Electric winding aging life evaluation method based on electrothermal composite stress index weight

Abstract

The invention discloses an electric winding aging life evaluation method based on an electrothermal composite stress index weight, and relates to the field of electric winding life evaluation, and the method comprises the steps: respectively building an electric winding aging model taking voltage as a stress variable, and an electric winding aging model taking temperature as a stress variable; extracting influence factors of the electric winding aging model of each single stress variable; calculating a weight coefficient of an influence factor corresponding to each single stress variable under the combined action of the electric stress and the thermal stress by using a CRITIC method; and weighting the calculated weight coefficient to an influence factor corresponding to each single stress variable in an exponential form so as to establish an electric winding aging model of the electric heating composite stress variable for evaluating the aging life of the electric winding. Compared with a traditional linear weighting algorithm, the whole evaluation method provided by the invention is high in accuracy and low in cost, and can be used for diagnosis and life evaluation of the electric winding.

Description

Technical Field

[0001] The invention relates to the field of electric winding life assessment, in particular to an electric winding aging life assessment method based on electric-thermal composite stress index weight. Background Art

[0002] The power winding is the heart of electrical equipment such as transformers and motors, and is one of the core components involved in power conversion. The reliability of the power winding is the basic guarantee for the long-term safe operation of electrical equipment such as transformers and motors. It not only directly affects the insulation performance of the equipment, but also has a great impact on its technical performance and economic indicators. After being subjected to external environmental factors such as temperature and electric field for a long time, the power winding will gradually deteriorate in quality and gradually damage in structure during operation. This process is called the aging process of the power winding. Once the aged electric winding cannot meet the normal operation requirements of the electrical equipment, it will affect the normal operation of a variety of electrical equipment and even the entire power system.

[0003] As the research on the reliability of electrical windings continues to deepen at home and abroad, more and more electrical winding aging life models are constantly being proposed. Most of the early life models are statistical models based on a large number of test results. Although this model has a high degree of characterization of the aging life, it also has the disadvantages of high cost and a single experimental environment, making it difficult to evaluate the aging life of electrical windings under composite stress. In recent years, with the rise of accelerated aging tests, electrical winding aging models based on accelerated aging tests have emerged in an endless stream, but there have been no breakthroughs in model fitting and fitting accuracy under composite stress, which restricts the evaluation of the aging life of electrical windings.

[0004] In view of the above problems, the present invention proposes an electric winding aging life assessment method based on the electric-thermal composite stress index weight for the assessment of the aging life of the electric winding, providing a new feasible solution for the diagnosis and assessment of the aging life of the electric winding. Summary of the invention

[0005] In response to the above-mentioned problems and technical needs, the inventors have proposed an aging life assessment method for electric windings based on the electric-thermal composite stress index weight, which is used to evaluate the status performance of electric windings, thereby providing guidance for the operation and maintenance of a series of electrical equipment such as motors and transformers, which has great engineering significance.

[0006] The technical solution of the present invention is as follows:

[0007] In a first aspect, the present application provides a method for evaluating the aging life of an electric winding based on an electrothermal composite stress index weight, comprising the following steps:

[0008] Establish an electrical winding aging model with voltage as stress variable and an electrical winding aging model with temperature as stress variable respectively, and extract the influencing factors of the electrical winding aging model with each single stress variable;

[0009] The CRITIC method is used to calculate the weight coefficient of the influencing factor corresponding to each single stress variable when electrical and thermal stresses act together;

[0010] The calculated weight coefficient is assigned to the influencing factor corresponding to each single stress variable in exponential form, so as to establish an electric winding aging model of electric-thermal composite stress variables for the evaluation of the aging life of the electric winding.

[0011] A further technical solution is to establish an electrical winding aging model with voltage as the stress variable, including:

[0012] Select an electrical winding with a certain insulation level to conduct accelerated electrical aging experiments, record the aging of the electrical winding and collect and organize the experimental data;

[0013] By fitting the physical model to the experimental data, the aging model of the electric winding with voltage as the stress variable is obtained, and the expression is:

[0014]

[0015] Among them, L e represents the life of the electric winding under a single electrical stress; A and B represent the correction coefficients of the model, which are obtained by minimizing the difference between the experimentally measured life of the electric winding and the life of the electric winding calculated by the model; L N Indicates the rated life of the electrical winding, U N represents the rated voltage, U represents the loading voltage of the accelerated electrical aging test, and n represents the index of the model.

[0016] A further technical solution is to establish an electrical winding aging model with temperature as the stress variable, including:

[0017] Select an electrical winding of a certain insulation level to conduct accelerated thermal aging test, record the aging of the electrical winding and collect and organize the experimental data;

[0018] By fitting the physical model to the experimental data, the aging model of the electric winding with temperature as the stress variable is obtained, and the expression is:

[0019]

[0020] Among them, L t represents the life of the electric winding under a single thermal stress; A and C represent the correction coefficients of the model, which are obtained by minimizing the difference between the experimentally measured life of the electric winding and the life of the electric winding calculated by the model; L N Indicates the rated life of the electrical winding, T N represents the rated temperature, and T represents the loading temperature of the accelerated thermal aging test.

[0021] A further technical solution is to extract the influencing factors of the electrical winding aging model of each single stress variable, including:

[0022] The influencing factor is extracted from the electrical winding aging model with voltage as the stress variable, denoted as L e * :

[0023]

[0024] The influencing factor is extracted from the electrical winding aging model with temperature as the stress variable, denoted as L t * :

[0025]

[0026] Wherein, B and C represent the correction coefficients of the model, which are obtained by minimizing the difference between the experimentally measured life of the electric winding and the life of the electric winding calculated by the model; U N represents the rated voltage, U represents the loading voltage of the electrical aging accelerated test, and n represents the index of the model; T N represents the rated temperature, T represents the loading temperature of the accelerated thermal aging test;

[0027] Among the influencing factors, a normalized single stress variable is used to characterize the influence of the relative deviation between the single stress and the rated working condition on the aging of the electric winding, so as to eliminate the difference in aging influence caused by the inconsistent dimensions of different stress types.

[0028] A further technical solution is to use the CRITIC method to calculate the weight coefficient of the influencing factor corresponding to each single stress variable when electrical and thermal stresses act together, including:

[0029] Based on the established electric winding aging models of each single stress variable, the aging life values ​​of the electric winding under different stresses are calculated and normalized;

[0030] For the normalized value of aging life of electric winding under different stresses, the CRITIC method is used to calculate the weight coefficient Q of the influence factor corresponding to the electric and thermal stress variables on the aging degree of electric winding when the electric and thermal stresses act together according to the international system of units. e , Q t .

[0031] A further technical solution is to calculate the weight coefficient Q of the influence factor corresponding to the electrical and thermal stress variables on the degree of influence of the electrical winding aging. e , Q t ,include:

[0032] Calculate the standard deviation S of the normalized value of the aging life of the electrical winding under electrical and thermal stress respectively i, the contrast R of the normalized value of the aging life of the electric winding under the action of electrical and thermal stress, the information content C of the normalized value of the aging life of the electric winding under the action of electrical and thermal stress i , the expressions are:

[0033]

[0034] Then the weight coefficient Q of the influence factor corresponding to the electrical stress variable on the degree of influence of the electrical winding aging is e , the weight coefficient Q of the influence factor corresponding to the thermal stress variable on the degree of influence of the electrical winding aging t It is expressed as:

[0035]

[0036] Where i = e or t, x j represents the normalized value of the aging life of the electrical winding under the jth electrical or thermal stress, represents the normalized average value of the aging life of the electrical winding under electrical or thermal stress, N represents the number of normalized values ​​of the aging life of the electrical winding under electrical or thermal stress, r xy It represents the correlation coefficient of the normalized value of the aging life of the electrical winding under electrical and thermal stress.

[0037] Its further technical solution is that the weight coefficient Q e , Q t As an index of the electrical winding aging model with a single stress variable, it indicates the contribution of each single stress to the aging of the electrical winding when electrical and thermal stresses act together. e +Q t =1.

[0038] A further technical solution is to establish an electric winding aging model with electric-thermal composite stress variables, including:

[0039] First, the influence factor L corresponding to the single stress variable e * , L t * Exponential weighting is performed to characterize the contribution of a single stress to the aging of the electrical winding, and the result is

[0040] Secondly, the product of the influencing factors corresponding to the single stress variable after exponential weighting is calculated to characterize the aging model of the electric winding under the combined action of electrical and thermal stresses. The expression is:

[0041]

[0042] Wherein, L represents the life of the electric winding under the action of electrothermal composite stress; B, C, and D represent the correction coefficients of the model. B and C are obtained by minimizing the difference between the experimentally measured life of the electric winding and the life of the electric winding calculated by the model, and D is obtained by the Euclidean distance and the shortest fitting between the experimentally measured life of the electric winding and the life of the electric winding calculated by the model; L N Indicates the rated life of the electrical winding, U N represents the rated voltage, U represents the loading voltage of the electrical aging accelerated test, and n represents the index of the model; T N represents the rated temperature, T represents the loading temperature of the thermal aging accelerated test; Q e , Q t are the weight coefficients of the influencing factors corresponding to the electrical and thermal stress variables respectively.

[0043] Its further technical solution is that the method further comprises:

[0044] If the established electric winding aging model of the electric thermal composite stress variable does not conform to the electric thermal composite aging accelerated experimental data, the electric winding aging model of the electric thermal composite stress variable is re-established by adjusting the correction coefficients B, C, and D.

[0045] In a second aspect, the present application further provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the method described in the first aspect are implemented.

[0046] The beneficial technical effects of the present invention are:

[0047] The present invention improves the traditional single stress electric winding aging model by using normalized stress variables, eliminating the influence of the relative deviation between single stress and rated working conditions. At the same time, the weighted contribution of different stresses to winding aging is calculated using the CRITIC method and in accordance with the International System of Units, and the influencing factors of each single stress electric winding aging model are assigned in the form of exponential weights, thereby establishing an electric winding aging model of electric thermal composite stress variables. Compared with the traditional linear weighting method, exponential weighting is used to process nonlinear relationship variable weighting, which is more sensitive to statistical outliers or extreme values. Exponential weighting can reflect the long-term fluctuations of data to improve the objectivity of prediction, and at the same time has higher prediction ability. All aging models are obtained by fitting experimental data and processed by MATLAB data, and the aging life curve of the aging model is used to realize the intuitive evaluation of the aging life of the electric winding. The entire evaluation method has a high degree of fitting and low cost, and can be used for the diagnosis and life evaluation of electric windings. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a flow chart of the electric winding aging life assessment method based on the electrothermal composite stress index weight provided in this application.

[0049] Figure 2 It is an aging life curve diagram of the electric winding aging model under single electrical stress provided in the present application.

[0050] FIG3( a ) is an aging life curve diagram of an electrical winding aging model under a single thermal stress (Kelvin temperature scale) provided in the present application.

[0051] FIG3( b ) is an aging life curve diagram of the electric winding aging model under single thermal stress (Celsius temperature scale) provided in the present application.

[0052] Figure 4 It is an aging life curve diagram of the electric winding aging model with electric-thermal composite stress variables provided in the present application.

[0053] Figure 5 It is a diagram of the internal structure of the electronic device provided in this application. DETAILED DESCRIPTION

[0054] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0055] Please refer to Figure 1 As shown, the present application provides an electric winding aging life assessment method based on electrothermal composite stress index weight, which specifically includes the following steps:

[0056] Step 1: Establish an electrical winding aging model with voltage as the stress variable and an electrical winding aging model with temperature as the stress variable, and extract the influencing factors of the electrical winding aging model with each single stress variable.

[0057] (1) An electrical winding of a certain insulation level is selected. In this embodiment, an electrical winding of Class F insulation is taken as an example. Based on the rated voltage and rated temperature, the electrical winding is subjected to accelerated electrical aging test and accelerated thermal aging test by continuously increasing the stress intensity. The aging condition of the electrical winding is recorded, and the experimental data is collected and collated.

[0058] (2) Fitting the physical model to the experimental data, we can obtain the electrical winding aging model with voltage as the stress variable and the electrical winding aging model with temperature as the stress variable. The expressions are as follows:

[0059]

[0060] Among them, A, B, and C represent the correction coefficients of the model, which are obtained by minimizing the difference between the experimentally measured electric winding life and the electric winding life calculated by the model. The correction coefficient will change with the type of electric winding and the specific application scenario. Taking the permanent magnet synchronous motor F-class insulation electric winding as an example, A=476.43~526.58, B=0.13~0.38, and C=25.67~28.37.

[0061] L eIndicates the life of the electric winding under a single electrical stress, L t Indicates the life of the electrical winding under a single thermal stress, L N Indicates the rated life of the electrical winding, U N represents the rated voltage, U represents the loading voltage of the electrical aging accelerated test, n represents the index of the electrical winding aging model under electrical stress, T N represents the rated temperature, and T represents the loading temperature of the accelerated thermal aging test.

[0062] (3) The influencing factors on the aging of the electrical winding are extracted from the electrical winding aging model with voltage as the stress variable and temperature as the stress variable, respectively. The expressions are:

[0063]

[0064] Among them, L e * represents the electrical stress influence factor, L t * Indicates the thermal stress influence factor. Among the influence factors, a normalized single stress variable is used to characterize the influence of the single stress on the aging of the electric winding under the relative deviation from the rated working condition, so as to eliminate the difference in aging influence caused by the inconsistent dimensions of different stress types.

[0065] Step 2: Use the CRITIC (Criteria Importance Through Intercrieria Correlation) method to calculate the weight coefficient of the influencing factor corresponding to each single stress variable.

[0066] (1) Based on the established electrical winding aging model formula (1) for each single stress variable, the aging life value of the electrical winding under different stresses is calculated respectively to form an array of normalized single stress variables and aging life values, namely: (ΔU%, ΔL e %)、(ΔT%,ΔL t %, where ΔU%=(UU N ) / U N , ΔT%=(TT N ) / T N , ΔL e % = (L N -L e ) / L N , ΔL t % = (L N -L t ) / L N , the specific values ​​are shown in Table 1, where the thermal stress variables in the first column adopt the Kelvin temperature scale, and the thermal stress variables in the second column adopt the Celsius temperature scale.

[0067] Table 1. Array of single stress variables and aging life values

[0068]

[0069]

[0070] Using the data in Table 1 and through interpolation processing, the aging life curve of the electric winding aging model of each single stress variable can be obtained, such as Figure 2 , as shown in Figure 3(a) and Figure 3(b).

[0071] (2) Normalized value ΔL of aging life of electrical windings under different stresses e %, ΔL t %, using the CRITIC method and according to the international system of units to calculate the weight coefficient Q of the influence factor corresponding to the electrical and thermal stress variables on the degree of influence of electrical winding aging when electrical and thermal stress act together e , Q t .

[0072] Specifically, the standard deviation S of the normalized value of the aging life of the electrical winding under electrical and thermal stress is calculated respectively. i , the contrast R of the normalized value of the aging life of the electric winding under the action of electrical and thermal stress, the information content C of the normalized value of the aging life of the electric winding under the action of electrical and thermal stress i , the expressions are:

[0073]

[0074] Then the weight coefficient Q of the influence factor corresponding to the electrical stress variable on the degree of influence of the electrical winding aging is e , the weight coefficient Q of the influence factor corresponding to the thermal stress variable on the degree of influence of the electrical winding aging t It is expressed as:

[0075]

[0076] Where i = e or t, x j represents the normalized value of the aging life of the electrical winding under the jth electrical or thermal stress, represents the normalized average value of the aging life of the electrical winding under electrical or thermal stress, N represents the number of normalized values ​​of the aging life of the electrical winding under electrical or thermal stress, r xy The correlation coefficient of the normalized value of the aging life of the electrical winding under electrical and thermal stress is calculated using the existing formula. e , Q t As the index of the electric winding aging model with a single stress variable under the action of electrical and thermal composite stress, it indicates the contribution of each single stress to the aging of the electric winding under the action of electrical and thermal stress. e+Q t = 1. This embodiment provides various parameter values ​​for calculating the weight coefficient, as shown in Table 2.

[0077] Table 2. Index weight coefficient calculation data

[0078]

[0079] Step 3: Assign the calculated weight coefficient to the influencing factor corresponding to each single stress variable in exponential form, so as to establish the electric winding aging model of the electric-thermal composite stress variable.

[0080] First, the influence factor L corresponding to the single stress variable e * , L t * Exponential weighting is performed to characterize the contribution of a single stress to the aging of the electrical winding, and the result is Secondly, the product of the influencing factors corresponding to the single stress variable after exponential weighting is calculated to characterize the aging model of the electric winding under the combined action of electrical and thermal stresses. The expression is:

[0081]

[0082] Where L represents the life of the electric winding under the action of electrothermal composite stress; D represents the correction coefficient of the model, which is obtained by the Euclidean distance and the shortest fit between the experimentally measured life of the electric winding and the life of the electric winding calculated by the model. Taking the electric winding with F grade insulation as an example, when the rated voltage U N 10kV, rated temperature T N When it is 313K, it can also be obtained through the empirical formula D=1.15A.

[0083] Finally, based on formula (5), the aging life curve of the electric winding aging model with electrothermal composite stress variables can be obtained, as shown in Figure 4 As shown, the life state of the electric winding is read from the aging life curve of the electric winding to realize the aging life evaluation of the electric winding. If the established electric winding aging model of the electric thermal composite stress variable does not conform to the electric thermal composite aging accelerated test data, the electric winding aging model of the electric thermal composite stress variable can be re-established by adjusting the correction coefficients B, C, and D.

[0084] The present application also provides an electronic device, which may be a terminal, and its internal structure diagram may be as shown in Figure 5As shown. The electronic device includes a processor, a memory, a communication interface, a display unit and an input device connected through a system bus. Among them, the processor of the electronic device is used to provide computing and control capabilities. The memory of the electronic device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the electronic device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a method for evaluating the aging life of an electric winding based on the weight of the electrothermal composite stress index is implemented. The display unit of the electronic device can be a liquid crystal display or an electronic ink display, and the input device of the electronic device can be a touch layer covered on the display, or a key, trackball or touchpad set on the housing of the electronic device, or an external keyboard, touchpad or mouse.

[0085] Those skilled in the art will understand that Figure 5 The structure shown in the figure is merely a block diagram of a partial structure related to the scheme of the present application, and does not constitute a limitation on the electronic device to which the scheme of the present application is applied. The specific electronic device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0086] The above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. A method for evaluating the aging life of electric windings based on the weight of electrothermal composite stress index. It is characterized in that The method comprises: Establish an electrical winding aging model with voltage as stress variable and an electrical winding aging model with temperature as stress variable respectively, and extract the influencing factors of the electrical winding aging model with each single stress variable; The CRITIC method is used to calculate the weight coefficient of the influencing factor corresponding to each single stress variable when electrical and thermal stresses act together; The calculated weight coefficient is assigned to the influencing factor corresponding to each single stress variable in exponential form, so as to establish an electric winding aging model of electric-thermal composite stress variables for the evaluation of the aging life of the electric winding.

2. The electric winding aging life assessment method based on the electric-thermal composite stress index weight according to claim 1, It is characterized in that Establish an aging model for electrical windings with voltage as stress variable, including: Select an electrical winding of a certain insulation level to conduct an accelerated electrical aging test, record the aging condition of the electrical winding and collect and organize the experimental data; The physical model is fitted to the experimental data to obtain the electrical winding aging model with voltage as the stress variable, which is expressed as: Among them, L e represents the life of the electric winding under a single electrical stress; A and B represent the correction coefficients of the model, which are obtained by minimizing the difference between the experimentally measured life of the electric winding and the life of the electric winding calculated by the model; L N Indicates the rated life of the electrical winding, U N represents the rated voltage, U represents the loading voltage of the electrical aging accelerated test, and n represents the index of the model.

3. The electric winding aging life assessment method based on the electric-thermal composite stress index weight according to claim 1, It is characterized in that Establish an aging model for electrical windings with temperature as stress variable, including: Select an electrical winding of a certain insulation level to conduct an accelerated thermal aging test, record the aging condition of the electrical winding and collect and organize the experimental data; The physical model is fitted to the experimental data to obtain the electrical winding aging model with temperature as the stress variable, which is expressed as follows: Among them, L t represents the life of the electric winding under a single thermal stress; A and C represent the correction coefficients of the model, which are obtained by minimizing the difference between the experimentally measured life of the electric winding and the life of the electric winding calculated by the model; L N represents the rated life of the electrical winding, T N represents the rated temperature, and T represents the loading temperature of the accelerated thermal aging test.

4. The electric winding aging life assessment method based on the electric-thermal composite stress index weight according to claim 1, It is characterized in that Extract the influencing factors of the electrical winding aging model for each single stress variable, including: The influencing factor is extracted from the electrical winding aging model with voltage as the stress variable, denoted as L e * : The influencing factor is extracted from the electrical winding aging model with temperature as the stress variable, denoted as L t * : Wherein, B and C represent the correction coefficients of the model, which are obtained by minimizing the difference between the experimentally measured life of the electric winding and the life of the electric winding calculated by the model; U N represents the rated voltage, U represents the loading voltage of the electrical aging accelerated test, and n represents the index of the model; T N represents the rated temperature, T represents the loading temperature of the accelerated thermal aging test; Among the influencing factors, a normalized single stress variable is used to characterize the influence of the single stress on the aging of the electric winding under the relative deviation from the rated working condition, so as to eliminate the difference in aging influence caused by the inconsistent dimensions of different stress types.

5. The electric winding aging life assessment method based on electrothermal composite stress index weight according to claim 1, It is characterized in that The CRITIC method is used to calculate the weight coefficient of the influencing factor corresponding to each single stress variable when electrical and thermal stresses act together, including: Based on the established electric winding aging models of each single stress variable, the aging life values ​​of the electric winding under different stresses are calculated and normalized; For the normalized value of aging life of electric winding under different stresses, the CRITIC method is used to calculate the weight coefficient Q of the influence factor corresponding to the electric and thermal stress variables on the aging degree of electric winding when the electric and thermal stresses act together according to the international system of units. e , Q t .

6. The method for evaluating the aging life of electric windings based on the electric-thermal composite stress index weight according to claim 5, It is characterized in that Calculate the weight coefficient Q of the influence factor corresponding to the electrical and thermal stress variables on the degree of influence of the electrical winding aging e , Q t ,include: Calculate the standard deviation S of the normalized value of the aging life of the electrical winding under electrical and thermal stress respectively i , the contrast R of the normalized value of the aging life of the electric winding under the action of electrical and thermal stress, the information content C of the normalized value of the aging life of the electric winding under the action of electrical and thermal stress i , the expressions are: R=1-r xy ,C i =S i ×R; Then the weight coefficient Q of the influence factor corresponding to the electrical stress variable on the degree of influence of the electrical winding aging is e , the weight coefficient Q of the influence factor corresponding to the thermal stress variable on the degree of influence of the electrical winding aging t It is expressed as: Where i = e or t, x j represents the normalized value of the aging life of the electrical winding under the jth electrical or thermal stress, represents the normalized average value of the aging life of the electrical winding under electrical or thermal stress, N represents the number of normalized values ​​of the aging life of the electrical winding under electrical or thermal stress, r xy It represents the correlation coefficient of the normalized value of the aging life of the electrical winding under electrical and thermal stress.

7. The electric winding aging life assessment method based on the electric-thermal composite stress index weight according to claim 5, It is characterized in that Weight coefficient Q e , Q t As an index of the electrical winding aging model with a single stress variable, it indicates the contribution of each single stress to the aging of the electrical winding when electrical and thermal stresses act together. e +Q t =1.

8. The electric winding aging life assessment method based on the electric-thermal composite stress index weight according to claim 1, It is characterized in that Establish an aging model for electric windings with electrothermal composite stress variables, including: First, the influence factor L corresponding to the single stress variable e * , L t * Exponential weighting is performed to characterize the contribution of a single stress to the aging of the electrical winding, and the result is Secondly, the product of the influencing factors corresponding to the single stress variable after exponential weighting is calculated to characterize the aging model of the electric winding under the combined action of electrical and thermal stresses. The expression is: Wherein, L represents the life of the electric winding under the action of electrothermal composite stress; B, C, and D represent the correction coefficients of the model. B and C are obtained by minimizing the difference between the experimentally measured life of the electric winding and the life of the electric winding calculated by the model, and D is obtained by the Euclidean distance and the shortest fitting between the experimentally measured life of the electric winding and the life of the electric winding calculated by the model; L N Indicates the rated life of the electrical winding, U N represents the rated voltage, U represents the loading voltage of the electrical aging accelerated test, and n represents the index of the model; T N represents the rated temperature, T represents the loading temperature of the thermal aging accelerated test; Q e , Q t are the weight coefficients of the influencing factors corresponding to the electrical and thermal stress variables respectively.

9. The electric winding aging life assessment method based on the electric-thermal composite stress index weight according to claim 8, It is characterized in that The method further comprises: If the established electric winding aging model of the electric thermal composite stress variable does not conform to the electric thermal composite aging accelerated experimental data, the electric winding aging model of the electric thermal composite stress variable is re-established by adjusting the correction coefficients B, C, and D.

10. An electronic device comprising a memory and a processor, wherein the memory stores a computer program. It is characterized in that When the processor executes the computer program, the steps of the method according to any one of claims 1 to 9 are implemented.

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