Capacitor film insulation state evaluation method, device and related product

Abstract

This application relates to the field of computer technology and discloses a method, apparatus, and related products for evaluating the insulation state of capacitor films. The method includes: acquiring the actual breakdown field strength and simulated electric field distortion data of the capacitor film to be evaluated; processing the simulated electric field distortion data using a pre-constructed breakdown field strength prediction model to obtain the theoretical breakdown field strength; calculating the breakdown field strength deviation data based on the theoretical and actual breakdown field strengths; and matching the corresponding intervals according to multiple preset breakdown field strength deviation data grading intervals to determine the insulation state evaluation result of the capacitor film to be evaluated. This application can achieve quantitative characterization of the degree of insulation performance deviation and refined grading of insulation state, reducing testing costs and improving testing efficiency while completing an accurate and comprehensive evaluation of the insulation state of capacitor films.

Description

Technical Field

[0001] This application relates to the field of power system technology, and more specifically, to a method, apparatus, and related products for assessing the insulation status of capacitor films. Background Technology

[0002] As a core component in new energy power generation, electric vehicles, and flexible DC transmission, the stability of film capacitors directly depends on the insulation performance of their internal dielectric films, such as polypropylene. Once the film deteriorates under the long-term influence of multiple physical fields, including electrical, thermal, and mechanical stress, it will directly lead to capacitor breakdown and failure, resulting in equipment downtime or even more serious safety accidents. Therefore, accurately assessing the insulation state of the film is of crucial engineering significance for equipment quality control, lifespan prediction, and the safe and stable operation of the power grid.

[0003] In related technologies, the destructive breakdown test method is generally used to evaluate the insulation state of capacitor film. This method takes the entire capacitor (or core structure) as the research object, and directly performs a step-up voltage test on the capacitor under test until the film insulation breaks down. The breakdown voltage is recorded and the breakdown field strength is calculated. The quality of the film insulation performance is judged based on the magnitude of the breakdown field strength.

[0004] However, this destructive breakdown test method, which targets the entire device, has the following drawbacks: First, the method is completely destructive; the tested device becomes unusable, requiring a large number of samples for evaluation, resulting in significant material waste, high evaluation costs, and low testing efficiency. Second, this method tests the entire device as a whole, failing to separate the insulation performance of the capacitor film from the specific electric field structure. It struggles to reflect the actual insulation performance of the film under different electric field distortion conditions and cannot comprehensively evaluate the electric field stress at the device structure level. It can only determine the material's breakdown capability in isolation, lacking a precise and comprehensive characterization of the film's insulation state under actual operating conditions. Therefore, it is urgent to solve this technical problem. Summary of the Invention

[0005] In view of the above situation, this application provides a method, apparatus and related products for evaluating the insulation status of capacitor film, which aims to solve the above problems or at least partially solve the above problems.

[0006] In a first aspect, embodiments of this application provide a method for evaluating the insulation state of a capacitor film, the method comprising: Obtain the actual breakdown field strength and simulated electric field distortion data of the capacitor film to be evaluated; The simulated electric field distortion data is processed using a pre-constructed breakdown field strength prediction model to obtain the theoretical breakdown field strength. Based on the theoretical breakdown field strength and the actual breakdown field strength, the breakdown field strength deviation data is calculated; Based on multiple preset breakdown field strength deviation data grading intervals, the insulation state evaluation result of the capacitor film to be evaluated is determined by matching the corresponding intervals according to the breakdown field strength deviation data.

[0007] Secondly, embodiments of this application also provide a capacitor film insulation state assessment device, the device comprising: The acquisition module is used to acquire the actual breakdown field strength and simulated electric field distortion data of the capacitor film to be evaluated; The first calculation module is used to process the simulated electric field distortion data using a pre-constructed breakdown field strength prediction model to obtain the theoretical breakdown field strength. The second calculation module is used to calculate the breakdown field strength deviation data based on the theoretical breakdown field strength and the actual breakdown field strength. The evaluation module is used to determine the insulation state evaluation result of the capacitor film to be evaluated by matching the corresponding intervals according to the preset multiple breakdown field strength deviation data ranges.

[0008] Thirdly, embodiments of this application also provide an electronic device, including: a processor; and a memory arranged to store computer-executable instructions, which, when executed, cause the processor to perform the steps of the above-described capacitor film insulation state assessment method.

[0009] Fourthly, embodiments of this application also provide a computer-readable storage medium storing one or more programs, which, when executed by an electronic device including multiple applications, cause the electronic device to perform the steps of the capacitor film insulation state assessment method described above.

[0010] By means of the above technical solutions, the capacitor film insulation state assessment method, device and related products provided in the embodiments of this application integrate simulation data that can accurately reflect the degree of electric field stress concentration, experimental data that characterizes the intrinsic strength of materials, and fuzzy mathematical theory that handles uncertainty, and propose an objective, quantitative and physically meaningful intelligent assessment method for capacitor film insulation state. Specifically, this application first obtains the actual breakdown field strength, which characterizes the true insulation withstand capability of the capacitor film under evaluation, and simulated electric field distortion data, which characterizes the electric field distribution distortion characteristics of the capacitor film under evaluation during actual operation. Using a pre-constructed breakdown field strength prediction model, the simulated electric field distortion data is processed to obtain the theoretical breakdown field strength. The breakdown field strength deviation data calculated based on the theoretical breakdown field strength and the actual breakdown field strength can effectively separate the influence of the film's own insulation performance and the electric field structure, and realize the quantitative characterization of the degree of insulation performance deviation. Based on multiple preset breakdown field strength deviation data grading intervals, the corresponding deviation data is matched to determine the insulation state evaluation result. This can achieve a refined grading judgment of the insulation state without destructive testing of the entire capacitor, which avoids the material waste and high cost problems caused by whole-machine testing, improves testing efficiency, and can achieve an accurate and comprehensive evaluation of the insulation state of the capacitor film by combining the actual electric field stress of the equipment.

[0011] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0012] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 A schematic flowchart of the capacitor film insulation state assessment method provided in an embodiment of this application is shown; Figure 2 The scatter plot and fitting curve plot of the data pairs provided in the embodiments of this application are shown; Figure 3 The insulation state evaluation results of each sample film provided in the embodiments of this application are shown; Figure 4 A schematic diagram of the structure of the capacitor film insulation condition assessment device provided in an embodiment of this application is shown; Figure 5 A schematic diagram of the structure of an electronic device provided in an embodiment of this application is shown. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0014] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0015] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the term "comprising" and its variations should be interpreted as open-ended terms meaning "including but not limited to."

[0016] As mentioned earlier, destructive breakdown testing is generally used to evaluate the insulation state of capacitor films in related technologies. This method takes the entire capacitor (or its core structure) as the research object, directly subjecting the capacitor under test to a stepwise voltage increase test until the film breaks down. The breakdown voltage is recorded and converted into the breakdown field strength, and the insulation performance of the film is judged based on the magnitude of the breakdown field strength. However, this destructive breakdown testing method, which focuses on the entire capacitor, has the following drawbacks: First, this method is completely destructive, and the tested capacitor cannot be used again. A large number of samples are required to complete the evaluation, resulting in serious material waste, high evaluation costs, and low testing efficiency. Second, this method tests the entire capacitor as a whole, making it impossible to separate the insulation performance of the capacitor film itself from the specific electric field structure. It is difficult to reflect the actual insulation performance of the film under different electric field distortion conditions, and it cannot be comprehensively evaluated in conjunction with the electric field stress at the structural level of the equipment. It can only judge the breakdown capability of the material itself, lacking a precise and comprehensive characterization of the insulation state of the film under actual working conditions. Based on this, the present invention proposes a method, apparatus and related products for evaluating the insulation status of capacitor films. The following is a detailed description of the present application through specific embodiments.

[0017] To facilitate understanding of this embodiment, a detailed description of the capacitor film insulation state assessment method disclosed in this application embodiment will be provided first. The execution entity of the capacitor film insulation state assessment method provided in this application embodiment is generally a computer device with certain computing capabilities. This computer device may include, for example, a terminal device, a server, or other processing devices. The terminal device may be a user equipment (UE), a mobile device, a user terminal, or a terminal, etc. In some possible implementations, the capacitor film insulation state assessment method can be implemented by a processor calling computer-readable instructions stored in memory.

[0018] Figure 1 This paper illustrates a flowchart of a capacitor film insulation state assessment method provided in an embodiment of this application. Figure 1 It can be seen that the embodiments of this application include at least steps S101-S104: S101: Obtain the actual breakdown field strength and simulated electric field distortion data of the capacitor film to be evaluated; S102: Using a pre-constructed breakdown field strength prediction model, the simulated electric field distortion data is processed to obtain the theoretical breakdown field strength; S103: Calculate the breakdown field strength deviation data based on the theoretical breakdown field strength and the actual breakdown field strength; S104: Based on multiple preset breakdown field strength deviation data grading intervals, match the corresponding intervals according to the breakdown field strength deviation data, and then determine the insulation state evaluation result of the capacitor film to be evaluated.

[0019] As can be seen, the embodiments of this application integrate simulation data that can accurately reflect the degree of electric field stress concentration, experimental data that characterizes the intrinsic strength of materials, and fuzzy mathematical theory that handles uncertainty, and propose an objective, quantitative, and physically meaningful intelligent evaluation method for the insulation state of capacitor films. Specifically, this application first obtains the actual breakdown field strength, which characterizes the true insulation withstand capability of the capacitor film under evaluation, and simulated electric field distortion data, which characterizes the electric field distribution distortion characteristics of the capacitor film under evaluation during actual operation. Using a pre-constructed breakdown field strength prediction model, the simulated electric field distortion data is processed to obtain the theoretical breakdown field strength. The breakdown field strength deviation data calculated based on the theoretical breakdown field strength and the actual breakdown field strength can effectively separate the influence of the film's own insulation performance and the electric field structure, and realize the quantitative characterization of the degree of insulation performance deviation. Based on multiple preset breakdown field strength deviation data grading intervals, the corresponding deviation data is matched to determine the insulation state evaluation result. This can achieve a refined grading judgment of the insulation state without destructive testing of the entire capacitor, which avoids the material waste and high cost problems caused by whole-machine testing, improves testing efficiency, and can achieve an accurate and comprehensive evaluation of the insulation state of the capacitor film by combining the actual electric field stress of the equipment.

[0020] The following provides a detailed explanation of S101-S104.

[0021] Regarding the above S101: First, obtain the actual breakdown field strength and simulated electric field distortion data of the capacitor film to be evaluated.

[0022] The actual breakdown field strength refers to the electric field strength value obtained by applying a gradually increasing DC voltage to the thin film of the capacitor to be evaluated until insulation breakdown occurs, and dividing the voltage value at the breakdown moment by the measured thickness of the thin film sample. Its physical meaning is an intrinsic strength parameter characterizing the ability of the thin film material to withstand electrical stress, and the unit is usually kilovolts per millimeter.

[0023] In practice, the voltage and current signals during the voltage boosting process can be recorded in real time in the DC breakdown test system using a computer-controlled high-voltage power supply and a data acquisition card. When a sudden increase in current is detected, indicating that breakdown has occurred, the computer automatically locks the voltage value at that moment. Then, the operator inputs the breakdown voltage and the pre-measured and recorded film thickness value into the data processing program. The program calculates the actual breakdown field strength and stores it in the database for use by the execution subject of this application embodiment.

[0024] Simulated electric field distortion data are characteristic parameters used to quantitatively describe the degree of non-uniformity of electric field distribution inside thin films. They can effectively reflect the degree of local electric field concentration caused by factors such as electrode structure, edge effects, or material thickness fluctuations.

[0025] In some embodiments, the simulated electric field distortion data is: the maximum electric field strength, the electric field non-uniformity coefficient, or the integral value of the electric field strength in the high-risk area.

[0026] Please provide a paragraph without formatting, defining these three types of distortion data and explaining why they can be used as electric field distortion data.

[0027] In this embodiment, the maximum electric field strength refers to the maximum value of the electric field distribution on the capacitor film, directly reflecting the severity of local electric field concentration and serving as the most intuitive indicator for determining whether the insulation faces a breakdown risk. The electric field non-uniformity coefficient is defined as the ratio of the maximum electric field strength to the average electric field strength, used to quantify the uniformity of the electric field distribution. A larger coefficient indicates more significant electric field distortion, making it easier to create local breakdown risks. The high-risk region electric field strength integral value is obtained by spatially integrating the electric field strength within a high-field region where the electric field strength exceeds a preset threshold. This considers both the area or volume of the distorted region and comprehensively reflects the accumulated level of electric field energy within that region. These three parameters characterize the electric field distortion features from three different dimensions: peak intensity, distribution uniformity, and overall energy of the high-risk region. They can all effectively characterize the abnormal electric field distribution caused by defects in the insulation structure design or manufacturing, and therefore can be used as simulated electric field distortion data for evaluating the insulation state of the capacitor film.

[0028] In some embodiments, the simulated electric field distortion data of the capacitor film to be evaluated is calculated according to the following method: A first simulation model corresponding to the capacitor film to be evaluated is established using simulation software; The first simulation model is discretized into a grid, and corresponding electric field boundary conditions are set. The numerical solver of the simulation software is used to calculate the numerical matrix of the electric field intensity distribution over the entire field of the capacitor film to be evaluated. Based on the numerical matrix of the electric field intensity distribution over the entire field of the capacitor film to be evaluated, the simulated electric field distortion data of the capacitor film to be evaluated are calculated.

[0029] In this embodiment, the geometric parameters of the capacitor film to be evaluated, such as thickness, length, electrode shape and position, are first read or imported through the preprocessing interface of the simulation software, and a geometric entity object is constructed in memory based on these parameters. Then, material properties, such as dielectric constant and conductivity, are assigned to different geometric regions to form an attribute database. Finally, the geometric entities and material properties are assembled to generate a multiphysics simulation model (two-dimensional axisymmetric winding model) for subsequent discretization, which is the first simulation model.

[0030] Next, the first simulation model is discretized into a mesh and electric field boundary conditions are set. Specifically, a mesh generation algorithm is first invoked to discretize the model into mesh data consisting of node coordinates, element connection relationships, and boundary markers, based on the preset mesh size and element type. This data is typically stored as an array or matrix. Then, electrostatic field simulation is performed based on the user-specified electric field boundary conditions, such as voltage excitation (applying a 1kV DC voltage), grounding, symmetrical boundaries, etc. These boundary conditions are transformed into constraint equations or load values ​​on mesh nodes or element surfaces and written into the boundary condition data structure to form a complete solution domain definition.

[0031] Then, the numerical solver of the simulation software is used to calculate the numerical matrix of the electric field intensity distribution. Specifically, firstly, the mesh data and boundary conditions are read, and the Maxwell's equations are discretized into a large sparse linear algebraic equation system using numerical methods such as the finite element method, and the stiffness matrix and load vector are constructed in memory; then, the linear equation solver is called, usually using iterative methods such as the conjugate gradient method or direct methods such as sparse matrix decomposition, to obtain the electric potential value at each node; finally, in the post-processing stage, gradient calculations are performed on each element or node according to the electric potential distribution to obtain the electric field intensity components at each spatial location, and the electric field intensity values ​​at all locations are organized into a multidimensional array, i.e., the numerical matrix of the electric field intensity distribution.

[0032] Finally, the simulated electric field distortion data is calculated based on the numerical matrix of electric field intensity distribution. Specifically, the calculation method can be adopted according to the data type: when the simulated electric field distortion data is the maximum electric field intensity, the maximum value can be directly extracted by traversing the electric field intensity values ​​of the entire domain through the numerical retrieval function of the simulation software; when it is the electric field non-uniformity coefficient, the average electric field intensity in the thin film evaluation area is first calculated by the statistical or integration function of the software, and then the extracted maximum electric field intensity is divided by the average value by the numerical calculation function. The resulting ratio is the electric field non-uniformity coefficient; when it is the electric field intensity integral value of the high-risk area, the high-risk area range is first delineated in the post-processing interface of the simulation model according to the thin film insulation failure law. The specific area is selected by the area selection function of the software, and then the integration function is called to perform spatial integration of the electric field intensity in the area. In the two-dimensional model, the area is discretized into small units and the product of electric field intensity and unit area is calculated and accumulated. In the three-dimensional model, the product of electric field intensity and unit volume is calculated and accumulated. The final accumulated value is the electric field intensity integral value of the preset high-risk area.

[0033] Regarding S102 above: In this step, the pre-constructed breakdown field strength prediction model can reflect the nonlinear mapping relationship between simulated electric field distortion data and theoretical breakdown field strength. That is, by taking the simulated distortion feature quantity that characterizes the degree of electric field concentration or non-uniformity of distribution as input, and learning the intrinsic correlation between it and the actual breakdown performance of the insulating material, the model can effectively predict the breakdown field strength of unknown samples.

[0034] In some embodiments, the training method for the breakdown field strength prediction model is as follows: using actual capacitor film samples under accelerated aging or different operating conditions as labels, and combining them with the corresponding simulated electric field distortion characteristics for supervised learning.

[0035] In other embodiments, the pre-built breakdown field strength prediction model is generated according to the following method: Data pairs of multiple sample films are acquired; the data pairs include the breakdown field strength of the sample films and the corresponding simulated electric field distortion data; wherein the following characteristic data of the sample films and the capacitor films to be evaluated are the same: inherent property data before service and operating condition data; The breakdown field strength prediction model is obtained by fitting the data pairs.

[0036] In this embodiment, to construct the breakdown field strength prediction model, it is first necessary to obtain a dataset, namely, data pairs of multiple sample films. In practice, for example, a wound core that has undergone electrothermal aging for a period of time can be disassembled, and BOPP films from different locations inside can be taken, such as 20 films from different locations as the multiple sample films.

[0037] To ensure the applicability of the model to the capacitor film to be evaluated, the following attribute data must be the same for the sample film and the capacitor film to be evaluated: inherent properties before service and operating conditions.

[0038] Pre-service inherent attribute data refers to the inherent material properties, structural parameters, and manufacturing process-related attributes of the capacitor film before it is put into actual operation and manufacturing. These attributes are determined during the production process and remain stable throughout subsequent service. Specifically, they include the film dielectric material grade, film geometric thickness, sheet resistance of the metallized electrode surface, relative permittivity of the film, DC conductivity, manufacturing batch number, casting process parameters, and vapor deposition process parameters. In practice, this data can be obtained by reading the factory parameter database of the capacitor manufacturing execution system and parsing the structured data file of the film factory inspection report.

[0039] Operating condition data refers to the external operating conditions, electrical stress conditions, and cumulative service status data that the capacitor film experiences in the actual power grid operating environment. This data characterizes the service environment characteristics of the sample film and the film to be evaluated. Specifically, it includes cumulative service time, operating ambient temperature, long-term applied electric field strength, ambient relative humidity, mechanical vibration stress level, charge / discharge cycle count, and operating voltage level. In practice, this data is obtained by accessing historical operating datasets from the capacitor online monitoring system and analyzing time-series monitoring data from the operation and maintenance management platform. After statistical mean calculation and feature extraction by the data processing unit, this data serves as the boundary condition parameters for the electric field simulation model and the adaptation constraint parameters for the breakdown field strength prediction model.

[0040] In practice, for example, a DC breakdown test with a boost rate of 1000V / s can be performed on the sample film i. The breakdown voltage is measured at room temperature, and the DC breakdown field strength of the sample film is obtained by dividing it by the measured thickness. E testi .

[0041] Furthermore, by constructing a simulation model of sample thin film i, the corresponding simulated electric field distortion data can be calculated. K qhi Specifically, in some embodiments, the simulated electric field distortion data of the sample thin film are calculated according to the following method: A second simulation model corresponding to the sample film was established using simulation software; The second simulation model is discretized into a mesh, and corresponding electric field boundary conditions are set. The numerical solver of the simulation software is used to calculate the numerical matrix of the electric field intensity distribution over the entire sample thin film. Based on the numerical matrix of the electric field intensity distribution over the entire sample thin film, the simulated electric field distortion data of the sample thin film is calculated.

[0042] In practice, for example, the geometric parameters of the sample thin film, such as thickness, length, electrode shape and position, are first read or imported through the preprocessing interface of the simulation software, and geometric entity objects are constructed in memory based on these parameters; then, material properties, such as dielectric constant and conductivity, are assigned to different geometric regions to form an attribute database; finally, the geometric entities and material properties are assembled to generate a complete geometric model data structure for subsequent discretization, which is the second simulation model.

[0043] Next, the second simulation model is discretized into a mesh and electric field boundary conditions are set. Specifically, a mesh generation algorithm is first invoked to discretize the geometric model into mesh data consisting of node coordinates, element connection relationships, and boundary markers, based on the preset mesh size and element type. This data is typically stored as an array or matrix. Then, electrostatic field simulation is performed based on the user-specified electric field boundary conditions, such as voltage excitation (applying a 1kV DC voltage), grounding, and symmetrical boundaries. These boundary conditions are transformed into constraint equations or load values ​​on mesh nodes or element surfaces and written into the boundary condition data structure to form a complete solution domain definition.

[0044] Then, the numerical solver of the simulation software is used to calculate the numerical matrix of the electric field intensity distribution. Specifically, firstly, the mesh data and boundary conditions are read, and the Maxwell's equations are discretized into a large sparse linear algebraic equation system using numerical methods such as the finite element method, and the stiffness matrix and load vector are constructed in memory; then, the linear equation solver is called, usually using iterative methods such as the conjugate gradient method or direct methods such as sparse matrix decomposition, to obtain the electric potential value at each node; finally, in the post-processing stage, gradient calculations are performed on each element or node according to the electric potential distribution to obtain the electric field intensity components at each spatial location, and the electric field intensity values ​​at all locations are organized into a multidimensional array, i.e., the numerical matrix of the electric field intensity distribution.

[0045] Finally, the simulated electric field distortion data is calculated based on the numerical matrix of electric field intensity distribution. Specifically, the calculation method can be adopted according to the data type: when the simulated electric field distortion data is the maximum electric field intensity, the maximum value can be directly extracted by traversing the electric field intensity values ​​of the entire domain through the numerical retrieval function of the simulation software; when it is the electric field non-uniformity coefficient, the average electric field intensity in the thin film evaluation area is first calculated by the statistical or integration function of the software, and then the extracted maximum electric field intensity is divided by the average value by the numerical calculation function. The resulting ratio is the electric field non-uniformity coefficient; when it is the electric field intensity integral value of the high-risk area, the high-risk area range is first delineated in the post-processing interface of the simulation model according to the thin film insulation failure law. The specific area is selected by the area selection function of the software, and then the integration function is called to perform spatial integration of the electric field intensity in the area. In the two-dimensional model, the area is discretized into small units and the product of electric field intensity and unit area is calculated and accumulated. In the three-dimensional model, the product of electric field intensity and unit volume is calculated and accumulated. The final accumulated value is the electric field intensity integral value of the preset high-risk area.

[0046] For example, Table 1 below shows the multiple data pairs obtained.

[0047] Table 1 Simulation and Measured Data

[0048] After obtaining multiple data pairs, each data pair is fitted to obtain a breakdown field strength prediction model. Specifically, a linear fitting method, such as the least squares method, can be used to fit the overall trend of the data points, resulting in a baseline correlation curve, which is the breakdown field strength prediction model. Its functional expression is denoted as... E test-base = f ( K qh This curve characterizes the expected relationship between electric field distortion and breakdown strength under typical conditions.

[0049] Figure 2 The diagram shows a scatter plot and a fitted curve of the data pairs provided in the embodiments of this application. Figure 2 In the figure, the horizontal axis represents the electric field non-uniformity coefficient. K qh The vertical axis represents the breakdown field strength. E test As can be seen, the data points show a clear negative correlation trend.

[0050] After obtaining the pre-constructed breakdown field strength prediction model, the simulated electric field distortion data is processed using the pre-constructed breakdown field strength prediction model to obtain the theoretical breakdown field strength.

[0051] Regarding the above S103: After obtaining the actual breakdown field strength and theoretical breakdown field strength of the capacitor film to be evaluated, the breakdown field strength deviation data is calculated based on the theoretical breakdown field strength and the actual breakdown field strength. The breakdown field strength deviation data can quantitatively characterize the degree to which the actual insulation performance of the capacitor film to be evaluated deviates from the benchmark expectation. It is the core basis for judging whether the film has abnormal conditions such as material defects, process fluctuations or aging during operation.

[0052] Specifically, in some embodiments, the breakdown field strength deviation data is calculated according to the following formula: γ = [ E test / f( K qh )] ×100% in, γ This indicates the deviation data of the breakdown field strength. E test This indicates the actual breakdown field strength. K qh The simulated electric field distortion data is represented by f(), and the breakdown field strength prediction model is represented by f().

[0053] In this embodiment, the breakdown field strength deviation data is the percentage deviation of the actual breakdown strength of the tested thin film from the baseline expected value under the same electric field distortion level (i.e., the same structural stress conditions).

[0054] For example, assuming a breakdown field strength prediction model is obtained by fitting a sample thin film, and testing is conducted on the thin film of the capacitor to be evaluated, the simulated electric field distortion data is obtained as 1.5. Substituting this value into the prediction model, the baseline breakdown field strength is calculated to be 120 kV / mm. At the same time, the actual breakdown field strength of the thin film is measured to be 108 kV / mm through a breakdown test. Substituting the above values ​​into the formula γ=[E test / f(K qh The calculation is performed by multiplying the breakdown field strength by 100%, and the final result is a breakdown field strength deviation of γ of 90%.

[0055] Regarding S104 above: After obtaining the breakdown field strength deviation data, the insulation state evaluation result of the capacitor film to be evaluated is determined by matching the corresponding intervals according to the preset multiple breakdown field strength deviation data grading intervals.

[0056] In some embodiments, the plurality of breakdown field strength deviation data grading intervals include a first interval, a second interval, a third interval, and a fourth interval; the breakdown field strength deviation data values ​​corresponding to the first interval, the second interval, the third interval, and the fourth interval decrease sequentially; the step of determining the insulation state assessment result of the capacitor film to be evaluated based on the preset plurality of breakdown field strength deviation data grading intervals, matching the corresponding intervals according to the breakdown field strength deviation data, and then determining the insulation state assessment result of the capacitor film to be evaluated includes: If the breakdown field strength deviation data belongs to the first interval, then the insulation state evaluation result of the capacitor film to be evaluated is determined to be excellent. If the breakdown field strength deviation data belongs to the second interval, then the insulation status assessment result of the capacitor film to be evaluated is determined to be good. If the breakdown field strength deviation data belongs to the third interval, then the insulation status assessment result of the capacitor film to be evaluated is determined to be a warning state. If the breakdown field strength deviation data belongs to the fourth interval, then the insulation status assessment result of the capacitor film to be evaluated is determined to be unsatisfactory.

[0057] During implementation, specific insulation condition description data for each evaluation result can also be output. For example, Table 1 below shows a condition grading evaluation standard provided in this embodiment.

[0058] Table 1. Status Grading Evaluation Criteria

[0059] In practice, after calculating the breakdown field strength deviation data of the capacitor film to be evaluated, this data is matched with the four graded intervals in Table 1. If the calculated deviation data is 120%, which is greater than or equal to 110%, it is matched with the first interval, the evaluation result is determined to be excellent, and the actual insulation strength is output as significantly higher than the baseline expectation, indicating that the material itself is of excellent quality or the structural design has sufficient margin. If the deviation data is 95%, which is between 90% and 110%, it is matched with the second interval, the evaluation result is determined to be good, and the actual insulation strength is output as near the baseline expectation, which is within the normal and acceptable range. If the deviation data is 80%, which is between 70% and 90%, it is matched with the third interval, the evaluation result is determined to be warning, and the actual insulation strength begins to fall below the baseline expectation, indicating that there may be slight material defects, process fluctuations, or initial aging. If the deviation data is 65%, which is less than 70%, it is matched with the fourth interval, the evaluation result is determined to be poor, and the actual insulation strength is significantly deteriorated, indicating a high risk of insulation failure.

[0060] The insulation condition assessment method provided in this embodiment divides the breakdown field strength deviation data into four intervals with progressively decreasing values, corresponding to four insulation condition levels: excellent, good, warning, and poor. This fully combines the inherent correlation between the degree of breakdown field strength deviation and insulation performance degradation, discretizing continuous deviation data into assessment levels with clear physical meaning. The decreasing value setting of each interval is consistent with the deterioration trend of the film insulation condition, allowing the assessment results to intuitively reflect the quality level of the film insulation performance. Ultimately, this embodiment can obtain more refined and easily quantifiable insulation condition assessment results.

[0061] Using the aforementioned pre-constructed breakdown field strength prediction model, the simulated electric field distortion data in the data pairs of the 20 sample films in step S102 are processed to obtain the corresponding theoretical breakdown field strength. Then, based on the theoretical breakdown field strength and the corresponding breakdown field strength in the data pairs, the corresponding breakdown field strength deviation data can be calculated. Finally, based on multiple preset breakdown field strength deviation data grading intervals, the corresponding intervals are matched according to each breakdown field strength deviation data to determine the insulation state assessment result of each sample film. Figure 3 As shown, Figure 3 The insulation status evaluation results of each sample film provided in the embodiments of this application are shown.

[0062] Those skilled in the art will understand that in the above-described method of the specific embodiments, the order in which the steps are written does not imply a strict execution order, but constitutes no limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic.

[0063] It should be noted that in practical applications, all the above-described possible implementation methods can be combined in any way to form possible embodiments of this application, and will not be described in detail here. The information (including but not limited to device information, user information, etc.) and data (including but not limited to data used for analysis, storage, and display) involved in this application are all information and data authorized by the user or fully authorized by all parties. The software tools or components appearing in the embodiments of this application are merely illustrative examples and do not represent actual use.

[0064] Based on the same concept, this application also provides a capacitor film insulation condition assessment device, which corresponds one-to-one with the capacitor film insulation condition assessment method in the above embodiments. Figure 4 A schematic diagram of the capacitor film insulation condition assessment device provided in this application embodiment is shown. See also: Figure 4 As shown, the capacitor film insulation condition assessment device 400 provided in this application embodiment includes: The acquisition module 401 is used to acquire the actual breakdown field strength and simulated electric field distortion data of the capacitor film to be evaluated. The first calculation module 402 is used to process the simulated electric field distortion data using a pre-constructed breakdown field strength prediction model to obtain the theoretical breakdown field strength. The second calculation module 403 is used to calculate the breakdown field strength deviation data based on the theoretical breakdown field strength and the actual breakdown field strength. The evaluation module 404 is used to determine the insulation state evaluation result of the capacitor film to be evaluated by matching the corresponding intervals according to the preset multiple breakdown field strength deviation data grading intervals.

[0065] In some embodiments, in the above-described apparatus, the simulated electric field distortion data is: the maximum electric field strength, the electric field non-uniformity coefficient, or the integral value of the electric field strength in the high-risk area.

[0066] In some embodiments, the apparatus further includes a first simulation calculation module, used for: A first simulation model corresponding to the capacitor film to be evaluated is established using simulation software; The first simulation model is discretized into a grid, and corresponding electric field boundary conditions are set. The numerical solver of the simulation software is used to calculate the numerical matrix of the electric field intensity distribution over the entire field of the capacitor film to be evaluated. Based on the numerical matrix of the electric field intensity distribution over the entire field of the capacitor film to be evaluated, the simulated electric field distortion data of the capacitor film to be evaluated are calculated.

[0067] In some embodiments, the apparatus further includes a generation module for: Data pairs of multiple sample films are acquired; the data pairs include the breakdown field strength of the sample films and the corresponding simulated electric field distortion data; wherein the following characteristic data of the sample films and the capacitor films to be evaluated are the same: inherent property data before service and operating condition data; The breakdown field strength prediction model is obtained by fitting the data pairs.

[0068] In some embodiments, the apparatus further includes a second simulation calculation module, used for: A second simulation model corresponding to the sample film was established using simulation software; The second simulation model is discretized into a mesh, and corresponding electric field boundary conditions are set. The numerical solver of the simulation software is used to calculate the numerical matrix of the electric field intensity distribution over the entire sample thin film. Based on the numerical matrix of the electric field intensity distribution over the entire sample thin film, the simulated electric field distortion data of the sample thin film is calculated.

[0069] In some embodiments, in the above-described apparatus, the second calculation module 403 is specifically used to: calculate the breakdown field strength deviation data according to the following formula: γ = [ E test / f( K qh )] ×100% in, γ This indicates the deviation data of the breakdown field strength. E test This indicates the actual breakdown field strength. K qh The simulated electric field distortion data is represented by f(), and the breakdown field strength prediction model is represented by f().

[0070] In some embodiments, in the above-described apparatus, the plurality of breakdown field strength deviation data grading intervals include a first interval, a second interval, a third interval, and a fourth interval; the breakdown field strength deviation data values ​​corresponding to the first interval, the second interval, the third interval, and the fourth interval decrease sequentially; the evaluation module 404 is specifically used for: If the breakdown field strength deviation data belongs to the first interval, then the insulation state evaluation result of the capacitor film to be evaluated is determined to be excellent. If the breakdown field strength deviation data belongs to the second interval, then the insulation status assessment result of the capacitor film to be evaluated is determined to be good. If the breakdown field strength deviation data belongs to the third interval, then the insulation status assessment result of the capacitor film to be evaluated is determined to be a warning state. If the breakdown field strength deviation data belongs to the fourth interval, then the insulation status assessment result of the capacitor film to be evaluated is determined to be unsatisfactory.

[0071] This invention provides a capacitor film insulation state assessment device that integrates simulation data that accurately reflects the degree of electric field stress concentration, experimental data that characterizes the intrinsic strength of materials, and fuzzy mathematical theory that handles uncertainties, proposing an objective, quantitative, and physically meaningful intelligent assessment method for capacitor film insulation state. Specifically, this application first obtains the actual breakdown field strength, which characterizes the true insulation withstand capability of the capacitor film under evaluation, and simulated electric field distortion data, which characterizes the electric field distribution distortion characteristics of the capacitor film under evaluation during actual operation. Using a pre-constructed breakdown field strength prediction model, the simulated electric field distortion data is processed to obtain the theoretical breakdown field strength. The breakdown field strength deviation data calculated based on the theoretical breakdown field strength and the actual breakdown field strength can effectively separate the influence of the film's own insulation performance and the electric field structure, and realize the quantitative characterization of the degree of insulation performance deviation. Based on multiple preset breakdown field strength deviation data grading intervals, the corresponding deviation data is matched to determine the insulation state evaluation result. This can achieve a refined grading judgment of the insulation state without destructive testing of the entire capacitor, which avoids the material waste and high cost problems caused by whole-machine testing, improves testing efficiency, and can achieve an accurate and comprehensive evaluation of the insulation state of the capacitor film by combining the actual electric field stress of the equipment.

[0072] Specific limitations regarding the capacitor film insulation condition assessment device can be found in the limitations of the capacitor film insulation condition assessment method described above, and will not be repeated here. Each module in the aforementioned capacitor film insulation condition assessment device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0073] Figure 5 A schematic diagram of the structure of an electronic device provided in an embodiment of this application is shown. Figure 5 As shown, at the hardware level, this electronic device includes a processor, and optionally also includes an internal bus, a network interface, and memory. The memory may include main memory, such as high-speed random-access memory (RAM), or it may include non-volatile memory, such as at least one disk drive. Of course, this electronic device may also include other hardware required for other business operations.

[0074] The processor, network interface, and memory can be interconnected via an internal bus, which can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 5 The symbol is represented by a single double-headed arrow, but this does not mean that there is only one bus or one type of bus.

[0075] Memory is used to store programs. Specifically, programs may include program code, which includes computer operation instructions. Memory may include main memory and non-volatile memory, and provides instructions and data to the processor.

[0076] The processor reads the corresponding computer program from non-volatile memory into main memory and then runs it, forming a capacitor film insulation state assessment device at the logical level. The processor executes the program stored in memory and specifically performs the aforementioned method.

[0077] The processor may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by integrated logic circuits in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in the memory, and the processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the above method.

[0078] This electronic device can execute the capacitor film insulation condition assessment method provided in several embodiments of this application, and is implemented as a capacitor film insulation condition assessment device. Figure 4 The functions of the embodiments shown are not described again in this application.

[0079] This application also proposes a computer-readable storage medium that stores one or more programs, the programs including instructions that, when executed by an electronic device including multiple applications, enable the electronic device to perform the capacitor film insulation state assessment method provided in several embodiments of this application.

[0080] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0081] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0082] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0083] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0084] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0085] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0086] Computer-readable media include both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0087] This application also provides a computer program product carrying program code. The program code includes instructions that can be used to execute the steps of the capacitor film insulation state evaluation method described in the above method embodiments. For details, please refer to the above method embodiments, which will not be repeated here.

[0088] The aforementioned computer program product can be implemented through hardware, software, or a combination thereof. In one optional embodiment, the computer program product is specifically embodied in a computer storage medium; in another optional embodiment, the computer program product is specifically embodied in a software product, such as a software development kit (SDK), etc.

[0089] It should also be noted that 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 defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0090] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0091] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for evaluating the insulation state of a capacitor film, characterized in that, The method includes: Obtain the actual breakdown field strength and simulated electric field distortion data of the capacitor film to be evaluated; The simulated electric field distortion data is processed using a pre-constructed breakdown field strength prediction model to obtain the theoretical breakdown field strength. Based on the theoretical breakdown field strength and the actual breakdown field strength, the breakdown field strength deviation data is calculated; Based on multiple preset breakdown field strength deviation data grading intervals, the insulation state evaluation result of the capacitor film to be evaluated is determined by matching the corresponding intervals according to the breakdown field strength deviation data.

2. The method for evaluating the insulation state of capacitor films according to claim 1, characterized in that, The simulated electric field distortion data are: the maximum electric field strength, the electric field non-uniformity coefficient, or the integral value of the electric field strength in the high-risk area.

3. The method for evaluating the insulation state of capacitor films according to claim 1, characterized in that, The simulated electric field distortion data of the capacitor film to be evaluated was calculated according to the following method: A first simulation model corresponding to the capacitor film to be evaluated is established using simulation software; The first simulation model is discretized into a grid, and corresponding electric field boundary conditions are set. The numerical solver of the simulation software is used to calculate the numerical matrix of the electric field intensity distribution over the entire field of the capacitor film to be evaluated. Based on the numerical matrix of the electric field intensity distribution over the entire field of the capacitor film to be evaluated, the simulated electric field distortion data of the capacitor film to be evaluated are calculated.

4. The method for evaluating the insulation status of capacitor films according to claim 1, characterized in that, The pre-built breakdown field strength prediction model is generated according to the following method: Data pairs of multiple sample films are acquired; the data pairs include the breakdown field strength of the sample films and the corresponding simulated electric field distortion data; wherein the following characteristic data of the sample films and the capacitor films to be evaluated are the same: inherent property data before service and operating condition data; The breakdown field strength prediction model is obtained by fitting the data pairs.

5. The method for evaluating the insulation state of capacitor films according to claim 4, characterized in that, The simulated electric field distortion data of the sample thin film were calculated using the following method: A second simulation model corresponding to the sample film was established using simulation software; The second simulation model is discretized into a mesh, and corresponding electric field boundary conditions are set. The numerical solver of the simulation software is used to calculate the numerical matrix of the electric field intensity distribution over the entire sample thin film. Based on the numerical matrix of the electric field intensity distribution over the entire sample thin film, the simulated electric field distortion data of the sample thin film is calculated.

6. The method for evaluating the insulation state of capacitor films according to claim 1, characterized in that, The breakdown field strength deviation data is calculated according to the following formula: γ = [ E test / f( K qh )] ×100% in, γ This indicates the deviation data of the breakdown field strength. E test This indicates the actual breakdown field strength. K qh The simulated electric field distortion data is represented by f(), and the breakdown field strength prediction model is represented by f().

7. The method for evaluating the insulation state of capacitor films according to any one of claims 1-6, characterized in that, The multiple breakdown field strength deviation data grading intervals include a first interval, a second interval, a third interval, and a fourth interval; the breakdown field strength deviation data values ​​corresponding to the first interval, the second interval, the third interval, and the fourth interval decrease sequentially; the step of determining the insulation state assessment result of the capacitor film to be evaluated based on the preset multiple breakdown field strength deviation data grading intervals, matching the corresponding intervals according to the breakdown field strength deviation data, and then: If the breakdown field strength deviation data belongs to the first interval, then the insulation state evaluation result of the capacitor film to be evaluated is determined to be excellent. If the breakdown field strength deviation data belongs to the second interval, then the insulation status assessment result of the capacitor film to be evaluated is determined to be good. If the breakdown field strength deviation data belongs to the third interval, then the insulation status assessment result of the capacitor film to be evaluated is determined to be a warning state. If the breakdown field strength deviation data belongs to the fourth interval, then the insulation status assessment result of the capacitor film to be evaluated is determined to be unsatisfactory.

8. A capacitor film insulation condition assessment device, characterized in that, The device includes: The acquisition module is used to acquire the actual breakdown field strength and simulated electric field distortion data of the capacitor film to be evaluated; The first calculation module is used to process the simulated electric field distortion data using a pre-constructed breakdown field strength prediction model to obtain the theoretical breakdown field strength. The second calculation module is used to calculate the breakdown field strength deviation data based on the theoretical breakdown field strength and the actual breakdown field strength. The evaluation module is used to determine the insulation state evaluation result of the capacitor film to be evaluated by matching the corresponding intervals according to the preset multiple breakdown field strength deviation data ranges.

9. An electronic device, comprising: processor; as well as A memory configured to store computer-executable instructions, characterized in that, when executed, the executable instructions cause the processor to perform the steps of the capacitor film insulation state assessment method as described in any one of claims 1-7.

10. A computer-readable storage medium storing one or more programs, characterized in that, When the one or more programs are executed by an electronic device including multiple applications, the electronic device performs the steps of the capacitor film insulation state assessment method as described in any one of claims 1-7.

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