A voltage transformer swing insulation test control method and device

Abstract

The application relates to the technical field of test control, and discloses a voltage transformer insulation test control method and device, the method comprising the following steps: collecting historical polarization absorption ratio data of voltage transformers with qualified insulation performance under different environmental conditions, and screening an initial judgment threshold value; randomly disturbing the initial judgment threshold value according to environmental parameters; using the candidate judgment threshold value to test the insulation performance of a voltage transformer to be detected, and calculating the area under the curve and the threshold safety margin; constructing a comprehensive evaluation function, calculating the comprehensive score of each candidate judgment threshold value, and screening the candidate judgment threshold value corresponding to the highest comprehensive score as a target threshold value to test the insulation performance of a target voltage transformer. The application effectively and reasonably sets the candidate judgment threshold value under different environmental conditions, and improves the accuracy of evaluating the insulation performance of the voltage transformer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of test control, in particular to a voltage transformer swing insulation test control method and device. BACKGROUND

[0002] The voltage transformer swing insulation test is an important means to evaluate the insulation performance of power equipment, especially after long-term use, the aging or damp of the insulation material often becomes a potential hidden danger of equipment failure. The voltage transformer swing insulation test judges the insulation performance by measuring the polarization absorption ratio of the insulation medium, so as to ensure the safe operation of the equipment.

[0003] The polarization absorption ratio is a key parameter for characterizing the polarization absorption characteristics of the insulation material, which reflects the absorption capacity of the insulation medium to the electric charge under the action of the electric field, and directly affects the electrical performance of the insulation layer. When the voltage transformer is subjected to swing insulation test, whether the insulation performance is abnormal is usually determined according to the set candidate judgment threshold. If the candidate judgment threshold is set too low, the damp or aged insulation material may be misjudged as normal, thereby reducing the reliability and safety of the test; and if the candidate judgment threshold is set too high, the voltage transformer swing insulation test may be misjudged under low temperature or high humidity and other environmental conditions, thereby affecting the efficiency and accuracy of the test.

[0004] Therefore, how to reasonably set the candidate judgment threshold to ensure that the insulation performance of the voltage transformer can be accurately evaluated under different environmental conditions has become a key problem for the safe operation of power equipment. SUMMARY

[0005] The present application provides a voltage transformer swing insulation test control method, which mainly aims to solve the problem that it is difficult to reasonably set the candidate polarization absorption ratio judgment threshold under different environmental conditions, resulting in low accuracy in evaluating the insulation performance of the voltage transformer.

[0006] In the first aspect, to achieve the above object, the present application provides a voltage transformer swing insulation test control method, and the swing insulation refers to the operation of insulation resistance test using a megohmmeter. The specific steps of the control method are as follows:

[0007] Collecting historical polarization absorption ratio data of voltage transformers with qualified insulation performance under different environmental conditions, and screening out the historical polarization absorption ratio data corresponding to the preset percentile as an initial polarization absorption ratio judgment threshold;

[0008] Obtaining environmental parameters of different environmental conditions, and randomly perturbing the initial polarization absorption ratio judgment threshold according to the environmental parameters to obtain a plurality of candidate polarization absorption ratio judgment thresholds;

[0009] The obtained voltage transformer to be detected is subjected to insulation performance test by using the candidate polarization absorption ratio judgment threshold, and the area under the curve and the threshold safety margin are calculated according to the insulation performance test result;

[0010] The comprehensive evaluation function is constructed according to the area under the curve and the threshold safety margin;

[0011] The comprehensive score of each candidate polarization absorption ratio judgment threshold is calculated by using the comprehensive evaluation function, and the candidate polarization absorption ratio judgment threshold corresponding to the highest comprehensive score is screened out;

[0012] The screened candidate polarization absorption ratio judgment threshold is used as a target threshold, and the target voltage transformer is subjected to insulation performance test by using the target threshold.

[0013] In a second aspect, the present application further provides a voltage transformer insulation performance test control device, which comprises:

[0014] An initial polarization absorption ratio judgment threshold screening module is configured to collect historical polarization absorption ratio data of voltage transformers with qualified insulation performance under different environmental conditions, and screen out the historical polarization absorption ratio data corresponding to a preset percentile as an initial polarization absorption ratio judgment threshold;

[0015] An initial polarization absorption ratio judgment threshold perturbation module is configured to obtain environmental parameters of different environmental conditions, and randomly perturb the initial polarization absorption ratio judgment threshold according to the environmental parameters to obtain a plurality of candidate polarization absorption ratio judgment thresholds;

[0016] An insulation performance test module is configured to use the candidate polarization absorption ratio judgment threshold to perform insulation performance test on the obtained voltage transformer to be detected, and calculate the area under the curve and the threshold safety margin according to the insulation performance test result;

[0017] An evaluation function construction module is configured to construct a comprehensive evaluation function according to the area under the curve and the threshold safety margin;

[0018] A comprehensive score calculation module is configured to calculate the comprehensive score of each candidate polarization absorption ratio judgment threshold by using the comprehensive evaluation function, and screen out the candidate polarization absorption ratio judgment threshold corresponding to the highest comprehensive score;

[0019] A target threshold screening module is configured to use the screened candidate polarization absorption ratio judgment threshold as a target threshold, and perform insulation performance test on a target voltage transformer by using the target threshold.

[0020] The application can more accurately identify the polarization absorption ratio characteristics under different environmental conditions by collecting the historical polarization absorption ratio data of voltage transformers with qualified insulation performance under different environmental conditions, and screening the historical polarization absorption ratio data corresponding to the preset percentile as the initial polarization absorption ratio judgment threshold, and then improving the reliability of the judgment threshold, obtaining the environmental parameters under different environmental conditions, randomly perturbing the initial polarization absorption ratio judgment threshold according to the environmental parameters, obtaining a plurality of candidate polarization absorption ratio judgment thresholds, and fully considering the potential influence of polarization absorption ratio judgment under different environmental conditions based on the random perturbation of the environmental parameters, using the candidate polarization absorption ratio judgment threshold to test the insulation performance of the obtained voltage transformer to be detected, and calculating the area under the curve and the threshold safety margin according to the insulation performance test result, calculating the true positive rate and the false positive rate, and drawing the performance curve, which can quantify the judgment ability of different thresholds, so as to select the best threshold to improve the test precision, screen out the minimum polarization absorption ratio and calculate the threshold safety margin, which is helpful to identify the performance of the equipment under the most extreme environment, construct a comprehensive evaluation function according to the area under the curve and the threshold safety margin, eliminate the absolute difference between different candidate thresholds by normalizing the area under the curve and the threshold safety margin, so that they can be compared on a unified scale. By combining the two normalized indicators through a nonlinear function, the comprehensive performance of each threshold can be more accurately evaluated to help select the optimal judgment standard, the comprehensive score of each candidate polarization absorption ratio judgment threshold is calculated using the comprehensive evaluation function, and the candidate polarization absorption ratio judgment threshold corresponding to the highest comprehensive score is screened out, which ensures that when selecting the judgment threshold, not only the area under the curve is used to measure the discrimination ability, but also the threshold safety margin takes into account the safety of the equipment under different environments. The selected candidate polarization absorption ratio judgment threshold is used as the target threshold, and the insulation performance of the target voltage transformer is tested using the target threshold. Under different environmental conditions, the candidate polarization absorption ratio judgment threshold is effectively and reasonably set, and the accuracy of evaluating the insulation performance of the voltage transformer is improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the description of the embodiments of the application. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0022] Figure 1 A flowchart of a voltage transformer insulation test control method provided by an embodiment of the application is shown in the figure.

[0023] Figure 2A module schematic diagram of a voltage transformer swing insulation test control device is provided for an embodiment of the present application.

[0024] The purposes, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0025] In order for those skilled in the technical field to better understand the technical solutions of the present disclosure, and to understand the implementation process of how the present disclosure applies technical means to solve technical problems and achieve corresponding technical effects, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, not all. The embodiments of the present disclosure and various features in the embodiments can be combined with each other without conflict, and the technical solutions formed thereby are all within the protection scope of the present disclosure. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative labor should be within the protection scope of the present disclosure.

[0026] It should be noted that the terms "first", "second", and the like in the specification and claims of the present disclosure and the above-described drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, device, product or apparatus including a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or apparatus.

[0027] The present application provides a voltage transformer swing insulation test control method, which can be executed by software or hardware installed in a terminal device or a server device. The server device includes but is not limited to a single server, a server cluster, a cloud server, or a cloud server cluster, etc. The server can be a stand-alone server, or a cloud server providing cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, content distribution networks (CDN), and big data and artificial intelligence platforms, etc. basic cloud computing services.

[0028] Reference Figure 1As shown, a flowchart of a voltage transformer insulation test control method provided by an embodiment of the application is shown. In this embodiment, the voltage transformer insulation test control method includes:

[0029] S1, collect historical polarization absorption ratio data of voltage transformers with qualified insulation performance under different environmental conditions, and select the historical polarization absorption ratio data corresponding to a preset percentile as an initial polarization absorption ratio judgment threshold.

[0030] In the embodiment of the application, different environmental conditions refer to combinations of external environmental parameters of voltage transformers during operation or testing, including but not limited to environmental temperature, relative humidity, atmospheric pressure, altitude, electric field intensity, and surrounding electromagnetic interference level, etc.

[0031] Voltage transformers with qualified insulation performance refer to voltage transformers whose insulation medium (such as insulation oil, paper, epoxy resin, etc.) meets the requirements of national or industry standards through factory or periodic test verification.

[0032] Historical polarization absorption ratio data refer to a collection of test result data of polarization absorption ratio in the historical test records of voltage transformers, which is usually calculated from the insulation resistance values at 1 minute and 10 minutes by an insulation resistance tester.

[0033] In detail, the selection of the historical polarization absorption ratio data corresponding to a preset percentile as an initial polarization absorption ratio judgment threshold includes:

[0034] Extracting environmental parameters of different environmental conditions;

[0035] Associating the environmental parameters with the historical polarization absorption ratio data to obtain labeled polarization absorption ratio data;

[0036] Randomly selecting one of the labeled polarization absorption ratio data as target polarization absorption ratio data;

[0037] Performing similarity analysis on the environmental parameters of the target polarization absorption ratio data and other labeled polarization absorption ratio data to obtain environmental similarity;

[0038] Performing cluster analysis on the labeled polarization absorption ratio data according to the environmental similarity to obtain several representative environmental clusters;

[0039] Sorting the labeled polarization absorption ratio data in the representative environmental clusters in ascending order to obtain sorted polarization absorption ratio data in each representative environmental cluster;

[0040] Selecting the screening polarization absorption ratio data of the first preset percentile from the sorted polarization absorption ratio data in each representative environmental cluster;

[0041] The initial polarized absorption ratio judgment threshold is generated by weighted average of all the screened polarized absorption ratio data.

[0042] In detail, by collecting data under different environmental conditions, relevant environmental parameters (such as temperature, humidity, atmospheric pressure, etc.) are extracted as important factors affecting the polarized absorption ratio. The environmental parameters collected under each environmental condition are associated with the corresponding historical polarized absorption ratio data to form polarized absorption ratio data with environmental annotations.

[0043] By comparing the environmental parameters of the target polarized absorption ratio data with the environmental parameters of other annotated polarized absorption ratio data, the environmental similarity between each polarized absorption ratio data is calculated by, for example, Euclidean distance, cosine similarity, etc. Based on the environmental similarity, a clustering algorithm (such as K-means or hierarchical clustering) is used to group all the annotated polarized absorption ratio data to obtain several representative environmental clusters.

[0044] The polarized absorption ratio data in each representative environmental cluster is sorted in ascending order, so that the polarized absorption ratio data is ordered by size to form sorted polarized absorption ratio data. From each sorted representative environmental cluster, the sorted polarized absorption ratio data at the corresponding position of the preset percentile (such as 90 percentile, 95 percentile, etc.) is selected as the screened polarized absorption ratio data.

[0045] According to the environmental conditions of the screened polarized absorption ratio data, different weights are given, and the screened polarized absorption ratio data is weighted and averaged according to the weights, that is, each screened polarized absorption ratio data value is multiplied by the corresponding weight and then added, and the final sum is obtained. The initial polarized absorption ratio judgment threshold is obtained.

[0046] By combining environmental parameters and historical polarized absorption ratio data, the polarized absorption ratio characteristics under different environmental conditions can be more accurately identified, thereby improving the reliability of the judgment threshold. Through clustering analysis and screening percentile data, outliers can be eliminated to ensure that the judgment threshold is more representative and robust. The weighted average operation makes each data reasonably reflect its importance, so that the initial polarized absorption ratio judgment threshold generated is more in line with actual application requirements, enhancing the judgment ability and accuracy of the system.

[0047] S2, obtain environmental parameters of different environmental conditions, and randomly perturb the initial polarized absorption ratio judgment threshold according to the environmental parameters to obtain several candidate polarized absorption ratio judgment thresholds.

[0048] In the embodiments of the present application, the environmental parameters of different environmental conditions refer to external environmental parameters affecting the insulation performance of the voltage transformer, including but not limited to: environmental temperature: the temperature of the air around the power equipment; relative humidity: the percentage of water vapor content in the air; atmospheric pressure: the air pressure level of the test or operation environment; electric field intensity: the local electric field around the transformer; other environmental interference factors: such as altitude, dust or electromagnetic interference.

[0049] The initial polarization absorption ratio judgment threshold value refers to a reference limit value obtained by statistically analyzing the historical polarization absorption ratio data of the voltage transformer with qualified insulation performance.

[0050] Random disturbance refers to introducing a certain random change on the basis of the initial polarization absorption ratio judgment threshold value, which is used to simulate the possible influence of environmental parameters on insulation characteristics.

[0051] The candidate polarization absorption ratio judgment threshold value refers to a number of possible threshold values obtained by randomly disturbing the initial polarization absorption ratio judgment threshold value, which is used for further screening or optimization to meet the insulation determination requirements under different environmental conditions.

[0052] In detail, the initial polarization absorption ratio judgment threshold value is randomly disturbed according to the environmental parameters to obtain a number of candidate polarization absorption ratio judgment threshold values, including:

[0053] Obtaining the standard environmental parameters of the standard environment, calculating the deviation degree of each environmental parameter relative to the standard environmental parameters;

[0054] Obtaining the sensitivity weight of each environmental parameter and the environmental amplification factor of the corresponding environmental condition, weighting and summing the deviation degree and the sensitivity weight to obtain a comprehensive environmental weight coefficient;

[0055] Generating an environmental disturbance index according to the comprehensive environmental weight coefficient and the environmental amplification factor;

[0056] Normally distributing the environmental disturbance index and the preset basic disturbance intensity to construct an environmental associated disturbance term;

[0057] Adding the initial polarization absorption ratio judgment threshold value and the environmental associated disturbance term to generate a number of candidate polarization absorption ratio judgment threshold values.

[0058] In detail, a standard environment is determined as a reference, and the deviation degree of each environmental parameter relative to the standard environmental parameters reflects the gap between the current environment and the standard environment, and the calculation formula is as follows:

[0059]

[0060] Wherein, represents the deviation degree of the i-th environmental parameter from the standard environmental parameter, represents the i-th environmental parameter, represents the standard environmental parameter of the standard environment.

[0061] The sensitivity weight of each environmental parameter represents the influence size of the environmental parameter change on the system result, and the environmental amplification factor of the environmental condition represents the amplification effect of the environmental change under the environmental condition. The calculation formula of the comprehensive environmental weight coefficient and the environmental disturbance index is as follows:

[0062]

[0063] wherein, represents the comprehensive environmental weight coefficient, represents the sensitivity weight of the i-th environmental parameter, represents the deviation degree of the i-th environmental parameter from the standard environmental parameter.

[0064]

[0065] wherein, represents the comprehensive environmental weight coefficient, represents the environmental amplification factor, represents the environmental disturbance index.

[0066] According to the basic disturbance intensity and the environmental disturbance index, an environmental related disturbance term is generated through a normal distribution model, and the calculation formula is as follows:

[0067]

[0068] wherein, represents the environmental disturbance index, represents the basic disturbance intensity, represents the normal distribution, represents the environmental related disturbance term.

[0069] The initial polarization absorption ratio judgment threshold considers the influence of environmental change, and forms a candidate polarization absorption ratio judgment threshold, and the calculation formula is as follows:

[0070]

[0071] wherein, represents the i-th candidate polarization absorption ratio judgment threshold, represents the initial polarization absorption ratio judgment threshold, represents the i-th environmental related disturbance term.

[0072] By randomly perturbing the initial polarization absorption ratio judgment threshold based on environmental parameters, the potential impact of polarization absorption ratio judgment under different environmental conditions can be fully considered. By comprehensively considering the environmental deviation degree, sensitivity weight and environmental amplification effect, multiple candidate thresholds can be dynamically generated, thereby improving the flexibility and adaptability of the judgment threshold. The environmental correlation disturbance term generated by the normal distribution further enhances the system's response to environmental changes, ensuring that the final generated judgment threshold is more stable, reliable and can effectively operate under different environments.

[0073] S3, using the candidate polarization absorption ratio judgment threshold to perform insulation performance test on the obtained voltage transformer to be detected, and calculating the area under the curve and the safety margin according to the insulation performance test result.

[0074] In the embodiments of the present application, the voltage transformer to be detected refers to the voltage transformer that needs to be tested for insulation performance. The voltage transformer is a device used for measuring high voltage and converting it into a low voltage signal. The insulation performance directly affects the safety and reliability of the work.

[0075] Insulation performance test refers to a test performed on a voltage transformer to evaluate the performance of the insulation material of the voltage transformer under different voltage, temperature and humidity conditions. The test result is used to determine whether the insulation of the voltage transformer is qualified and whether it can safely operate in the expected working environment.

[0076] Area under the curve (AUC): In the insulation performance test, a curve related to the test time or voltage is usually generated. The area under the curve refers to the area enclosed between the curve and the horizontal axis. In insulation performance evaluation, AUC can be used to quantify the response characteristics of the voltage transformer during the test. The larger the area, the better the insulation performance.

[0077] Safety margin: refers to the difference between the actual polarization absorption ratio and the preset polarization absorption ratio threshold. It represents the buffer space of system safety, that is, a safety margin that the system can still maintain normal work when an abnormality occurs. In voltage transformer testing, a larger safety margin usually means that the insulation performance is more reliable and can withstand higher working stress.

[0078] In detail, the insulation performance test of the obtained voltage transformer to be detected using the candidate polarization absorption ratio judgment threshold comprises:

[0079] Obtain the voltage transformer to be detected, apply a standardized direct current insulation test voltage to the voltage transformer to be detected under different environmental conditions, and record the insulation resistance value at a preset time point;

[0080] Calculate the actual polarization absorption ratio of the voltage transformer to be detected according to the insulation resistance value.

[0081] randomly select one of the candidate polarization absorption ratio judgment thresholds as a test polarization absorption ratio judgment threshold;

[0082] determine whether the actual polarization absorption ratio is greater than or equal to the test polarization absorption ratio judgment threshold;

[0083] If the actual polarization absorption ratio is greater than or equal to the test polarization absorption ratio judgment threshold, the voltage transformer to be tested is marked as qualified, and qualified is taken as the insulation performance test result;

[0084] If the actual polarization absorption ratio is less than the test polarization absorption ratio judgment threshold, the voltage transformer to be tested is marked as unqualified, and unqualified is taken as the insulation performance test result.

[0085] In detail, during the insulation performance test, a standardized DC insulation test voltage is applied to the voltage transformer to be tested to ensure that the voltage level meets the requirements of industry standards or technical specifications, and the voltage transformer to be tested is tested under different environmental conditions (such as different temperatures, humidities, etc.). During the test, the insulation resistance value at the preset time point (such as 1 minute, 10 minutes, etc.) is recorded.

[0086] The actual polarization absorption ratio is calculated by comparing the insulation resistance values at different time points (for example, 1 minute and 10 minutes), reflecting the polarization characteristics of the voltage transformer insulation material, and then evaluating the insulation performance stability and reliability under specific environmental conditions. The calculation formula is as follows:

[0087]

[0088] wherein, represents the actual polarization absorption ratio, represents the insulation resistance value at 10 minutes, represents the insulation resistance value at 1 minute.

[0089] In detail, the curve area and safety margin are calculated according to the insulation performance test result, including:

[0090] Obtain the actual performance result of the voltage transformer to be tested under different environmental conditions;

[0091] According to the actual performance result and the insulation performance test result, the true positive rate and the false positive rate of each candidate polarization absorption ratio judgment threshold are calculated;

[0092] Take the false positive rate as the horizontal axis and the true positive rate as the vertical axis;

[0093] Draw a performance curve according to the horizontal axis and the vertical axis, and calculate the curve area according to the performance curve;

[0094] Screening a minimum polarization absorption ratio from the actual polarization absorption ratios of the voltage transformer to be detected under different environmental conditions;

[0095] Subtracting the minimum polarization absorption ratio from the candidate polarization absorption ratio judgment threshold value to obtain a safety margin.

[0096] In detail, the actual performance results of the voltage transformer to be detected passing the previous standard test or experience are obtained, and the subsequent insulation performance test results are compared.

[0097] In detail, the true positive rate and false positive rate of each candidate polarization absorption ratio judgment threshold value are calculated according to the actual performance results and the insulation performance test results, including:

[0098] According to the actual performance results and the insulation performance test results, the number of actual performance results being qualified and the insulation performance test results being qualified is counted as a true positive value;

[0099] According to the actual performance results and the insulation performance test results, the number of actual performance results being unqualified and the insulation performance test results being qualified is counted as a false positive value;

[0100] According to the actual performance results and the insulation performance test results, the number of actual performance results being unqualified and the insulation performance test results being unqualified is counted as a true negative value;

[0101] According to the actual performance results and the insulation performance test results, the number of actual performance results being qualified and the insulation performance test results being unqualified is counted as a false negative value;

[0102] The true positive rate of each candidate polarization absorption ratio judgment threshold value is calculated according to the true positive value and the false negative value;

[0103] The false positive rate of each candidate polarization absorption ratio judgment threshold value is calculated according to the false positive value and the true negative value.

[0104] In detail, the true positive value TP is the number of samples determined to be qualified and actually qualified. The false positive value FP is the number of samples determined to be qualified but actually unqualified. The true negative value TN is the number of samples determined to be unqualified and actually unqualified. The false negative value FN is the number of samples determined to be unqualified but actually qualified.

[0105] The true positive rate and false positive rate calculation formula of the candidate polarization absorption ratio judgment threshold value is as follows:

[0106]

[0107] wherein, represents the true positive rate, represents the true positive value, represents the false negative value.

[0108]

[0109] wherein, represents the false positive rate, represents the false positive value, represents the true negative value.

[0110] In detail, when drawing the performance curve, the false positive rate is taken as the horizontal axis, and the true positive rate is taken as the vertical axis to form a binary classification performance evaluation chart. The overall performance of the voltage transformer to be detected is evaluated by calculating the area under the curve (AUC). The larger the AUC value, the higher the accuracy of the candidate polarization absorption ratio judgment threshold.

[0111] In all insulation performance tests, the minimum value of the actual polarization absorption ratio of the voltage transformer to be detected under different environmental conditions is screened out, which reflects the performance of the voltage transformer under the most adverse environmental conditions.

[0112] The difference between the minimum polarization absorption ratio and the candidate polarization absorption ratio judgment threshold is calculated to obtain the safety margin, which represents the fault tolerance space of the voltage transformer relative to the threshold under the current environment. The larger the safety margin, the safer the device.

[0113] By combining environmental conditions and actual performance tests, the insulation performance of the voltage transformer can be more comprehensively evaluated, and the accuracy of the test results can be ensured by comparing the candidate polarization absorption ratio judgment threshold. By calculating the true positive rate and the false positive rate and drawing the performance curve, the judgment ability of different thresholds can be quantified, so as to select the best threshold to improve the test precision. At the same time, screening out the minimum polarization absorption ratio and calculating the safety margin can help to identify the performance of the device under the most extreme environment, so as to ensure that the device can operate stably under various conditions, not only improving the reliability of the judgment, but also enhancing the adaptability of the system to environmental changes, providing a guarantee for the long-term reliability of the device.

[0114] S4, constructing a threshold comprehensive evaluation function according to the area under the curve and the safety margin.

[0115] In the embodiment of the present application, the threshold comprehensive evaluation function is an evaluation function that comprehensively considers the area under the curve and the safety margin. By combining AUC and safety margin, the overall performance of each candidate polarization absorption ratio judgment threshold is evaluated. The area under the curve reflects the judgment accuracy of the candidate polarization absorption ratio judgment threshold, and the safety margin reflects the stability and reliability of the voltage transformer under different environmental conditions.

[0116] In detail, the threshold comprehensive evaluation function is constructed according to the area under the curve and the safety margin, and the threshold comprehensive evaluation function comprises:

[0117] An area maximum value and an area minimum value of the area under the curve corresponding to all the candidate polarization absorption ratio judgment thresholds are obtained.

[0118] A first difference value is obtained by subtracting the area minimum value from the area maximum value.

[0119] A second difference value is obtained by subtracting the area minimum value from the area under the curve corresponding to each candidate polarization absorption ratio judgment threshold.

[0120] A normalized area under the curve corresponding to each candidate polarization absorption ratio judgment threshold is obtained by dividing the first difference value by the second difference value.

[0121] A safety margin maximum value and a safety margin minimum value of the safety margin corresponding to all the candidate polarization absorption ratio judgment thresholds are obtained.

[0122] A third difference value is obtained by subtracting the safety margin minimum value from the safety margin maximum value.

[0123] A fourth difference value is obtained by subtracting the safety margin minimum value from the safety margin corresponding to each candidate polarization absorption ratio judgment threshold.

[0124] A normalized safety margin corresponding to each candidate polarization absorption ratio judgment threshold is obtained by dividing the third difference value by the fourth difference value.

[0125] Nonlinear function construction is performed on the normalized area under the curve and the normalized safety margin to obtain a threshold comprehensive evaluation function.

[0126] In detail, the threshold comprehensive evaluation function is calculated according to the following formula:

[0127]

[0128] wherein, the threshold comprehensive evaluation function of the i th candidate polarization absorption ratio judgment threshold is represented by f i, the area under the curve corresponding to the i th candidate polarization absorption ratio judgment threshold is represented by A i, the area maximum value of the area under the curve is represented by A max, the area minimum value of the area under the curve is represented by A min, the safety margin corresponding to the i th candidate polarization absorption ratio judgment threshold is represented by S i, the safety margin minimum value is represented by S min, the safety margin maximum value is represented by S max.

[0129] By constructing a threshold comprehensive evaluation function, the two key indicators of the area under the curve and the safety margin can be comprehensively considered, thereby providing a comprehensive evaluation standard for judging the threshold of each candidate polarization absorption ratio. By normalizing the area under the curve and the safety margin, the absolute difference between different candidate thresholds is eliminated, enabling them to be compared on a unified scale. By combining the two normalized indicators through a nonlinear function, the comprehensive performance of each threshold can be more accurately evaluated, helping to select the optimal judgment standard. Not only does this improve the accuracy and stability of the test, but it also enhances the system's adaptability to different environmental changes, ensuring that the voltage transformer maintains excellent performance under various working conditions.

[0130] S5, calculating the comprehensive score of each candidate polarization absorption ratio judgment threshold using the threshold comprehensive evaluation function, and screening out the candidate polarization absorption ratio judgment threshold corresponding to the highest comprehensive score.

[0131] In the embodiments of the present application, the comprehensive score is calculated according to the normalized area under the curve and the normalized safety margin corresponding to each candidate polarization absorption ratio judgment threshold, reflecting the overall performance of the threshold in terms of discrimination ability and safety margin. By comparing the comprehensive scores of all candidate polarization absorption ratio judgment thresholds, the candidate threshold with the highest score is selected, representing the optimal judgment standard.

[0132] In detail, the threshold comprehensive evaluation function is used to calculate the comprehensive score of each candidate polarization absorption ratio judgment threshold, and the candidate polarization absorption ratio judgment threshold corresponding to the highest comprehensive score is screened out, comprising:

[0133] Using the threshold comprehensive evaluation function, the comprehensive score is generated according to the area under the curve and the safety margin of the candidate polarization absorption ratio judgment threshold;

[0134] The candidate polarization absorption ratio judgment thresholds are sorted according to the comprehensive scores, and the candidate polarization absorption ratio judgment threshold corresponding to the highest comprehensive score is screened out according to the sorting result.

[0135] In detail, by using the threshold comprehensive evaluation function, the two key indicators of the area under the curve and the safety margin can be combined to generate a comprehensive score for each candidate polarization absorption ratio judgment threshold. This ensures that when selecting a judgment threshold, not only is the discrimination ability measured by the area under the curve, but also the safety of the device under different environments is considered through the safety margin. By sorting all candidate thresholds, the threshold with the highest comprehensive score is finally selected, thereby selecting the optimal judgment standard, improving the accuracy and reliability of the insulation performance test, and ensuring that the selected threshold can provide the best judgment effect and safety guarantee under different environmental conditions.

[0136] S6, taking the screened candidate polarization absorption ratio judgment threshold as a target polarization absorption ratio judgment threshold, and using the target polarization absorption ratio judgment threshold to test the insulation performance of a target voltage transformer.

[0137] In the embodiment of the application, the candidate polarization absorption ratio judgment threshold with the highest comprehensive score is screened out and determined as the target polarization absorption ratio judgment threshold. The target polarization absorption ratio judgment threshold is used to test the insulation performance of a target voltage transformer. In the test process, the target voltage transformer is placed in a standardized test condition, a predetermined direct current voltage is applied, and a corresponding insulation resistance value is recorded. According to the test results, the actual polarization absorption ratio is calculated and compared with the target polarization absorption ratio judgment threshold to determine whether the insulation performance of the voltage transformer is qualified, thereby obtaining a final test conclusion.

[0138] In detail, the taking of the screened candidate polarization absorption ratio judgment threshold as a target polarization absorption ratio judgment threshold comprises:

[0139] The total number of the screened candidate polarization absorption ratio judgment thresholds is counted.

[0140] According to the total number of the thresholds, it is determined whether the screened candidate polarization absorption ratio judgment threshold is unique.

[0141] When the screened candidate polarization absorption ratio judgment threshold is unique, the screened candidate polarization absorption ratio judgment threshold is taken as a target polarization absorption ratio judgment threshold.

[0142] When the screened candidate polarization absorption ratio judgment threshold is not unique, the safety margin of the screened candidate polarization absorption ratio judgment threshold is obtained.

[0143] From the screened candidate polarization absorption ratio judgment thresholds, the candidate polarization absorption ratio judgment threshold corresponding to the highest safety margin is selected as a target polarization absorption ratio judgment threshold.

[0144] In detail, according to the total number of the thresholds, it is determined whether only one candidate polarization absorption ratio judgment threshold is screened out. When the screened candidate polarization absorption ratio judgment threshold is unique, the candidate polarization absorption ratio judgment threshold is directly taken as a target polarization absorption ratio judgment threshold.

[0145] If the screened candidate polarization absorption ratio judgment threshold is not unique, the safety margin corresponding to the candidate polarization absorption ratio judgment threshold is further obtained. By comparing the safety margins, the candidate polarization absorption ratio judgment threshold with the highest safety margin is selected as a final target polarization absorption ratio judgment threshold, so as to ensure that the threshold with the highest safety and adaptability is selected as the final judgment standard from multiple possible thresholds.

[0146] The most suitable target threshold is ensured to be finally selected from multiple candidate polarization absorption ratio judgment thresholds. If the selected candidate polarization absorption ratio judgment threshold is unique, it is directly used as the target threshold, ensuring that the judgment process is simple and clear. When the candidate polarization absorption ratio judgment threshold is not unique, the target polarization absorption ratio judgment threshold is further selected through the safety margin, ensuring that the selected target polarization absorption ratio judgment threshold not only meets the performance standard, but also has a high safety margin, thereby improving the stability and reliability of the device in actual application, enhancing the accuracy and adaptability of the judgment standard, and enabling the voltage transformer to obtain the optimal insulation performance evaluation under various working conditions.

[0147] It should be understood that the size of the serial number of each step in the above embodiment does not mean the order of execution, and the execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0148] As shown in Figure 2 , it is a functional module diagram of a voltage transformer swing insulation test control device provided by an embodiment of the present application.

[0149] In the embodiment of the present disclosure, a voltage transformer swing insulation test control device is provided, which corresponds to the voltage transformer swing insulation test control method described above. As shown in Figure 2 , the voltage transformer swing insulation test control device 100 includes an initial threshold screening module 101, an initial threshold disturbance module 102, an insulation performance test module 103, an evaluation function construction module 104, a comprehensive score calculation module 105, and a target threshold screening module 106. The detailed description of each functional module is as follows:

[0150] The initial threshold screening module 101 is used to collect historical polarization absorption ratio data of voltage transformers with qualified insulation performance under different environmental conditions, and screen out the historical polarization absorption ratio data corresponding to the preset percentile as the initial polarization absorption ratio judgment threshold;

[0151] The initial threshold disturbance module 102 is used to obtain environmental parameters of different environmental conditions, and randomly disturb the initial polarization absorption ratio judgment threshold according to the environmental parameters to obtain a plurality of candidate polarization absorption ratio judgment thresholds;

[0152] The insulation performance test module 103 is used to test the insulation performance of the obtained voltage transformer to be detected by using the candidate polarization absorption ratio judgment threshold, and calculate the area under the curve and the safety margin according to the insulation performance test result;

[0153] The evaluation function construction module 104 is used to construct a threshold comprehensive evaluation function according to the area under the curve and the safety margin;

[0154] The comprehensive score calculation module 105 is configured to calculate a comprehensive score of each candidate polarization absorption ratio judgment threshold by using the threshold comprehensive evaluation function, and screen out a candidate polarization absorption ratio judgment threshold corresponding to the highest comprehensive score.

[0155] The target threshold screening module 106 is configured to screen out the candidate polarization absorption ratio judgment threshold as a target polarization absorption ratio judgment threshold, and perform insulation performance testing on a target voltage mutual inductor by using the target polarization absorption ratio judgment threshold.

[0156] In an embodiment, when the initial threshold screening module 101 performs screening of the historical polarization absorption ratio data corresponding to a preset percentile as an initial polarization absorption ratio judgment threshold, the initial threshold screening module 101 is configured to:

[0157] extract environment parameters of different environment conditions;

[0158] associate and label the environment parameters with the historical polarization absorption ratio data to obtain labeled polarization absorption ratio data;

[0159] randomly select one of the labeled polarization absorption ratio data as target polarization absorption ratio data;

[0160] perform similarity analysis on the environment parameters of the target polarization absorption ratio data and other labeled polarization absorption ratio data to obtain an environment similarity;

[0161] perform cluster analysis on the labeled polarization absorption ratio data according to the environment similarity to obtain a plurality of representative environment clusters;

[0162] sort the labeled polarization absorption ratio data in the representative environment clusters in ascending order to obtain sorted polarization absorption ratio data in each representative environment cluster;

[0163] screen out a screening polarization absorption ratio data at a preset percentile from the sorted polarization absorption ratio data in each representative environment cluster;

[0164] perform weighted average on all the screening polarization absorption ratio data to generate an initial polarization absorption ratio judgment threshold.

[0165] In an embodiment, when the initial threshold perturbation module 102 performs random perturbation on the initial polarization absorption ratio judgment threshold according to the environment parameters to obtain a plurality of candidate polarization absorption ratio judgment thresholds, the initial threshold perturbation module 102 is configured to:

[0166] obtain standard environment parameters of a standard environment, and calculate a deviation degree of each environment parameter relative to the standard environment parameters;

[0167] obtaining a sensitivity weight of each of the environment parameters and an environment amplification factor of a corresponding environment condition, performing weighted summation on the deviation degree and the sensitivity weight to obtain a comprehensive environment weight coefficient;

[0168] generating an environment disturbance index according to the comprehensive environment weight coefficient and the environment amplification factor;

[0169] performing normal distribution on the environment disturbance index and a preset basic disturbance intensity to construct an environment-related disturbance term;

[0170] adding the initial polarization absorption ratio judgment threshold and the environment-related disturbance term to generate a plurality of candidate polarization absorption ratio judgment thresholds.

[0171] In an embodiment, the insulation performance test module 103, when performing insulation performance test on the obtained voltage transformer to be detected by using the candidate polarization absorption ratio judgment threshold, is configured to:

[0172] obtaining a voltage transformer to be detected, applying a standardized direct-current insulation test voltage to the voltage transformer to be detected under different environment conditions, and recording an insulation resistance value at a preset time point;

[0173] calculating an actual polarization absorption ratio of the voltage transformer to be detected according to the insulation resistance value;

[0174] randomly selecting one of the candidate polarization absorption ratio judgment thresholds as a test polarization absorption ratio judgment threshold;

[0175] judging whether the actual polarization absorption ratio is greater than or equal to the test polarization absorption ratio judgment threshold;

[0176] if the actual polarization absorption ratio is greater than or equal to the test polarization absorption ratio judgment threshold, marking the voltage transformer to be detected as qualified, and taking the qualification as an insulation performance test result;

[0177] if the actual polarization absorption ratio is less than the test polarization absorption ratio judgment threshold, marking the voltage transformer to be detected as unqualified, and taking the unqualification as an insulation performance test result.

[0178] In an embodiment, the insulation performance test module 103, when performing calculation of area under curve and safety margin according to the insulation performance test result, is configured to:

[0179] obtaining actual performance results of the voltage transformer to be detected under different environment conditions;

[0180] calculating a true positive rate and a false positive rate of each of the candidate polarization absorption ratio judgment thresholds according to the actual performance results and the insulation performance test result;

[0181] plot the false positive rate as the horizontal axis and the true positive rate as the vertical axis;

[0182] plot a performance curve according to the horizontal axis and the vertical axis, and calculate an area under the curve according to the performance curve;

[0183] screen a minimum polarization absorption ratio from the actual polarization absorption ratios of the voltage transformer to be detected under different environmental conditions;

[0184] obtain a safety margin by subtracting the minimum polarization absorption ratio from the candidate polarization absorption ratio judgment threshold.

[0185] In an embodiment, the insulation performance test module 103 is configured to:

[0186] count the number of qualified actual performance results and qualified insulation performance test results as true positive values according to the actual performance results and the insulation performance test results;

[0187] count the number of unqualified actual performance results and qualified insulation performance test results as false positive values according to the actual performance results and the insulation performance test results;

[0188] count the number of unqualified actual performance results and unqualified insulation performance test results as true negative values according to the actual performance results and the insulation performance test results;

[0189] count the number of qualified actual performance results and unqualified insulation performance test results as false negative values according to the actual performance results and the insulation performance test results;

[0190] calculate the true positive rate of each candidate polarization absorption ratio judgment threshold according to the true positive values and the false negative values;

[0191] calculate the false positive rate of each candidate polarization absorption ratio judgment threshold according to the false positive values and the true negative values.

[0192] In an embodiment, the evaluation function construction module 104 is configured to:

[0193] obtain the maximum and minimum areas of the areas under the curves corresponding to all the candidate polarization absorption ratio judgment thresholds;

[0194] obtain a first difference value by subtracting the minimum area from the maximum area;

[0195] Subtracting the area minimum value from the area under the curve corresponding to each candidate polarization absorption ratio judgment threshold value, a second difference value is obtained;

[0196] Taking the quotient of the first difference value and the second difference value, a normalized area under the curve corresponding to each candidate polarization absorption ratio judgment threshold value is obtained;

[0197] Obtaining a safety margin maximum value and a safety margin minimum value of the safety margin corresponding to all candidate polarization absorption ratio judgment threshold values;

[0198] Subtracting the safety margin maximum value from the safety margin minimum value, a third difference value is obtained;

[0199] Subtracting the safety margin corresponding to each candidate polarization absorption ratio judgment threshold value from the safety margin minimum value, a fourth difference value is obtained;

[0200] Taking the quotient of the third difference value and the fourth difference value, a normalized safety margin corresponding to each candidate polarization absorption ratio judgment threshold value is obtained;

[0201] Nonlinear function construction is performed on the normalized area under the curve and the normalized safety margin, and a threshold comprehensive evaluation function is obtained.

[0202] In an embodiment, when the comprehensive score calculation module 105 performs the following operations, it is used for:

[0203] Generating a comprehensive score according to the area under the curve and the safety margin of the candidate polarization absorption ratio judgment threshold value by using the threshold comprehensive evaluation function;

[0204] According to the comprehensive score, the candidate polarization absorption ratio judgment threshold values are sorted, and according to the sorting result, the candidate polarization absorption ratio judgment threshold value corresponding to the highest comprehensive score is selected.

[0205] In an embodiment, when the target threshold screening module 106 performs the following operations, it is used for:

[0206] Counting the total number of thresholds of the selected candidate polarization absorption ratio judgment threshold value;

[0207] According to the total number of thresholds, it is judged whether the selected candidate polarization absorption ratio judgment threshold value is unique or not;

[0208] When the selected candidate polarization absorption ratio judgment threshold value is unique, the selected candidate polarization absorption ratio judgment threshold value is taken as the target polarization absorption ratio judgment threshold value.

[0209] When the screened candidate polarization absorption ratio judgment threshold is not unique, a safety margin of the screened candidate polarization absorption ratio judgment threshold is obtained;

[0210] From the screened candidate polarization absorption ratio judgment threshold, a candidate polarization absorption ratio judgment threshold corresponding to the highest safety margin is selected as a target polarization absorption ratio judgment threshold.

[0211] In the present application, the specific limitations of the voltage transformer swing insulation test control device can be referred to the limitations of the voltage transformer swing insulation test control method in the above, which will not be repeated here. Each module in the above voltage transformer swing insulation test control device can be realized by software, hardware and their combinations. The above modules can be embedded in or independent of the processor in the computer device in hardware form, or can be stored in the memory in the computer device in software form, so that the processor calls and executes the operations corresponding to each module.

[0212] In the embodiments provided by the present application, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of the modules is only a logical function division. In actual implementation, another division manner can be used.

[0213] In addition, each function module in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware, or in the form of hardware plus software function module.

[0214] Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims to which they relate.

[0215] It is obvious for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application.

[0216] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when the computer program is executed, the processes of the above-mentioned embodiments of the methods can be included. Any reference to memory, storage, database or other medium used in each embodiment provided by the present application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration but not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0217] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of functional units and modules is exemplified, and in actual application, the above-mentioned functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above.

[0218] In the embodiments provided in this disclosure, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using dedicated hardware-based apparatus that performs the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0219] It should be noted that, in this disclosure, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element limited by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0220] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A voltage transformer shake insulation test control method, characterized by, The method includes: Historical polarization absorption ratio data of voltage transformers with qualified insulation performance under different environmental conditions are collected, and an initial polarization absorption ratio judgment threshold is generated based on the preset percentile. By randomly perturbing the initial polarization absorption ratio judgment threshold in combination with environmental parameters, multiple candidate polarization absorption ratio judgment thresholds are generated. The threshold value of each candidate polarization absorption ratio is used to determine the insulation performance of the voltage transformer under test, and the area under the curve and the threshold safety margin are calculated based on the test results. A comprehensive evaluation function is constructed based on the area under the curve and the threshold safety margin; The optimal candidate polarization absorption ratio is selected based on the comprehensive evaluation function, and the threshold is determined as the target threshold. The insulation performance of the target voltage transformer is then tested using the target threshold.

2. The voltage transformer insulation test control method of claim 1, wherein, The method for generating the initial polarization absorption ratio determination threshold includes: Collect historical polarization absorptivity data and correlate it with corresponding environmental parameters; Clustering of associated data based on environmental similarity forms multiple representative environmental clusters. The clustering process includes randomly selecting a data sample, calculating the similarity of its environmental parameters with other samples, and dividing the data according to the similarity. The polarization absorption ratio data within each environmental cluster are sorted, and a uniform preset percentile value is extracted. A weighted average of all extracted percentile values ​​is used to generate the initial polarization absorption ratio judgment threshold.

3. The voltage transformer insulation test control method of claim 1, wherein, The initial polarization absorption ratio judgment threshold is randomly perturbed by combining environmental parameters to generate multiple candidate polarization absorption ratio judgment thresholds, including: Calculate the degree of deviation of environmental parameters from the standard environment; The environmental disturbance index is calculated based on the degree of deviation, the preset sensitivity weight, and the environmental amplification factor. The environmental disturbance index and the basic disturbance intensity are normally distributed to generate environmental associated disturbance terms; The initial polarization absorption ratio judgment threshold is superimposed with the environmental associated perturbation term to generate multiple candidate polarization absorption ratio judgment thresholds.

4. The voltage transformer insulation test control method of claim 1, wherein, The method of using the candidate polarization absorption ratio to determine the threshold for insulation performance testing of the voltage transformer under test includes: Perform a standardized DC withstand voltage test on the voltage transformer under test and measure the insulation resistance value at a preset timing. The actual polarization absorption ratio is calculated based on the insulation resistance value; One of the candidate polarization absorption ratio judgment thresholds is randomly selected as the test polarization absorption ratio judgment threshold; The actual polarization absorption ratio is compared with the test polarization absorption ratio judgment threshold; Based on the comparison results, an insulation diagnosis conclusion is output.

5. The voltage transformer insulation test control method of claim 4, wherein, The calculation of the area under the curve and the threshold safety margin based on the test results includes: Based on the insulation performance test results and actual performance results, the true anode rate and false anode rate of each candidate polarization absorption ratio judgment threshold are calculated. Plot performance curves based on the true positive rate and false positive rate, and calculate the area under the curve. Obtain the minimum actual polarization absorption ratio of the voltage transformer under test, and calculate the difference between it and the candidate polarization absorption ratio judgment threshold as the threshold safety margin.

6. The voltage transformer insulation test control method of claim 5, wherein, The calculation of the true anode rate and false anode rate for each candidate polarization absorption ratio judgment threshold based on insulation performance test results and actual performance results includes: Based on the comparison between actual performance results and insulation performance test results, a confusion matrix is ​​constructed to obtain true positive value, false positive value, true negative value and false negative value; And according to the confusion matrix, true positive rate and false positive rate of each candidate polarization absorption ratio judgment threshold are calculated.

7. The voltage transformer insulation test control method of claim 1, wherein, The comprehensive evaluation function is constructed based on the area under the curve and the threshold safety margin, and the construction method comprises the following steps: The area under the curve corresponding to the candidate polarization absorption ratio judgment threshold and the threshold safety margin are normalized respectively; The comprehensive evaluation function is constructed by a nonlinear function based on the normalized area under the curve and the threshold safety margin.

8. The voltage transformer insulation test control method of claim 1, wherein, The optimal candidate polarization absorption ratio judgment threshold is selected as the target threshold according to the comprehensive evaluation function, and the selection method comprises the following steps: The comprehensive score of each candidate polarization absorption ratio judgment threshold based on the area under the curve and the threshold safety margin is calculated; The candidate polarization absorption ratio judgment threshold is sorted according to the comprehensive score, and the threshold corresponding to the highest score is selected as the optimal judgment threshold.

9. The voltage transformer insulation test control method of claim 1, wherein, The optimal candidate polarization absorption ratio judgment threshold is selected as the target threshold, and the selection method comprises the following steps: The total number of thresholds of the selected candidate polarization absorption ratio judgment threshold is counted; Whether the selected candidate polarization absorption ratio judgment threshold is unique is judged according to the total number of thresholds; When the candidate polarization absorption ratio judgment threshold selected based on the comprehensive evaluation is unique, it is directly determined as the target threshold; when multiple candidate polarization absorption ratio judgment thresholds are selected, the one with the highest threshold safety margin is selected as the target threshold.

10. A voltage transformer insulation test control device, characterized by, The device comprises: An initial polarization absorption ratio judgment threshold screening module is configured to collect historical polarization absorption ratio data of voltage transformers with qualified insulation performance, and generate an initial polarization absorption ratio judgment threshold based on a preset percentile; An initial polarization absorption ratio judgment threshold perturbation module is configured to randomly perturb the initial polarization absorption ratio judgment threshold in combination with environmental parameters to generate multiple candidate polarization absorption ratio judgment thresholds; An insulation performance testing module is configured to test the insulation performance of a to-be-tested voltage transformer using each candidate polarization absorption ratio judgment threshold, and calculate the area under the curve and the threshold safety margin according to the test results; An evaluation function construction module is configured to construct a comprehensive evaluation function based on the area under the curve and the threshold safety margin; A comprehensive score calculation module is configured to select the optimal candidate polarization absorption ratio judgment threshold as the target threshold according to the comprehensive evaluation function; A target threshold screening module is configured to test the insulation performance of a target voltage transformer using the target threshold.

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