An epoxy insulator deep defect phased array ultrasonic detection method, system, device and medium

Abstract

This invention relates to the field of non-destructive testing technology for insulating equipment, and particularly to a phased array ultrasonic testing method, system, equipment, and medium for deep defects in epoxy resin insulators. The method includes: obtaining measured equivalent sound velocity parameters matching the epoxy resin insulator under test; acquiring the element position parameters of the phased array probe and capturing ultrasonic echo data across the entire matrix, and dividing the detection area into grids; defining the grid points participating in imaging and the effective time range of the ultrasonic echo data based on the search depth range; determining the total propagation time corresponding to each transmitting and receiving array element combination for each participating grid point based on the element position parameters, grid point positions, and equivalent sound velocity parameters; determining the sampling positions corresponding to the propagation time within the effective time range, and interpolating sampling for non-integer sampling positions; performing time-delayed focusing superposition on the sampled signals of each transmitting and receiving array element combination to obtain the imaging amplitude of each grid point, and obtaining the deep defect detection result based on the imaging amplitude.

Description

Technical Field

[0001] This invention relates to the technical field of non-destructive testing of insulating equipment, and in particular to a phased array ultrasonic testing method, system, equipment and medium for deep defects in epoxy resin insulators. Background Technology

[0002] Epoxy resin insulators are critical insulation components in power equipment. Defects such as porosity and inclusions can develop internally during casting, curing, assembly, and service, affecting their mechanical strength and insulation performance. Existing X-ray, industrial CT, partial discharge, and conventional ultrasonic testing methods have limitations in terms of equipment cost, field applicability, spatial positioning, and image display. Phased array ultrasound, combining full-matrix capture and full-focus imaging, can utilize multi-element transmission and reception information to perform time-delayed superimposed imaging of the inspection area.

[0003] However, existing full-focus imaging typically employs a fixed sound velocity and simple time-delay calculations. For epoxy resin insulators with high attenuation, thick walls, and significant dispersion in acoustic parameters, when the sound velocity is inaccurate, the search depth is set improperly, or the sampling delay is too coarse, the actual defect echo cannot accurately correspond to the calculated propagation time, easily leading to focus offset, positioning errors, boundary blurring, and insufficient coherent superposition of deep echoes. Simultaneously, the echoes from deep defects are weak, and background scattering and structural noise further affect defect identification.

[0004] Therefore, there is an urgent need to provide a phased array ultrasonic testing method that matches the actual acoustic characteristics of epoxy resin insulators. This method can improve the focusing imaging and localization results of deep defects by coordinating the processing of equivalent sound velocity, propagation time, search depth, and sampling position. Summary of the Invention

[0005] This invention provides a phased array ultrasonic testing method, system, equipment, and medium for deep defects in epoxy resin insulators that can reduce propagation time calculation and sampling quantization errors, reduce non-target depth echo interference, and improve the stability of deep defect focusing imaging. It can effectively solve the problems in the background art.

[0006] To achieve the above objectives, the technical solution adopted by this invention is: a phased array ultrasonic testing method for deep defects in epoxy resin insulators, comprising the following steps: Equivalent sound velocity parameters matching the epoxy resin insulator under test were obtained through actual measurement; the array element position parameters of the phased array probe and the full matrix capture ultrasonic echo data were acquired, and the detection area was divided into grids. The effective time range of the ultrasonic echo data is limited based on the search depth range, which restricts the grid points involved in imaging. For each grid point involved in imaging, the total propagation time corresponding to each transmit-receive array element combination is determined based on the array element position parameters, grid point positions, and equivalent sound velocity parameters; Within the effective time range, determine the sampling positions corresponding to the total propagation time, and perform interpolation sampling on non-integer sampling positions; The sampled signals from each transmit and receive array element combination are delayed, focused, and superimposed to obtain the imaging amplitude of each grid point, and the deep defect detection result is obtained based on the imaging amplitude.

[0007] Furthermore, the measured equivalent sound velocity parameters that match the epoxy resin insulator under test include: The thickness of the epoxy resin insulator to be tested is measured, and the echo time of the longitudinal wave bottom surface or the echo time of the transverse wave bottom surface is obtained by pulse echo method. The longitudinal wave velocity or transverse wave velocity is determined based on the thickness and the corresponding bottom surface echo time, and the corresponding longitudinal wave velocity or transverse wave velocity is determined as the equivalent sound velocity parameter according to the propagation waveform used in phased array ultrasonic testing.

[0008] Furthermore, the calculation expression for the longitudinal wave velocity is as follows: ; In the formula, For longitudinal wave sound speed, This refers to the thickness of the epoxy resin insulator. The echo time at the bottom of the longitudinal wave; The expression for calculating the transverse wave velocity is: ; In the formula, For transverse wave sound speed, The echo time at the bottom of the transverse wave is denoted as .

[0009] Furthermore, the search depth range is determined based on the thickness of the epoxy resin insulator to be detected, the target detection area, the near-field interference area, and the bottom echo position; grid points whose depth positions are within the search depth range are determined as grid points participating in imaging, and the effective time range for participating in time-delay sampling in the full matrix capture ultrasonic echo data is limited according to the search depth range.

[0010] Furthermore, the method for obtaining the total propagation time includes: For any grid point participating in imaging, the direct propagation distance from each array element to the grid point is determined based on the grid point position parameters and the position parameters of each array element. Based on the direct propagation distance and the equivalent sound velocity parameters that match the epoxy resin insulator to be tested, the one-way propagation time from each array element to the grid point is determined. The one-way propagation time is repeatedly calculated for each grid point and each array element involved in imaging, and the propagation time matrix of the array element grid points is established. For any grid point participating in imaging and any combination of transmit and receive array elements, the one-way propagation time from the transmit array element to the grid point and from the grid point to the receive array element is obtained from the propagation time matrix. The total propagation time of the transmit and receive array elements corresponding to the grid point is obtained by adding the one-way propagation time from the transmit and receive array elements to the grid point.

[0011] Furthermore, the expression for calculating the direct propagation distance is: ; In the formula, Indicates the direct transmission distance. and They represent the first The horizontal and depth positions of each array element and Representing grid points respectively The horizontal and depth positions.

[0012] Furthermore, the expression for calculating the one-way propagation time is as follows: ; In the formula, Indicates the first Individual elements to grid points One-way transmission time, This represents the equivalent speed of sound parameter.

[0013] Furthermore, the total propagation time is: ; In the formula, Indicates the total propagation time. Indicates the launch array element To grid point One-way transmission time, Represents grid points To the receiving array element The one-way transmission time.

[0014] Furthermore, the method for obtaining the deep defect detection results includes: For any grid point participating in imaging, a transmitting element is fixed, and the sampled signals of each receiving channel corresponding to the transmitting element are accumulated to obtain the partial beamforming signal corresponding to the transmitting element. The sign-preserving square root amplitude compression of each part of the beamforming signal is performed to obtain the compressed partial beamforming signal; The compressed beamforming signals corresponding to each transmitting array element are summed together to obtain the imaging amplitude of the current grid point. By traversing all grid points involved in imaging, the imaging amplitude of each grid point is obtained, and the imaging amplitude is normalized and grayscale mapped to obtain the phased array ultrasonic detection results of deep defects.

[0015] Furthermore, the expression for calculating the imaging amplitude of the grid points is as follows: ; In the formula, The imaging amplitude of the current grid point. This is a compressed portion of the beamforming signal. Indicates the first Each phased array element serves as a transmitting element. This represents the total number of transmitting array elements involved in the imaging calculation.

[0016] This invention also provides a phased array ultrasonic testing system for deep defects in epoxy resin insulators, comprising: The data acquisition and mesh generation module obtains the equivalent sound velocity parameters that match the epoxy resin insulator under test through actual measurement; acquires the array element position parameters of the phased array probe and the full matrix capture of ultrasonic echo data, and performs mesh generation on the detection area; The effective imaging range constraint module limits the grid points participating in imaging and the effective time range of the ultrasonic echo data based on the search depth range. The propagation time calculation module determines the total propagation time for each combination of transmitting and receiving array elements based on the array element position parameters, grid point positions, and equivalent sound velocity parameters for each grid point involved in imaging. An ultrasonic signal interpolation sampling module determines the sampling position corresponding to the propagation time within the effective time range, and performs interpolation sampling on non-integer sampling positions; The defect detection module performs delayed focusing and superposition of the sampled signals from each transmit and receive array element combination to obtain the imaging amplitude of each grid point, and obtains the deep defect detection result based on the imaging amplitude.

[0017] The present invention also provides an electronic device, including a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the phased array ultrasonic detection method for deep defects in epoxy resin insulators as described in any of the preceding claims.

[0018] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the phased array ultrasonic detection method for deep defects in epoxy resin insulators as described in any of the preceding claims.

[0019] The technical solution of this invention can achieve the following technical effects: By characterizing epoxy resin insulators as homogeneous or angle-dependent equivalent homogeneous acoustic media, and establishing an acoustic parameter model matching the object under test using measured sound velocities or angle-dependent equivalent sound velocities, the influence of empirical sound velocity deviations on propagation time calculation, defect location, and focusing imaging can be reduced. By establishing the propagation time matrix of array element grid points and the search depth propagation angle equivalent sound velocity matrix, a unified parameter basis is provided for subsequent propagation time calls and imaging calculations. By limiting the effective imaging area and effective sampling time range by the search depth range, the participation of near-field coupling signals, surface direct waves, and non-target depth echoes in focusing calculations can be reduced. By accumulating the corresponding receiving channels one by one according to the transmitting array element, and combining linear interpolation of non-integer sampling positions, the sampling positions of each transmitting and receiving array element combination correspond to the calculated propagation time, reducing the time quantization deviation caused by discrete sampling. On this basis, by processing the focusing results through Hilbert transform enhancement, sign-preserving amplitude compression, normalization, and grayscale mapping, the influence of strong reflection and background scattering on the dynamic range of the image can be weakened, so that the echo response corresponding to deep defects can be stably characterized in the imaging results. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A flowchart of a phased array ultrasonic testing method for deep defects in epoxy resin insulators; Figure 2 Comparison of single-pore defect imaging obtained by conventional full-focusing method and by the method of the present invention; Figure 3 This is a comparative imaging image of a single pore defect at another detection location or under another parameter condition; Figure 4 Comparison of images of multi-pore defects under different detection areas; Figure 5 Comparison of images of multi-pore defects at different processing stages; Figure 6 This is a structural diagram of a phased array ultrasonic testing system for deep defects in epoxy resin insulators. Figure 7 This is a schematic diagram of the structure of the computer electronic device in this invention. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0023] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] like Figure 1 The method for phased array ultrasonic testing of deep defects in epoxy resin insulators, as shown, includes the following steps: S1. Obtain the equivalent sound velocity parameters that match the epoxy resin insulator under test by actual measurement; acquire the array element position parameters of the phased array probe and the full matrix capture ultrasonic echo data, and divide the detection area into grids. S2. The effective time range of the ultrasonic echo data and the grid points participating in imaging are limited based on the search depth range. S3. For each grid point involved in imaging, determine the propagation time corresponding to each transmit and receive array element combination based on the array element position parameters, grid point positions, and equivalent sound velocity parameters. S4. Within the effective time range, determine the sampling position corresponding to the propagation time, and perform interpolation sampling on non-integer sampling positions; S5. Delay and focus the sampling signals of each transmit and receive array element combination to obtain the imaging amplitude of each grid point, and obtain the deep defect detection result based on the imaging amplitude.

[0026] In this embodiment, by characterizing the epoxy resin insulator as a homogeneous or angle-dependent equivalent homogeneous acoustic medium, and establishing an acoustic parameter model matching the object under test using measured sound velocity or angle-dependent equivalent sound velocity, the influence of empirical sound velocity deviation on propagation time calculation, defect location, and focusing imaging can be reduced. By establishing the propagation time matrix of array element grid points and the search depth propagation angle equivalent sound velocity matrix, a unified parameter basis is provided for subsequent propagation time retrieval and imaging calculation. By limiting the effective imaging area and effective sampling time range by the search depth range, the participation of near-field coupling signals, surface direct waves, and non-target depth echoes in focusing calculation can be reduced. By accumulating the corresponding receiving channels one by one according to the transmitting array element, and combining linear interpolation of non-integer sampling positions, the sampling position of each transmitting and receiving array element combination corresponds to the calculated propagation time, reducing the time quantization deviation caused by discrete sampling. On this basis, by processing the focusing results through Hilbert transform enhancement, sign-preserving amplitude compression, normalization, and grayscale mapping, the influence of strong reflection and background scattering on the dynamic range of the image can be weakened, so that the echo response corresponding to deep defects can be stably characterized in the imaging results.

[0027] Based on the above embodiments, the thickness of the epoxy resin insulator to be tested is measured. Ultrasonic waves are emitted into the epoxy resin insulator using a pulse-echo method, and the bottom echo returned from the bottom surface of the insulator is received. When longitudinal wave detection is used, the bottom echo time of the longitudinal wave is recorded, and the longitudinal wave velocity is calculated according to the correspondence between the two-way propagation distance and propagation time. The expression for calculating the longitudinal wave velocity is: ; In the formula, For longitudinal wave sound speed, This refers to the thickness of the epoxy resin insulator. The echo time at the bottom of the transverse wave; When using shear wave detection, record the echo time at the bottom of the shear wave and calculate the shear wave velocity. The expression is: ; In the formula, For longitudinal wave sound speed, This refers to the thickness of the epoxy resin insulator. The echo time at the bottom of the transverse wave; Based on the propagation waveform used in phased array ultrasonic testing, the corresponding measured longitudinal wave velocity or measured transverse wave velocity is determined as the equivalent sound velocity parameter of the epoxy resin insulator to be tested. The total number of array elements, the spacing between array elements, and the position parameters of each array element are obtained. The position parameters of each array element are determined according to the array structure of the phased array probe, and a correspondence is established between the array element number and the transmission and reception channels in the subsequent full matrix acquisition data, so that each transmission array element and each reception array element has a definite spatial position. The phased array probe is directly coupled to the surface of the epoxy resin insulator under test, and ultrasonic echo data is acquired using a full matrix capture method. During the acquisition process, each array element is used as a transmitting element in sequence. When any array element transmits, all array elements synchronously receive the ultrasonic echo signal. After all array elements have transmitted in sequence, full matrix capture data with a correspondence between the transmitting array element index and the receiving array element index is obtained. When acquiring full matrix capture data, the corresponding sampling frequency is recorded at the same time to establish the correspondence between the sampling point and the ultrasonic propagation time. The detection area is discretized according to its lateral and depth positions, and any imaging grid point is represented as... ,in, Indicates the lateral position of the grid point. Indicates the depth position of the grid point.

[0028] In this embodiment, the equivalent sound velocity parameter is derived from the pulse echo measurement of the epoxy resin insulator to be tested, which can reduce the impact of the sound velocity value deviation caused by directly using the empirical sound velocity constant on the subsequent propagation time calculation; the array element position and the grid point position constitute the spatial parameters required for propagation path calculation; the full matrix capture data saves the time domain echo corresponding to each transmit-receive array element combination, providing received data for subsequent delay sampling and focusing superposition based on propagation time.

[0029] Based on the above embodiments, the search depth range is determined according to the thickness of the epoxy resin insulator to be tested, the target detection area, the near-field interference area, and the bottom echo position. The search depth range is set within the actual thickness range of the insulator, and avoids the near-field area and the area corresponding to the bottom echo that are not the target of this defect detection. Read the depth coordinates of each grid point obtained from the mesh generation Grid points whose depth coordinates are within the set search depth range are identified as grid points participating in imaging, while grid points whose depth coordinates are outside the search depth range are excluded from subsequent propagation time calculation and time-delay focusing processing. The effective time range corresponding to the search depth range in the full matrix capture ultrasound echo data is determined based on the search depth range. The effective time range covers the sampling period corresponding to the target echo within the search depth range, and excludes the sampling period corresponding to near-field coupling signals, surface direct signals, and echoes outside the search depth range. For each transmit-receive array element combination, the effective time range of its full matrix acquisition data is retained, and the original transmit element index, receive element index, and sampling order of each channel are not changed in this step. Subsequently, after determining the propagation time for the grid points participating in imaging, the corresponding receive data is called for delayed sampling only when the sampling position corresponding to the corresponding propagation time is within the effective time range. Sampling data outside the effective time range does not participate in the focusing calculation of the grid point.

[0030] In this embodiment, the search depth range simultaneously forms both spatial and temporal constraints. The spatial constraints are used to determine the set of grid points participating in imaging, while the temporal constraints are used to determine the sampling intervals in the full matrix capture data that are allowed to participate in subsequent time-delay sampling. Both use the same search depth range as the limiting basis, so that the subsequent propagation time calculation and echo sampling are concentrated in the target depth region, and the near-field coupling signal, surface direct signal and non-target depth echo enter the focusing and superposition process.

[0031] Based on the above embodiments, for any grid point participating in imaging, its position parameters are read. and read the first Position parameters of each phased array element The position of the first element is determined based on the position of the array element and the position of the grid point. Individual elements to grid points The direct propagation distance, the propagation distance calculation expression is: ; In the formula, Indicates the direct transmission distance. and They represent the first The horizontal and depth positions of each array element and Representing grid points respectively The lateral and depth positions; the direct propagation distance characterizes the geometric length of the direct acoustic path between the corresponding array element and the current grid point; The equivalent sound velocity parameters, matched to those of the epoxy resin insulator under test, are used to determine the first [instrument / type] based on the direct propagation distance. Individual elements to grid points The one-way propagation time is expressed as: ; In the formula, Indicates the first Individual elements to grid points One-way transmission time, Indicates the direct transmission distance. Represents the equivalent speed of sound parameter; The above calculations are performed on each grid point involved in imaging and each element of the phased array probe to establish the propagation time correspondence between the array elements and the grid points. This correspondence is stored in an array element-grid point propagation time matrix, where each matrix element corresponds to the one-way propagation time from an array element to a grid point. For any transmitting element, any receiving element, and the current grid point in the full matrix capture data, obtain the one-way propagation time from the transmitting element to the grid point and the one-way propagation time from the grid point to the receiving element from the element-grid-point propagation time matrix; add the two one-way propagation times to determine the total propagation time of the propagation path formed by the transmitting element, the grid point, and the receiving element: ; In the formula, Indicates the total propagation time. Indicates the launch array element To grid point One-way transmission time, Represents grid points To the receiving array element The one-way propagation time; the total propagation time corresponds to the propagation time required for the ultrasonic wave to travel from the transmitting element to the current grid point and back from the current grid point to the receiving element; Based on the correspondence between each participating imaging grid point, each transmitting array element, and each receiving array element, the total propagation time is repeatedly determined so that each participating imaging grid point has a propagation time corresponding to the combination of each transmitting and receiving array element; a time correspondence is established between the transmitting channel, receiving channel in the full matrix capture data and the grid points in the detection area.

[0032] In this embodiment, the propagation time is not based on a uniform preset delay for all array elements, but is determined by the array element position, the current grid point position, and the equivalent sound velocity of the epoxy resin insulator to be tested. The array element position and grid point position determine the ultrasonic propagation path length, while the equivalent sound velocity determines the propagation time corresponding to that path. Therefore, different transmit / receive array element combinations have a total propagation time corresponding to their respective propagation paths for the same grid point, providing a time basis for subsequently obtaining echo signals corresponding to the same grid point from each channel. The array element-grid point propagation time matrix stores the single-trip propagation time and allows different transmit-receive array element combinations to call upon the already determined propagation time between the same array element and grid point, reducing redundant calculations of the same array element-grid point propagation relationship.

[0033] Based on the above embodiments, when the equivalent sound velocity of the epoxy resin insulator changes with the direction of ultrasonic propagation, if the same equivalent sound velocity is used for different propagation directions, the propagation time from the array element to different grid points will be calculated according to the same sound velocity parameter, which is difficult to reflect the difference in equivalent sound velocity corresponding to the change in propagation direction. In view of this situation, this embodiment uses angle-related equivalent sound velocity to determine the one-way propagation time from the array element to the grid point. For any grid point involved in imaging and the first For each array element, the propagation direction from the element to the grid point is determined based on the element's position and the grid point's position, and the corresponding propagation angle is calculated: ; Based on the calculated propagation angle, the equivalent sound velocity corresponding to the propagation angle is called from the pre-established equivalent sound velocity correspondence relationship of the propagation angle; when the same array element corresponds to different grid points, the corresponding equivalent sound velocity parameters can be adopted according to their respective propagation directions, rather than uniformly adopting the same sound velocity value for all propagation paths. Based on the direct propagation distance from the array element to the grid point and the equivalent sound speed corresponding to the propagation angle, determine the first... One-way propagation time from an array element to a grid point: ; The above processing is performed on each phased array element and each grid point participating in imaging to obtain the one-way propagation time corresponding to the propagation path of each array element grid point; subsequently, for any transmitting array element and any receiving array element, the one-way propagation time corresponding to the current grid point is called respectively, and the total propagation time of the corresponding transmitting and receiving array element combination is determined in the aforementioned manner.

[0034] Based on the above embodiments, for any grid point participating in imaging and any transmit-receive array element combination corresponding to that grid point, the total propagation time is read, and it is determined whether the sampling time corresponding to the total propagation time is within the effective time range. For the total propagation time within the effective time range, its sampling position in the corresponding transmit / receive channel is determined based on the sampling frequency of the full matrix capture data and the system delay compensation amount; the sampling position corresponding to the total propagation time is: ; In the formula, This is the compensation amount for system zero-point delay, probe delay, or equivalent delay of coupling layer. The sampling frequency; When the sampling position is an integer, the signal amplitude corresponding to the integer sampling position is read as the sampling result of the current transmit-receive array element combination for the current grid point; When the sampling position is not an integer, it is represented as ,in, The integer sampling point number is not greater than the sampling position. This is the fractional offset of the sampling position relative to the integer sampling point, and Read sampling points With adjacent sampling points The amplitude of a signal of 1 is obtained by linear interpolation. The linear interpolation formula is as follows: ; In the formula, For the first The signal amplitude at each sampling point For the first The signal amplitude at one sampling point, This represents the interpolated amplitude at the non-integer sampling position corresponding to the total propagation time.

[0035] In this embodiment, the propagation time corresponding to each transmit-receive array element combination is used as the sampling basis, and the effective time range limited by the search depth is used to constrain the data that can participate in the sampling. When the propagation time is mapped to a non-integer sampling position, the signal amplitude corresponding to that position is determined by linear interpolation of adjacent sampling points. This avoids the sampling delay quantization deviation caused by using the nearest neighbor integer sampling point, thereby ensuring a more accurate time correspondence between the sampling signal provided for subsequent delay focusing and superposition and the calculated propagation time.

[0036] Based on the above embodiments, for any grid point participating in imaging, one transmitting element is fixed, and the sampled signals corresponding to the combination of the transmitting element and each receiving element at that grid point are read sequentially; the sampled signals of all receiving channels corresponding to the same transmitting element are accumulated, and the accumulated result is used as the partial beamforming signal of the transmitting element at the current grid point; the remaining transmitting elements are processed in the same way to obtain the partial beamforming signals corresponding to each transmitting element at the current grid point, and the beamforming signal calculation expression is: ; In the formula, For the first Each element is launched, the first The full matrix capture time-domain signal received by each array element is enhanced by Hilbert transform, filtered, or enveloped, and then sampled at the corresponding propagation time. Each sampled signal corresponds to the propagation time determined by its respective transmit-receive propagation path for the current grid point. Through the above accumulation, the sampled results of different receive channels under the same transmit array element for the current grid point are aggregated to that grid point. Each transmitting element is processed sequentially in the same manner to obtain the partial beamforming signal corresponding to each transmitting element. This embodiment performs sign-preserving square root amplitude compression on each part of the beamforming signal; for the first... The partial beamforming signal corresponding to each transmitting element, the compressed partial beamforming signal is: ; in, The sign function is used to retain the positive and negative signs of some beamforming signals while reducing the numerical range between signals of different amplitudes, thus reducing the dominance of strong reflection signals on the dynamic range of subsequent image display. The compressed beamforming signals corresponding to all transmitting array elements are summed to obtain the imaging amplitude of the current grid point: ; Each participating imaging grid point obtains a corresponding imaging amplitude; for implementations that do not employ amplitude compression, the partial beamforming signals corresponding to each transmitting array element can also be directly accumulated as a whole, and the accumulated result can be used as the imaging amplitude of the corresponding grid point. The imaging amplitude set of each grid point is obtained by traversing all grid points involved in imaging in the above manner; the corresponding imaging amplitudes are arranged according to the spatial position of each grid point, and the imaging amplitudes are normalized to convert the amplitudes of different grid points to a uniform display scale; then grayscale mapping is performed according to the normalized imaging amplitudes to generate a two-dimensional phased array ultrasound imaging result corresponding to the spatial position of the detection area.

[0037] In this embodiment, the obtained imaging results characterize the ultrasonic reflection response at the corresponding spatial location using the imaging amplitude of each grid point, displaying the imaging area corresponding to the deep defects inside the epoxy resin insulator to be tested. Since each sampled signal involved in focusing has been obtained according to the propagation time corresponding to each transmission and reception propagation path, focusing and superimposing these sampled signals at the same grid point enables the echoes corresponding to the propagation time of that grid point to jointly form the imaging response of that grid point. The sign-preserving square root compression further limits the influence of strong reflection signals on the display dynamic range, making the overall accumulated imaging amplitude suitable for subsequent normalization and image mapping.

[0038] Based on the above embodiments, a phased array ultrasonic system is used to test epoxy resin insulator samples. The samples are equipped with single pore defects and group pore defects. Before testing, the thickness of the epoxy resin insulator is measured first, and the bottom surface echo time is obtained by longitudinal wave or transverse wave pulse echo method, and the sound velocity parameters of the epoxy resin material are calculated. During the testing process, the phased array probe is directly coupled to the surface of the epoxy resin insulator, and data is acquired using a full matrix capture method. Each element of the phased array probe is used as a transmitting element in sequence, and all elements are used as receiving elements to obtain an A-scan time-domain signal containing information on the combination of transmitting and receiving elements. The testing area is divided into imaging grids according to the lateral and depth positions, with the grid spacing set to 0.1mm to 0.2mm. The search depth range covers the areas where single pore defects and group pore defects are located. During imaging, the direct propagation distance from the array element to the grid point is first calculated based on the equivalent sound velocity of epoxy resin, the array element coordinates, and the grid point coordinates, and an array element-grid point propagation time matrix is ​​established. Then, according to the per-transmit array element accumulation method, delay sampling, linear interpolation, and Hilbert transform enhancement are performed on all receiving channels corresponding to each transmitting array element. Subsequently, the partial beamforming signals corresponding to each transmitting array element are subjected to sign-preserving square root compression, overall accumulation, and normalization to obtain the final imaging result. like Figure 2 As shown, in conventional imaging results, the amplitude response of the defect area is weak, the background scattering signal is obvious, and the defect boundary is poorly distinguishable. After using the method of the present invention, the single pore defect location shows an isolated and compact high amplitude response, the defect boundary is clearer, and the background noise is significantly reduced. like Figure 3 As shown, the method of the present invention can still stably enhance the defect echo under different detection conditions. The defect morphology presents as a high-amplitude region that is approximately circular or elliptical, which is consistent with the acoustic scattering characteristics of porosity defects. like Figures 4 to 5 As shown, in conventional imaging methods, multiple pore defects are easily affected by background noise and sidelobe interference, and local defect boundaries are overlapped. After adopting the method of the present invention, multiple pore defects can form independent high-amplitude responses, and the defect spacing and distribution pattern are clearer, which is conducive to identifying the location, number and spatial distribution characteristics of group pore defects. To quantitatively evaluate the imaging results, the defect amplitude Ad is read at the defect peak location, and the background noise amplitude An is selected in the defect-free area behind or adjacent to the defect. The signal-to-noise ratio is then calculated using the following formula: ; Meanwhile, the lateral amplitude curve is extracted at the depth of the defect, and the lateral resolution is evaluated by the width at which the peak value drops to a set threshold. The improvement effect of the method of the present invention in displaying deep defects, suppressing background noise, and improving positioning accuracy is verified by indicators such as defect amplitude, background noise amplitude, signal-to-noise ratio, and lateral resolution.

[0039] like Figure 6 As shown, the present invention also provides a phased array ultrasonic testing system for deep defects in epoxy resin insulators, which specifically includes the following modules; The data acquisition and mesh generation module obtains the equivalent sound velocity parameters that match the epoxy resin insulator under test through actual measurement; acquires the array element position parameters of the phased array probe and the full matrix capture of ultrasonic echo data, and performs mesh generation on the detection area; The effective imaging range constraint module limits the grid points participating in imaging and the effective time range of the ultrasonic echo data based on the search depth range. The propagation time calculation module determines the total propagation time for each combination of transmitting and receiving array elements based on the array element position parameters, grid point positions, and equivalent sound velocity parameters for each grid point involved in imaging. An ultrasonic signal interpolation sampling module determines the sampling position corresponding to the propagation time within the effective time range, and performs interpolation sampling on non-integer sampling positions; The defect detection module performs delayed focusing and superposition of the sampled signals from each transmit and receive array element combination to obtain the imaging amplitude of each grid point, and obtains the deep defect detection result based on the imaging amplitude.

[0040] like Figure 7 As shown, the present invention also provides an electronic device, characterized in that it includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps of the phased array ultrasonic detection method for deep defects in epoxy resin insulators as described above, including the following steps: obtaining equivalent sound velocity parameters matching the epoxy resin insulator to be detected by actual measurement; acquiring the array element position parameters of the phased array probe and the full matrix capture ultrasonic echo data, and dividing the detection area into grids; defining the grid points participating in imaging and the effective time range of the ultrasonic echo data based on the search depth range; for each grid point participating in imaging, determining the total propagation time corresponding to each transmitting and receiving array element combination based on the array element position parameters, the grid point position, and the equivalent sound velocity parameters; determining the sampling position corresponding to the propagation time within the effective time range, and performing interpolation sampling on non-integer sampling positions; performing time-delayed focusing superposition on the sampling signals of each transmitting and receiving array element combination to obtain the imaging amplitude of each grid point, and obtaining the deep defect detection result based on the imaging amplitude.

[0041] This invention also provides a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the steps of the phased array ultrasonic detection method for deep defects in epoxy resin insulators as described in any of the preceding claims, including the following steps: obtaining equivalent sound velocity parameters matching the epoxy resin insulator to be tested; acquiring the element position parameters of the phased array probe and the full matrix capture ultrasonic echo data, and dividing the detection area into grids; defining the grid points participating in imaging and the effective time range of the ultrasonic echo data based on the search depth range; for each grid point participating in imaging, determining the total propagation time corresponding to each transmitting and receiving array element combination based on the element position parameters, grid point positions, and equivalent sound velocity parameters; determining the sampling positions corresponding to the propagation time within the effective time range, and performing interpolation sampling on non-integer sampling positions; performing time-delayed focusing superposition on the sampling signals of each transmitting and receiving array element combination to obtain the imaging amplitude of each grid point, and obtaining the deep defect detection result based on the imaging amplitude.

[0042] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. "A plurality of" means two or more, unless otherwise explicitly specified.

[0043] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0044] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0045] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as will be understood by those skilled in the art to which embodiments of the invention pertain.

[0046] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0047] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0048] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0049] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for the ultrasonic testing of deep defects in an epoxy resin insulator using a phased array, characterized in that, Includes the following steps: Equivalent sound velocity parameters matching the epoxy resin insulator under test were obtained through actual measurement; the array element position parameters of the phased array probe and the full matrix capture ultrasonic echo data were acquired, and the detection area was divided into grids. The effective time range of the ultrasonic echo data is limited based on the search depth range, which restricts the grid points involved in imaging. For each grid point involved in imaging, the total propagation time corresponding to each transmit-receive array element combination is determined based on the array element position parameters, grid point positions, and equivalent sound velocity parameters; Within the effective time range, determine the sampling positions corresponding to the total propagation time, and perform interpolation sampling on non-integer sampling positions; The sampled signals from each transmit and receive array element combination are delayed, focused, and superimposed to obtain the imaging amplitude of each grid point, and the deep defect detection result is obtained based on the imaging amplitude.

2. The method of claim 1, wherein the epoxy insulator deep defect phased array ultrasonic testing method is characterized by, The measured equivalent sound velocity parameters that match the epoxy resin insulator under test include: The thickness of the epoxy resin insulator to be tested is measured, and the echo time of the longitudinal wave bottom surface or the echo time of the transverse wave bottom surface is obtained by pulse echo method. The longitudinal wave velocity or transverse wave velocity is determined based on the thickness and the corresponding bottom surface echo time, and the corresponding longitudinal wave velocity or transverse wave velocity is determined as the equivalent sound velocity parameter according to the propagation waveform used in phased array ultrasonic testing.

3. The method of claim 2, wherein the epoxy insulator is a post insulator. The formula for calculating the longitudinal wave velocity is: ； wherein is the longitudinal wave speed, is the thickness of the epoxy insulator, is the longitudinal wave bottom surface echo time; The expression for calculating the transverse wave velocity is: ； wherein is the shear wave velocity, is the shear wave bottom time.

4. The method of claim 1, wherein the epoxy insulator deep defect phased array ultrasonic inspection method is characterized by, The search depth range is determined based on the thickness of the epoxy resin insulator to be detected, the target detection area, the near-field interference area, and the bottom echo position. Grid points whose depth positions are within the search depth range are determined as grid points participating in imaging, and the effective time range for participating in time-delay sampling in the full matrix capture ultrasonic echo data is limited according to the search depth range.

5. The method of claim 1, wherein the epoxy insulator deep defect phased array ultrasonic inspection method is characterized by, The method for obtaining the total propagation time includes: For any grid point participating in imaging, the direct propagation distance from each array element to the grid point is determined based on the grid point position parameters and the position parameters of each array element. Based on the direct propagation distance and the equivalent sound velocity parameters that match the epoxy resin insulator to be tested, the one-way propagation time from each array element to the grid point is determined. The one-way propagation time is repeatedly calculated for each grid point and each array element involved in imaging, and the propagation time matrix of the array element grid points is established. For any grid point participating in imaging and any combination of transmit and receive array elements, the one-way propagation time from the transmit array element to the grid point and from the grid point to the receive array element is obtained from the propagation time matrix. The total propagation time of the transmit and receive array elements corresponding to the grid point is obtained by adding the one-way propagation time from the transmit and receive array elements to the grid point.

6. The method of claim 5, wherein the epoxy insulator is a deep flaw phased array ultrasonic inspection method. The expression for calculating the direct propagation distance is: ； wherein, denotes the direct propagation distance, and denote the lateral position and the depth position of the th array element, respectively, and denote the lateral position and the depth position of the grid point , respectively.

7. The method of claim 6, wherein the method further comprises, The expression for calculating the one-way propagation time is: ； wherein represents the one-way propagation time from the element to the grid point , represents the equivalent sound speed parameter.

8. The method of claim 7, wherein the epoxy insulator is a deep flaw phased array ultrasonic inspection method. The total propagation time is: ； In the formula, Indicates the total propagation time. Indicates the launch array element To grid point One-way transmission time, Represents grid points To the receiving array element The one-way transmission time.

9. The phased array ultrasonic testing method for deep defects in epoxy resin insulators according to claim 1, characterized in that, The method for obtaining the deep defect detection results includes: For any grid point participating in imaging, a transmitting element is fixed, and the sampled signals of each receiving channel corresponding to the transmitting element are accumulated to obtain the partial beamforming signal corresponding to the transmitting element. The sign-preserving square root amplitude compression of each part of the beamforming signal is performed to obtain the compressed partial beamforming signal; The compressed beamforming signals corresponding to each transmitting array element are summed together to obtain the imaging amplitude of the current grid point. By traversing all grid points involved in imaging, the imaging amplitude of each grid point is obtained, and the imaging amplitude is normalized and grayscale mapped to obtain the phased array ultrasonic detection results of deep defects.

10. The phased array ultrasonic testing method for deep defects in epoxy resin insulators according to claim 9, characterized in that, The expression for calculating the imaging amplitude of the grid points is: ； In the formula, The imaging amplitude of the current grid point. This is a compressed portion of the beamforming signal. Indicates the first Each phased array element serves as a transmitting element. This represents the total number of transmitting array elements involved in the imaging calculation.

11. A phased array ultrasonic testing system for deep defects in epoxy resin insulators, characterized in that, include: The data acquisition and mesh generation module obtains the equivalent sound velocity parameters that match the epoxy resin insulator under test through actual measurement; acquires the array element position parameters of the phased array probe and the full matrix capture of ultrasonic echo data, and performs mesh generation on the detection area; The effective imaging range constraint module limits the grid points participating in imaging and the effective time range of the ultrasonic echo data based on the search depth range. The propagation time calculation module determines the total propagation time for each combination of transmitting and receiving array elements based on the array element position parameters, grid point positions, and equivalent sound velocity parameters for each grid point involved in imaging. An ultrasonic signal interpolation sampling module determines the sampling position corresponding to the propagation time within the effective time range, and performs interpolation sampling on non-integer sampling positions; The defect detection module performs delayed focusing and superposition of the sampled signals from each transmit and receive array element combination to obtain the imaging amplitude of each grid point, and obtains the deep defect detection result based on the imaging amplitude.

12. An electronic device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps of the phased array ultrasonic testing method for deep defects in epoxy resin insulators as described in any one of claims 1 to 10.

13. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, which, when executed by a processor, implements the steps of the phased array ultrasonic testing method for deep defects in epoxy resin insulators as described in any one of claims 1 to 10.

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