Capacitor testing method, system and device and storage medium

Abstract

The invention discloses a capacitor testing method, system and device and a storage medium. The method comprises the steps that testing data under preset parameters are acquired through testing equipment; according to the test data, performing parameter extraction operation to obtain a capacitance parameter, a loss angle tangent value and a leakage current value; performing data preprocessing operation according to the capacitance parameter, the loss angle tangent value and the leakage current value to obtain a test parameter; according to the test data and the test parameters, carrying out change rate calculation to obtain a capacitance parameter change rate, a loss angle tangent value change rate and a leakage current value change rate of each capacitor; and performing result analysis according to the capacitance parameter change rate, the loss angle tangent value change rate and the leakage current value change rate to obtain capacitor test result data. The method can improve the evaluation accuracy and reduce the evaluation time.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitor testing, and in particular to a capacitor testing method, system, device and storage medium. Background Art

[0002] At present, capacitors play a vital role in modern power systems and electronic equipment. They are not only used for energy storage, but also widely used in signal coupling, power filtering, energy conversion and other fields. With the rapid development of power and electronic technology, the demand and performance requirements of capacitors are constantly increasing. The performance stability of capacitors is directly related to the reliability and safety of the power system. Therefore, it is particularly important to accurately evaluate the performance of capacitors during design and operation. The failure of capacitors may lead to instability in the power system and even cause serious safety accidents. In the power grid, the failure of capacitors may cause voltage instability and affect the power supply quality of the power grid; in the communication field, the performance degradation of capacitors may cause interruption of signal transmission; in the automotive field, the failure of capacitors may affect the stability of the power system. Therefore, the performance evaluation of capacitors is not only a technical issue, but also an important issue involving safety and economy.

[0003] In existing technologies, capacitor testing methods mainly rely on measuring parameters such as no-load voltage and no-load current under specific conditions simulated in the laboratory, and judging the performance and life of the capacitor based on the changes in these parameters. This method usually involves placing the capacitor in a high or low temperature environment, and then measuring its electrical characteristics under these extreme conditions, in order to evaluate the impact of various environmental factors that may be encountered in actual applications on its performance. However, this method has some limitations because it cannot fully simulate the complex and changing environment and load conditions that capacitors encounter under actual working conditions. In addition, this method can often only provide a snapshot of the performance of the capacitor at a certain moment, and cannot continuously monitor its performance changes over time, making it difficult to predict the long-term reliability and life of the capacitor.

[0004] The existing technology has the problem of single evaluation parameters and lacks comprehensive consideration of changes in multiple parameters of capacitors. Summary of the invention

[0005] The present invention provides a capacitor testing method, system, device and storage medium to achieve multi-parameter evaluation to more accurately reflect the performance of the capacitor under actual working conditions.

[0006] In a first aspect, in order to solve the above technical problems, the present invention provides a capacitor testing method, comprising: Acquire test data under preset parameters through test equipment; According to the test data, a parameter extraction operation is performed to obtain capacitance parameters, loss tangent values ​​and leakage current values; Performing data preprocessing operations according to the capacitance parameter, the loss tangent value, and the leakage current value to obtain test parameters; Calculate the change rate according to the test data and the test parameters to obtain the capacitance parameter change rate, loss tangent value change rate and leakage current value change rate of each capacitor; The results are analyzed based on the capacitance parameter change rate, the loss tangent value change rate, and the leakage current value change rate to obtain capacitor test result data.

[0007] Preferably, in an optional implementation manner, the capacitor testing method is characterized in that obtaining test data under preset parameters by a testing device comprises: Based on the test equipment, a preset frequency and a preset voltage are applied to the capacitor within a preset test time period, and test data is collected to obtain test data.

[0008] Preferably, in an optional implementation manner, the capacitor testing method is characterized in that the parameter extraction operation is performed according to the test data to obtain the capacitance parameter, the loss tangent value and the leakage current value, including: According to the test data, the capacitance parameters of each capacitor are calculated using the following formula: in, is the capacitance parameter; a test capacitance parameter of the test capacitor output by the test device; is the standard capacitance parameter of the capacitor under working conditions in the initial state; is the temperature of the capacitor under the initial working condition; The temperature coefficient for the operating conditions of the capacitor; According to the test data, the loss tangent value of each capacitor is calculated using the following formula: in, is the loss tangent value; is the loss current of the capacitor; is the voltage of the capacitor; is the operating angular frequency of the capacitor; is the capacitance parameter; According to the test data, the leakage current value of each capacitor is calculated using the following formula: in, is the leakage current value; is the voltage on the capacitor; is the insulation resistance of the dielectric material.

[0009] Preferably, in an optional implementation manner, the capacitor testing method is characterized in that, according to the capacitance parameter, the loss tangent value and the leakage current value, a data preprocessing operation is performed to obtain the test parameters, including: Performing data statistical operations according to the capacitance parameter, the loss tangent value and the leakage current value to obtain statistical parameters; According to the statistical model formula and the preset confidence level and degree of freedom, the statistical parameter is subjected to standard error calculation operation to obtain the standard error of each group of data to evaluate the validity of the statistical parameter, thereby obtaining the deviation threshold; According to the deviation threshold, an abnormal data elimination operation is performed on the statistical parameters to eliminate abnormal data exceeding the threshold to obtain effective test parameters; According to the valid test parameters, an average value operation is performed on the valid test parameters to obtain an average value of the remaining valid data as a test result; According to the test results, a validity processing operation is performed on the capacitor to obtain test parameters.

[0010] Preferably, in an optional embodiment, the capacitor testing method is characterized in that, according to the statistical model formula and the set confidence level and degree of freedom, the statistical parameter is subjected to a standard error calculation operation to obtain the standard error of each set of data to evaluate the validity of the statistical parameter, thereby obtaining the deviation threshold, including: Statistical model formula: in, is the intercept term, which means that when =0 when the predicted value; , , , are the coefficients of the model, corresponding to , , , The coefficient of is the input statistical parameter; is the highest degree of the polynomial; For Capacitor No. Test data, the calculation formula is as follows: in, It is Capacitor No. Test values ​​of test data; It is Capacitor No. Various test parameters of the test data; The calculation formula for the deviation threshold is as follows: in, is the deviation threshold; is a statistical parameter; is the coefficient determined based on the confidence level; is the standard deviation of the statistical parameter.

[0011] Preferably, in an optional implementation manner, the capacitor testing method is characterized in that the change rate calculation is performed according to the test data and the test parameters to obtain the capacitance parameter change rate, loss tangent value change rate and leakage current value change rate of each capacitor, including: According to the test data and the test parameters, the capacitance parameter change rate is obtained by using a capacitance parameter change rate calculation formula; According to the test data and the test parameters, the loss tangent value change rate is obtained by using the loss tangent value change rate calculation formula; According to the test data and the test parameters, the leakage current value change rate is obtained by using a leakage current value change rate calculation formula; The calculation formula for the capacitance parameter change rate is as follows: in, is the capacitance parameter change rate; To test the capacitance parameters; is the capacitance test parameter; The formula for calculating the loss tangent change rate is as follows: in, is the rate of change of loss tangent; is the loss tangent value; is the loss tangent value test parameter; The formula for calculating the leakage current value change rate is as follows: in, is the leakage current value change rate; is the leakage current value; It is the leakage current value test parameter.

[0012] Preferably, in an optional implementation manner, the capacitor testing method is characterized in that, according to the capacitance parameter change rate, the loss tangent value change rate, and the leakage current value change rate, a result analysis is performed to obtain capacitor test result data, including: According to the test parameters, a parameter analysis operation is performed to obtain an analysis threshold table; According to the analysis threshold table, the capacitance parameter change rate, the loss tangent value change rate and the leakage current value change rate, a result analysis operation is performed to obtain capacitor test result data.

[0013] In a second aspect, the present invention provides a capacitor testing system, comprising: A data acquisition module, used to acquire test data under preset parameters through a test device; A data preprocessing module, used to perform data processing operations according to the test data to obtain capacitance parameters, loss tangent values ​​and leakage current values; A data processing module, used to perform data processing operations according to the capacitance parameter, the loss tangent value and the leakage current value to obtain test parameters; A change rate calculation module, used to calculate the change rate according to the test data and the test parameters, and obtain the capacitance parameter change rate, loss tangent value change rate and leakage current value change rate of each capacitor; The test data output module is used to perform data calculation according to the capacitance parameter change rate, the loss tangent value change rate, the leakage current value change rate and the analysis threshold table to obtain capacitor test result data.

[0014] In a third aspect, the present invention further provides an electronic device, comprising a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor implements any one of the above-mentioned capacitor testing methods when executing the computer program.

[0015] In a fourth aspect, the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium includes a stored computer program, wherein when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute any one of the capacitor testing methods described above.

[0016] Compared with the prior art, the present invention has the following beneficial effects: acquiring test data under preset parameters through a test device; performing parameter extraction operations according to the test data to obtain capacitance parameters, loss tangent values ​​and leakage current values; performing data preprocessing operations according to the capacitance parameters, the loss tangent values ​​and the leakage current values ​​to obtain test parameters; performing change rate calculations according to the test data and the test parameters to obtain capacitance parameter change rates, loss tangent value change rates and leakage current value change rates of each capacitor; performing result analysis according to the capacitance parameter change rates, the loss tangent value change rates and the leakage current value change rates to obtain capacitor test result data.

[0017] The present invention uses a statistical model to analyze data, solving the problem of single evaluation parameters in the prior art. This method can comprehensively consider the changes in multiple parameters such as capacitance parameters, loss tangent value and leakage current value, and achieve a comprehensive evaluation of capacitor performance, thereby improving the accuracy of the evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a flow chart of a capacitor testing method provided by a first embodiment of the present invention; Figure 2 It is a structural schematic diagram of a capacitor testing device provided in the second embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Reference Figure 1 The first embodiment of the present invention provides a capacitor testing method, comprising the following steps: S11, obtaining test data under preset parameters through a test device; S12, performing a parameter extraction operation according to the test data to obtain a capacitance parameter, a loss tangent value, and a leakage current value; S13, performing data preprocessing operations according to the capacitance parameter, the loss tangent value and the leakage current value to obtain test parameters; S14, performing change rate calculation according to the test data and the test parameters to obtain the capacitance parameter change rate, loss tangent value change rate and leakage current value change rate of each capacitor; S15, analyzing the results according to the capacitance parameter change rate, the loss tangent value change rate, and the leakage current value change rate to obtain capacitor test result data.

[0021] It should be noted that the existing method obtains the changes in the capacitor's equivalent series resistance, capacitor equivalent capacitance and loss tangent parameters by measuring the changes in the capacitor's voltage and current parameters under aging conditions, thereby calculating the capacitor performance evaluation function value, and using the capacitor performance evaluation function value to detect and evaluate the performance of the capacitor. However, this method only uses a single capacitor parameter as an indicator for evaluation, and cannot fully and accurately reflect the performance and life of the capacitor. In addition, capacitor parameters are usually a changing process, and currently the main evaluation is whether the parameters exceed the failure threshold. When the capacitor parameters do not exceed the failure threshold, but the parameters change abnormally, resulting in a significant attenuation of the capacitor performance, no attention is paid to the parameter changes.

[0022] In the present invention, the data of capacitors in multiple use stages under different preset parameter conditions are collected by the test equipment, and the parameter data of multiple capacitors are statistically analyzed by the statistical model to obtain the test value, and the parameter change rate is calculated by the test value to obtain the test result data of the capacitor. This method can comprehensively consider the changes in multiple parameters such as capacitance parameters, loss tangent value and leakage current value, and realize a comprehensive evaluation of capacitor performance.

[0023] In step S11, obtaining test data under preset parameters by means of a test device includes: Based on the test equipment, a preset frequency and a preset voltage are applied to the capacitor within a preset test time period, and test data is collected to obtain test data.

[0024] It should be noted that the test data of the capacitor is obtained under preset parameter conditions through specific test equipment. These preset parameters include the operating voltage, frequency, and temperature of the capacitor. Among them, the process of obtaining these data involves the use of high-precision test equipment, AC withstand voltage testers and capacitance testers, which can apply preset voltages and frequencies to capacitors in a controlled environment, while measuring and recording the test data of the capacitor. These test data include voltage, current, capacitance value, loss tangent value, and leakage current. The test data obtained will be used in subsequent performance evaluation steps.

[0025] It should be noted that the specific implementation method of step S11 is as follows: first, design and construct a test bench that can accommodate multiple capacitors and provide the necessary electrical connections for each capacitor. The capacitor to be tested is installed on the test bench in a predetermined manner. Each capacitor needs to be fixed in place and the correctness of the electrical connection is ensured. In order to ensure the accuracy and traceability of the test data, each capacitor installed on the test bench needs to be uniquely numbered. These numbers can be physical labels or use modern identification methods such as barcodes / QR codes. Each capacitor is connected to the test equipment through a precise electrical connection to ensure that the preset voltage and frequency can be accurately applied during the test process, and the response of the capacitor can be accurately measured. A data recording system is set up to automatically record all relevant data of each capacitor during the test process.

[0026] In step S12, the parameter extraction operation is performed according to the test data to obtain capacitance parameters, loss tangent values ​​and leakage current values, including: According to the test data, the capacitance parameters of each capacitor are calculated using the following formula: in, is the capacitance parameter; a test capacitance parameter of the test capacitor output by the test device; is the standard capacitance parameter of the capacitor under working conditions in the initial state; is the temperature of the capacitor under the initial working condition; The temperature coefficient for the operating conditions of the capacitor; According to the test data, the loss tangent value of each capacitor is calculated using the following formula: in, is the loss tangent value; is the loss current of the capacitor; is the voltage of the capacitor; is the operating angular frequency of the capacitor; is the capacitance parameter; According to the test data, the leakage current value of each capacitor is calculated using the following formula: in, is the leakage current value; is the voltage on the capacitor; is the insulation resistance of the dielectric material.

[0027] It should be noted that in the calculation formula of capacitance parameters, The value refers to the temperature coefficient of the capacitor, which describes the degree to which the capacitance of the capacitor changes with temperature. The temperature coefficient is an important capacitor characteristic because in many applications, the working environment of the capacitor may experience temperature changes, and this change can have an impact on the performance of the circuit. The temperature coefficient can be positive or negative. A positive temperature coefficient indicates that the capacitance value increases with increasing temperature, and a negative temperature coefficient indicates that the capacitance value decreases with increasing temperature. The temperature coefficient is usually provided by the manufacturer of the capacitor and it will be given in the capacitor's specification sheet.

[0028] Capacitance parameter refers to the ability of a capacitor to store charge under specific conditions. The capacitance parameter of the test capacitor output by the test equipment obtained by the test equipment in step S11, the standard capacitance parameter of the capacitor under the working conditions in the initial state, and the temperature of the capacitor under the working conditions in the initial state are used to calculate the capacitance parameter using the capacitance parameter calculation formula. This capacitance parameter is used to adjust and calibrate the actual capacitance value of the capacitor to adapt to different operating temperatures and conditions. This is crucial to ensure the reliability and performance of the capacitor under different environmental conditions.

[0029] The loss tangent of the capacitor It is an important parameter to measure the energy loss of capacitors in AC circuits. It reflects the energy loss of capacitors in AC fields due to the resistance of dielectric materials and the hysteresis effect of dielectric polarization. The loss tangent is defined as the tangent of the dielectric loss angle δ, that is, the tangent of the angle between the current vector and the voltage vector flowing through the dielectric under an alternating electric field.

[0030] In the calculation formula of the loss tangent value of the capacitor, is the loss current of the capacitor, obtained by the test equipment in step S11. is the voltage of the capacitor, is the operating angular frequency of the capacitor, and both are preset parameters during testing by the test equipment. is the capacitance parameter, which is obtained by the capacitance parameter calculation formula. The leakage current of a capacitor refers to the current that leaks from the circuit when the rated DC working voltage is applied across the capacitor. The leakage current value is one of the key factors affecting the performance of the capacitor, and has a direct or indirect impact on the thermal management, energy efficiency, circuit stability, safety and service life of the capacitor. In the leakage current value calculation formula, It is the voltage on the capacitor, which is the preset parameter applied to the capacitor during testing by the test equipment. The insulation resistance of dielectric materials is an important parameter for measuring the insulation performance of capacitors. It is defined as the resistance corresponding to the leakage current flowing through the dielectric after a certain period of polarization process after a DC voltage is applied to the dielectric. The insulation resistance reflects the ability of the material to prevent the passage of current. The larger the resistance value, the better the insulation performance of the material, which is crucial to ensure that electrical equipment will not cause safety problems due to leakage during normal operation. It is usually provided by the manufacturer of the capacitor and given in the capacitor specification.

[0031] In step S13, a data preprocessing operation is performed according to the capacitance parameter, the loss tangent value and the leakage current value to obtain test parameters, including: Performing data statistical operations according to the capacitance parameter, the loss tangent value and the leakage current value to obtain statistical parameters; According to the statistical model formula and the preset confidence level and degree of freedom, the statistical parameter is subjected to standard error calculation operation to obtain the standard error of each group of data to evaluate the validity of the statistical parameter, thereby obtaining the deviation threshold; According to the deviation threshold, an abnormal data elimination operation is performed on the statistical parameters to eliminate abnormal data exceeding the threshold to obtain effective test parameters; According to the valid test parameters, an average value operation is performed on the valid test parameters to obtain an average value of the remaining valid data as a test result; According to the test results, a validity processing operation is performed on the capacitor to obtain test parameters.

[0032] It should be noted that the standard error of each group of test data is calculated according to the formula and the preset confidence and degree of freedom, and the standard error is used to characterize the deviation of each group of test data during the test, so as to judge the validity of the measured data of the capacitor at the preset frequency and preset voltage, and the standard error of each group of test data is calculated. The statistical deviation of each group of test data is calculated according to the standard error, and the preset deviation threshold is set. If the statistical deviation of each group of test data does not exceed the deviation threshold, the average value of the group of test data is calculated as the test parameter value of the capacitor, and the statistical model is used to calculate the average value of the test parameter value of the capacitor in each group of test data. If the statistical deviation of each group of test data exceeds the deviation threshold, the test data of the group is eliminated, and the test data of other groups are reselected until the average value of the test parameter value of the capacitor in all test data is obtained, and the average value of the test parameter values ​​of all capacitors is used as the final test parameter. If all test data in the group of test data are eliminated, the capacitor is deleted, and other capacitors re-screened by the average weighted algorithm are used as the object of the next calculation of the standard error of each group of test data to ensure the data volume, thereby avoiding inaccurate final results due to incomplete collected data or too large errors. For example, in the embodiment of the present invention, the preset frequency and voltage are 50 Hz and 220 V, respectively, and the preset confidence and degree of freedom are 90% and n-1, respectively. Of course, according to different actual application scenarios and user needs, the preset frequency and voltage can also be set to 60 Hz and 120 V, etc., and the preset confidence and degree of freedom are 95% and n-2, respectively. The present invention is not limited to this.

[0033] The statistical model formula and the confidence and freedom degrees are set to calculate the standard error of the statistical parameter, and the standard error of each group of data is obtained to evaluate the validity of the statistical parameter, thereby obtaining the deviation threshold, including: Statistical model formula: in, is the intercept term (that is, when =0); , , , are the coefficients of the model, corresponding to , , , The coefficient of is the input statistical parameter; is the highest degree of the polynomial; For Capacitor No. Test data, the calculation formula is as follows: in, It is Capacitor No. Test values ​​of test data; It is Capacitor No. Various test parameters of the test data; The calculation formula for the deviation threshold is as follows: in, is the deviation threshold; is a statistical parameter; is the coefficient determined based on the confidence level; is the standard deviation of the statistical parameter.

[0034] It should be noted that statistical models are usually used in regression analysis to predict or describe a dependent variable (in this case and one or more independent variables The polynomial model is particularly useful when the relationship between the variables is unknown or nonlinear. In the context of capacitor performance analysis, this model can be used to predict the capacitance parameters, loss tangent value, and leakage current value of the capacitor as a function of its operating conditions voltage, frequency, and temperature. Here, represents the independent variable (voltage, frequency, temperature), and represents the dependent variables (capacitor capacitance parameters, loss tangent value, and leakage current value). , , , are the coefficients of the model, corresponding to , , , The coefficients of are determined by fitting the data to a statistical model. is the highest degree of the polynomial, select the highest degree of the polynomial model is an important decision that should be based on the characteristics of the data and the complexity of the problem. Too low a degree may not capture all the characteristics of the data, while too high a degree may lead to overfitting, that is, the model is so complex that it starts to fit the noise in the data rather than the underlying pattern. Exemplarily, in an embodiment of the present invention, the highest degree of the general polynomial model in the statistical model formula is The value is 10. Of course, depending on the actual application scenario and user needs, the highest degree of the polynomial model is set to 5. In the calculation formula of the deviation threshold, the coefficient determined based on the confidence level The value is 1.96 at 95% confidence level. Of course, the coefficient determined by the confidence level may vary depending on the actual application scenario and user needs. The value is 1.645 at 90% confidence level, which is not limited in the present invention.

[0035] The capacitor is marked as the nth capacitor, where n ≥ 1 and is an integer, the nth capacitor is tested, and the test values ​​of multiple parameters in the test data are marked as , put the pth test data of the nth capacitor into The test values ​​of multiple parameters are calculated in the formula.

[0036] In step S14, the change rate is calculated according to the test data and the test parameters to obtain the capacitance parameter change rate, loss tangent value change rate and leakage current value change rate of each capacitor, including: According to the test data and the test parameters, the capacitance parameter change rate is obtained by using a capacitance parameter change rate calculation formula; According to the test data and the test parameters, the loss tangent value change rate is obtained by using the loss tangent value change rate calculation formula; According to the test data and the test parameters, the leakage current value change rate is obtained by using a leakage current value change rate calculation formula; The calculation formula for the capacitance parameter change rate is as follows: in, is the capacitance parameter change rate; To test the capacitance parameters; is the capacitance test parameter; The formula for calculating the loss tangent change rate is as follows: in, is the rate of change of loss tangent; is the loss tangent value; is the loss tangent value test parameter; The formula for calculating the leakage current value change rate is as follows: in, is the leakage current value change rate; is the leakage current value; It is the leakage current value test parameter.

[0037] It should be noted that It measures the degree of deviation between the actual capacitance value of the capacitor and its standard value. A high value of may mean that the capacitor is unstable or has a manufacturing defect. is the capacitance test parameter, which is the capacitance test parameter obtained in step S13 and serves as the standard value of the capacitance parameter change rate. To test the capacitance parameters, the actual capacitance value of the capacitor needs to be tested. It measures the change in the capacitor's loss tangent, which reflects the energy loss of the capacitor in an AC circuit. The loss tangent is a measure of the energy dissipated by a capacitor in an AC circuit. Changes in can indicate aging or performance degradation of the capacitor material. is the loss tangent value, which is the loss tangent value of the capacitor to be tested. is the loss tangent value test parameter, which is the loss tangent value test parameter obtained in step S13 and serves as the standard value of the loss tangent value change rate. It measures the change in capacitor leakage current, which reflects the ability of the capacitor to isolate DC current. Leakage current is the current that should not exist in the capacitor under ideal conditions. The increase in indicates that the insulation performance of the capacitor has decreased. is the leakage current value test parameter, which is the leakage current test parameter obtained in step S13 and is used as the standard value of the leakage current change rate. is the leakage current value, which is the leakage current value of the capacitor to be tested.

[0038] In step S15, the result analysis is performed according to the capacitance parameter change rate, the loss tangent value change rate, and the leakage current value change rate to obtain capacitor test result data, including: According to the test parameters, a parameter analysis operation is performed to obtain an analysis threshold table; According to the analysis threshold table, the capacitance parameter change rate, the loss tangent value change rate and the leakage current value change rate, a result analysis operation is performed to obtain capacitor test result data.

[0039] It should be noted that the analysis threshold table includes thresholds for capacitance parameter change rate, loss tangent value change rate, and leakage current value change rate, which are used to distinguish different quality levels of capacitors. It includes performance indicators under different conditions, such as temperature, voltage, frequency, etc., which affect the performance of the capacitor. When the capacitance parameter change rate is less than the first capacitance parameter change rate, the loss tangent value change rate is greater than the first loss tangent value change rate, and the leakage current value change rate is less than the first leakage current value change rate, the first capacitor is marked as a second quality capacitor, and the second quality capacitor is recorded as a secondary capacitor. The secondary capacitor is a capacitor whose service life exceeds the period; when the capacitance parameter change rate is less than the first capacitance parameter change rate, the loss tangent value change rate is greater than the first loss tangent value change rate, and the leakage current value change rate is greater than the first leakage current value change rate, the first capacitor is marked as a third quality capacitor, and the third quality capacitor is recorded as a third-level capacitor. The third-level capacitor is a capacitor during the extended service life; when the capacitance parameter change rate is greater than the first capacitance parameter change rate, the loss tangent value change rate is less than the first loss tangent value change rate, and the leakage current value change rate is greater than the first leakage current value change rate. When the capacitance parameter change rate is greater than the first capacitance parameter change rate, the loss tangent value change rate is greater than the first loss tangent value change rate, and the leakage current value change rate is less than the first leakage current value change rate, the first capacitor is marked as a fifth quality capacitor, the fifth quality capacitor is recorded as a fifth quality capacitor, and the fifth quality capacitor is a capacitor that is about to fail; when the capacitance parameter change rate is greater than the first capacitance parameter change rate, the loss tangent value change rate is greater than the first loss tangent value change rate, and the leakage current value change rate is greater than the first leakage current value change rate, the first capacitor is marked as a sixth quality capacitor, the sixth quality capacitor is recorded as a sixth quality capacitor, and the sixth quality capacitor is a failed capacitor.

[0040] In order to facilitate the understanding of the present invention, some preferred embodiments of the present invention are further described below.

[0041] An electric power company is responsible for maintaining a large substation that uses a large number of capacitors to improve the power factor and stability of the power grid. In order to ensure the reliability of these capacitors and extend their service life, the company decided to perform performance tests on the capacitors regularly.

[0042] Step 1: Test equipment obtains test data under preset parameters. During the planned maintenance window, technicians use high-precision AC withstand voltage testers and capacitance testers to test capacitors in the substation. They apply preset voltage and frequency to each capacitor and record parameters such as voltage, current, capacitance value, loss tangent value, and leakage current. Each capacitor is uniquely numbered to ensure data accuracy and traceability.

[0043] Step 2: Perform parameter extraction operation. The technicians use the corresponding capacitance parameter formula, loss tangent value formula, and leakage current value formula to calculate the capacitance parameters, loss tangent value, and leakage current value of each capacitor.

[0044] Step 3: Data preprocessing: The technician inputs the calculated capacitance parameters, loss tangent value and leakage current value into the statistical model for statistical analysis, calculates the standard error of each set of data, and determines the deviation threshold based on 95% confidence and corresponding degrees of freedom. Any data exceeding this threshold is marked as abnormal and eliminated. The remaining valid data is used to calculate the average value as the test parameter of the capacitor.

[0045] Step 4: Change rate calculation. The technicians use the corresponding capacitance parameter change rate formula, loss tangent value change rate formula, and leakage current value change rate formula to calculate the capacitance parameter change rate, loss tangent value parameter change rate, and leakage current value parameter change rate of each capacitor.

[0046] Step 5: Result analysis: The technicians classified the performance of the capacitors according to the capacitance parameter change rate, loss tangent value parameter change rate, leakage current value parameter change rate and the preset analysis threshold table of each capacitor. For example, when the capacitance parameter change rate is less than the first capacitance parameter change rate, the loss tangent value change rate is greater than the first loss tangent value change rate, and the leakage current value change rate is less than the first leakage current value change rate, the first capacitor is marked.

[0047] In the above scenario, the capacitor testing method of the present invention provides a systematic and data-driven way for power companies to evaluate and maintain the performance of capacitors in substations. The data obtained by high-precision testing equipment is combined with statistical analysis and rate of change calculation. This method provides a comprehensive capacitor performance evaluation by comprehensively considering multiple key parameters such as capacitance parameters, loss tangent values, and leakage current values. This method helps to identify capacitors with degraded performance, thereby prioritizing necessary maintenance or replacement, reducing the risk of unexpected failures, and improving the stability and reliability of the power grid.

[0048] In summary, the present invention has the following beneficial effects: obtaining test data under preset parameters through the test equipment; performing parameter extraction operation according to the test data to obtain capacitance parameters, loss tangent value and leakage current value; performing data preprocessing operation according to the capacitance parameters, loss tangent value and leakage current value to obtain test parameters; performing change rate calculation according to the test data and the test parameters to obtain the capacitance parameter change rate, loss tangent value change rate and leakage current value change rate of each capacitor; performing result analysis according to the capacitance parameter change rate, loss tangent value change rate and leakage current value change rate to obtain capacitor test result data. The present invention adopts a statistical model to analyze the data, which solves the problem of single evaluation parameters in the prior art. This method can comprehensively consider the changes of multiple parameters such as capacitance parameters, loss tangent value and leakage current value, and realize a comprehensive evaluation of capacitor performance.

[0049] Reference Figure 2 A second embodiment of the present invention provides a capacitor testing system, comprising: A data acquisition module, used to acquire test data under preset parameters through a test device; A data preprocessing module, used to perform data processing operations according to the test data to obtain capacitance parameters, loss tangent values ​​and leakage current values; A data processing module, used to perform data processing operations according to the capacitance parameter, the loss tangent value and the leakage current value to obtain test parameters; A change rate calculation module, used to calculate the change rate according to the test data and the test parameters, and obtain the capacitance parameter change rate, loss tangent value change rate and leakage current value change rate of each capacitor; The test data output module is used to perform data calculation according to the capacitance parameter change rate, the loss tangent value change rate, the leakage current value change rate and the analysis threshold table to obtain capacitor test result data.

[0050] It should be noted that a capacitor testing system provided in an embodiment of the present invention is used to execute all process steps of a capacitor testing method in the above embodiment, and the beneficial effects of the two correspond one to one, so they are not described in detail.

[0051] The embodiment of the present invention further provides an electronic device. The electronic device includes: a processor, a memory, and a computer program stored in the memory and executable on the processor, such as a capacitor testing program. When the processor executes the computer program, the steps in the above-mentioned capacitor testing method embodiments are implemented, such as Figure 1Alternatively, when the processor executes the computer program, the functions of each module / unit in the above-mentioned device embodiments are implemented, such as the data acquisition module.

[0052] Exemplarily, the computer program may be divided into one or more modules / units, which are stored in the memory and executed by the processor to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program in the electronic device.

[0053] The electronic device may be a computing device such as a desktop computer, a notebook, a PDA, and a smart tablet. The electronic device may include, but is not limited to, a processor and a memory. Those skilled in the art will appreciate that the above components are merely examples of electronic devices and do not constitute a limitation on the electronic device. The electronic device may include more or fewer components than the above components, or may combine certain components, or different components. For example, the electronic device may also include input and output devices, network access devices, buses, etc.

[0054] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of the electronic device, and uses various interfaces and lines to connect various parts of the entire electronic device.

[0055] The memory can be used to store the computer program and / or module, and the processor realizes various functions of the electronic device by running or executing the computer program and / or module stored in the memory, and calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area can store data created according to the use of the mobile phone (such as audio data, a phone book, etc.), etc. In addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0056] Wherein, if the module / unit integrated in the electronic device is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Wherein, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can 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, computer-readable media do not include electric carrier signals and telecommunication signals.

[0057] It should be noted that the device embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. In addition, in the accompanying drawings of the device embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines. A person of ordinary skill in the art may understand and implement it without paying any creative effort.

[0058] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A capacitor testing method, characterized in that: Executed by a computer, including: Acquire test data under preset parameters through test equipment; According to the test data, a parameter extraction operation is performed to obtain capacitance parameters, loss tangent values ​​and leakage current values; Performing data preprocessing operations according to the capacitance parameter, the loss tangent value, and the leakage current value to obtain test parameters; Calculate the change rate according to the test data and the test parameters to obtain the capacitance parameter change rate, loss tangent value change rate and leakage current value change rate of each capacitor; The results are analyzed based on the capacitance parameter change rate, the loss tangent value change rate, and the leakage current value change rate to obtain capacitor test result data.

2. The capacitor testing method according to claim 1, characterized in that: The step of obtaining test data under preset parameters by means of a test device includes: Based on the test equipment, a preset frequency and a preset voltage are applied to the capacitor within a preset test time period, and test data is collected to obtain test data.

3. The capacitor testing method according to claim 1, characterized in that: The method of performing parameter extraction operation according to the test data to obtain capacitance parameters, loss tangent value and leakage current value includes: According to the test data, the capacitance parameters of each capacitor are calculated using the following formula: in, is the capacitance parameter; a test capacitance parameter of the test capacitor output by the test device; is the standard capacitance parameter of the capacitor under working conditions in the initial state; is the temperature of the capacitor under the initial working condition; The temperature coefficient for the operating conditions of the capacitor; According to the test data, the loss tangent value of each capacitor is calculated using the following formula: in, is the loss tangent value; is the loss current of the capacitor; is the voltage of the capacitor; is the operating angular frequency of the capacitor; is the capacitance parameter; According to the test data, the leakage current value of each capacitor is calculated using the following formula: in, is the leakage current value; is the voltage on the capacitor; is the insulation resistance of the dielectric material.

4. The capacitor testing method according to claim 1, characterized in that: According to the capacitance parameter, the loss tangent value and the leakage current value, a data preprocessing operation is performed to obtain a test parameter, including: Performing data statistical operations according to the capacitance parameter, the loss tangent value and the leakage current value to obtain statistical parameters; According to the statistical model formula and the preset confidence level and degree of freedom, the statistical parameter is subjected to standard error calculation operation to obtain the standard error of each group of data to evaluate the validity of the statistical parameter, thereby obtaining the deviation threshold; According to the deviation threshold, an abnormal data elimination operation is performed on the statistical parameters to eliminate abnormal data exceeding the threshold to obtain effective test parameters; According to the valid test parameters, an average value operation is performed on the valid test parameters to obtain an average value of the remaining valid data as a test result; According to the test results, a validity processing operation is performed on the capacitor to obtain test parameters.

5. The capacitor testing method according to claim 4, characterized in that: The statistical model formula and the confidence and freedom degrees are set to calculate the standard error of the statistical parameters, and the standard error of each group of data is obtained to evaluate the validity of the statistical parameters, thereby obtaining the deviation threshold, including: Statistical model formula: in, is the intercept term, which means that when =0 when the predicted value; , , , are the coefficients of the model, corresponding to , , , The coefficient of is the input statistical parameter; is the highest degree of the polynomial; For Capacitor No. Test data, the calculation formula is as follows: in, It is Capacitor No. Test values ​​of test data; It is Capacitor No. Various test parameters of the test data; The calculation formula for the deviation threshold is as follows: in, is the deviation threshold; is a statistical parameter; is the coefficient determined based on the confidence level; is the standard deviation of the statistical parameter.

6. The capacitor testing method according to claim 1, characterized in that: The calculation of the change rate is performed according to the test data and the test parameters to obtain the capacitance parameter change rate, loss tangent value change rate and leakage current value change rate of each capacitor, including: According to the test data and the test parameters, the capacitance parameter change rate is obtained by using a capacitance parameter change rate calculation formula; According to the test data and the test parameters, the loss tangent value change rate is obtained by using the loss tangent value change rate calculation formula; According to the test data and the test parameters, the leakage current value change rate is obtained by using a leakage current value change rate calculation formula; The calculation formula for the capacitance parameter change rate is as follows: in, is the capacitance parameter change rate; To test the capacitance parameters; is the capacitance test parameter; The formula for calculating the loss tangent change rate is as follows: in, is the rate of change of loss tangent; is the loss tangent value; is the loss tangent value test parameter; The formula for calculating the leakage current value change rate is as follows: in, is the leakage current value change rate; is the leakage current value; It is the leakage current value test parameter.

7. The capacitor testing method according to claim 1, characterized in that: The method of performing result analysis according to the capacitance parameter change rate, the loss tangent value change rate, and the leakage current value change rate to obtain capacitor test result data includes: According to the test parameters, a parameter analysis operation is performed to obtain an analysis threshold table; According to the analysis threshold table, the capacitance parameter change rate, the loss tangent value change rate and the leakage current value change rate, a result analysis operation is performed to obtain capacitor test result data.

8. A capacitor testing system, characterized in that: include: A data acquisition module, used to acquire test data under preset parameters through a test device; A data preprocessing module, used to perform data processing operations according to the test data to obtain capacitance parameters, loss tangent values ​​and leakage current values; A data processing module, used to perform data processing operations according to the capacitance parameter, the loss tangent value and the leakage current value to obtain test parameters; A change rate calculation module, used to calculate the change rate according to the test data and the test parameters, and obtain the capacitance parameter change rate, loss tangent value change rate and leakage current value change rate of each capacitor; The test data output module is used to perform data calculation according to the capacitance parameter change rate, the loss tangent value change rate, the leakage current value change rate and the analysis threshold table to obtain capacitor test result data.

9. An electronic device, characterized in that: The method comprises a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor implements the capacitor testing method according to any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored computer program, wherein when the computer program is executed, the device where the computer-readable storage medium is located is controlled to execute the capacitor testing method according to any one of claims 1 to 7.

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