Method, system, device and storage medium for identifying defects in distribution transformer windings

Abstract

The present application discloses a method, system, device and computer-readable storage medium for identifying defects in a distribution transformer winding, including: injecting a detection voltage signal with specified parameters into the distribution transformer to be tested; obtaining the frequency response signal of the distribution transformer to be tested corresponding to the detection voltage signal; making a current control chart according to the frequency response signal and a preset abnormal frequency response signal; judging whether the difference between the current control chart and a preset standard control chart exceeds a preset judgment criterion; if the difference exceeds the judgment criterion, there are defects in the winding of the distribution transformer to be tested, and a detection result is generated. The present application pre-makes a corresponding standard control chart when the distribution transformer to be tested is normal. During the commissioning test, the detection voltage signal is injected again to obtain the current control chart. By comparing whether the difference between the two control charts before and after exceeds the preset judgment criterion, it can accurately, quickly and efficiently judge whether there are already defects in the distribution transformer to be tested.

Description

Technical Field

[0001] The present invention relates to the field of transformers, and particularly to a method, system, device and computer-readable storage medium for identifying defects in a distribution transformer winding. Background Art

[0002] Distribution transformers are an important part of power supply, and their reliability is of great significance to the safe and efficient operation of the power grid. Mechanical and electrical stresses in the winding can affect the performance of the transformer. When a defect occurs in the transformer winding, it is necessary to detect it in time and perform power-off maintenance to prevent the defect from further developing and causing an expansion of the accident range, or even damaging the transformer.

[0003] Therefore, there is an urgent need for a method capable of identifying winding defects. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method, system, device and computer-readable storage medium for identifying defects in a distribution transformer winding, which can identify winding defects. The specific solutions are as follows:

[0005] A method for identifying defects in a distribution transformer winding includes:

[0006] Injecting a detection voltage signal with specified parameters into the distribution transformer to be measured;

[0007] Obtaining the frequency response signal of the distribution transformer to be measured corresponding to the detection voltage signal;

[0008] Making a current control chart according to the frequency response signal and a preset abnormal frequency response signal;

[0009] Judging whether the difference between the current control chart and a preset standard control chart exceeds a preset judgment standard;

[0010] If the difference exceeds the judgment standard, there are defects in the winding of the distribution transformer to be measured, and a detection result is generated;

[0011] Wherein, the abnormal frequency response signal is the frequency response signal obtained by presetting different defect states for the distribution transformer to be measured in a defect-free state; the standard control chart is drawn in advance by using the historical normal frequency response signal measured by the distribution transformer to be measured in a defect-free state and the abnormal frequency response signal.

[0012] Optionally, the process of injecting a detection voltage signal with specified parameters into the distribution transformer to be measured includes:

[0013] Injecting a sinusoidal detection voltage signal with an amplitude varying between -100 dB and 20 dB and a frequency varying between 50 Hz and 1 MHz into the distribution transformer to be measured.

[0014] Optionally, the process of obtaining the frequency response signal of the distribution transformer under test corresponding to the detected voltage signal includes:

[0015] Adjust the frequency of the detected voltage signal according to a preset frequency band division, and respectively obtain multiple frequency response signals under different frequency bands.

[0016] Optionally, the process of creating the current control chart based on the frequency response signal and a preset abnormal frequency response signal includes:

[0017] Use the multiple frequency response signals under different frequency bands and the abnormal frequency response signals of the corresponding frequency bands to obtain the current mean control chart, current range control chart, and current standard deviation control chart for each frequency band.

[0018] Optionally, the process of using the multiple frequency response signals under different frequency bands and the abnormal frequency response signals of the corresponding frequency bands to obtain the current mean control chart, current range control chart, and current standard deviation control chart for each frequency band includes:

[0019] Use the multiple frequency response signals under different frequency bands, the abnormal frequency response signals of the corresponding frequency bands, and the mean center line CL formula, mean upper control limit UCL formula, and mean lower control limit LCL formula of the mean control chart to obtain the current mean control chart for different frequency bands;

[0020] Use the multiple frequency response signals under different frequency bands, the abnormal frequency response signals of the corresponding frequency bands, the range center line CL formula, range upper control limit UCL formula, and range lower control limit LCL formula of the range control chart to obtain the current range control chart for different frequency bands;

[0021] Use the multiple frequency response signals under different frequency bands, the abnormal frequency response signals of the corresponding frequency bands, the standard deviation center line CL formula, standard deviation upper control limit UCL formula, and standard deviation lower control limit LCL formula of the standard deviation control chart to obtain the current standard deviation control chart for different frequency bands;

[0022] Among them, the mean center line CL formula is:

[0023] The mean upper control limit UCL formula is:

[0024] The mean lower control limit LCL formula is:

[0025] The range center line CL formula is:

[0026] The formula for the upper control limit UCL of the range is as follows:

[0027] The formula for the lower control limit LCL of the range is as follows:

[0028] The formula for the center line CL of the standard deviation is as follows:

[0029] The formula for the upper control limit UCL of the standard deviation is as follows:

[0030] The formula for the lower control limit LCL of the standard deviation is as follows:

[0031] In the formula, X ij =Z ij -Y ij , R i =X ijmax -X ijmin , Z ij (i = 1,..., k, j = 1,..., n) represents the frequency response signal, and Y ij (i = 1,..., k, j = 1,..., n) represents the abnormal frequency response signal. The subscripts i and j represent the j-th measurement data point of sample i. is the mean of the differences of the i-th sample, is the mean of the differences of k samples, and A1 is a constant related to the number of samples. is the mean of the ranges of the differences of k samples, and R i is the range of the differences of the i-th sample. D1 and D2 are constants related to the number of samples respectively. S i is the standard deviation of the differences of the i-th sample, is the mean of the standard deviations of the differences of k samples. B1 and B2 are constants related to the number of samples.

[0032] The present invention also discloses a distribution transformer winding defect identification system, including:

[0033] A detection signal injection module for injecting a detection voltage signal with specified parameters into the distribution transformer to be tested;

[0034] A response signal acquisition module for acquiring the frequency response signal of the distribution transformer to be tested corresponding to the detection voltage signal;

[0035] A control chart making module for making a current control chart according to the frequency response signal and a preset abnormal frequency response signal;

[0036] A difference judgment module, configured to judge whether the difference between the current control chart and a preset standard control chart exceeds a preset judgment criterion;

[0037] A result generation module, configured to generate a detection result if the difference judgment module determines that the difference exceeds the judgment criterion, indicating that there is a defect in the winding of the distribution transformer to be tested;

[0038] Wherein, the abnormal frequency response signal is a frequency response signal obtained by presetting different defect states for the distribution transformer to be tested in a defect-free state; the standard control chart is drawn in advance using the historical normal frequency response signal and the abnormal frequency response signal measured by the distribution transformer to be tested in a defect-free state.

[0039] Optionally, the response signal acquisition module is specifically configured to adjust the frequency of the detection voltage signal according to a preset frequency band division, and respectively acquire a plurality of frequency response signals in different frequency bands.

[0040] Optionally, the control chart making module is specifically configured to use a plurality of frequency response signals in different frequency bands and the abnormal frequency response signal of the corresponding frequency band to obtain a current mean control chart, a current range control chart, and a current standard deviation control chart for each frequency band.

[0041] The present invention also discloses a device for identifying defects in the winding of a distribution transformer, including:

[0042] A memory, configured to store a computer program;

[0043] A processor, configured to execute the computer program to implement the method for identifying defects in the winding of a distribution transformer as described above.

[0044] The present invention also discloses a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the method for identifying defects in the winding of a distribution transformer as described above is implemented.

[0045] In the present invention, a method for identifying defects in a distribution transformer winding includes: injecting a detection voltage signal with specified parameters into the distribution transformer to be tested; obtaining the frequency response signal of the distribution transformer to be tested corresponding to the detection voltage signal; creating a current control chart based on the frequency response signal and a preset abnormal frequency response signal; determining whether the difference between the current control chart and a preset standard control chart exceeds a preset judgment criterion; if the difference exceeds the judgment criterion, it indicates that there are defects in the winding of the distribution transformer to be tested, and a detection result is generated; wherein, the abnormal frequency response signal is the frequency response signal obtained after presetting different defect states for the distribution transformer to be tested in a defect-free state; and the standard control chart is drawn in advance using the historical normal frequency response signal and abnormal frequency response signal measured for the distribution transformer to be tested in a defect-free state.

[0046] In the present invention, a corresponding standard control chart is made in advance when the distribution transformer to be tested is normal. During the commissioning test, the detection voltage signal is injected again to obtain the current control chart. By comparing whether the difference between the two control charts before and after exceeds the preset judgment criterion, it can accurately, quickly and efficiently determine whether there are already defects in the distribution transformer to be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0048] Figure 1 It is a schematic flowchart of a method for identifying defects in a distribution transformer winding disclosed in an embodiment of the present invention;

[0049] Figure 2 It is a schematic flowchart of another method for identifying defects in a distribution transformer winding disclosed in an embodiment of the present invention;

[0050] Figure 3 It is a schematic structural diagram of a system for identifying defects in a distribution transformer winding disclosed in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0051] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0052] An embodiment of the present invention discloses a method for identifying defects in a distribution transformer winding. Refer to Figure 1 As shown, the method includes:

[0053] S11: Inject a detection voltage signal with specified parameters into the distribution transformer to be tested.

[0054] Specifically, the detection voltage signal with specified parameters can be injected during the shutdown detection of the distribution transformer to be tested, so as to obtain the corresponding frequency response signal subsequently.

[0055] Among them, the detection voltage signal can be a low-amplitude, variable-frequency sine wave voltage signal with an amplitude between -100 dB and 20 dB and a frequency variable between 50 Hz and 1 MHz.

[0056] S12: Obtain the frequency response signal of the distribution transformer to be tested corresponding to the detection voltage signal.

[0057] Specifically, after injecting the detection voltage signal into the distribution transformer to be tested, the corresponding frequency response signal of the distribution transformer to be tested can be received. Since the detection voltage signal is a controllable signal, the obtained frequency response signal is directly related to the state of the distribution transformer to be tested. Therefore, the frequency response signal can be used to reflect the state of the distribution transformer to be tested.

[0058] S13: Make a current control chart according to the frequency response signal and the preset abnormal frequency response signal.

[0059] Specifically, the abnormal frequency response signal is the frequency response signal obtained after presetting different defect states for the distribution transformer to be tested in a defect-free state. For example, when the distribution transformer to be tested leaves the factory, it can be ensured that the distribution transformer to be tested is in a defect-free state. In this state, different defect states can be deliberately set artificially. For example, three kinds of defects, namely short circuit, axial displacement and radial deformation, are set to make the corresponding frequency response signals under different defect states, that is, the abnormal frequency response signals, for subsequent comparison as a reference value after being put into operation.

[0060] Specifically, the current control chart is obtained by comparing the currently measured frequency response signal with the previously obtained abnormal frequency response signal.

[0061] S14: Determine whether the difference between the current control chart and the preset standard control chart exceeds the preset judgment criterion.

[0062] Specifically, the standard control chart is drawn in advance by using the historical normal frequency response signal and the abnormal frequency response signal measured when the distribution transformer to be tested is in a defect-free state. For example, the historical normal frequency response signal is obtained when the distribution transformer to be tested leaves the factory, and then compared with the abnormal frequency response signal to obtain the standard control chart.

[0063] Specifically, by comparing the differences between the current control chart and the standard control chart initially obtained for the transformer under test, the magnitude of the differences between the two control charts can reflect whether the state of the transformer under test has changed, thereby determining whether there are defects in the windings of the transformer under test.

[0064] Specifically, the preset judgment criteria may include: 1. A data point on the current control chart is outside the upper control limit or the lower control limit of the standard control chart; 2. Nine consecutive data points on the current control chart are arranged below or above the center line of the standard control chart; 3. There is a tendency of continuous increase or decrease in not less than six consecutive data points on the current control chart; 4. Among 14 consecutive data points on the current control chart, adjacent points alternate up and down; 5. For two of the three consecutive data points on the current control chart, the distance from the CL of the standard control chart exceeds two standard deviations; 6. For four of the five consecutive data points on the current control chart, the distance from the CL of the standard control chart exceeds one standard deviation; 7. Fifteen consecutive data points on the current control chart are within one standard deviation of the CL of the standard control chart; 8. Eight consecutive data points on the current control chart are outside one standard deviation of the CL of the standard control chart. When any of the above conditions is met, it is considered that there are defects in the windings of the distribution transformer under test.

[0065] S15: If the difference exceeds the judgment criteria, there are defects in the windings of the distribution transformer under test, and a detection result is generated.

[0066] Specifically, if the above judgment criteria are exceeded, it is determined that there are defects, and a detection result finally recording the existence of defects is generated, realizing fast and efficient identification of defects in the windings of the distribution transformer.

[0067] It can be understood that if the judgment criteria are not exceeded, it means that the windings of the distribution transformer under test are normal and there are no obvious defects.

[0068] It can be seen that in the embodiment of the present invention, a corresponding standard control chart is made in advance when the distribution transformer under test is normal. During the commissioning test, a detection voltage signal is injected again to obtain the current control chart. By comparing whether the difference between the two control charts before and after exceeds the preset judgment criteria, it is possible to accurately, quickly and efficiently determine whether there are already defects in the distribution transformer under test.

[0069] The embodiment of the present invention discloses a specific method for identifying defects in the windings of a distribution transformer. Compared with the previous embodiment, this embodiment further explains and optimizes the technical solution. See Figure 2 As shown, specifically:

[0070] S21: Inject a detection voltage signal with specified parameters into the distribution transformer under test;

[0071] S22: Adjust the frequency of the detected voltage signal according to the preset frequency band division, and respectively obtain multiple frequency response signals under different frequency bands.

[0072] Specifically, different faults show different degrees of differences from the normal state at different frequencies. Therefore, three types of frequency bands can be divided: the low-frequency band where the frequency of the detected voltage signal is less than 100 kHz, the medium-frequency band where the frequency of the detected voltage signal is between 100 - 600 kHz, and the high-frequency band where the frequency of the detected voltage signal is greater than 600 kHz. Modulate the detected voltage signal into each frequency band respectively, and obtain the frequency response signals within each frequency band. The multiple frequency response signals obtained within each frequency band can be made into an operating state database, and then the frequency response signals within each frequency band are equally spaced and extracted from the operating state database to obtain the frequency response signal samples required for finally making the control chart. For example, k samples are equally spaced and extracted from each frequency band database, and each sample consists of n measurement data points (n is usually 4 or 5 or more). For each frequency band, the sample value can be named Z ij (i = 1,..., k, j = 1,..., n), where the subscripts i and j represent the j-th measurement data point of sample i. Among them, the samples correspond to the injection tests in the healthy or faulty conditions in sequence, and the measurement data points represent the signal data points obtained in the case of this sample.

[0073] S23: Use the multiple frequency response signals under different frequency bands and the abnormal frequency response signals corresponding to the respective frequency bands to obtain the current mean control chart, current range control chart, and current standard deviation control chart for each frequency band.

[0074] Specifically, by subtracting the frequency response signals corresponding to different frequency bands from the abnormal frequency response signals of different defects in the same frequency band respectively, and then obtaining the current mean control chart, current range control chart, and current standard deviation control chart for each frequency band according to the differences. On the premise of the three medium-frequency bands, a total of 9 control charts will be obtained.

[0075] Furthermore, the specific generation process of the control chart can include S231 to S233; among them,

[0076] S231: Use the multiple frequency response signals under different frequency bands, the abnormal frequency response signals corresponding to the respective frequency bands, and the mean center line CL formula, mean upper control limit UCL formula, and mean lower control limit LCL formula of the mean control chart to obtain the current mean control chart for different frequency bands;

[0077] S232: Use the multiple frequency response signals under different frequency bands, the abnormal frequency response signals corresponding to the respective frequency bands, the range center line CL formula, range upper control limit UCL formula, and range lower control limit LCL formula of the range control chart to obtain the current range control chart for different frequency bands;

[0078] S233: Obtain the current standard deviation control chart for different frequency bands by using multiple frequency response signals in different frequency bands, the abnormal frequency response signals of the corresponding frequency bands, the standard deviation center line CL formula of the standard deviation control chart, the standard deviation upper control limit UCL formula, and the standard deviation lower control limit LCL formula.

[0079] Specifically, calculate the key data through the calculation formulas of different control charts to obtain the current mean control chart, the current range control chart, and the current standard deviation control chart for different frequency bands.

[0080] Among them, the mean center line CL formula is:

[0081] The mean upper control limit UCL formula is:

[0082] The mean lower control limit LCL formula is:

[0083] The range center line CL formula is:

[0084] The range upper control limit UCL formula is:

[0085] The range lower control limit LCL formula is:

[0086] The standard deviation center line CL formula is:

[0087] The standard deviation upper control limit UCL formula is:

[0088] The standard deviation lower control limit LCL formula is:

[0089] In the formula, X ij = Z ij - Y ij , R i = X ijmax - X ijmin , Z ij (i = 1,..., k, j = 1,..., n) represents the frequency response signal, Y ij (i = 1,..., k, j = 1,..., n) represents the abnormal frequency response signal, and the subscripts i and j represent the jth measurement data point of sample i. is the mean of the differences of the ith sample, is the mean of the differences of k samples, A1 is a constant related to the number of samples, is the mean of the ranges of the differences of k samples, R iis the range of the i-th sample difference, D1 and D2 are constants related to the number of samples, and S i is the standard deviation of the i-th sample difference, is the mean of the standard deviations of k sample differences, and B1 and B2 are constants related to the number of samples.

[0090] S24: Determine whether the difference between the current control chart and the preset standard control chart exceeds the preset judgment criterion;

[0091] S25: If the difference exceeds the judgment criterion, there is a defect in the winding of the distribution transformer to be tested, and a detection result is generated;

[0092] Among them, the abnormal frequency response signal is the frequency response signal obtained by presetting different defect states for the distribution transformer to be tested in a defect-free state; the standard control chart is drawn in advance using the historical normal frequency response signal and abnormal frequency response signal measured by the distribution transformer to be tested in a defect-free state.

[0093] Correspondingly, an embodiment of the present invention also discloses a distribution transformer winding defect identification system. Refer to Figure 3 as shown, the system includes:

[0094] A detection signal injection module 11 for injecting a detection voltage signal with specified parameters into the distribution transformer to be tested;

[0095] A response signal acquisition module 12 for acquiring the frequency response signal of the distribution transformer to be tested corresponding to the detection voltage signal;

[0096] A control chart making module 13 for making a current control chart according to the frequency response signal and the preset abnormal frequency response signal;

[0097] A difference judgment module 14 for judging whether the difference between the current control chart and the preset standard control chart exceeds the preset judgment criterion;

[0098] A result generation module 15 for, if the difference judgment module 14 determines that the difference exceeds the judgment criterion, there is a defect in the winding of the distribution transformer to be tested, and generating a detection result;

[0099] Among them, the abnormal frequency response signal is the frequency response signal obtained by presetting different defect states for the distribution transformer to be tested in a defect-free state; the standard control chart is drawn in advance using the historical normal frequency response signal and abnormal frequency response signal measured by the distribution transformer to be tested in a defect-free state.

[0100] It can be seen that in the embodiment of the present invention, a corresponding standard control chart is pre-made when the distribution transformer to be tested is normal. During the commissioning test, a detection voltage signal is injected again to obtain the current control chart. By comparing whether the difference between the two control charts before and after exceeds the preset judgment standard, it can be accurately, quickly and efficiently judged whether there are defects in the distribution transformer to be tested.

[0101] Specifically, the detection signal injection module 11 can be specifically used to inject a sinusoidal detection voltage signal with an amplitude variable between -100 dB and 20 dB and a frequency variable between 50 Hz and 1 MHz into the distribution transformer to be tested.

[0102] Specifically, the response signal acquisition module 12 is specifically used to adjust the frequency of the detection voltage signal according to the preset frequency band division, and respectively acquire multiple frequency response signals under different frequency bands.

[0103] Specifically, the control chart production module 13 can be specifically used to obtain the current mean control chart, current range control chart and current standard deviation control chart for each frequency band by using multiple frequency response signals under different frequency bands and the abnormal frequency response signals of the corresponding frequency bands.

[0104] Specifically, the control chart production module 13 may include: a mean control chart production unit, a range control chart production unit and a standard deviation control chart production unit; where

[0105] The mean control chart production unit is used to obtain the current mean control chart for different frequency bands by using multiple frequency response signals under different frequency bands, the abnormal frequency response signals of the corresponding frequency bands, and the mean center line CL formula, mean upper control limit UCL formula and mean lower control limit LCL formula of the mean control chart.

[0106] The range control chart production unit is used to obtain the current range control chart for different frequency bands by using multiple frequency response signals under different frequency bands, the abnormal frequency response signals of the corresponding frequency bands, the range center line CL formula, range upper control limit UCL formula and range lower control limit LCL formula of the range control chart.

[0107] The standard deviation control chart production unit is used to obtain the current standard deviation control chart for different frequency bands by using multiple frequency response signals under different frequency bands, the abnormal frequency response signals of the corresponding frequency bands, the standard deviation center line CL formula, standard deviation upper control limit UCL formula and standard deviation lower control limit LCL formula of the standard deviation control chart.

[0108] Among them, the mean center line CL formula is:

[0109] The mean upper control limit UCL formula is:

[0110] The formula for the lower control limit LCL of the mean is:

[0111] The formula for the center line CL of the range is:

[0112] The formula for the upper control limit UCL of the range is:

[0113] The formula for the lower control limit LCL of the range is:

[0114] The formula for the center line CL of the standard deviation is:

[0115] The formula for the upper control limit UCL of the standard deviation is:

[0116] The formula for the lower control limit LCL of the standard deviation is:

[0117] In the formula, X ij = Z ij - Y ij , R i = X ijmax - X ijmin , Z ij (i = 1,..., k, j = 1,..., n) represents the frequency response signal, Y ij (i = 1,..., k, j = 1,..., n) represents the abnormal frequency response signal, and the subscripts i and j represent the jth measurement data point of sample i. is the mean of the differences of the ith sample, is the mean of the differences of k samples, and A1 is a constant related to the number of samples. is the mean of the ranges of the differences of k samples, R i is the range of the differences of the ith sample, and D1 and D2 are constants related to the number of samples respectively. S i is the standard deviation of the differences of the ith sample, is the mean of the standard deviations of the differences of k samples, and B1 and B2 are constants related to the number of samples.

[0118] In addition, the embodiment of the present invention also discloses a device for identifying defects in a distribution transformer winding, including:

[0119] A memory for storing a computer program;

[0120] A processor for executing the computer program to implement the method for identifying defects in a distribution transformer winding as described above.

[0121] In addition, an embodiment of the present invention also discloses a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the above-described method for identifying defects in a distribution transformer winding is implemented.

[0122] Finally, it should also be noted that in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0123] Those skilled in the art can further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in this document can be implemented by electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to their functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Skilled professionals can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0124] The above provides a detailed introduction to the technical content provided by the present invention. Specific examples are used in this document to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A method for identifying defects in a distribution transformer winding, characterized in that, Including: Injecting a detection voltage signal with specified parameters into the distribution transformer to be tested; Obtaining the frequency response signal of the distribution transformer to be tested corresponding to the detection voltage signal; Using multiple frequency response signals in different frequency bands and the abnormal frequency response signals in the corresponding frequency bands to obtain the current mean control chart, current range control chart and current standard deviation control chart for each frequency band, where the current mean control chart, current range control chart and current standard deviation control chart together serve as the current control chart; Judging whether the difference between the current control chart and the preset standard control chart exceeds the preset judgment standard; If the difference exceeds the judgment standard, there are defects in the winding of the distribution transformer to be tested, and a detection result is generated; Wherein, the abnormal frequency response signal is the frequency response signal obtained after presetting different defect states for the distribution transformer to be tested in a defect-free state; the standard control chart is drawn in advance using the historical normal frequency response signals and the abnormal frequency response signals measured for the distribution transformer to be tested in a defect-free state; Wherein, the process of using multiple frequency response signals in different frequency bands and the abnormal frequency response signals in the corresponding frequency bands to obtain the current mean control chart, current range control chart and current standard deviation control chart for each frequency band includes: Using multiple frequency response signals in different frequency bands, the abnormal frequency response signals in the corresponding frequency bands, and the mean center line CL formula, mean upper control limit UCL formula and mean lower control limit LCL formula of the mean control chart to obtain the current mean control chart for different frequency bands; Using multiple frequency response signals in different frequency bands, the abnormal frequency response signals in the corresponding frequency bands, the range center line CL formula, range upper control limit UCL formula and range lower control limit LCL formula of the range control chart to obtain the current range control chart for different frequency bands; Using multiple frequency response signals in different frequency bands, the abnormal frequency response signals in the corresponding frequency bands, the standard deviation center line CL formula, standard deviation upper control limit UCL formula and standard deviation lower control limit LCL formula of the standard deviation control chart to obtain the current standard deviation control chart for different frequency bands; Among them, the formula for the mean center line CL is: The upper control limit UCL formula for the mean is as follows: The formula for the lower control limit LCL of the mean is as follows: The formula for the range center line CL is as follows: The formula for the upper control limit UCL of the range is as follows: The lower control limit LCL formula for the range is as follows: The formula for the standard deviation center line CL is as follows: The upper control limit UCL formula for the standard deviation is as follows: The formula for the lower control limit LCL under the said standard deviation is as follows: Wherein, X ij =Z ij -Y ij , R i =X ijmax -X ijmin , Z ij (i = 1,..., k, j = 1,..., n) represents the frequency response signal, Y ij (i = 1,..., k, j = 1,..., n) represents the abnormal frequency response signal, and the subscripts i and j represent the j-th measurement data point of the i-th sample, is the mean value of the i-th sample difference, is the mean value of k sample differences, and A1 is a constant related to the number of samples, is the mean value of the ranges of k sample differences, R i is the range of the i-th sample difference, and D1 and D2 are constants related to the number of samples respectively, S i is the standard deviation of the i-th sample difference, is the mean value of the standard deviations of k sample differences, and B1 and B2 are constants related to the number of samples.

2. The method for identifying defects in a distribution transformer winding according to claim 1, wherein The process of injecting a detection voltage signal with specified parameters into the distribution transformer to be tested includes: Injecting a sinusoidal detection voltage signal with an amplitude variable between -100 dB and 20 dB and a frequency variable between 50 Hz and 1 MHz into the distribution transformer to be tested.

3. The method for identifying defects in a distribution transformer winding according to claim 2, wherein The process of obtaining the frequency response signal of the distribution transformer to be tested corresponding to the detection voltage signal includes: Adjusting the frequency of the detection voltage signal according to the preset frequency band division, and respectively obtaining multiple frequency response signals in different frequency bands.

4. A distribution transformer winding defect identification system, characterized in that, Including: A detection signal injection module for injecting a detection voltage signal with specified parameters into the distribution transformer to be tested; A response signal acquisition module for obtaining the frequency response signal of the distribution transformer to be tested corresponding to the detection voltage signal; A control chart making module, which is used to obtain the current mean control chart, current range control chart and current standard deviation control chart for each frequency band by using multiple frequency response signals in different frequency bands and the abnormal frequency response signals corresponding to the frequency bands. Among them, the current mean control chart, current range control chart and current standard deviation control chart together serve as the current control chart; A difference judgment module, which is used to judge whether the difference between the current control chart and the preset standard control chart exceeds the preset judgment standard; A result generation module, which is used to generate a detection result if the difference judgment module determines that the difference exceeds the judgment standard, indicating that there is a defect in the winding of the distribution transformer to be tested; Among them, the abnormal frequency response signal is the frequency response signal obtained after presetting different defect states for the distribution transformer to be tested in a defect-free state; the standard control chart is drawn in advance by using the historical normal frequency response signals and the abnormal frequency response signals measured for the distribution transformer to be tested in a defect-free state; Among them, the control chart making module is specifically used to obtain the current mean control chart for different frequency bands by using multiple frequency response signals in different frequency bands, the abnormal frequency response signals corresponding to the frequency bands, and the mean center line CL formula, mean upper control limit UCL formula and mean lower control limit LCL formula of the mean control chart; obtain the current range control chart for different frequency bands by using multiple frequency response signals in different frequency bands, the abnormal frequency response signals corresponding to the frequency bands, the range center line CL formula, range upper control limit UCL formula and range lower control limit LCL formula of the range control chart; obtain the current standard deviation control chart for different frequency bands by using multiple frequency response signals in different frequency bands, the abnormal frequency response signals corresponding to the frequency bands, the standard deviation center line CL formula, standard deviation upper control limit UCL formula and standard deviation lower control limit LCL formula of the standard deviation control chart; Among them, the formula for the mean center line CL is as follows: The formula for the upper control limit UCL of the mean is as follows: The formula for the lower control limit LCL of the mean is as follows: The formula for the range center line CL is as follows: The upper control limit UCL formula for the range is as follows: The formula for the lower control limit LCL of the range is as follows: The formula for the standard deviation center line CL is as follows: The upper control limit UCL formula for the standard deviation is as follows: The formula for the lower control limit LCL of the standard deviation is as follows: Wherein, X ij =Z ij -Y ij , R i =X ijmax -X ijmin , Z ij (i = 1, …, k, j = 1, …, n) represents the said frequency response signal, Y ij (i = 1, …, k, j = 1, …, n) represents the said abnormal frequency response signal, the subscripts i, j represent the j-th measurement data point of the i-th sample, is the mean value of the i-th sample difference, is the mean value of k sample differences, A1 is a constant related to the number of samples, is the mean value of the ranges of k sample differences, R i is the range of the i-th sample difference, D1, D2 are constants related to the number of samples respectively, S i is the standard deviation of the i-th sample difference, is the mean value of the standard deviations of k sample differences, B1, B2 are constants related to the number of samples.

5. The distribution transformer winding defect identification system according to claim 4, wherein The response signal acquisition module is specifically used to adjust the frequency of the detection voltage signal according to the preset frequency band division, and respectively acquire multiple frequency response signals in different frequency bands.

6. A device for identifying defects in a distribution transformer winding, characterized in that, It includes: A memory, which is used to store computer programs; A processor, which is used to execute the computer program to implement the distribution transformer winding defect identification method according to any one of claims 1 to 3.

7. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium, and when the computer program is executed by the processor, it implements the distribution transformer winding defect identification method according to any one of claims 1 to 3.

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