical take-off and landing, making it widely used in various fields. In the power industry, the specially designed quadcopter inspection drone 21 is able to resist electromagnetic interference generated by power equipment. In recent years, it has been increasingly used in distribution network inspection tasks, significantly improving the efficiency of distribution network inspections.

[0047] As distribution networks continue to grow in size and load, the number of transformers used in these networks has also increased significantly. Existing transformer partial discharge detection technologies are unable to meet the safety and security requirements of distribution networks. Therefore, new and more efficient transformer partial discharge detection technologies are needed.

[0048] This manual first provides a transformer partial discharge detection method based on multiple sensors. Figure 1 , including the steps of:

[0049] Step S101) The inspection drone 21 carries an ultrasonic acquisition device. Based on the wireless communication connection established between the inspection drone 21 and the ultrasonic acquisition device, time synchronization, acquisition duration and acquisition frequency are set, and then the ultrasonic acquisition device is coupled to a predetermined position of the target transformer housing 11.

[0050] Step S102 ) After waiting for a preset time, the ultrasonic acquisition device is removed, and the sound data collected by the ultrasonic acquisition device is obtained through the wireless communication connection.

[0051] Step S103 ) extracts features from the sound data and compares them with reference sound features stored in the inspection drone 21 . If the features match, it is determined that there is no partial discharge.

[0052] Step S104 ) When the comparison does not match, the inspection drone 21 is controlled to carry ultrasonic acquisition devices one by one from the designated location 30 , set time synchronization, acquisition duration and acquisition frequency, and couple to multiple pre-marked marking points 12 on the target transformer housing 11 .

[0053] Step S105 ) After waiting for a preset time period, the plurality of ultrasonic collection devices are removed one by one, and the sound data collected by the plurality of ultrasonic collection devices are obtained through the wireless communication connection.

[0054] Step S106) After aligning the plurality of sound data along the time axis, the sound data corresponding to the designated mark point 12 is selected to calibrate a discharge pulse, and based on the remaining sound data, the sound propagation delay generated by the discharge pulse at the remaining calibration points is obtained to obtain a delay vector.

[0055] Step S107) Obtain the position recognition result of the partial discharge according to the delay vector and the delay positioning reference table pre-stored by the inspection drone 21. The delay positioning reference table is an association table of the position recognition results and delay vectors of the same model and the same marked point 12 obtained under laboratory conditions.

[0056] The transformer includes a housing 11, equipment inside the housing 11, and an oil conservator. Partial discharge usually occurs in the equipment inside the housing 11. Figure 2 In this embodiment, a plurality of marking points 12 are provided on the housing 11. The marking points 12 are used to control the position where the ultrasonic acquisition device is coupled with the housing 11 of the transformer. Figure 3 The ultrasonic collection device is placed on the transformer casing 11 by the inspection drone 21 and coupled with the casing 11. After the collection is completed, the ultrasonic collection device is also removed by the inspection drone 21. A support rod 22 is provided on the inspection drone 21, and a magnetic head 23 is installed at the end of the support rod 22. The magnetic head 23 is a permanent magnet 33. The support rod 22 has a long extension length and should at least extend relative to the rotor. In terms of height, the height difference between the magnetic head 23 and the rotor should be small, so that the inspection drone 21 can install the ultrasonic collection device at a higher marking point 12. At the same time, prevent the rotor from touching the power equipment or cables above. Anti-electromagnetic radiation technology can be carried out using the technology disclosed in this field.

[0057] This specification provides an implementation of an ultrasonic acquisition device. Figure 4 and attached Figure 5 The ultrasonic collection device includes a shell 31, several electromagnets 32, several magnets 33, a sound collector 34, an elastic bracket 35, a back magnet 36, a communication module, a controller and a battery. The back magnet 36 is installed on the back of the shell 31 for cooperating with the magnetic head 23. Several magnets 33 are installed in the front of the shell 31. The electromagnet 32 ​​is installed in the shell 31 and its position matches the magnet 33 one by one. The sound collector 34 is installed on the shell 31 through the elastic bracket 35, and the sound collector 34 extends relative to the magnet 33; the electromagnet 32, communication module and sound collector 34 are all connected to the controller, and the battery supplies power to the remaining components.

[0058] Please see the attached Figure 6 A substation has multiple transformers. Multiple ultrasonic acquisition devices are placed at designated locations 30 in the substation. Magnets 33 of the devices are attached to steel plates fixed at designated locations 30. Inspection drones 21, using a pre-programmed program, use their cameras to capture and identify the ultrasonic acquisition devices and the marked points 12 on the transformer casing 11 in real time.

[0059] The process of the inspection drone 21 installing the ultrasonic collection device on the transformer casing 11 is as follows: the inspection drone 21 uses the magnetic suction head 23 to attract the back magnet 36 of an ultrasonic collection device, and through communication, the electromagnet 32 ​​of the corresponding ultrasonic collection device generates a magnetic field in the opposite direction of the magnetic pole of the magnet 33. The two basically cancel each other out, so that the ultrasonic collection device can be removed from the steel plate. After removal, the electromagnet 32 ​​is powered off to save energy.

[0060] The inspection drone 21, carrying the ultrasonic acquisition device, then flies to a selected marked point 12. Through flight control and attitude control, the magnetic head 23 on the support rod 22 aligns the ultrasonic acquisition device with the marked point 12. However, it still needs to maintain a certain distance from the housing 11. The electromagnet 32 ​​is controlled to generate a magnetic field with a polarity opposite to that of the magnet 33, so that the two magnetic fields substantially cancel each other out. The inspection drone 21 is controlled to continue approaching the housing 11, aligning the ultrasonic acquisition device with the marked point 12 and bringing it close to the transformer housing 11. The electromagnet 32 ​​is then de-energized, and the ultrasonic acquisition device is now firmly attached to the transformer housing 11 via the magnet 33, forming a coupling with the housing 11. The inspection drone 21 then retreats. The attraction between the magnetic head 23 and the back magnet 36 is less than the attraction between the magnet 33 and the transformer housing 11, causing the magnetic head 23 to detach from the back magnet 36. The inspection drone 21 also needs to synchronize time with the ultrasonic acquisition device. This synchronization is accomplished using techniques known in the art.

[0061] The inspection drone 21 continues to sequentially place multiple ultrasonic collection devices at multiple marking points 12. After collecting ultrasonic data for a preset time period, the inspection drone 21 removes the ultrasonic collection device from the transformer.

[0062] The steps for the inspection drone 21 to remove the ultrasonic acquisition device from the transformer casing 11 include: the inspection drone 21 uses flight control and attitude control to attract the magnetic head 23 to the back magnet 36 of the ultrasonic acquisition device; then controls the electromagnet 32 ​​to generate a magnetic field in the opposite direction of the magnetic pole of the magnet 33, so that the two magnetic fields basically cancel each other out; the inspection drone 21 flies backward, so that the magnetic head 23 drives the ultrasonic acquisition device to separate from the transformer casing 11, and then controls the electromagnet 32 ​​to cut off the power; the inspection drone 21 uses flight control and attitude control to transport the ultrasonic acquisition device to a place close to the placed steel plate. When it is a certain distance away from the steel plate, the electromagnet 32 ​​is controlled to generate a magnetic field in the opposite direction of the magnetic pole of the magnet 33. After the position is completed, the electromagnet 32 ​​is cut off and the inspection drone 21 can fly away.

[0063] The transformers in the substation do not necessarily have partial discharge. Therefore, this embodiment first uses a single ultrasonic acquisition device to collect sound data from the transformer, extracts the characteristics of the sound data, and compares them with the reference sound characteristics stored in the inspection drone 21. The reference sound characteristics are the characteristics corresponding to the sound data when the transformer is operating normally. Therefore, when the characteristics of the extracted sound data match the reference sound characteristics, it is determined that there is no partial discharge. The method for extracting the characteristics of the sound data includes: extracting the frequency components of the sound data and obtaining the amplitude of each frequency component; calculating the sum of the amplitudes of all frequency components and calculating the amplitude ratio of each frequency component; and obtaining the characteristics of the sound data based on the amplitude ratio of all frequency components.

[0064] Since the sound data is different under different load conditions, this embodiment provides a reference sound feature stored in the inspection drone 21, including the frequency composition and amplitude ratio of the sound data collected at the same predetermined position corresponding to several transformer load intervals. Figure 7 The method of comparing the characteristics of the sound data with the reference sound characteristics stored in the inspection drone 21 includes:

[0065] Step S201) Select the frequency components of the sound data within a preset frequency range, and construct a vector of the selected frequency components and their amplitude ratios, which is recorded as a first vector.

[0066] Step S202) According to the frequency components included in the first vector, corresponding frequency components and their amplitude proportions are selected from the frequency components of the sound data corresponding to each transformer load interval to obtain a plurality of second vectors.

[0067] Step S203) Calculate the similarity between the first vector and each of the second vectors respectively. When there is a similarity value higher than a preset reference similarity threshold, determine that the comparison is matched. When there is no similarity value higher than the preset reference similarity threshold, determine that the comparison is not matched.

[0068] By dividing the load intervals and comparing them using amplitude ratios, changes in the sound data caused by load differences can be offset, improving the accuracy of the comparison. The distance calculation between vectors can be performed using techniques disclosed in the art.

[0069] If a mismatch is detected, the inspection drone 21 carries ultrasonic acquisition devices one by one from the designated location 30, sets time synchronization, acquisition duration, and acquisition frequency, and couples them to multiple pre-marked locations 12 on the target transformer housing 11. After waiting for a preset period of time, the multiple ultrasonic acquisition devices are removed one by one, and the sound data collected by the multiple ultrasonic acquisition devices is obtained through the wireless communication connection.

[0070] Ultrasonic waves from a partial discharge fault within the transformer are transmitted via a multi-media path to an ultrasonic sensor coupled to the wall. The ultrasonic sensors are mounted on the transformer oil tank casing 11 according to a specific geometric pattern. The time difference between the partial discharge time measured by each sensor and the reference time, as well as the coordinates of each sensor, is determined. The measured delay is used as the time from the discharge point to the sensor. Multiplying the delay by the equivalent wave velocity v yields the spatial position from the discharge point to each sensor. Substituting this into a nonlinear overdetermined equation yields the location of the discharge source. This involves establishing the spherical equation:

[0071] (x0-x i ) 2 +(y0-y i ) 2+ (z0-z i ) 2 =(vt i ) 2

[0072] Where i=1,2,3,…,n, represents the serial number of the ultrasonic acquisition device, x i 、y i 、z i represents the coordinates of the ith ultrasonic acquisition device, and x0, y0, and z0 represent the location of the partial discharge point. i represents the delay corresponding to each ultrasonic acquisition device, and v is the equivalent wave velocity. Because ultrasonic wave propagation within the transformer is not a constant but rather has a certain range, the wave velocity is considered a variable, namely the equivalent wave velocity v. Adding the coordinates of the desired partial discharge point, there are four variables. Using at least four ultrasonic acquisition devices, the coordinates of the partial discharge point and the equivalent wave velocity can be obtained. The spherical equation can be solved using the least squares method.

[0073] However, the least squares method is a nonlinear algorithm with long computation time and high memory usage. Furthermore, the results are significantly affected by initial values ​​and step size. Improper selection can result in an unsolvable system of equations or significant errors. Therefore, this embodiment provides a time-delayed location reference table that allows for rapid determination of the approximate location of a partial discharge (PD). Based on the structure at the approximate location, the structure with the PD fault can be identified for subsequent reference.

[0074] Please see the attached Figure 8 , the method for obtaining the delayed positioning reference table includes:

[0075] Step S301) Divide the interior space of the selected transformer into multiple grids. Grids suitable for pulse discharge testing under laboratory conditions are grouped as a first group, and the remaining grids are grouped as a second group. Exemplary grids are 30×30×30 grids. In this example transformer, each grid is approximately a square with a side length of 0.2 m.

[0076] The internal structure of the transformer is complex, and the multi-layer dielectric path for ultrasonic signal propagation may experience transmission, diffraction, scattering, and other phenomena. The equivalent wave velocity of each path is generally different and difficult to determine. Therefore, it is difficult to use a certain value of equivalent wave velocity for positioning calculations. Therefore, this embodiment divides these grids into two groups. The most accurate equivalent wave velocity can be obtained by directly testing under laboratory conditions. Since the grids in the second group cannot be directly tested, the material of the path between the second group and the grid closest to the grid in the first group is often relatively simple. Therefore, after superimposing the theoretical sound velocity, a relatively accurate equivalent wave velocity v can also be obtained.

[0077] Step S302 ) For the grids in the first group, pulse discharge tests are performed on the grids in turn under laboratory conditions.

[0078] Step S303) Acquire the sound data collected by multiple ultrasonic acquisition devices coupled to the transformer housing 11 according to the marking point 12 and align them according to the time axis. The moment of discharge under laboratory conditions is known, so when the time axis is aligned, the delay can be directly obtained, and then the equivalent wave velocity can be obtained. Or directly record in the form of delay. Since the detection is carried out on the same model of transformer and the same marking point 12, either delay or equivalent wave velocity can be used. The reason is that in the delay positioning reference table, the equivalent wave velocity can be calculated from the delay, and the delay can also be calculated from the equivalent wave velocity. It is only necessary to use the same quantity for comparison when the subsequent inspection drone 21 collects data through the ultrasonic acquisition device. For example, a discharge test is carried out at the center of each grid.

[0079] Step S304) Identify the time corresponding to the discharge pulse in the sound data corresponding to the designated mark point 12, and use this time as a reference to obtain the sound propagation delay generated by the discharge pulse in the remaining ultrasonic acquisition devices.

[0080] Step S305) A delay vector corresponding to the grid is established based on the sound propagation delays corresponding to all ultrasonic acquisition devices.

[0081] Step S306) Traverse the grids in the second group and find the grid in the first group closest to the grid on the ultrasonic wave propagation path from the grid to each marked point 12, and record it as the reference grid.

[0082] Step S307) Calculate the sound propagation time between the grid and each reference grid, and obtain the time it takes for the grid to reach the ultrasonic collection device at each marked point 12 based on the sound propagation time and the time it takes for the reference grid to reach the ultrasonic collection device at the corresponding marked point 12 during the pulse discharge test.

[0083] Step S308 ) According to the time length for the grid to reach the ultrasonic collection device at each marking point 12 , a delay vector corresponding to the grid is obtained.

[0084] Step S309) Obtain the delay positioning reference table according to the delay vectors of all grids.

[0085] The delayed positioning reference table allows the inspection drone 21 to quickly determine the preliminary location of a partial discharge (PD) by looking up the table, eliminating the need for extensive calculations. The accuracy of the preliminary PD location is determined by the process of obtaining the delayed positioning reference table. The preliminary PD location is generally sufficient to assist in determining the structure where the PD fault has occurred.

[0086] The method for obtaining the position identification result of the partial discharge according to the delay vector and the delay positioning reference table pre-stored by the inspection drone 21 includes:

[0087] respectively calculating the similarity between the delay vector and each delay vector in the delay positioning reference table;

[0088] The grid corresponding to the delay vector with the highest similarity is used as the position recognition result of the partial discharge.

[0089] On the other hand, this specification provides a transformer partial discharge detection system based on multiple sensors, including an inspection drone 21 and multiple ultrasonic acquisition devices, wherein the inspection drone 21 performs the following steps:

[0090] The inspection drone 21 carries an ultrasonic acquisition device. Based on the wireless communication connection established between the inspection drone 21 and the ultrasonic acquisition device, the ultrasonic acquisition device is coupled to a predetermined position of the target transformer housing 11 after setting time synchronization, acquisition duration, and acquisition frequency.

[0091] After waiting for a preset time, the ultrasonic acquisition device is removed, and the sound data collected by the ultrasonic acquisition device is obtained through the wireless communication connection;

[0092] Extracting features of the sound data and comparing them with reference sound features stored in the inspection drone 21 , and determining that there is no partial discharge if the comparison matches;

[0093] When the comparison does not match, the inspection drone 21 is controlled to carry the ultrasonic acquisition device one by one from the designated position 30, set the time synchronization, acquisition duration and acquisition frequency, and couple to the multiple marked points 12 pre-marked on the target transformer housing 11;

[0094] After waiting for a preset period of time, the plurality of ultrasonic collection devices are removed one by one, and the sound data collected by the plurality of ultrasonic collection devices are obtained through the wireless communication connection;

[0095] After aligning the plurality of sound data along the time axis, the sound data corresponding to the designated marking point 12 is selected to calibrate a discharge pulse, and based on the remaining sound data, the sound propagation delay generated by the discharge pulse at the remaining calibration points is obtained to obtain a delay vector;

[0096] The position recognition result of the partial discharge is obtained according to the delay vector and the delay positioning reference table pre-stored in the inspection drone 21. The delay positioning reference table is an association table of the position recognition results and delay vectors of the same model and the same marked point 12 obtained under laboratory conditions.

[0097] See also Figure 9 The figure shows a schematic diagram of the structure of an electronic device provided by an embodiment of this specification.

[0098] like Figure 9 As shown, the electronic device 1100 may include: at least one processor 1101, at least one network interface 1104, a user interface 1103, a memory 1105, and at least one communication bus 1102. The communication bus 1102 may be used to enable communication between the aforementioned components. The user interface 1103 may include buttons, and optionally may also include a standard wired interface or a wireless interface. The network interface 1104 may include, but is not limited to, a Bluetooth module, an NFC module, a Wi-Fi module, etc. The processor 1101 may include one or more processing cores. The processor 1101 utilizes various interfaces and circuits to connect the various components within the electronic device 1100. By running or executing instructions, programs, code sets, or instruction sets stored in the memory 1105 and accessing data stored in the memory 1105, it performs various functions of the routing device 1100 and processes data. Optionally, the processor 1101 may be implemented in hardware using at least one of a DSP, an FPGA, and a PLA. The processor 1101 may integrate one or a combination of a CPU, a GPU, and a modem. The CPU primarily processes the operating system, user interface, and applications; the GPU is responsible for rendering and drawing content displayed on the display; and the modem handles wireless communications.

[0099] It is understandable that the above-mentioned modem may not be integrated into the processor 1101, but may be implemented by a separate chip.

[0100] Memory 1105 may include either RAM or ROM. Optionally, memory 1105 may include non-transitory computer-readable media. Memory 1105 may be used to store instructions, programs, codes, code sets, or instruction sets. Memory 1105 may include a program storage area and a data storage area. The program storage area may store instructions for implementing an operating system, instructions for at least one function (such as a touch function, sound playback function, image playback function, etc.), instructions for implementing the aforementioned method embodiments, etc.; the data storage area may store data related to the aforementioned method embodiments, etc. Memory 1105 may also optionally be at least one storage device located remotely from the aforementioned processor 1101. Memory 1105, as a computer storage medium, may include an operating system, a network communication module, a user interface module, and application programs. Processor 1101 may be configured to invoke the application programs stored in memory 1105 and execute the methods described in the aforementioned embodiments.

[0101] The embodiments of this specification also provide a computer-readable storage medium having instructions stored therein that, when executed on a computer or processor, cause the computer or processor to perform the steps of the aforementioned embodiments. If the components of the aforementioned electronic device are implemented as software functional units and sold or used as independent products, they may be stored in the computer-readable storage medium.

[0102] The embodiments of this specification also provide a computer program product, including a computer program, which implements multiple steps in the above embodiments when executed by a processor.

[0103] In the absence of conflict, the technical features in this embodiment and implementation scheme can be combined arbitrarily.

[0104] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product comprises multiple computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this specification are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted via the computer-readable storage medium. The computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, optical fiber, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium accessible by a computer or a data storage device such as a server or data center that integrates multiple available media. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital versatile disc (DVD)), or a semiconductor medium (eg, a solid state drive (SSD)).

[0105] When implemented via hardware or firmware, the aforementioned method flow is programmed into the hardware circuit to obtain the corresponding hardware circuit structure and realize the corresponding function. For example, a programmable logic device (PLD) (such as a field programmable gate array (FPGA)) is such an integrated circuit, whose logical function is determined by the user's device programming. Designers can "integrate" a digital system on a PLD through self-programming, eliminating the need for chip manufacturers to design and manufacture dedicated integrated circuit chips. Moreover, today, instead of manually manufacturing integrated circuit chips, this programming is often performed using "logic compiler" software. This is similar to the software compiler used in program development. Before compilation, the original code must also be written in a specific programming language, called a hardware description language (HDL). There are not just one HDL, but many. Those skilled in the art will also understand that simply by programming the method flow in one of the aforementioned hardware description languages ​​and programming it into the integrated circuit, a hardware circuit that implements the logical method flow can be easily obtained.

[0106] The embodiments described above are merely preferred embodiments of this specification and are not intended to limit the scope of this specification. Without departing from the design spirit of this specification, various modifications and improvements made to the technical solutions of this specification by ordinary technicians in this field should fall within the scope of protection determined by the claims of this specification.

Claims

1. A transformer partial discharge detection method based on multiple sensors, characterized in that: Including steps: The inspection drone carries an ultrasonic acquisition device, and based on a wireless communication connection established between the inspection drone and the ultrasonic acquisition device, after setting time synchronization, acquisition duration, and acquisition frequency, the ultrasonic acquisition device is coupled to a predetermined position of the target transformer housing; After waiting for a preset time, the ultrasonic acquisition device is removed, and the sound data collected by the ultrasonic acquisition device is obtained through the wireless communication connection; Extracting features from the sound data and comparing them with reference sound features stored in the inspection drone, and determining that there is no partial discharge if the comparison matches; When the comparison does not match, the inspection drone is controlled to carry the ultrasonic acquisition device one by one from the designated location, set time synchronization, acquisition duration and acquisition frequency, and couple to multiple pre-marked points on the target transformer housing; After waiting for a preset period of time, the plurality of ultrasonic collection devices are removed one by one, and the sound data collected by the plurality of ultrasonic collection devices are obtained through the wireless communication connection; After aligning the plurality of sound data along the time axis, selecting the sound data corresponding to the designated marked point to calibrate a discharge pulse, and obtaining the sound propagation delay generated by the discharge pulse at the remaining calibrated points based on the remaining sound data to obtain a delay vector; Obtaining a position recognition result of the partial discharge according to the delay vector and a delay positioning reference table pre-stored by the inspection drone, wherein the delay positioning reference table is an association table between position recognition results of the same model and the same marked point obtained under laboratory conditions and the delay vector; Methods for obtaining a delayed positioning reference table include: The internal space of the selected transformer model is divided into multiple grids, and the grids that can be used for pulse discharge tests under laboratory conditions are classified into the first group, and the remaining grids are classified into the second group; For the grids in the first group, pulse discharge tests are carried out in the grid range under laboratory conditions in turn; Acquire sound data collected by multiple ultrasonic collection devices coupled to the transformer housing according to the marked points and align them according to the time axis; Identify the time corresponding to the discharge pulse in the sound data corresponding to the designated mark point, and use the time reference to obtain the sound propagation delay generated by the discharge pulse in the remaining ultrasonic acquisition devices; According to the sound propagation delays corresponding to all ultrasonic acquisition devices, a delay vector corresponding to the grid is established; Traversing the grids in the second group, finding the grid in the first group that is closest to the grid on the ultrasonic wave propagation path from the grid to each marked point, and recording it as the reference grid; Calculating the sound propagation time between the grid and each reference grid, and obtaining the time it takes for the grid to reach the ultrasonic collection device at each marked point based on the sound propagation time and the time it takes for the reference grid to reach the ultrasonic collection device at the corresponding marked point during the pulse discharge test; Obtaining a delay vector corresponding to the grid according to the time it takes for the grid to reach the ultrasonic acquisition device at each marked point; The delay positioning reference table is obtained according to the delay vectors of all grids.

2. A transformer partial discharge detection method based on multiple sensors according to claim 1, characterized in that: The method for extracting the features of the sound data includes: Extracting the frequency components of the sound data and obtaining the amplitude of each frequency component; Calculate the sum of the amplitudes of all frequency components and calculate the amplitude ratio of each frequency component; The characteristics of the sound data are obtained according to the amplitude ratio of all frequency components.

3. The transformer partial discharge detection method based on multiple sensors according to claim 2 is characterized in that: The reference sound features stored in the inspection drone include the frequency composition and amplitude ratio of the sound data collected at the same predetermined position corresponding to several transformer load intervals. The method of comparing the characteristics of the sound data with the reference sound characteristics stored in the inspection drone includes: Selecting a frequency component of the sound data within a preset frequency range, and constructing a vector of the selected frequency component and its amplitude ratio, which is recorded as a first vector; According to the frequency components included in the first vector, select corresponding frequency components and their amplitude proportions from the frequency components of the sound data corresponding to each transformer load interval to obtain multiple second vectors; The similarity between the first vector and each of the second vectors is calculated respectively. When a similarity value is higher than a preset reference similarity threshold, the comparison is determined to be matched; when no similarity value is higher than the preset reference similarity threshold, the comparison is determined to be mismatched.

4. A transformer partial discharge detection method based on multiple sensors according to any one of claims 1 to 3, characterized in that: The method for obtaining a position identification result of a partial discharge according to the delay vector and the delay positioning reference table pre-stored by the inspection drone includes: respectively calculating the similarity between the delay vector and each delay vector in the delay positioning reference table; The grid corresponding to the delay vector with the highest similarity is used as the position recognition result of the partial discharge.

5. A transformer partial discharge detection method based on multiple sensors according to any one of claims 1 to 3, characterized in that: The inspection drone comprises a drone body, a support rod and a magnetic head, wherein the magnetic head is mounted on the drone body through the support rod. The ultrasonic collection device includes a shell, several electromagnets, several magnets, a sound collector, an elastic bracket, a back magnet, a communication module, a controller and a battery. The back magnet is installed on the back of the shell to cooperate with the magnetic head. A plurality of magnets are mounted on the front of the housing, the electromagnets are mounted in the housing and their positions match the magnets one by one, the sound collector is mounted on the housing via the elastic bracket, and the sound collector extends relative to the magnets; The electromagnet, the communication module and the sound collector are all connected to the controller, and the battery provides power for the remaining components.

6. A transformer partial discharge detection system based on multiple sensors, characterized in that: Including inspection drones and multiple ultrasonic collection devices, The inspection drone performs the following steps: The inspection drone carries an ultrasonic acquisition device, and based on a wireless communication connection established between the inspection drone and the ultrasonic acquisition device, after setting time synchronization, acquisition duration, and acquisition frequency, the ultrasonic acquisition device is coupled to a predetermined position of the target transformer housing; After waiting for a preset time, the ultrasonic acquisition device is removed, and the sound data collected by the ultrasonic acquisition device is obtained through the wireless communication connection; Extracting features from the sound data and comparing them with reference sound features stored in the inspection drone, and determining that there is no partial discharge if the comparison matches; When the comparison does not match, the inspection drone is controlled to carry the ultrasonic acquisition device one by one from the designated location, set time synchronization, acquisition duration and acquisition frequency, and couple to multiple pre-marked points on the target transformer housing; After waiting for a preset period of time, the plurality of ultrasonic collection devices are removed one by one, and the sound data collected by the plurality of ultrasonic collection devices are obtained through the wireless communication connection; After aligning the plurality of sound data along the time axis, selecting the sound data corresponding to the designated marked point to calibrate a discharge pulse, and obtaining the sound propagation delay generated by the discharge pulse at the remaining calibrated points based on the remaining sound data to obtain a delay vector; Obtaining a position recognition result of the partial discharge according to the delay vector and a delay positioning reference table pre-stored by the inspection drone, wherein the delay positioning reference table is an association table between position recognition results of the same model and the same marked point obtained under laboratory conditions and the delay vector; Methods for obtaining a delayed positioning reference table include: The internal space of the selected transformer model is divided into multiple grids, and the grids that can be used for pulse discharge tests under laboratory conditions are classified into the first group, and the remaining grids are classified into the second group; For the grids in the first group, pulse discharge tests are carried out in the grid range under laboratory conditions in turn; Acquire sound data collected by multiple ultrasonic collection devices coupled to the transformer housing according to the marked points and align them according to the time axis; Identify the time corresponding to the discharge pulse in the sound data corresponding to the designated mark point, and use the time reference to obtain the sound propagation delay generated by the discharge pulse in the remaining ultrasonic acquisition devices; According to the sound propagation delays corresponding to all ultrasonic acquisition devices, a delay vector corresponding to the grid is established; Traversing the grids in the second group, finding the grid in the first group that is closest to the grid on the ultrasonic wave propagation path from the grid to each marked point, and recording it as the reference grid; Calculating the sound propagation time between the grid and each reference grid, and obtaining the time it takes for the grid to reach the ultrasonic collection device at each marked point based on the sound propagation time and the time it takes for the reference grid to reach the ultrasonic collection device at the corresponding marked point during the pulse discharge test; Obtaining a delay vector corresponding to the grid according to the time it takes for the grid to reach the ultrasonic acquisition device at each marked point; The delay positioning reference table is obtained according to the delay vectors of all grids.

7. An electronic device, characterized in that: including a processor and a memory; The processor is connected to the memory; The memory is used to store executable program code; The processor runs a program corresponding to the executable program code by reading the executable program code stored in the memory, so as to execute the method according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

9. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

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