Ultrasonic phased array positioning diagnosis method for dry type bushing capacitor core body containing microcrack defects

Abstract

The invention belongs to the technical field of ultrasonic positioning diagnosis, and discloses an ultrasonic phased array positioning diagnosis method for a dry-type bushing capacitor core with a microcrack defect, and the ultrasonic detection technology is a nondestructive detection method, and cannot damage a detected insulating material, so that the ultrasonic phased array positioning diagnosis method is suitable for long-term monitoring and preventive maintenance. As the ultrasonic wave has very high frequency and energy, the ultrasonic wave can penetrate through a thicker layer of the insulating material, so that tiny defects and changes can be found. The ultrasonic detection technology can find out the defects of aging, bubbles, impurities, cracks and the like in the insulating material, and can also be applied to other types of electrical equipment, such as cables, transformers and the like, so as to evaluate the insulating properties of the electrical equipment. And taking the discharge signal starting time measured by an electric detection method as a reference to obtain time delay data of all the sensors, and then carrying out next positioning calculation.

Description

Technical Field

[0001] The invention belongs to the technical field of ultrasonic positioning diagnosis, and in particular relates to an ultrasonic phased array positioning diagnosis method for a dry-type bushing capacitor core containing microcrack defects. Background Art

[0002] With the rapid development of electrical engineering technology, the safety and reliability of high-voltage power equipment have received increasing attention. As an indispensable component in the power system, the insulation performance of dry bushings is directly related to the stable operation of the entire system. However, in actual operation, the core of dry bushing capacitors often produces microcrack defects due to factors such as material aging and environmental stress. If these defects are not discovered and repaired in time, they will seriously threaten the safety of the power system.

[0003] Traditional detection methods such as visual inspection and partial discharge detection have limitations in the precise positioning and quantitative evaluation of microcracks, and are difficult to meet the high requirements of modern power systems for detection accuracy and efficiency. The main insulation structure of the rubber-impregnated paper bushing is mainly cast with bisphenol A epoxy resin, anhydride curing agent and catalyst. The defects such as internal cracks and uneven density of the rubber-impregnated paper composite insulation caused by factors such as structural design, process manufacturing, or multi-field coupling such as electricity, heat, and mechanical are relatively small in the early stage. Although it will not cause a significant reduction in its insulation performance, long-term operation will lead to gradual deterioration of insulation performance, and eventually cause surface flashover or insulation breakdown, and even cause explosions, resulting in power outages. Therefore, it is extremely important to detect as many tiny defects as possible in the rubber-impregnated paper bushing before it is put into the power grid.

[0004] In order to detect crack defects inside epoxy impregnated paper composite insulation materials used in glue-impregnated paper bushings, many scholars at home and abroad have proposed various other methods in addition to traditional partial discharge detection. Xi'an Jiaotong University used ultrasound to detect simulated air gaps and cracks at a depth of 20mm inside epoxy samples, and used the spectrum characteristics of the bottom surface reflection wave to distinguish air gaps of different apertures and cracks of different orientations; Tianjin University of Technology used Lamb waves to detect microcracks and tiny attachments 1mm high on the sample surface, but it was necessary to embed piezoelectric ceramic sheets into the edge of the material, and it was not possible to detect defective workpieces that had been produced or put into operation; Zhejiang University used ultrasonic guided wave positioning to detect 0.2mm surface cracks and 2mm diameter internal pores of the sample; South China University of Technology used ultrasonic reflection method and critical refraction longitudinal wave method to detect internal defects of epoxy materials, and found that 1MHz ultrasonic longitudinal wave probe can be used to detect bubble defects with a depth of 50mm and an internal diameter of 2mm and transverse crack defects with a depth of 40mm and an internal diameter of 1mm, and 2.5MHz ultrasonic critically refracted longitudinal waves (critically refracted longitudinal waves, LCR) can be used to detect surface microcracks with a height of 0.5mm;

[0005] At present, the crack defect detection of the resin-impregnated paper composite insulation mainly relies on the changes in characteristic quantities such as electromagnetic waves, currents, sound waves, ultraviolet rays, and chemical compositions generated by partial discharge. The ultra-high frequency method and the pulse current method have high detection sensitivity, but the former cannot quantitatively analyze the discharge and cannot determine the severity of the defect development, and the latter cannot accurately locate the defect. The partial discharge ultrasonic detection is not sensitive to the discharge signal generated by the internal cracks of the insulator, and it is difficult to locate. X-rays are difficult to detect cracks with smaller widths, and their convenience and safety need to be improved. The ultrasonic detection method is inefficient, and the density distribution ultrasonic detection method needs to be improved. The chemical detection method takes a long time to analyze the components and is difficult to monitor on site. Therefore, it is urgent to propose an efficient diagnostic method for the detection and diagnosis of microcrack defects in the core of the resin-impregnated paper bushing.

[0006] Through the above analysis, the problems and defects of the prior art are as follows:

[0007] Traditional detection methods such as visual inspection and partial discharge detection have limitations in the precise positioning and quantitative evaluation of microcracks, and are unable to meet the high requirements of modern power systems for detection accuracy and efficiency. Summary of the invention

[0008] In view of the problems existing in the prior art, the present invention provides an ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core containing microcrack defects.

[0009] The present invention is implemented as follows: an ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core containing microcrack defects comprises:

[0010] Step 1: The front-end signal acquisition module is responsible for transmitting and receiving ultrasonic signals, and the phased array probe is used to focus and scan the sound beam;

[0011] Step 2, amplifying, filtering, detecting and A / D converting the received echo signal through the signal processing module to extract useful information;

[0012] Step 3: Store massive amounts of test data through a big data storage module.

[0013] Step 4: Use advanced algorithms to process these data through the back-end image processing module to generate clear two-dimensional or three-dimensional images to intuitively display the internal structure of the inspected object.

[0014] Furthermore, the phased array probe is composed of a plurality of independent piezoelectric chips arranged according to a certain rule, and the excitation timing of each chip is controlled by an electronic system to achieve focusing and deflection of the sound beam.

[0015] Furthermore, the front-end signal acquisition module includes: a signal generator: generates a high-voltage electrical pulse signal to excite the chip in the phased array probe and emit an ultrasonic beam.

[0016] Furthermore, the ultrasonic signal needs to use an ultrasonic generator to generate a high-frequency ultrasonic signal;

[0017] Ultrasonic signals are generated by electronic devices and transmitted to the insulating material to be tested; when the ultrasonic wave enters the insulating material, it is disturbed by the internal structure of the material, causing changes in the propagation speed, amplitude and waveform.

[0018] Furthermore, the signal processing module utilizes a signal processor to process the received echo signal and extract characteristic information reflecting the internal structure of the object under inspection.

[0019] Furthermore, the back-end image processing module utilizes an imaging system: based on the processed signal data, an internal image of the inspected object is reconstructed through an algorithm to display the size, shape and position of defects such as cracks.

[0020] Another object of the present invention is to provide an ultrasonic phased array positioning and diagnostic system for a dry-type bushing capacitor core containing microcrack defects, comprising:

[0021] The front-end signal acquisition module is responsible for transmitting and receiving ultrasonic signals, and realizing the focusing and scanning of the sound beam through the phased array probe;

[0022] The signal processing module is used to amplify, filter, detect and A / D convert the received echo signal to extract useful information;

[0023] Big data storage module, used to store massive detection data.

[0024] The back-end image processing module is used to process these data using advanced algorithms to generate clear two-dimensional or three-dimensional images, intuitively displaying the internal structure of the inspected object.

[0025] Another object of the present invention is to provide a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core containing microcrack defects.

[0026] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, enables the processor to perform the steps of the ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core containing microcrack defects.

[0027] Another object of the present invention is to provide an information data processing terminal, which is used to implement the ultrasonic phased array positioning and diagnosis system of the dry-type bushing capacitor core containing microcrack defects.

[0028] In combination with the above technical solutions and the technical problems solved, please analyze the advantages and positive effects of the technical solutions to be protected by the present invention from the following aspects:

[0029] First, in view of the technical problems existing in the above-mentioned prior art and the difficulty of solving the problems, the technical solutions to be protected by the present invention and the results and data during the research and development process are closely combined to analyze in detail and deeply how the technical solutions of the present invention solve the technical problems, and some creative technical effects brought about after solving the problems. The specific description is as follows:

[0030] The present invention is a method for locating and diagnosing dry-type bushing capacitor cores with microcrack defects based on ultrasonic phased array. By deeply studying the application mechanism and key technologies of ultrasonic phased array technology in microcrack detection, the invention aims to improve the accuracy and efficiency of dry-type bushing defect detection and provide a strong guarantee for the safe operation of the power system. The present invention not only has important theoretical value, but also has broad application prospects.

[0031] The ultrasonic phased array detection technology of the present invention is a non-destructive detection method that will not cause damage to the insulating material being tested, and is therefore suitable for long-term monitoring and preventive maintenance. Since ultrasonic waves have very high frequency and energy, they can penetrate thicker layers of insulating materials to detect tiny defects and changes. Ultrasonic detection technology can detect defects such as aging, bubbles, impurities and cracks inside insulating materials, and can also be applied to other types of power equipment, such as cables, transformers, etc., to evaluate their insulation properties. The present invention selects a suitable sound source and coupling agent, the main function of which is to reduce the attenuation of ultrasonic waves, ensure the detection of bottom echoes, and ensure the effectiveness of the detection. . Consider the influence of environmental factors such as temperature and humidity on the propagation characteristics of ultrasonic waves to reduce errors. Use appropriate algorithms and methods to process and analyze the collected ultrasonic data to improve detection accuracy.

[0032] Second, the technical solution of the present invention aims at the problems of low accuracy, poor efficiency, and great diagnostic difficulty in the detection of micro-crack defects inside the core of dry-type bushing capacitors in the prior art, and proposes a positioning diagnosis method based on ultrasonic phased array. By applying phased array technology, the present invention can accurately control the propagation path and focal position of ultrasonic waves, realize comprehensive scanning and detection of the complex structure inside the capacitor core, and significantly improve the detection accuracy.

[0033] In addition, the present invention effectively removes noise and interference in the ultrasonic echo signal through the optimized design of the signal processing module, ensuring the high fidelity of the signal. Compared with the traditional ultrasonic detection method, the present invention introduces advanced filtering and detection technology in the signal processing stage, combined with A / D conversion, making the detection results more reliable and accurate, further improving the reliability of diagnosis.

[0034] In terms of data storage and processing, the present invention uses a large data storage module and advanced image processing algorithms, which can process and store massive amounts of test data and generate clear two-dimensional or three-dimensional images to intuitively display the microcrack defects inside the capacitor core. Compared with traditional detection methods that can only provide limited defect information, the present invention can provide more detailed and visual diagnostic results, greatly improving the efficiency and accuracy of fault analysis.

[0035] In summary, the present invention solves the technical difficulties in detecting micro-crack defects inside the core of dry-type bushing capacitors in the prior art through innovative ultrasonic phased array technology and multi-module collaboration, achieves significant technological progress, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0037] Figure 1 The present invention provides a flowchart of an ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core containing microcrack defects provided by an embodiment of the present invention.

[0038] Figure 2 The present invention is a block diagram of the structure of an ultrasonic phased array positioning and diagnosis system for a dry-type bushing capacitor core with microcrack defects provided by an embodiment of the present invention.

[0039] Figure 3 It is a schematic diagram of sample preparation and defect setting provided in an embodiment of the present invention.

[0040] Figure 4 It is a test result diagram provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0041] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention as detailed in the appended claims.

[0042] like Figure 1 As shown, an ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core with microcrack defects provided by an embodiment of the present invention is as follows:

[0043] S101 is responsible for transmitting and receiving ultrasonic signals through the front-end signal acquisition module, and realizing the focusing and scanning of the sound beam through the phased array probe;

[0044] S102, amplifying, filtering, detecting and A / D converting the received echo signal through a signal processing module to extract useful information;

[0045] S103, storing massive amounts of detection data in a big data storage module,

[0046] S104, the data are processed by a back-end image processing module using advanced algorithms to generate clear two-dimensional or three-dimensional images to intuitively display the internal structure of the inspected object.

[0047] The embodiment of the present invention provides an ultrasonic phased array positioning diagnosis method, which can accurately detect microcrack defects in the core of a dry-type bushing capacitor. The specific steps can be summarized as follows:

[0048] First, the front-end signal acquisition module transmits ultrasonic signals and uses the phased array probe to focus and scan the sound beam. The phased array probe can achieve multi-channel synchronous transmission and reception of signals through electronic control, and flexibly adjust the direction and focus position of the sound beam to ensure that the ultrasonic wave can cover all areas of the workpiece being tested, especially deep into the micro-crack defect area. This precise control technology ensures that the transmission and reception of ultrasonic waves are more efficient and improves the accuracy of detection.

[0049] Secondly, when the ultrasonic wave enters the interior of the workpiece, if there is a defect in the workpiece, an interface is formed between the defect and the workpiece body. Due to the difference in acoustic impedance, the ultrasonic wave will be reflected and transmitted when encountering the interface. The reflected signal is related to the orientation, size and acoustic impedance of the defect, and can reflect the specific nature of the defect.

[0050] After that, the phased array probe synchronously receives the ultrasonic signals reflected from the inside of the workpiece. These echo signals are accurately collected and recorded, reflecting the internal structure of the workpiece and its possible defects. By analyzing the echo signals, detailed information related to the defects can be obtained, including the size, location, shape, etc. of the defects.

[0051] Finally, the analysis module processes the received ultrasonic signal, combines it with the scanning data of the phased array system, accurately locates the position of the defect, and generates a diagnosis result. Through this process, the health of the workpiece can be fully evaluated, and the presence of defects such as cracks can be determined based on the test results, providing a basis for subsequent maintenance and quality control.

[0052] Next, the signal processing module performs a series of processing operations on the received ultrasonic echo signal, including amplification, filtering, detection and A / D conversion. The purpose of this series of processing steps is to remove noise and interference from the original signal and extract signal features containing effective information. Through A / D conversion, the signal is converted into a digital signal for subsequent accurate analysis and processing. The processed signal can clearly reflect the micro-crack defect characteristics inside the core of the dry-type bushing capacitor.

[0053] Then, the big data storage module stores and manages the massive amount of test data. These data include ultrasonic signals and processed echo signals in multiple test processes. Through efficient storage management, the system can store a large amount of test data in an orderly manner, providing sufficient data support for subsequent analysis. At the same time, the storage of these data also provides a basis for possible historical data comparison and fault diagnosis in the future.

[0054] Finally, the back-end image processing module uses advanced algorithms to deeply process the stored data and generate clear two-dimensional or three-dimensional images. The image processing algorithm combines the spatial distribution information of the data with the echo signal strength, and can intuitively display the internal structure of the dry-type bushing capacitor core. Through these images, users can clearly see the specific location and morphology of microcrack defects, greatly improving the accuracy and efficiency of fault location and diagnosis.

[0055] The phased array probe provided in the embodiment of the present invention is composed of a plurality of independent piezoelectric chips arranged according to a certain rule, and the excitation timing of each chip is controlled by an electronic system to achieve focusing and deflection of the sound beam.

[0056] The front-end signal acquisition module provided by the embodiment of the present invention includes: a signal generator: generates a high-voltage electric pulse signal, excites the chip in the phased array probe, and emits an ultrasonic beam.

[0057] The ultrasonic signal provided in the embodiment of the present invention requires the use of an ultrasonic generator to generate a high-frequency ultrasonic signal;

[0058] Ultrasonic signals are generated by electronic devices and transmitted to the insulating material to be tested; when the ultrasonic wave enters the insulating material, it is disturbed by the internal structure of the material, causing changes in the propagation speed, amplitude and waveform.

[0059] The signal processing module provided in the embodiment of the present invention utilizes a signal processor to process the received echo signal and extract characteristic information reflecting the internal structure of the object under inspection.

[0060] The back-end image processing module provided in the embodiment of the present invention utilizes an imaging system: based on the processed signal data, an internal image of the inspected object is reconstructed through an algorithm to display the size, shape and position of defects such as cracks.

[0061] like Figure 2 As shown, another object of the present invention is to provide an ultrasonic phased array positioning and diagnostic system for a dry-type bushing capacitor core containing microcrack defects, comprising:

[0062] The front-end signal acquisition module transmits ultrasonic signals through a phased array probe. The phased array probe can flexibly control the focusing and scanning of the sound beam through electronic control. By adjusting the transmission delay of multiple channels, the sound beam can be focused in multiple directions, so that the sound waves can accurately cover different areas of the test sample and achieve comprehensive detection of the internal structure of the sample.

[0063] Secondly, the signal acquisition module transmits the ultrasonic wave from the phased array probe to the test sample through the coupling medium. The coupling medium (such as coupling fluid or coupling glue) plays the role of conducting sound energy and reducing the energy loss of sound waves caused by air resistance during transmission. When the sound wave propagates from the probe to the test sample, the coupling medium is used to achieve efficient transmission of sound energy, ensuring that the ultrasonic wave can smoothly enter the sample.

[0064] During the transmission of sound waves, the front-end signal acquisition module precisely controls the ultrasonic signal, so that the sound waves undergo mode conversion or refraction at the appropriate angle according to Snell's law. This mode conversion includes the conversion of longitudinal waves into transverse waves, or transverse waves into longitudinal waves, so that the sound waves can enter the sample in the most suitable way. This waveform mode conversion and refraction allows the ultrasonic wave to propagate at the best angle and method according to the characteristics of the sample material, thereby maximizing the effectiveness of the detection.

[0065] When receiving the reflected ultrasonic signal, the signal acquisition module can accurately capture the signal reflected by the defect or interface. According to the intensity, time and angle of the reflected signal, the module can analyze the possible defects inside the sample, such as cracks or gaps. Through this workflow, the front-end signal acquisition module provides a high-precision raw data basis for subsequent analysis and positioning.

[0066] The signal processing module is used to amplify, filter, detect and A / D convert the received echo signal to extract useful information;

[0067] Big data storage module, used to store massive test data.

[0068] The back-end image processing module is used to process these data using advanced algorithms to generate clear two-dimensional or three-dimensional images, intuitively displaying the internal structure of the inspected object.

[0069] Another object of the present invention is to provide a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core containing microcrack defects.

[0070] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, enables the processor to perform the steps of the ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core containing microcrack defects.

[0071] Another object of the present invention is to provide an information data processing terminal, which is used to implement the ultrasonic phased array positioning and diagnosis system of the dry-type bushing capacitor core containing microcrack defects.

[0072] Introduction to ultrasonic phased array principle and detection method

[0073] Ultrasonic phased array technology, as an advanced non-destructive testing technology, is based on the principle of radar electromagnetic wave phased array technology. By controlling the time delay of the excitation pulse of each array element in the transducer array, it can achieve precise control of the ultrasonic beam, including shape, axis deflection angle and focal position, etc. This technology is known for its high precision, high resolution and real-time imaging capabilities, and is particularly suitable for the detection of complex structural parts and tiny defects.

[0074] Ultrasonic phased array data processing theory

[0075] Ultrasonic phased array technology is based on the Huygens principle and the wavefront synthesis principle. It achieves the focusing and dynamic deflection of the ultrasonic beam in space by precisely controlling the excitation phase difference (denoted as Δφ) of each array element in the transducer array. The core of this technology is the beamforming algorithm, which adjusts the excitation timing of each array element so that the ultrasonic beam scans at the desired angle and position. In this process, the array element spacing (denoted as d), the wavelength of the ultrasonic wave in the medium (denoted as λ) and the beam deflection angle (denoted as θ) satisfy the geometric relationship: sin(θ) = Δφ*λ / 2πd.

[0076] At the receiving end, the echo signal is first amplified by a preamplifier, and then filtered out noise and clutter to retain useful signal components. Subsequently, digital signal processing technology, such as Delay-And-Sum (DAS) or more complex adaptive beamforming algorithms, is used to perform phase correction and signal enhancement on the received signal to improve the signal-to-noise ratio and resolution.

[0077] In the data processing stage, the fast Fourier transform (FFT) is used to perform spectrum analysis on the echo signal to obtain the frequency characteristics of the signal. At the same time, combined with the principle of time-of-flight (TOF), by measuring the time difference from ultrasonic emission to reception (denoted as Δt), the depth of the defect (denoted as z) can be calculated. The calculation formula is: z = c*Δt / 2, where c is the propagation speed of ultrasonic waves in the medium.

[0078] Finally, the processed signal is post-processed through image reconstruction algorithms (such as back-projection algorithm, synthetic aperture focusing technology, etc.) to generate the internal image of the inspected object, thereby achieving accurate positioning and size assessment of defects such as microcracks. In this process, it is necessary to accurately control various parameters to ensure the accuracy and reliability of the data.

[0079] The ultrasonic phased array system is mainly composed of a front-end signal acquisition module, a signal processing module, a big data storage module and a back-end image processing module. The front-end signal acquisition module is responsible for transmitting and receiving ultrasonic signals, and focusing and scanning the sound beam through the phased array probe. The signal processing module amplifies, filters, detects and A / D converts the received echo signal to extract useful information. The big data storage module is used to store massive amounts of detection data, while the back-end image processing module uses advanced algorithms to process these data to generate clear two-dimensional or three-dimensional images, intuitively displaying the internal structure of the object being inspected.

[0080] Function introduction of each part

[0081] Phased array probe: It is composed of multiple independent piezoelectric chips arranged according to a certain rule. The excitation timing of each chip is controlled by an electronic system to achieve the focusing and deflection of the sound beam.

[0082] Signal generator: Generates high-voltage electrical pulse signals to excite the chip in the phased array probe and emit ultrasonic beams.

[0083] Signal processor: Processes the received echo signal and extracts characteristic information reflecting the internal structure of the object being inspected.

[0084] Imaging system: Based on the processed signal data, the internal image of the inspected object is reconstructed through an algorithm to show the size, shape and location of defects such as cracks.

[0085] During the ultrasonic phased array detection process, by adjusting the excitation timing and focusing law of the array elements, scanning at different depths and directions inside the object being inspected can be achieved. When the ultrasonic beam encounters defects such as cracks, reflection, scattering and other phenomena will occur, generating specific echo signals. By analyzing these echo signals, parameters such as the depth, length and direction of the crack can be calculated. At the same time, combined with image reconstruction technology, clear two-dimensional or three-dimensional images can be generated to intuitively display the size, shape and position of the crack. In addition, by comparing the detection results at different angles and positions, the accuracy and reliability of crack diagnosis can be further improved.

[0086] In the field of electrical engineering, the dry-type bushing capacitor core is a key insulating component, and the detection and diagnosis of its internal microcrack defects are crucial to ensure the safe operation of power equipment. This paper uses epoxy impregnated paper specimens as the research object, aiming to achieve simulated detection of microcrack defects through ultrasonic phased array technology, and then verify the effectiveness of this method. This section describes in detail the preparation process of epoxy impregnated paper specimens, especially the preparation method of cracked specimens and their equivalence with glue-impregnated paper bushings in testing.

[0087] Epoxy impregnated paper was selected as the equivalent model in this study because of its similarity with the rubber impregnated paper bushing in terms of material composition, insulation performance and manufacturing process. By simulating the microcrack defects inside the bushing, that is, introducing cracks of predetermined size and depth into the epoxy impregnated paper sample, the damage that may occur to the actual bushing during long-term use can be more realistically reflected. Therefore, the response characteristics of the cracked epoxy impregnated paper sample prepared in this paper in ultrasonic phased array testing can be regarded as an effective prediction and verification of the internal microcrack detection of the rubber impregnated paper bushing.

[0088] In order to fully evaluate the detection capability of ultrasonic phased array technology for microcrack defects, a variety of cracks of different sizes and depths were set in this study. As shown in the figure, the crack depth ranges from 2mm to 5mm, and the size is 0.15mm and 0.3mm thick. It should be noted that this schematic diagram only illustrates the size and depth of the crack defect. The crack settings exist separately in each defective sample, not in the same sample. By precisely controlling the size and embedding position of the PTFE film, the precise setting of the crack size and depth is achieved.

[0089] Material preparation: Select high-quality crepe paper as the substrate to ensure that it has good flexibility and insulation properties. At the same time, prepare epoxy resin and its curing agent, mix them evenly in a certain proportion and set aside. In addition, according to the experimental design, prepare polytetrafluoroethylene (PTFE) films of different sizes and thicknesses as crack simulation materials.

[0090] Crack pre-embedding: First, the crepe paper is stacked in a predetermined number of layers, and the cut PTFE film is embedded between specific layers to simulate cracks of different depths and lengths. To ensure the accuracy and stability of the cracks, the embedding position and size of the PTFE film must be precisely controlled.

[0091] Epoxy impregnation: Place the pre-cracked corrugated paper into the epoxy resin impregnation tank and fully impregnate to ensure that the resin completely penetrates between the paper layers and wraps the PTFE film. Then, take out the impregnated sample, remove the excess resin, and place it in a dry and ventilated place for preliminary curing.

[0092] Curing and molding: Put the initially cured sample into an oven and heat and cure it according to the predetermined curing process curve to fully cross-link and cure the epoxy resin to form a hard insulator. The temperature and time must be strictly controlled during the curing process to ensure the stability and consistency of the sample performance.

[0093] Sample processing: After curing is completed, the sample is subjected to necessary post-processing, such as grinding and cleaning, to remove surface defects and impurities for subsequent ultrasonic phased array testing.

[0094] Testing process

[0095] Select the ultrasonic equipment CTS-PA22B type maintenance wheel rim phased array ultrasonic detector. Its specific parameters are shown in the table below. Connect the phased array probe 4L16-1.0*10-C10, select the SC10-N0L longitudinal wave wedge, install the wedge on the probe, create a new file, set the workpiece thickness to 3mm, the longitudinal wave sound velocity to 3000, select 4 for the aperture, set the focal length to the workpiece thickness value of 6mm, and the sound path range is generally set to 1.2 times the workpiece thickness. To set a certain threshold, set it to 10mm, save the file, and click Test. Before the test, evenly apply the ultrasonic coupling agent on the workpiece, and use the wedge to slide on the workpiece at a constant force and uniform speed to obtain the test results.

[0096] Table 1 shows the specific parameters of the CTS-PA22B phased array ultrasonic detector for locomotive wheel rims

[0097]

[0098]

[0099] Test results such as Figure 4 As shown in the figure, the phased array ultrasonic equipment can effectively detect the prefabricated crack defects. By observing the figure, it can be concluded that the positions of the defects are basically consistent with the position and size of the pre-embedded polytetrafluoroethylene film. Affected by the molding process, the double-layer polytetrafluoroethylene film may have a slight deviation, with the maximum deviation value being 6.67% and the minimum deviation value being 2.0%. The overall deviation of the prefabricated defects of the test block is small, meeting the expected requirements.

[0100] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. An ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core with microcrack defects, characterized in that: The following steps are involved: Step 1: The front-end signal acquisition module is responsible for transmitting and receiving ultrasonic signals, and the phased array probe is used to focus and scan the sound beam; Step 2, amplifying, filtering, detecting and A / D converting the received echo signal through the signal processing module to extract useful information; Step 3: Store massive amounts of test data through a big data storage module. Step 4: Use advanced algorithms to process these data through the back-end image processing module to generate clear two-dimensional or three-dimensional images to intuitively display the internal structure of the inspected object.

2. The ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core with microcrack defects as claimed in claim 1, characterized in that: The phased array probe is composed of a plurality of independent piezoelectric chips arranged according to a certain rule, and the excitation timing of each chip is controlled by an electronic system to achieve the focusing and deflection of the sound beam.

3. The ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core with microcrack defects as claimed in claim 1, characterized in that: The front-end signal acquisition module includes: a signal generator: generates a high-voltage electric pulse signal to excite the chip in the phased array probe and emit an ultrasonic beam.

4. The ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core with microcrack defects as claimed in claim 1, characterized in that: The ultrasonic signal needs to use an ultrasonic generator to generate a high-frequency ultrasonic signal; Ultrasonic signals are generated by electronic devices and transmitted to the insulating material to be tested; when the ultrasonic wave enters the insulating material, it is disturbed by the internal structure of the material, causing changes in the propagation speed, amplitude and waveform.

5. The ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core with microcrack defects as claimed in claim 4, characterized in that: The signal processing module utilizes a signal processor to process the received echo signal and extract characteristic information reflecting the internal structure of the object under inspection.

6. The ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core with microcrack defects as claimed in claim 1, characterized in that: The back-end image processing module utilizes an imaging system to reconstruct the internal image of the inspected object through an algorithm based on the processed signal data, and to display the size, shape and position of defects such as cracks.

7. An ultrasonic phased array positioning and diagnosis system for a dry-type bushing capacitor core containing microcrack defects, which implements the ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core containing microcrack defects as claimed in any one of claims 1 to 6, characterized in that: The ultrasonic phased array positioning and diagnosis system for a dry-type bushing capacitor core containing microcrack defects comprises: The front-end signal acquisition module is responsible for transmitting and receiving ultrasonic signals, and realizing the focusing and scanning of the sound beam through the phased array probe; The signal processing module is used to amplify, filter, detect and A / D convert the received echo signal to extract useful information; Big data storage module, used to store massive test data. The back-end image processing module is used to process these data using advanced algorithms to generate clear two-dimensional or three-dimensional images, intuitively displaying the internal structure of the inspected object.

8. A computer device, characterized in that: The computer device includes a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core containing microcrack defects as described in any one of claims 1 to 6.

9. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of the ultrasonic phased array positioning and diagnosis method for a dry-type bushing capacitor core containing microcrack defects according to any one of claims 1 to 6.

10. An information data processing terminal, characterized in that: The information data processing terminal is used to implement the ultrasonic phased array positioning and diagnosis system for the dry-type bushing capacitor core containing microcrack defects as described in claim 7.

Images