A method for detecting micro-defects of enamel film of enameled wire by wet development

Abstract

The application discloses a kind of enameled wire insulating paint film microdefect wet development detection methods, it is related to enameled wire insulation detection technical field, including the surface state standardization processing to be measured enameled wire;Establish reference section;Make wet development liquid respectively with the insulating paint film of reference section and the insulating paint film of the measured section on the measured enameled wire;Under the same detection condition, obtain the reference response of the reference section and the local response of the measured section;According to the main parameter deviation rate of the local response relative to the reference response, combined with continuous window condition, determine abnormal area;Determine and output the abnormal area.The application improves the identification sensitivity and determination stability of paint film microdefect, especially local continuity abnormal area, reduces misjudgment and omission, and is conducive to realizing the fine evaluation and early defect screening of enameled wire insulation quality.

Description

Technical Field

[0001] This invention relates to the field of enameled wire insulation testing technology, and in particular to a wetting and developing method for detecting micro-defects in the enamel film of enameled wire insulation. Background Technology

[0002] Enameled wire is widely used in motor windings, transformer coils, new energy drive systems, and electronic components. Its insulation performance mainly depends on the integrity and continuity of the surface insulating varnish film. As products develop towards higher withstand voltage, smaller wire diameter, and higher winding density, pinholes, local weak areas, shrinkage cavities, and areas with local continuity damage in the insulating varnish film are more likely to cause a decline in insulation performance, and in severe cases, they can become the starting point of electrical failure.

[0003] In the early stages, existing micro-defects in the insulation film of enameled wire typically manifest only as minor anomalies in local wetting characteristics or film continuity. Before a clear breakdown channel or visible morphological defect is formed, existing detection technologies struggle to reliably identify them. This is especially true when there are fluctuations in different batches of products, surface conditions, and testing conditions. Existing technologies often rely on absolute test results for judgment, lacking a comparative mechanism based on the response deviation between the reference section and the tested section under the same testing conditions. Consequently, they are easily affected by differences in the film itself, residual process factors, and changes in the testing environment, resulting in insufficient sensitivity in micro-defect identification, a high false positive rate, and difficulty in accurately detecting local anomalies in film continuity. Summary of the Invention

[0004] This invention provides a method for detecting wetting and development defects in the insulation film of enameled wire, comprising the following steps: The surface condition of the enameled wire to be tested is standardized. Establish a reference section; The wetting and developing liquid is brought into contact with the insulating varnish film of the reference section and the insulating varnish film of the section to be tested on the enameled wire. Under the same detection conditions, the reference response of the reference segment and the local response of the segment to be tested are obtained; Based on the deviation rate of the main parameters of the local response relative to the reference response, and in conjunction with the continuous window condition, the abnormal region is determined; Identify and output the abnormal region.

[0005] Preferably, the surface condition standardization process includes: Remove residual lubricating oil and / or surface contaminants from the surface of the enameled wire to be tested, and then dry it.

[0006] Preferably, a reference segment is established, including: Candidate reference sections are pre-selected on the enameled wire to be tested, and the response stability of the candidate reference sections is tested. The mean value of the main parameters of the candidate reference segment that passes the response stability test is compared with the normal response range pre-established for qualified enameled wire samples of the same specification. The candidate reference segment that falls within the normal response range is used as the reference segment. When none of the candidate reference sections from the same enameled wire under test fall within the normal response range, a standard sample section or independent standard section of the same specification as the enameled wire under test is used as a reference section, and it is confirmed by pre-scanning under the same testing conditions as the enameled wire under test to meet the conditions for response stability testing.

[0007] Preferably, the wetting and developing liquid is a mixture of glycerol and saturated saline solution.

[0008] Preferably, the main parameter is a quantitative parameter characterizing the reference response and the local response, including at least one of spreading length, retention area and local optical intensity; The quantitative parameters of the reference response are used as reference response parameters, which are the segment averages of all reference windows in the final reference segment on the corresponding main parameters. The deviation rate of the main parameter is calculated based on the relative deviation of the local response parameter of the test section from the corresponding reference response parameter of the reference section.

[0009] Preferably, the conditions for the same test include keeping the following conditions consistent: the amount of wetting and developing liquid applied, the contact time between the wetting and developing liquid and the insulating varnish film, the orientation and / or rotation angle of the enameled wire to be tested, and the response acquisition conditions.

[0010] Preferably, the local response parameters and the corresponding reference response parameters are matched according to the correspondence of the same main parameters, the same sampling window length, and the same sampling time or the same position; The determination condition is: at least one main parameter deviation rate reaches a preset threshold, and the situation of the main parameter deviation rate reaching the preset threshold occurs within no less than a preset number of consecutive detection windows; The test section that meets the judgment criteria is identified as an abnormal area, which is a local continuity abnormality area of ​​the insulating varnish film.

[0011] Preferably, during the contact process between the wetting and developing liquid and the insulating varnish film, at least one of the following is applied between the enameled wire conductor to be tested and the counter electrode located near the corresponding section to be tested: a pulse voltage with a peak value lower than the insulation breakdown threshold, a stepped boost voltage, or a current-limiting AC voltage, so as to apply local electrical excitation to the reference section and the section to be tested. When applying local electrical excitation for detection, the reference response parameters of the reference section are reacquired under the same electrical excitation conditions.

[0012] Preferably, the wetting and developing detection method further includes a step of confirming the abnormal area, specifically including at least one of repeated detection, local repair before and after comparison, microscopic verification, cross-section verification, and pressure resistance comparison.

[0013] Preferably, when using a before-and-after comparison of local repairs to confirm abnormal areas, the repair material is an insulating varnish system of the same type as the original varnish film or a compatible insulating covering material, and the difference in static contact angle between the repaired surface and the adjacent intact area before repair does not exceed 10°.

[0014] The beneficial effects of this invention are as follows: This invention standardizes the surface condition of the enameled wire under test and establishes a reference section under the same testing conditions. By comparing the local response of the section under test with the reference response, it solves the problems of relying solely on absolute test results for judgment in the prior art, which is susceptible to batch differences, surface residue factors, and fluctuations in testing conditions. It improves the sensitivity and stability of identifying micro-defects in the enamel film, especially local continuous abnormal areas, reduces false and false judgments, and facilitates the refined evaluation of the insulation quality of enameled wire and early defect screening. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a flowchart of the wetting and developing detection method for micro-defects in the insulation varnish film of enameled wire in Example 1; Figure 2 This is a flowchart illustrating the establishment of the reference section in Example 2; Figure 3 This is a flowchart of the electrical excitation enhancement and abnormal region confirmation in Example 3. Detailed Implementation

[0017] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0018] Example 1 refer to Figure 1This embodiment is used to detect abnormal areas in the insulation varnish of enameled wire that are indicative of local continuity anomalies. The test sample is a round enameled copper wire with a nominal conductor diameter of 0.09 mm. The insulation varnish system is polyurethane or polyesterimide. The length of each sample is 1.20 m, of which the effective test length is 1.00 m, and 0.10 m are reserved at each end as clamping sections. During the test, the amount of wetting and developing liquid applied, the contact time between the liquid and the insulation varnish, the orientation of the wire under test, and the response acquisition conditions are kept consistent.

[0019] This embodiment provides a method for detecting wetting and development defects in the insulation enamel film of enameled wire, including the following steps: Before testing, the surface condition of the enameled wire to be tested is standardized. The specific method is as follows: place the sample flat on the support plate and fix both ends; immerse the sample in n-hexane and ultrasonically clean for 2 minutes to remove residual lubricating oil and adhering contaminants on the surface; after taking it out, rinse it in fresh n-hexane for 30 seconds; then place it in a 40℃ forced-air drying oven for 10 minutes to dry; after taking it out, let it stand at 23±2℃ for 5 minutes to allow the residual solvent to evaporate.

[0020] After the above treatment, a clean and dry enameled wire to be tested is obtained. For the insulating varnish system involved in this embodiment, no observable damage to the varnish film was observed after the above treatment. For other insulating varnish film systems, preliminary experiments should be conducted to confirm that the selected cleaning solvent and drying conditions will not cause swelling, cracking, peeling, or surface roughening of the varnish film. Only after confirming that it will not affect the subsequent wetting and developing test results can it be used for surface condition standardization treatment.

[0021] The wetting and developing liquid used in this embodiment is a mixture of glycerol and saturated saline solution. The saturated saline solution is prepared at 23±2℃, allowed to stand for 30 min, and filtered through a 0.45μm filter membrane. Glycerol and saturated saline solution are mixed at a mass ratio of 85:15, mechanically stirred for 10 min, and allowed to stand for degassing for 20 min to obtain the wetting and developing liquid. After the wetting and developing liquid comes into contact with the insulating varnish film, it forms a collectable spreading response, retention response, and optical response.

[0022] The formal testing process includes a reference segment pre-scanning and screening stage and a test segment comparison and testing stage. First, candidate reference segments are pre-selected within the effective detection length of the sample. These candidate reference segments are then pre-scanned, and response values ​​for each window are acquired under the same principal parameter under the same liquid application volume, contact duration, and acquisition conditions. If a candidate reference segment meets the response stability condition and its mean principal parameter falls within the pre-established normal response range for qualified samples of the same specification, that candidate reference segment is determined as the final reference segment; otherwise, a new candidate reference segment is selected as the reference segment (also known as a reference window). After the final reference section is determined, the remaining effective detection lengths, excluding the reference section, are divided into test windows (also known as test sections) with the same sampling window length. Formal detection is then performed under the same detection conditions as the reference section to achieve a correspondence between the local response of the test window and the reference response of the reference section.

[0023] During testing, the sample is horizontally tensioned and fixed on the testing platform, with the sample axis parallel to the platform baseline and the line rotation angle controlled at 0°. A micro-dip dispenser is used to apply wetting and developing liquid to the center of each testing window at a rate of 2.0 μL / window, with an allowable error of ±0.1 μL. Timing begins after the liquid contacts the insulating varnish film. Images are acquired 5 seconds after contact to calculate the spreading length and retention area, and images are acquired 10 seconds after contact to calculate the local optical intensity. The reference window and the window under test are kept consistent in terms of liquid application amount, contact time, line posture, and response acquisition conditions.

[0024] This embodiment employs an industrial camera, a telecentric lens, and a ring-shaped cold light source to form an image acquisition system. The industrial camera is positioned directly above the sample, with the lens optical axis perpendicular to the plane containing the sample axis. A single acquisition field of view covers a 5mm detection window. Before image acquisition, brightness calibration is performed using a standard reflector, and the camera gain, exposure time, lens magnification, imaging distance, and light source brightness are fixed. The acquired image undergoes background correction first, and then a fixed grayscale threshold segmentation method is used to extract the droplet contour. The spreading length is defined as the maximum projected length of the droplet contour along the axial direction of the conductor; the retention area is defined as the area value of the pixel area enclosed by the droplet contour after pixel size calibration; and the local optical intensity is defined as the average grayscale value within the droplet contour area after subtracting the background grayscale. The same parameter extraction method is used for the reference section and the section to be tested.

[0025] The reference response parameters and local response parameters are matched according to the same principal parameter, the same sampling window length, and the same sampling time or the same location. When the spreading length is used as the principal parameter, the reference response parameter is the average spreading length of all reference windows in the reference section 5 seconds after contact. When the retention area is used as the principal parameter, the reference response parameter is the average retention area of ​​all reference windows in the reference section 5 seconds after contact. When the local optical intensity is used as the principal parameter, the reference response parameter is the average local optical intensity of all reference windows in the reference section 10 seconds after contact. The local response parameters of the window under test are only compared with the reference response parameters of the corresponding principal parameters.

[0026] The deviation rate of the main parameters is calculated using the following formula: ; in, The deviation rate of the main parameter. Let be the local response parameters of the i-th test window. As a reference response parameter corresponding to the main parameter, in this embodiment, the main parameter is at least one of spreading length, retention area and local optical intensity. The spreading length deviation rate threshold is preferably set to 15%, the retention area deviation rate threshold is preferably set to 20%, and the local optical intensity deviation rate threshold is preferably set to 12%.

[0027] Abnormal areas are determined by a combination of the main parameter deviation rate threshold and the continuous window condition. Specifically, when the deviation rate of at least one main parameter in a certain window to be tested reaches the corresponding threshold, and the situation of reaching the threshold occurs continuously in no less than 3 consecutive detection windows, the axial segment corresponding to the continuous detection window is determined to be an abnormal area. If only a single window reaches the threshold and none of its adjacent windows reach the corresponding threshold, then the single window is not determined to be an abnormal area. In this embodiment, the sampling window length is 5mm, so the length of the abnormal segment corresponding to three consecutive detection windows is 15mm, and the detection result is output in the form of abnormal segment.

[0028] After the detection is completed, the starting window number, ending window number, and corresponding main parameter deviation rate of the abnormal section that meets the judgment conditions will be used as the output results, which can also be converted into the axial position range relative to the sample starting point.

[0029] In this embodiment, the hexane washing time, the ratio of glycerol to saturated saline solution, the amount of liquid applied, the sampling window length, the sampling time, the deviation rate threshold, and the number of consecutive windows are a set of preferred implementation conditions. Those skilled in the art can adjust the above parameters based on the nominal diameter of the conductor of the sample to be tested, the insulating varnish system, and the detection accuracy requirements, based on preliminary experiments. However, the adjusted implementation method should still meet the following conditions: the sample to be tested undergoes surface state standardization treatment; the wetting and developing liquid is still a mixture of glycerol and saturated saline solution; the detection response is limited to spreading response, retention response, and / or optical response; the main parameter is limited to at least one of spreading length, retention area, and local optical intensity; the reference section is determined by pre-scanning and qualification screening; the local response parameters and the reference response parameters are matched according to the same main parameter, the same sampling window length, and the same sampling time or the same position; and the abnormal area is determined based on the deviation rate of the main parameter and the consecutive window conditions.

[0030] Example 2 refer to Figure 2 This embodiment is used to establish a reference section in the wetting and developing test of the insulation varnish film of enameled wire. In this embodiment, the surface state standardization treatment, the composition and preparation of the wetting and developing liquid, the application method of the wetting and developing liquid, the response acquisition conditions, the definition of the main parameters, and the extraction method of the main parameters all adopt the corresponding methods in Embodiment 1. This embodiment focuses on explaining the source of the candidate reference section, the response stability test, the qualification screening, and the determination method of the final reference section.

[0031] In this embodiment, samples of the same specification include at least conductors with the same nominal diameter and insulation film system, and preferably with the same film grade. The test sample is a round enameled copper wire with a conductor nominal diameter of 0.09 mm and an insulation film of polyurethane or polyesterimide. The qualified samples used to establish the normal response range are preferably from the same or adjacent production batches as the test sample. When the conductor nominal diameter, insulation film system, film grade, production batch, production process conditions or testing conditions change, the corresponding normal response range should be re-established.

[0032] Candidate reference segments can be derived from segments on the same enameled wire to be tested, or from standard samples or standard segments of the same specification as the enameled wire to be tested. Preferably, candidate reference segments are first selected from the same enameled wire to be tested. When no candidate reference segment meets the conditions in the same enameled wire to be tested, a standard sample or standard segment of the same specification is used as the reference source. For candidate reference segments derived from the same enameled wire to be tested, response stability testing and qualification screening should be performed sequentially. For reference sources derived from standard samples or standard segments of the same specification, competitive screening among multiple candidate segments is not required, but a pre-scan should still be performed under the same testing conditions as the sample to be tested, and it should be confirmed that it meets the preset response stability conditions.

[0033] In practice, multiple candidate reference segments are pre-selected within the effective detection length of the sample to be tested. In this embodiment, the effective detection length of the sample is 1.00m. It is preferable to set three candidate reference segments, which are located in the middle, the first 1 / 4 and the last 1 / 4 of the sample axial position, respectively. The length of each candidate reference segment is 100mm.

[0034] The above positions and quantities are preferred settings and can be adjusted according to the actual production batch, line status, sample length and testing needs. They are not limited to three segments or must be located in the above positions. Each candidate reference segment is divided into several windows with the same sampling window length as the formal testing in Example 1. In this example, the sampling window length is 5mm, so each candidate reference segment contains 20 sampling windows.

[0035] When pre-scanning candidate reference sections, the main parameters used should be consistent with the main parameters used for anomaly determination in the formal detection of Example 1. The main parameters are limited to one, two, or three of the following: spreading length, retention area, and local optical intensity. Taking spreading length, retention area, and local optical intensity as main parameters as an example, under the same liquid application amount, the same contact time, and the same acquisition conditions, the main parameter response values ​​of each window in the candidate reference section at the corresponding sampling time are obtained to ensure that the reference section selection is consistent with the formal detection parameter system.

[0036] The response stability test is performed as follows: the mean, standard deviation, and coefficient of variation of each principal parameter within the candidate reference segment are calculated, and the changing trend of the response of adjacent windows is checked in window order. In this embodiment, a candidate reference segment is deemed to have passed the response stability test when it simultaneously meets the following conditions: the coefficient of variation of the spreading length is not greater than 5%; the coefficient of variation of the retention area is not greater than 6%; when the local optical intensity is involved in the formal detection and judgment, the coefficient of variation of the local optical intensity is not greater than 5%; there is no drift trend of unidirectional increase or unidirectional decrease between three or more consecutive windows along the line; and within the same candidate reference segment, there is no situation where any principal parameter of two or more consecutive windows deviates from the mean of the corresponding principal parameter of the segment by more than 8%. Candidate reference segments that meet the above conditions enter the qualification screening step; candidate reference segments that do not meet the above conditions are directly eliminated.

[0037] The qualification screening is based on the response range of qualified samples of the same specification as the enameled wire to be tested. In this embodiment, 30 enameled wires of the same specification that have passed the withstand voltage test and appearance inspection are selected as qualified samples in advance. A 100mm long sample section is cut from each qualified sample as a statistical section and divided according to the same sampling window length as in this embodiment. Under the same surface condition standardization treatment, wetting and developing liquid application method, contact time and response acquisition conditions as the sample to be tested, the main parameter response values ​​of each statistical section are measured. For each qualified sample, the section mean of its statistical section on the corresponding main parameter is calculated first. Then, the section mean of the main parameter corresponding to the 30 qualified samples is used to form a statistical sample set, and the overall mean μ and standard deviation σ of the main parameter are calculated respectively. μ±2σ is determined as the normal response range of the main parameter.

[0038] During the qualification screening, the mean values ​​of each main parameter segment of the candidate reference segment that has passed the response stability test are compared with the normal response range of the corresponding main parameter of the qualified sample of the same specification. When the mean values ​​of all main parameter segments used by the candidate reference segment fall within their respective normal response ranges, the candidate reference segment is determined to have passed the qualification screening; when the mean value of any main parameter segment exceeds the corresponding normal response range, the candidate reference segment is determined to have failed the qualification screening.

[0039] When multiple candidate reference segments pass the qualification screening, the final reference segment is determined by the principle of minimizing the normalized comprehensive deviation. After the final reference segment is determined, for each main parameter used in the formal detection, the average value of all reference windows of the final reference segment at the corresponding sampling time is used as the reference response parameter, and it is compared with the local response parameter of the window to be tested.

[0040] When all candidate reference segments from the same enameled wire to be tested fail the qualification screening, a standard sample or standard segment of the same specification is used as the reference source. When using a standard sample or standard segment, no competitive screening among multiple candidate segments is performed, but a pre-scan should be performed under the same testing conditions as the sample to be tested, and it should be confirmed that the selected standard segment meets the same response stability conditions as mentioned above. After confirming that the response stability conditions are met, the average value of all reference windows of the standard segment on the corresponding main parameters is obtained according to the same main parameter extraction rules as the sample to be tested, and the average value of the segment is used as the reference response parameter. Regardless of whether the reference segment comes from the same enameled wire to be tested or from a standard sample or standard segment of the same specification, the final reference response parameter comes from the average value of all reference windows of the final reference segment.

[0041] After establishing the final reference segment, for each main parameter used in the formal test of Example 1, the average value of all reference windows in the final reference segment on the corresponding main parameter is taken as the reference response parameter, and compared with the local response parameter of the corresponding window of the segment to be tested. By using the method of candidate reference segment pre-selection - response stability test - qualification screening of response range of qualified samples of the same specification - final reference segment determination, the reliability of reference segment establishment can be improved and the stability of abnormal area judgment can be improved.

[0042] In this embodiment, the number, location, length, upper limit of coefficient of variation, continuous drift criterion, local deviation criterion, number of qualified samples, and establishment method of normal response range of candidate reference segments are all preferred implementations. These can be adjusted according to the conductor nominal diameter, insulating varnish system, varnish grade, sampling window length, and detection accuracy requirements, but the adjusted implementation should still meet the following basic requirements: candidate reference segments originate from segments on the same enameled wire to be tested and / or standard samples or standard segments of the same specification as the enameled wire to be tested; when candidate reference segments originate from the same enameled wire to be tested, a response stability test should be performed first, and then qualification screening should be conducted based on the response range of qualified samples of the same specification as the enameled wire to be tested, with the selected candidate reference segments serving as reference segments; when standard samples or standard segments are used as reference sources, they should be pre-scanned under consistent testing conditions to confirm that they meet the response stability conditions, and the main parameters used for selecting reference segments preferably cover at least all the main parameters used in the formal testing.

[0043] Example 3 refer to Figure 3This embodiment is used to perform enhanced electrical excitation detection and confirmation on the abnormal area identified in Embodiment 1. The surface state standardization treatment, composition and preparation of the wetting and developing liquid, local application method, response acquisition conditions, main parameter definition, main parameter extraction method, deviation rate calculation method and abnormal area judgment rules in Embodiment 1, and the reference segment establishment method in Embodiment 2 are all unchanged in this embodiment. This embodiment focuses on describing the method of applying electrical excitation with a peak value lower than the insulation breakdown threshold to the enameled wire under test while keeping the local application of wetting and developing liquid method unchanged in Embodiment 1, and performing repeated detection, comparison before and after local repair, and auxiliary verification of the abnormal area.

[0044] In this embodiment, the test sample still uses the circular enameled copper wire from Example 1. To apply electrical excitation, a 5mm long layer of enamel film is stripped from one end of each test sample to expose the conductor and connect it to the output terminal of the high-voltage power supply. The counter electrode uses a needle-shaped or sheet-shaped stainless steel electrode and is connected to the other end of the high-voltage power supply circuit. During implementation, the detection windows of the test sample are still locally liquid-applied window by window according to the method of Example 1. A quantitative amount of wetting and developing liquid is applied to the center of each detection window. After the droplet is applied, the counter electrode is placed near the droplet of the corresponding detection window, preferably 0.5mm to 2mm outside the edge of the droplet, so that the conductor of the test sample, the electrode and the droplet area covering the detection window form a local electrical excitation area. The relative position, angle and spacing of the counter electrode in each window remain consistent in the same detection.

[0045] To ensure that the peak value of the applied electrical excitation is lower than the insulation breakdown risk range under the corresponding test conditions, 10 additional samples are taken from the samples of the same specifications and coating system as the sample to be tested and which have passed the withstand voltage test. The reference breakdown threshold is determined under the same local liquid application method, electrode arrangement method and test conditions as in this embodiment. It is preferable to use the same method as the electrical excitation waveform to be used in the formal test for the determination.

[0046] The average measured breakdown voltage is denoted as U, and the standard deviation is denoted as s. U is then... The difference between s and s is used as the reference breakdown threshold U in this embodiment. b .

[0047] When the coefficient of variation of breakdown voltage exceeds 10%, the sample size is increased to 20 and the test is repeated to improve U. b For stability testing, the electrical excitation waveform used in the formal test should be consistent with the measured U. b The electrical excitation waveform should be consistent with the actual waveform; if the waveforms are inconsistent, the U value under the corresponding waveform should be remeasured. b If an electrical excitation test is subsequently performed, and the test is not repeated due to objective reasons, the result of that electrical excitation test should not be used as the sole basis for final confirmation.

[0048] During formal testing, the peak value of the applied electrical excitation is controlled within the reference breakdown threshold U. b Within the range of 0.55 to 0.85 times, it is preferred to control it within U. b Within the range of 0.70 to 0.80 times, the above-mentioned U b Both represent the reference breakdown threshold measured under the corresponding waveform and detection conditions.

[0049] In practice, a routine test without electrical excitation was first performed according to the method in Example 1 to obtain the initial abnormal area. Subsequently, the same test segment of the same sample was locally cleaned and dried, and fresh wetting and developing solution was reapplied.

[0050] During the retest, the reference section still uses the final reference section determined in Example 2; however, the reference response parameters should be reacquired under the same electrical excitation conditions as this retest. Specifically, under the same electrical excitation waveform, the same voltage peak, the same liquid application amount, the same contact time, and the same acquisition conditions, the average value of the main parameters corresponding to all reference windows of the reference section should be remeasured, and this average value should be used as the reference response parameter under the current electrical excitation test conditions; then, the local response parameters of the section to be tested under the same electrical excitation conditions should be compared with the reference response parameters, and the abnormal area should be determined according to the deviation rate threshold and continuous window conditions in Example 1.

[0051] The abnormal areas obtained from the second detection are compared with the initial abnormal areas according to the window number. When the overlap rate of the abnormal windows obtained from the two detections is not less than 70%, and the axial expansion or contraction of the abnormal segment does not exceed 2 sampling windows, the repeated detection results are considered to be consistent. The overlap rate is calculated as the ratio of the number of intersections of the abnormal windows in the two detections to the number of unions of the abnormal windows in the two detections.

[0052] Based on repeated testing, this embodiment further confirms the abnormal area by comparing the results before and after local repair. During local repair, the abnormal area is first located under a microscope according to the location of the abnormal area output in Embodiment 1, and a repair coverage boundary is established by extending 2mm outwards from both ends of the abnormal area. Then, an insulating varnish system similar to the original varnish film or a compatible insulating covering material is used for local repair. For polyurethane insulating varnish films, a similar polyurethane insulating varnish is preferred as the repair material; for polyesterimide insulating varnish films, a compatible polyesterimide insulating covering material is preferred as the repair material. Before repair, the same method as in Embodiment 1 is used to remove... The contaminated solvent is used to locally clean the abnormal section and allows it to evaporate naturally. During repair, a micro-application needle or fine brush is used to evenly apply the repair material to the surface of the abnormal section, covering the abnormal area and extending to both sides. After repair, the surface should maintain a continuous transition with the adjacent intact area without forming visible steps. After repair, the repair material is cured according to its curing conditions. In this embodiment, when using polyurethane-based repair materials, the curing temperature is preferably 120°C and the curing time is preferably 10 min to 15 min. When using polyesterimide-based repair materials, the curing temperature is preferably 130°C to 150°C and the curing time is preferably 10 min to 20 min.

[0053] To control the deviation in the interaction characteristics between the repair material and the wetting and developing liquid, the static contact angle between the repaired area and the adjacent intact area before repair was measured after the repair curing was completed. During the measurement, the same wetting and developing liquid as in Example 1 was used. 1.0 μL droplets were applied to the surface of the repaired area and the surface of the adjacent intact area at 23±2℃. The droplet profile was obtained using a side-view imaging method, and the angle between the droplet profile boundary and the tangent of the sample surface was taken as the static contact angle. For circular wires, the side-view profile of the droplet was photographed along the axial direction of the sample, and the average value of the apparent contact angles of the leading and trailing edges of the droplet was taken as the static contact angle at that location. Each measurement point was measured three times, and the average value was taken as the static contact angle at that point. When the difference in static contact angle between the surface of the repaired area and the adjacent intact area before repair did not exceed 10°, it was considered that the repair material and the original paint film met the preset tolerance requirements in terms of liquid interaction characteristics. When the difference in contact angle was greater than 10°, the repair result was not used as the confirmation basis, and the repair material or repair process was readjusted.

[0054] After completing the local repair and confirming that the contact angle difference does not exceed the preset tolerance, the repaired area is re-tested according to the detection process of Example 1. If the continuous window that was determined to be an abnormal area before the repair no longer meets the deviation rate threshold and continuous window condition in Example 1 after the repair, it is confirmed that the original abnormal area is related to the local continuity abnormality of the insulating varnish film. If the abnormal area determination condition is still met after the repair, it is confirmed by combining microscopic verification, cross-sectional verification or withstand voltage comparison. Re-testing and comparison before and after local repair are the preferred confirmation methods in this example, while microscopic verification, cross-sectional verification and withstand voltage comparison are auxiliary confirmation methods.

[0055] When using microscopic verification, after marking the location of the abnormal area, the sample surface is observed using an optical microscope with a magnification of 200x to 500x to check for microcracks, pinholes, dents, localized paint film accumulation, or traces of continuous damage. When using sectional verification, the abnormal section is embedded in resin and sliced ​​along a direction perpendicular to the conductor axis to observe whether there are abrupt changes or local discontinuities in the cross-sectional thickness of the insulating paint film. When using withstand voltage comparison, withstand voltage is applied to sample sections containing abnormal areas and complete sample sections of the same specification without abnormal areas, and their withstand voltage performance is compared. To determine the threshold for the deviation rate of the main parameters and the number of continuous windows, in addition to selecting normal samples of the same specifications, pinhole samples and scratch samples were artificially prepared on qualified enameled wire samples as artificial defect samples in the preliminary experiment to compare the difference in response distribution between normal samples and abnormal samples under different judgment rules. The artificial defect sample control can be used as a parameter preliminary experiment or comparative verification method to help explain the rationality of the parameter settings of the present invention, but it is not used as an abnormal area confirmation step as defined in the claims of the present invention.

[0056] In this embodiment, if the sample is determined by Example 1 to have an abnormal region in windows 41 to 43, the detection is first repeated once without electrical excitation, and then the peak value of 0.75U is applied. b Under pulse voltage conditions of 30ms pulse width, 200ms pulse interval, and 5 pulses, a second test is performed, and the reference response parameters of the reference section are re-acquired under the same pulse conditions. If the overlap rate of the abnormal window in the two tests is not less than 70%, and the change of the abnormal area boundary does not exceed 2 sampling windows, then the repeated test is determined to be consistent. Subsequently, the 41st to 43rd windows and the sections extending 2mm at each end are locally repaired. After curing, the static contact angle difference between the repaired area and the adjacent intact area is measured to be 6°, which meets the preset tolerance requirement of not more than 10°. The repaired area is then tested according to the conditions of Example 1. If the 41st to 43rd windows no longer meet the abnormal area determination conditions, then it is confirmed that the original abnormal area is related to the local continuity abnormality of the insulating varnish film.

[0057] In this embodiment, the electrical excitation method, voltage peak range, pulse width, pulse interval, overlap rate criterion, type of repair material, curing conditions, and static contact angle difference tolerance are all preferred implementation conditions. Those skilled in the art can adjust these parameters based on preliminary experiments, according to the conductor's nominal diameter, insulating varnish system, sample length, and detection sensitivity requirements. However, the adjusted implementation should still meet the following basic requirements: during the contact between the glycerol and saturated saline solution and the insulating varnish, at least one of the following electrical excitations—a pulse voltage, a stepped boost voltage, or a current-limiting AC voltage—with a peak value lower than the corresponding reference breakdown threshold is applied to the enameled wire under test; When the excitation is retested, the reference response parameters of the reference section should be reacquired under the same electrical excitation conditions. For abnormal areas, at least one of the following methods should be used for confirmation: repeated testing, comparison before and after local repair, microscopic verification, cross-sectional verification, and withstand voltage comparison. When using comparison before and after local repair for confirmation, the repair material should be an insulating varnish system of the same type as the original varnish film or a compatible insulating covering material, and the difference in static contact angle between the repaired surface and the adjacent intact area before repair should not exceed the preset tolerance. When the nominal diameter of the conductor, the insulating varnish film system, the liquid application method, or the testing conditions change, the reference breakdown threshold under the corresponding conditions should be re-determined, and the electrical excitation peak value should be adjusted accordingly.

[0058] Basis for parameter determination: The main parameters used in this invention, including the deviation rate threshold, number of continuous windows, reference section stability test threshold, contact angle tolerance, and electrical excitation peak range, are all determined comprehensively through preliminary experimental results of normal samples, artificially defective samples, and confirmation samples of the same specification. The purpose of the parameter determination process is to keep the false alarm rate of normal samples at a low level and to ensure that samples with local continuity anomalies have a high detection rate and relatively stable repeat detection results. The following parameter ranges and preferred values ​​are used to illustrate the parameter determination principle of this invention under a preferred embodiment, and do not mean that this invention is limited to these specific values. Under the same determination logic, those skilled in the art can make equivalent adjustments for different conductor nominal diameters, insulating varnish systems, varnish grades, wetting and developing liquid systems, or detection conditions.

[0059] 1. Basis for determining the deviation rate threshold The main parameter deviation rate thresholds include the spread length deviation rate threshold, the retention area deviation rate threshold, and the local optical intensity deviation rate threshold. In the preliminary experiment, normal samples and artificial defect samples of the same specifications were selected first. Under the same detection conditions as in Example 1, the main parameter response values ​​of each detection window were obtained. The average value of the main parameter corresponding to the reference segment was used as the reference response parameter. The main parameter deviation rate of each detection window was calculated. The deviation rate distribution of each window in the normal sample was compared with the deviation rate distribution of the defect area window in the artificial defect sample. The deviation rate threshold of each main parameter was determined on the premise of taking into account both the false alarm rate of the normal sample and the detection rate of the artificial defect sample.

[0060] In a preferred embodiment of the present invention, the spread length deviation rate threshold is set to 15%, the retention area deviation rate threshold is set to 20%, and the local optical intensity deviation rate threshold is set to 12%. The above thresholds can keep the number of abnormal judgments of normal samples at a low level and make the abnormal windows in artificial defect samples have a high detection probability. For samples with different conductor nominal diameters, different insulating varnish systems, or different sampling window lengths, the deviation rate distribution of normal samples and abnormal samples can be obtained again under the same detection process, and the thresholds can be re-determined accordingly.

[0061] 2. Basis for determining the number of consecutive windows The number of consecutive windows is used to limit the impact of random fluctuations in a single detection window on the anomaly detection results. In the preliminary experiment, comparisons were made using single-window detection, two consecutive windows, three consecutive windows, and four consecutive windows. The preliminary experimental results showed that when using single-window detection, although the detection rate of artificial defects could reach 100%, the number of false anomaly areas in the intact sample was relatively large, the overlap rate of repeated detection anomaly windows was low, and the average number of drift windows at the anomaly boundary was relatively large. When using two consecutive windows, the false alarms decreased, but boundary expansion was still likely to occur around the real anomaly area. When using four consecutive windows, although the false alarms were further reduced, the detection rate of artificial defects decreased. In comparison, when using three consecutive windows, a high defect detection rate could be maintained, and false alarms and boundary drift could be significantly reduced. Therefore, it is preferable to use no less than three consecutive detection windows as the condition for anomaly area detection.

[0062] 3. Basis for determining the stability test threshold of the reference section The reference segment stability test threshold is used to determine whether a candidate reference segment is suitable as the basis for obtaining a reference response. In the preliminary experiment, qualified samples of the same specifications are selected, and the candidate reference segment is pre-scanned under the same conditions as the formal test. The spread length, retention area, and, when necessary, the mean, standard deviation, and coefficient of variation of the local optical intensity of the segment are statistically analyzed. The drift trend of the window along the line is observed. By comparing the response stability of the candidate reference segment in multiple groups of normal samples, the threshold range of the response stability test is determined.

[0063] In a preferred embodiment of the present invention, the coefficient of variation of the spreading length is no greater than 5%, and the coefficient of variation of the retention area is no greater than 6%. When the local optical intensity is involved in the formal detection and judgment, the coefficient of variation of the local optical intensity is no greater than 5%. At the same time, there is no drift trend of unidirectional increase or unidirectional decrease between three or more consecutive windows along the line, and there is no situation where any principal parameter of two or more consecutive windows deviates from the average value of the corresponding principal parameter of the segment by more than 8%. The above thresholds can better distinguish between candidate reference segments with stable response and candidate reference segments with obvious fluctuations or overall shifts. For different coating systems, different conductor diameters, or different combinations of principal parameters, they can be recalibrated using the same method.

[0064] 4. Basis for determining contact angle tolerance Contact angle tolerance is used to limit the difference in the interaction characteristics between the surface and the wetting and developing liquid before and after local repair. In the preliminary experiment, local repairs were carried out using an insulating varnish system similar to the original varnish film or a compatible insulating covering material. Under the same curing conditions, the static contact angle of the repaired area surface and the adjacent intact area surface before repair were measured. The impact of the contact angle difference on the confirmation result of abnormal area was compared with the test results before and after repair.

[0065] In a preferred embodiment of the present invention, the difference in static contact angle between the repaired surface and the adjacent intact area before repair does not exceed 10°. When the contact angle difference does not exceed this range, the repaired area and the adjacent intact area are relatively similar in terms of liquid interaction characteristics, and the comparison results before and after repair have good comparability. When the contact angle difference significantly exceeds this range, the repair material itself may have too much influence on liquid spreading and retention behavior, and should not be used as a basis for confirmation. It is preferable to repeat the measurement of the static contact angle 3 times and take the average value.

[0066] 5. Basis for determining the peak value range of electrical excitation The electrical excitation peak range is used to enhance the response difference between abnormal and non-abnormal regions without causing insulation breakdown. In the preliminary experiment, the reference breakdown threshold is first determined in a sample with the same specifications and coating system as the sample to be tested and which has passed the withstand voltage test. Then, the repeat detection overlap rate, abnormal boundary stability and whether the sample has local breakdown are examined under different electrical excitation peaks.

[0067] In a preferred embodiment of the present invention, the reference breakdown threshold is denoted as U. b The peak value of the electrical excitation was controlled at 0.55U. b ~0.85U b Within the range, 0.70U is preferred. b ~0.80U b When the peak value of the electrical excitation is below 0.55U bAt that time, the response enhancement effect between the abnormal and non-abnormal regions was weak; when the peak value of the electrical excitation was higher than 0.85U... b When the electrical excitation waveform used in the formal test is inconsistent with the waveform used to determine the reference breakdown threshold, it is preferable to re-determine the reference breakdown threshold using the same waveform; if it is not re-determined, it is preferable to use a lower peak range.

[0068] The above parameters are preferred parameters of this invention. Their specific values ​​can be adjusted based on preliminary experiments according to the nominal diameter of the conductor, the insulating varnish system, the sample batch, the sampling window length, and the detection sensitivity requirements. In this embodiment, the wetting and developing liquid is limited to a mixture of glycerol and saturated saline solution. The method for determining the parameters should be consistent, that is, they should all be determined by comprehensively considering the preliminary experimental results of normal samples, artificially defective samples, and confirmation samples of the same specification.

[0069] Comparative test To verify the impact of surface state standardization, reference section qualification screening, and continuous window conditions on the detection effect in this invention, an example group of this invention and three single-factor comparative groups were set up for comparison. Each comparative group only changed the corresponding single technical feature, while keeping the other experimental conditions the same. The specific grouping, detection process, and results are as follows.

[0070] Round enameled copper wires of the same production batch and specification were selected as samples. The nominal diameter of the conductor was 0.09 mm, and the insulating varnish was polyurethane. A total of 48 samples were taken and divided into the example group, comparative example 1 group, comparative example 2 group, and comparative example 3 group, with 12 samples in each group. Eight samples in each group were used for artificial micro-defect detection, and the other four samples were kept intact to examine the false alarm situation. Only one artificial micro-defect was set on each artificial defect sample. Therefore, the total number of artificial micro-defects in each group was 8. The artificial micro-defects were all set in the range of 420 mm to 435 mm from the starting point of the sample. The same fine needle and the same fine cutter were used to prepare point defects or short scratch defects in the same way.

[0071] In this invention, the detection was performed according to the methods of Examples 1 and 2. Comparative Example 1 only omits the surface condition standardization process, that is, after the sample is cut off, no residual lubricating oil and surface contaminants are removed and no drying process is performed. The sample directly enters the reference section establishment and wetting and developing detection process. Comparative Example 2 retains the surface condition standardization process, but does not perform response stability testing and qualification screening when establishing the reference section. Instead, it directly uses the 100mm section in the middle of the sample as the reference section. Comparative Example 3 retains the surface condition standardization process and the reference section establishment process, but does not use the continuous window condition when judging anomalies. Instead, it judges anomalies only when the deviation rate of the main parameter of a single window reaches the threshold.

[0072] Apart from the aforementioned distinguishing features, the source of each group of samples, the composition of the wetting and developing liquid, the amount of liquid applied, the length of the sampling window, the contact time between the liquid and the insulating varnish film, the image acquisition conditions, the method of extracting the main parameters, the calculation method of the deviation rate, and the confirmation process are all consistent.

[0073] All samples were randomly numbered and cross-tested over two consecutive days, with 6 samples tested in each group each day. All tests were performed by the same operator on the same testing platform. Each group of samples underwent three rounds of repeated testing. Continuous indicators in the table below are expressed as the average ± standard deviation of the three rounds of testing results. Count indicators use a single artificial defect location or a single abnormal segment in a single sample as the statistical unit. If an area is judged as abnormal in at least two of the three rounds of testing, it is included in the final statistical result. The total number of initially judged abnormal areas included in the statistics in Table 2 refers to the number of initially judged abnormal areas included in the final statistics according to the above repeated testing statistical rules, not the number of abnormal areas obtained from a single test. All initially judged abnormal areas adopted the same confirmation process: repeated testing followed by microscopic verification. Abnormal areas meeting the location and operational conditions underwent further local repair comparisons before and after. For abnormal areas not meeting the local repair conditions, the results of repeated testing and microscopic verification were used as the confirmation basis.

[0074] The number of samples that were replaced with standard references refers to the number of samples whose candidate reference segments on the same line failed the qualification screening and therefore were replaced with standard reference segments of the same specification to establish reference responses. The average overlap rate of abnormal windows in repeated detections refers to the proportion of the number of overlapping windows to the total number of abnormal windows in the set of windows that were judged as abnormal in three rounds of repeated detections for the same sample, and the average of the three sets of comparison results is taken. The average number of abnormal boundary drift windows refers to the change in the starting window number and the ending window number obtained in each round of detection for the same abnormal area corresponding to the position of the same sample in three rounds of repeated detections, and the average of the changes is taken. For isolated abnormal areas that cannot be matched, this indicator is not included, but is included in the false positive statistics.

[0075] Table 1. Comparison of reference segment establishment and detection stability between the present invention example and three single-factor comparative examples (exemplary results)

[0076] Note: Comparative Example 2 did not undergo reference section qualification screening. Its use of the same line reference section refers to directly using the middle 100mm section of the sample as the reference section, which does not mean that the quality of its reference section is better than that of the present invention.

[0077] As can be seen from Table 1, the present invention is superior to the three single-factor comparative examples in terms of reference segment establishment and detection stability. In Comparative Example 1, the coefficients of variation of the three main parameters of the selected reference segment are significantly increased, and the number of samples using standard samples as references is significantly increased. This indicates that without surface condition standardization, residual lubricating oil and surface contaminants will significantly increase the internal response dispersion of the candidate reference segment and reduce the success rate of establishing the co-linear reference segment. Although all samples in Comparative Example 2 use co-linear reference segments, the coefficients of variation of the three main parameters of the selected reference segment are still significantly higher than those of the present invention. This indicates that directly using a fixed segment without response stability testing and qualification screening can easily lead to using a segment with an unsatisfactory surface condition or response level as the reference segment. The reference segment establishment quality of Comparative Example 3 is close to that of the present invention, but its repeated detection anomaly window overlap rate and the number of anomaly boundary drift windows are significantly worse than those of the present invention. This indicates that the continuous window condition mainly affects the stability of anomaly determination, rather than directly affecting the establishment of the reference segment itself.

[0078] Table 2 Comparison of anomaly detection and confirmation results between the present invention example and three single-factor comparative examples (exemplary results)

[0079] The consistency rate between the abnormal area and the confirmed result is calculated as the ratio of the number of confirmed real abnormal areas to the total number of initially judged abnormal areas included in the statistics; the number of false positives includes falsely reported abnormal areas in intact samples and additional abnormal areas in defective samples that do not correspond to the location of artificial micro-defects and are confirmed not to be real abnormalities.

[0080] As shown in Table 2, the present invention outperforms the three comparative examples in terms of artificial micro-defect detection capability, false alarm control, and final confirmation consistency. Although Comparative Example 1 can still detect most artificial micro-defects, the total number of initially judged abnormal areas included in the statistics has increased significantly. The number of false alarm abnormal areas in intact samples and the number of abnormal areas outside the defective samples have both increased significantly. This indicates that when surface state standardization processing is not performed, the interference of non-defect factors on the local response is significantly enhanced. Comparative Example 2 shows that retaining only the pre-processing without reference segment qualification screening, although the false alarm situation is improved compared to Comparative Example 1, is still significantly worse than the present invention example. This indicates that response stability testing and qualified sample response range qualification screening have practical effects on establishing a reliable reference response. In Comparative Example 3, the number of artificial micro-defects detected is the same as the present invention example, but the total number of initially judged abnormal areas included in the statistics, the total number of false alarm abnormal areas in intact samples, the number of abnormal areas outside the defective samples, and the number of false positives are the highest among the four groups, and the consistency rate is the lowest. This indicates that the single-window threshold determination is easily affected by random fluctuations, reflection changes, and local droplet boundary disturbances.

[0081] Further statistical analysis of the eight additional anomaly regions generated by the defect sample in Comparative Example 3 revealed that five of them overlapped with the window containing the real defect, exhibiting anomaly region boundary expansion; the remaining three were isolated anomaly regions with no corresponding relationship to the location of the real defect. This result indicates that the continuous window condition not only reduces isolated false alarms but also suppresses unstable boundary expansion around the real anomaly region, thereby improving the stability of the anomaly region boundary and the consistency of confirmation.

[0082] As can be seen from Tables 1 and 2, the present invention does not simply set up preprocessing, reference segment establishment, and anomaly judgment rules in parallel. Instead, it achieves the overall technical effect through the synergistic effect of multiple technical features: surface state standardization reduces the interference of surface contamination on wetting and developing response; reference segment qualification screening improves the reliability of reference response; and continuous window conditions improve the stability of anomaly judgment and the consistency of final confirmation. Compared with Comparative Examples 1, 2, and 3, the present invention performs better in terms of reference segment establishment success rate, reference segment response stability, repeat detection consistency, false alarm control, and confirmation result consistency rate. This indicates that the method of the present invention, while maintaining a high defect detection capability, helps to reduce the burden of subsequent manual review and can be stably implemented under actual detection conditions.

[0083] It should be noted that the above results are exemplary results. In practical applications, the method of the present invention can be adjusted according to the nominal diameter of the conductor, the insulating varnish system, the wetting and developing liquid system, and the detection sensitivity requirements, including the amount of liquid applied, the length of the sampling window, the deviation rate threshold, the number of consecutive windows, and the reference segment screening parameters. For samples from different batches or different detection days, the same comparison framework can be used for repeated verification to improve statistical reliability and implementation robustness.

Claims

1. A method for detecting wetting and developing micro-defects in the insulation film of enameled wire, characterized in that, Includes the following steps: The surface condition of the enameled wire to be tested is standardized. Establish a reference section; The wetting and developing liquid is brought into contact with the insulating varnish film of the reference section and the insulating varnish film of the section to be tested on the enameled wire. Under the same testing conditions, obtain the reference response of the reference section and the local response of the section to be tested; Based on the deviation rate of the main parameters of the local response relative to the reference response, and in combination with the continuous window condition, the abnormal region is determined; Identify and output the abnormal region.

2. The wetting and developing detection method according to claim 1, characterized in that, The surface condition standardization process includes: Remove residual lubricating oil and / or surface contaminants from the surface of the enameled wire to be tested, and then dry it.

3. The wetting and developing detection method according to claim 1, characterized in that, The establishment of the reference segment includes: Candidate reference sections are pre-selected on the enameled wire to be tested, and the response stability of the candidate reference sections is tested. The mean value of the main parameters of the candidate reference segment that passes the response stability test is compared with the normal response range pre-established for qualified enameled wire samples of the same specification. The candidate reference segment that falls within the normal response range is used as the reference segment. When none of the candidate reference sections from the same enameled wire under test fall within the normal response range, a standard sample section or independent standard section of the same specification as the enameled wire under test is used as a reference section, and it is confirmed by pre-scanning under the same testing conditions as the enameled wire under test to meet the conditions for response stability testing.

4. The wetting and developing detection method according to claim 1, characterized in that, The wetting and developing liquid is a mixture of glycerol and saturated saline solution.

5. The wetting and developing detection method according to claim 1, characterized in that, The main parameters are quantitative parameters characterizing the reference response and the local response, including at least one of spreading length, retention area and local optical intensity; The quantitative parameters of the reference response are used as reference response parameters, which are the segment averages of all reference windows in the final reference segment on the corresponding main parameters. The main parameter deviation rate is calculated based on the relative deviation of the local response parameters of the test section from the corresponding reference response parameters of the reference section.

6. The wetting and developing detection method according to claim 1, characterized in that, The conditions for the same test include keeping the following conditions consistent: the amount of wetting and developing liquid applied, the contact time between the wetting and developing liquid and the insulating varnish film, the orientation and / or rotation angle of the enameled wire under test, and the response acquisition conditions.

7. The wetting and developing detection method according to claim 5, characterized in that, The local response parameters and the corresponding reference response parameters are matched according to the correspondence of the same main parameters, the same sampling window length, and the same sampling time or the same position; The determination condition is: at least one main parameter deviation rate reaches a preset threshold, and the situation of the main parameter deviation rate reaching the preset threshold occurs within no less than a preset number of consecutive detection windows; The test section that meets the judgment criteria is identified as an abnormal area, which is a local continuity abnormality area of ​​the insulating varnish film.

8. The wetting and developing detection method according to claim 1, characterized in that, During the contact process between the wetting and developing liquid and the insulating varnish film, at least one of the following is applied between the enameled wire conductor to be tested and the counter electrode located near the corresponding section to be tested: a pulse voltage with a peak value lower than the insulation breakdown threshold, a stepped boost voltage, or a current-limiting AC voltage, so as to apply local electrical excitation to the reference section and the section to be tested. When applying local electrical excitation for detection, the reference response parameters of the reference section are reacquired under the same electrical excitation conditions.

9. The wetting and developing detection method according to claim 1, characterized in that, The wetting and developing detection method also includes a step of confirming abnormal areas, specifically including at least one of repeated detection, local repair before and after comparison, microscopic verification, cross-section verification, and pressure resistance comparison.

10. The wetting and developing detection method according to claim 9, characterized in that, When using a before-and-after comparison of local repairs to identify abnormal areas, the repair material should be an insulating varnish system of the same type as the original varnish film or a compatible insulating covering material, and the difference in static contact angle between the repaired surface and the adjacent intact area before repair should not exceed 10°.

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