A method for evaluating the dielectric loss of a high-voltage capacitor and related apparatus

Abstract

This invention belongs to the field of high-voltage capacitors and discloses a method and related apparatus for evaluating the dielectric loss of high-voltage capacitors. First, by collecting low-voltage dielectric loss data and corresponding rated high-voltage loss data of high-voltage capacitor samples at various voltages and frequencies, a mapping table from low-voltage to high-voltage loss is constructed. Iterative partitioning and optimization of the dividing points are then used to ensure mapping accuracy. This method learns the overall law of loss variation with voltage in a data-driven manner, thereby avoiding the deviation caused by the Garton effect in direct low-voltage measurements and avoiding errors caused by parameter sensitivity in traditional nonlinear fitting. Using this method, high-voltage dielectric loss can be conveniently evaluated in engineering sites using only low-voltage measurements, without the need for high-voltage experimental conditions and professional operators, significantly reducing measurement costs and complexity, while effectively improving the accuracy and engineering applicability of loss evaluation.

Description

Technical Field

[0001] This invention belongs to the field of high voltage capacitor technology, specifically to the field of high voltage capacitor loss measurement, and particularly relates to a method and related apparatus for evaluating the dielectric loss of high voltage capacitors. Background Technology

[0002] High-voltage capacitors, as key components in power systems, industrial frequency converters, and new energy power generation systems, undertake important functions such as reactive power compensation, voltage stabilization, and pulse power buffering. Their operating status directly affects the safety, stability, and energy efficiency of the entire power system and related equipment. Dielectric loss tangent (or simply loss) is a core indicator for evaluating the insulation performance and operational reliability of high-voltage capacitors. Accurately measuring the loss value is crucial for timely detection of capacitor insulation defects and preventing equipment failure. Currently, the industry primarily uses high-voltage bridges (such as high-voltage Schering bridges) to measure high-voltage capacitor losses. This method achieves accurate detection of loss values ​​through the principle of balance measurement and is the most widely used measurement method in existing technology.

[0003] Existing high-voltage capacitor loss measurement technologies have many shortcomings and are difficult to meet the needs of practical engineering applications. The current mainstream high-voltage bridge measurement method suffers from three major problems: First, the measurement environment is harsh. High-voltage bridges require dedicated standard capacitors, professional electromagnetic shielding environments, and high-voltage experimental conditions. The equipment structure is complex and cannot adapt to the complex working conditions of engineering sites, making real-time on-site measurement difficult. Second, high-voltage operation is difficult. The loss measurement process requires standardized operation by personnel with relevant professional qualifications, placing high demands on the professional skills of the operators and limiting the convenience of measurement work. Third, the measurement cost is high. Since on-site measurement cannot be completed, high-voltage capacitors must be disassembled and transported to a professional laboratory for testing. Especially when a large number of devices need to be inspected, the transportation and testing costs increase significantly. To address the aforementioned issues, two closest improvement schemes have been proposed in the existing technology, but they still have significant shortcomings: First, directly using a low-voltage bridge to measure the loss of high-voltage capacitors is problematic. Since the rated voltage of high-voltage capacitors is as high as several kilovolts, while the test voltage of the low-voltage bridge is only tens of volts, the loss of high-voltage capacitors varies significantly with voltage due to the Garton effect. This results in a large deviation between the low-voltage measurement results and the loss values ​​under actual operating conditions, failing to reflect the true insulation state of the capacitor. Second, using a nonlinear fitting algorithm to calculate the main parameters of the Garton effect and then substituting them into the mathematical and physical model of loss to solve for the loss under the target voltage is problematic. Since the curve of loss changing with voltage is related to multiple microscopic parameters and is extremely sensitive, small errors in the parameter fitting process can lead to serious deviations in the final calculation results, affecting the accuracy of the measurement.

[0004] It is evident that the measurement of the dielectric loss tangent of high-voltage capacitors in the existing technology suffers from problems such as inconvenience in field application, high measurement cost, high operational difficulty, and insufficient measurement accuracy. Summary of the Invention

[0005] This invention provides a method and related apparatus for evaluating the dielectric loss of high-voltage capacitors. This method can solve the problems of inconvenience in field application, high measurement cost, high operation difficulty and insufficient measurement accuracy in the measurement of dielectric loss tangent of high-voltage capacitors in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for evaluating the dielectric loss of a high-voltage capacitor, comprising: Acquire sample datasets and low-voltage dielectric loss data of the high-voltage capacitor under test; wherein, the sample datasets include low-voltage dielectric loss data of multiple high-voltage capacitor samples at different voltages and frequencies, as well as high-voltage dielectric loss data of each high-voltage capacitor sample at rated voltage and rated frequency. The low-pressure dielectric loss data in the sample dataset is iteratively divided to construct a mapping relationship from low-pressure dielectric loss data to high-pressure dielectric loss data, resulting in a mapping table. Each division is based on a split point, which optimizes the evaluation index of the two sets of high-pressure dielectric loss data after the division. Based on the mapping table and the low-voltage dielectric loss data of the high-voltage capacitor under test, the high-voltage dielectric loss evaluation result of the high-voltage capacitor under test is obtained.

[0007] Furthermore, the iterative partitioning of the low-pressure dielectric loss data in the sample dataset to construct a mapping relationship from low-pressure dielectric loss data to high-pressure dielectric loss data includes: Select an unprocessed test point from a combination of low-voltage dielectric loss data of different voltages and frequencies; Based on the low-voltage dielectric loss data of multiple capacitor samples at this unprocessed test point, a split point is searched so that the evaluation index of the high-voltage dielectric loss data of each of the two subsets is optimal after dividing the multiple capacitor samples into two subsets according to the split point. Within each subset, the steps of selecting unprocessed test points, searching for split points, and dividing the subset are executed recursively until the subset contains only one high-voltage capacitor sample. The high-pressure dielectric loss data corresponding to each subset obtained from the final division is determined as the mapping output value of the leaf node corresponding to the subset, thus obtaining the mapping table.

[0008] Furthermore, the evaluation metric is any one of the following: sum of squared errors, information entropy, and covariance; Wherein, the sum of squared errors The specific calculation formula is as follows:

[0009] In the formula, , ; and The two subsets obtained by partitioning; For the first High-voltage dielectric loss data for a sample of high-voltage capacitors. for The mean of all high-pressure dielectric loss data in the subset; for The mean of all high-pressure dielectric loss data in the subset; , These represent the number of high-voltage capacitor samples corresponding to the two subsets, respectively.

[0010] Furthermore, the specific steps for searching for the segmentation point are as follows: Traverse the numerical distribution range of low-pressure medium loss data and set several candidate segmentation points; Calculate the evaluation index of the high-pressure dielectric loss data after partitioning the data into subsets for each candidate segmentation point, and select the candidate segmentation point with the best evaluation index as the final segmentation point.

[0011] Furthermore, before mapping the high-voltage dielectric loss assessment result of the high-voltage capacitor under test based on the mapping table and the low-voltage dielectric loss data of the high-voltage capacitor under test, the process further includes: Repeat the steps of iteratively dividing the low-pressure dielectric loss data in the sample dataset and constructing a mapping relationship from low-pressure dielectric loss data to high-pressure dielectric loss data multiple times to obtain multiple mapping tables with different structures. The low-voltage dielectric loss data of the high-voltage capacitor under test is mapped through multiple mapping tables to obtain multiple high-voltage dielectric loss evaluation results. Calculate the average value of multiple high-voltage dielectric loss assessment results, and output the average value as the final high-voltage dielectric loss assessment result of the high-voltage capacitor under test.

[0012] Furthermore, the specific steps for obtaining the sample dataset and the low-voltage dielectric loss data of the high-voltage capacitor under test are as follows: N high-voltage capacitors of different models were randomly selected as samples. The dielectric loss of each sample was measured at H group test voltage and K group test frequency, and a voltage-frequency-dielectric loss matrix was formed as low-voltage dielectric loss data. At the same time, the standard dielectric loss value of each sample at rated voltage and rated frequency was measured as high-voltage dielectric loss data. Among them, the n The test results for each sample are represented by a matrix as follows:

[0013] In the formula, x i，j Indicates voltage as V i , frequency is f j The loss of the capacitor at that time, i For 1, 2, 3 ，...，H j is 1, 2, 3 ，...，K .

[0014] Furthermore, the low-voltage dielectric loss data of the high-voltage capacitor under test has the same voltage and frequency as the low-voltage dielectric loss data of the sample dataset.

[0015] A high-voltage capacitor dielectric loss assessment system, comprising: The acquisition module is used to acquire sample datasets and low-voltage dielectric loss data of the high-voltage capacitor under test; wherein, the sample dataset includes low-voltage dielectric loss data of multiple high-voltage capacitor samples at different voltages and frequencies, as well as high-voltage dielectric loss data of each high-voltage capacitor sample at rated voltage and rated frequency. The construction module is used to iteratively divide the low-pressure dielectric loss data in the sample dataset, construct a mapping relationship from low-pressure dielectric loss data to high-pressure dielectric loss data, and obtain a mapping table; wherein, each division is based on the split point, and the split point can make the evaluation index of the two sets of high-pressure dielectric loss data optimal after the division. The evaluation module is used to map the high-voltage dielectric loss evaluation result of the high-voltage capacitor under test based on the mapping table and the low-voltage dielectric loss data of the high-voltage capacitor under test.

[0016] A high-voltage capacitor dielectric loss assessment device, comprising: Memory, used to store computer programs; A processor is used to implement the above-described high-voltage capacitor dielectric loss assessment method when executing the computer program.

[0017] A computer-readable storage medium storing a computer program, which, when executed by a processor, is used to implement the above-described high-voltage capacitor dielectric loss assessment method.

[0018] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for evaluating the dielectric loss of high-voltage capacitors. First, by collecting low-voltage dielectric loss data and corresponding rated high-voltage loss data of high-voltage capacitor samples at various voltages and frequencies, a mapping table from low-voltage to high-voltage loss is constructed. Iterative partitioning and optimization of the segmentation points are then used to ensure mapping accuracy. This method learns the overall law of loss variation with voltage in a data-driven manner, thus avoiding the bias caused by the Garton effect in direct low-voltage measurements and avoiding errors caused by parameter sensitivity in traditional nonlinear fitting. Using this method, high-voltage dielectric loss can be conveniently evaluated in engineering fields using only low-voltage measurements, without the need for high-voltage experimental conditions and professional operators, significantly reducing measurement costs and complexity, while effectively improving the accuracy and engineering applicability of loss evaluation. Attached Figure Description

[0019] Figure 1 A comparison chart of the results of the high-voltage capacitor dielectric loss assessment method provided in the embodiments of the present invention and the traditional high-voltage Schering bridge measurement method is shown. Figure 2 This is a core flowchart of a high-voltage capacitor dielectric loss assessment method provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of a high-voltage capacitor dielectric loss assessment system provided in an embodiment of the present invention. Detailed Implementation

[0020] To further understand the content of this invention, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0021] The technical terms used in this invention are explained as follows: Garton effect: refers to the phenomenon in devices containing composite insulating media such as paper, oil or plastic (such as high-voltage capacitors) where the electric field strength affects the movement of charged particles of impurities in the medium, resulting in the dielectric loss tangent at lower voltages being 1 to 10 times that at higher voltages.

[0022] As mentioned in the background section, traditional measurement methods for assessing the losses of high-voltage capacitors have the following drawbacks: First, the rated voltage of high-voltage capacitors can reach several thousand volts, while the test voltage of low-voltage bridge is only tens of volts. Due to the Garton effect, the loss of high-voltage capacitors changes significantly with voltage. Therefore, the results of direct measurement using low-voltage bridge are very different from the loss of capacitors under actual operating conditions.

[0023] Second, since the curve of loss versus voltage is related to several micro-parameters and has high sensitivity, small errors in parameter fitting may cause serious deviations in the final calculation results.

[0024] To address the aforementioned issues, this embodiment provides a method for evaluating the dielectric loss of high-voltage capacitors. This method is based on the mapping relationship between the low-voltage loss and the rated voltage loss of the capacitor, effectively solving the problem that losses can only be measured using a high-voltage Schering bridge and cannot be measured on-site.

[0025] For example, such as Figure 2 As shown, this embodiment provides a method for evaluating the dielectric loss of a high-voltage capacitor, including: Acquire sample datasets and low-voltage dielectric loss data of the high-voltage capacitor under test; wherein, the sample datasets include low-voltage dielectric loss data of multiple high-voltage capacitor samples at different voltages and frequencies, as well as high-voltage dielectric loss data of each high-voltage capacitor sample at rated voltage and rated frequency. The low-pressure dielectric loss data in the sample dataset is iteratively divided to construct a mapping relationship from low-pressure dielectric loss data to high-pressure dielectric loss data, resulting in a mapping table. Each division is based on a split point, which optimizes the evaluation index of the two sets of high-pressure dielectric loss data after the division. Based on the mapping table and the low-voltage dielectric loss data of the high-voltage capacitor under test, the high-voltage dielectric loss evaluation result of the high-voltage capacitor under test is obtained.

[0026] The evaluation method provided in this embodiment will be further explained below: This embodiment provides a method for evaluating the dielectric loss of high-voltage capacitors, the specific principle of which is as follows: First, a capacitor voltage-frequency-loss database is established. Second, the mapping path between low-voltage loss and rated voltage (high voltage) loss is obtained by iteratively dividing the low-voltage loss. Finally, the loss of the test sample under low voltage is measured and mapped to the rated voltage (high voltage) loss using a mapping table.

[0027] For example, the evaluation method provided in this embodiment has the following specific steps: Step 1: Randomly select high-voltage capacitors of different models. N Taiwan, N For each sample, the low-voltage dielectric loss is measured at different voltages and frequencies. If the measured voltage is... V i The frequency is f j , i 1, 2, 3 ,...,H j is 1, 2, 3 ,...,K That is, for each sample there is H × K The test data, the first n The test results for each sample are represented by a matrix:

[0028] In the formula, x i,j Indicates voltage as V i , frequency is f j The loss of the capacitor; n ) indicates the first n One sample.

[0029] Step 2: Measure the loss of each sample at rated voltage and frequency using a high-voltage Schering bridge. n The measurement results of each sample are y ( n ).

[0030] Step 3, in X Randomly select one element from (n). , N The results for each sample are ~ Then the high-pressure dielectric loss corresponding to N samples is: y (1)~ y ( N ); y ( N ) represents the high-pressure dielectric loss corresponding to the Nth sample.

[0031] Step 4: Set candidate split points s Will ~ It is divided into two parts: and ; and These are the two subsets obtained by partitioning.

[0032] Step 5: The high-voltage dielectric loss at the corresponding rated voltage and frequency is also divided into two parts. , .

[0033] Step 6: Calculate the evaluation function In the formula, , . for The mean of all high-pressure dielectric loss data in the subset; for The mean of all high-pressure dielectric loss data in the subset; , These represent the number of high-voltage capacitor samples corresponding to the two subsets, respectively.

[0034] It should be noted that the above evaluation indicators can be any one of the sum of squared errors, information entropy, and covariance; when the evaluation indicator is information entropy, the specific calculation formula is as follows: ,in, For subset The proportion of the sample size in the middle to the total sample size is used to select the split point that minimizes the sum of the information entropy of the two subsets after the split as the final split point. Information entropy; When the evaluation metric is covariance, the specific calculation formula is as follows: ,in, For subset The mean of the medium and high pressure dielectric loss data is used to select the dividing point that minimizes the covariance as the final dividing point; For covariance.

[0035] Step 7: Traverse the numerical distribution range of low-pressure medium loss data and set several candidate segmentation points; Calculate the evaluation index of the high-pressure dielectric loss data after partitioning the dataset for each candidate split point, and select the candidate split point with the optimal evaluation index as the final split point. Specifically, sort the measured values ​​of all low-pressure dielectric loss data in the current subset in ascending order, and use the midpoint between any two adjacent data points as candidate split points. That is, change the value of s to find the s value that minimizes L, denoted as s0. min .but ~ It is divided into two parts: and .

[0036] Step 8, for and Steps three through seven are executed repeatedly across the two regions until the subsets cannot be further divided, meaning each subset contains only one sample. The element numbers a and b selected each time are recorded, thus obtaining a mapping table. During the iterative execution of steps three through seven, unprocessed test points (i.e., unprocessed elements) are selected each time.

[0037] Step 9: Repeat steps 3 to 8 M times to obtain M mapping tables with different structures.

[0038] Step 10: Obtain the low-voltage dielectric loss data of the high-voltage capacitor under test. The loss was evaluated using low-voltage dielectric loss data with the same voltage and frequency as the sample.

[0039] Map the M mapping tables recorded in steps three through nine to obtain M evaluation results. Take the average value of all evaluation results, which is the final loss evaluation result under rated voltage (the final high-voltage dielectric loss evaluation result of the high-voltage capacitor under test).

[0040] For example, a specific application of the evaluation method provided in this embodiment was also implemented. The evaluation method and the high-voltage Schering bridge measurement were used to measure 20 capacitors respectively. The loss obtained by mapping using this method was compared with the result of the high-voltage Schering bridge measurement. Figure 1 As shown, the relative error between the two methods is less than 2%, which meets the accuracy requirements for capacitor loss measurement.

[0041] like Figure 3 As shown, this embodiment also provides a high-voltage capacitor dielectric loss evaluation system, including: an acquisition module, used to acquire a sample dataset and low-voltage dielectric loss data of the high-voltage capacitor under test; wherein, the sample dataset includes low-voltage dielectric loss data of multiple high-voltage capacitor samples at different voltages and frequencies, and high-voltage dielectric loss data of each high-voltage capacitor sample at rated voltage and rated frequency. The construction module is used to iteratively divide the low-pressure dielectric loss data in the sample dataset, construct a mapping relationship from low-pressure dielectric loss data to high-pressure dielectric loss data, and obtain a mapping table; wherein, each division is based on the split point, and the split point can make the evaluation index of the two sets of high-pressure dielectric loss data optimal after the division. The evaluation module is used to map the high-voltage dielectric loss evaluation result of the high-voltage capacitor under test based on the mapping table and the low-voltage dielectric loss data of the high-voltage capacitor under test.

[0042] The present invention also provides a high-voltage capacitor dielectric loss assessment device, comprising: a memory for storing a computer program; and a processor for executing the computer program to implement the steps of the high-voltage capacitor dielectric loss assessment method.

[0043] The present invention also provides a computer program product, including a computer program / instructions that, when executed by a processor, implement the steps of the high-voltage capacitor dielectric loss assessment method.

[0044] When the processor executes the computer program, it implements the above-mentioned steps for evaluating the dielectric loss of high-voltage capacitors, such as: acquiring a sample dataset; wherein, the sample dataset includes low-voltage dielectric loss data of multiple high-voltage capacitor samples at different voltages and frequencies, and high-voltage dielectric loss data of each high-voltage capacitor sample at rated voltage and rated frequency; Obtain low-voltage dielectric loss data of the high-voltage capacitor under test; The low-pressure dielectric loss data in the sample dataset is iteratively divided to construct a mapping relationship from low-pressure dielectric loss data to high-pressure dielectric loss data, resulting in a mapping table. Each division is based on a split point, which optimizes the evaluation index of the two sets of high-pressure dielectric loss data after the division. Based on the mapping table and the low-voltage dielectric loss data of the high-voltage capacitor under test, the high-voltage dielectric loss evaluation result of the high-voltage capacitor under test is obtained.

[0045] For example, the computer program may be divided into one or more modules / units, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units may be a series of computer program instruction segments capable of performing preset functions, the instruction segments describing the execution process of the computer program in the high-voltage capacitor dielectric loss assessment device. For example, the computer program can be divided into an acquisition module, a construction module, and an evaluation module; the specific functions are as follows: the acquisition module is used to acquire a sample dataset and low-voltage dielectric loss data of the high-voltage capacitor under test; wherein, the sample dataset includes low-voltage dielectric loss data of multiple high-voltage capacitor samples at different voltages and frequencies, and high-voltage dielectric loss data of each high-voltage capacitor sample at rated voltage and rated frequency; the construction module is used to iteratively divide the low-voltage dielectric loss data in the sample dataset, construct a mapping relationship from low-voltage dielectric loss data to high-voltage dielectric loss data, and obtain a mapping table; wherein, each division is based on a dividing point, and the dividing point enables the evaluation index of the two sets of high-voltage dielectric loss data after division to be optimal; the evaluation module is used to map and obtain the high-voltage dielectric loss evaluation result of the high-voltage capacitor under test based on the mapping table and the low-voltage dielectric loss data of the high-voltage capacitor under test.

[0046] The high-voltage capacitor dielectric loss assessment device can be a desktop computer, laptop, handheld computer, or cloud server, etc. The high-voltage capacitor dielectric loss assessment device may include, but is not limited to, a processor and memory. Those skilled in the art will understand that the above are examples of high-voltage capacitor dielectric loss assessment devices and do not constitute a limitation on the high-voltage capacitor dielectric loss assessment device. It may include more components than described above, or combine certain components, or different components. For example, the high-voltage capacitor dielectric loss assessment device may also include input / output devices, network access devices, buses, etc.

[0047] The processor referred to can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or any conventional processor, etc. The processor is the control center for the high-voltage capacitor dielectric loss assessment, connecting various parts of the high-voltage capacitor dielectric loss assessment equipment via various interfaces and lines.

[0048] The memory can be used to store the computer program and / or modules. The processor implements various functions of the high-voltage capacitor dielectric loss assessment device by running or executing the computer program and / or modules stored in the memory and calling the data stored in the memory.

[0049] The memory may primarily include a program storage area and a data storage area. The program storage area may store the operating system and at least one application program required for a function (such as sound playback, image playback, etc.). The data storage area may store data created based on the use of the mobile phone (such as audio data, phonebook, etc.). Furthermore, the memory may include high-speed random access memory and non-volatile memory, such as hard disks, RAM, plug-in hard disks, smart media cards (SMC), secure digital cards (SD cards), flash cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0050] The present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the high-voltage capacitor dielectric loss assessment method.

[0051] If the modules / units integrated in the high-voltage capacitor dielectric loss assessment system are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium.

[0052] Based on this understanding, the present invention can implement all or part of the processes in the above-described high-voltage capacitor dielectric loss assessment method, or it can be accomplished by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the above-described high-voltage capacitor dielectric loss assessment method. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or a preset intermediate form, etc.

[0053] The computer-readable storage medium may include: any entity or device capable of carrying the computer program code, recording media, USB flash drive, portable hard drive, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0054] It should be noted that the content contained in the computer-readable storage medium may be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable storage medium does not include electrical carrier signals and telecommunication signals.

[0055] In summary, compared with existing measurement methods, this invention provides a method for evaluating the dielectric loss of high-voltage capacitors, which has the following advantages: This invention utilizes a large number of capacitor loss test results from different models to obtain a mapping table from low-voltage loss to rated voltage loss. Furthermore, by randomly selecting the starting point of the mapping table, a generalized mapping relationship is achieved, avoiding excessive weighting of specific data points. Additionally, multiple different mapping tables are used to map the same set of measurement data, reducing the impact of some special mapping relationships on the overall result. This method enables low-voltage measurement of rated voltage loss of capacitors without requiring high-voltage testing conditions, thus improving measurement safety. Based on low-voltage measurement, on-site measurement of capacitor loss is achieved, facilitating application in engineering fields and reducing measurement costs.

[0056] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for evaluating the dielectric loss of a high-voltage capacitor, characterized in that, include: Acquire sample datasets and low-voltage dielectric loss data of the high-voltage capacitor under test; wherein, the sample datasets include low-voltage dielectric loss data of multiple high-voltage capacitor samples at different voltages and frequencies, as well as high-voltage dielectric loss data of each high-voltage capacitor sample at rated voltage and rated frequency. The low-pressure dielectric loss data in the sample dataset is iteratively divided to construct a mapping relationship from low-pressure dielectric loss data to high-pressure dielectric loss data, resulting in a mapping table. Each division is based on a split point, which optimizes the evaluation index of the two sets of high-pressure dielectric loss data after the division. Based on the mapping table and the low-voltage dielectric loss data of the high-voltage capacitor under test, the high-voltage dielectric loss evaluation result of the high-voltage capacitor under test is obtained.

2. The method for evaluating the dielectric loss of a high-voltage capacitor according to claim 1, characterized in that, The step of iteratively dividing the low-pressure dielectric loss data in the sample dataset and constructing a mapping relationship from low-pressure dielectric loss data to high-pressure dielectric loss data includes: Select an unprocessed test point from a combination of low-voltage dielectric loss data of different voltages and frequencies; Based on the low-voltage dielectric loss data of multiple capacitor samples at this unprocessed test point, a split point is searched so that the evaluation index of the high-voltage dielectric loss data of each of the two subsets is optimal after dividing the multiple capacitor samples into two subsets according to the split point. Within each subset, the steps of selecting unprocessed test points, searching for split points, and dividing the subset are executed recursively until the subset contains only one high-voltage capacitor sample. The high-pressure dielectric loss data corresponding to each subset obtained from the final division is determined as the mapping output value of the leaf node corresponding to the subset, thus obtaining the mapping table.

3. The method for evaluating the dielectric loss of a high-voltage capacitor according to claim 2, characterized in that, The evaluation metric is any one of the following: sum of squared errors, information entropy, and covariance. Wherein, the sum of squared errors The specific calculation formula is as follows: In the formula, , ; and The two subsets obtained by partitioning; For the first High-voltage dielectric loss data for a sample of high-voltage capacitors. for The mean of all high-pressure dielectric loss data in the subset; for The mean of all high-pressure dielectric loss data in the subset; , These represent the number of high-voltage capacitor samples corresponding to the two subsets, respectively.

4. The method for evaluating the dielectric loss of a high-voltage capacitor according to claim 2, characterized in that, The specific steps for searching for the split point are as follows: Traverse the numerical distribution range of low-pressure medium loss data and set several candidate segmentation points; Calculate the evaluation index of the high-pressure dielectric loss data after partitioning the data into subsets for each candidate segmentation point, and select the candidate segmentation point with the best evaluation index as the final segmentation point.

5. The method for evaluating the dielectric loss of a high-voltage capacitor according to claim 1, characterized in that, Before mapping the high-voltage dielectric loss assessment result of the high-voltage capacitor under test based on the mapping table and the low-voltage dielectric loss data of the high-voltage capacitor under test, the process further includes: Repeat the steps of iteratively dividing the low-pressure dielectric loss data in the sample dataset and constructing a mapping relationship from low-pressure dielectric loss data to high-pressure dielectric loss data multiple times to obtain multiple mapping tables with different structures. The low-voltage dielectric loss data of the high-voltage capacitor under test is mapped through multiple mapping tables to obtain multiple high-voltage dielectric loss evaluation results. Calculate the average value of multiple high-voltage dielectric loss assessment results, and output the average value as the final high-voltage dielectric loss assessment result of the high-voltage capacitor under test.

6. The method for evaluating the dielectric loss of a high-voltage capacitor according to claim 1, characterized in that, The specific steps for obtaining the sample dataset and the low-voltage dielectric loss data of the high-voltage capacitor under test are as follows: N high-voltage capacitors of different models were randomly selected as samples. The dielectric loss of each sample was measured at H group test voltage and K group test frequency, and a voltage-frequency-dielectric loss matrix was formed as low-voltage dielectric loss data. At the same time, the standard dielectric loss value of each sample at rated voltage and rated frequency was measured as high-voltage dielectric loss data. Among them, the n The test results for each sample are represented by a matrix as follows: In the formula, x i，j Indicates voltage as V i , frequency is f j The loss of the capacitor at that time i For 1, 2, 3 ，...，H j is 1, 2, 3 ，...，K .

7. The method for evaluating the dielectric loss of a high-voltage capacitor according to claim 6, characterized in that, The low-voltage dielectric loss data of the high-voltage capacitor under test has the same voltage and frequency as the low-voltage dielectric loss data of the sample dataset.

8. A high-voltage capacitor dielectric loss assessment system, characterized in that, include: The acquisition module is used to acquire sample datasets and low-voltage dielectric loss data of the high-voltage capacitor under test; wherein, the sample dataset includes low-voltage dielectric loss data of multiple high-voltage capacitor samples at different voltages and frequencies, as well as high-voltage dielectric loss data of each high-voltage capacitor sample at rated voltage and rated frequency. The construction module is used to iteratively divide the low-pressure dielectric loss data in the sample dataset, construct a mapping relationship from low-pressure dielectric loss data to high-pressure dielectric loss data, and obtain a mapping table; wherein, each division is based on the split point, and the split point can make the evaluation index of the two sets of high-pressure dielectric loss data optimal after the division. The evaluation module is used to map the high-voltage dielectric loss evaluation result of the high-voltage capacitor under test based on the mapping table and the low-voltage dielectric loss data of the high-voltage capacitor under test.

9. A high-voltage capacitor dielectric loss assessment device, characterized in that, include: Memory, used to store computer programs; A processor, configured to implement the high-voltage capacitor dielectric loss assessment method according to any one of claims 1-7 when executing the computer program.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it is used to implement the high-voltage capacitor dielectric loss assessment method according to any one of claims 1-7.

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