Transformer short-circuit resistance reliability test method, device and computer equipment

Abstract

The present application relates to a method, device and computer equipment for testing the reliability of a transformer's ability to withstand short circuits. The method includes: obtaining a transformer finite element simulation model and a simulation result of the transformer finite element simulation model under a short-circuit condition, determining the electromagnetic force of the transformer center coil under a short-circuit condition based on the transformer finite element simulation model and the simulation result, obtaining the allowable value of the state characteristic quantity of the coil under a short-circuit condition, and obtaining the actual value of the state characteristic quantity of the coil under a short-circuit condition based on the electromagnetic force of the coil under a short-circuit condition, the state characteristic quantity characterizing the transformer's ability to withstand short circuits, obtaining the ratio of the allowable value to the actual value under a short-circuit condition, and determining the transformer's safety factor based on the ratio, the safety factor being positively correlated with the reliability of the transformer's ability to withstand short circuits. The above scheme provides an implementation standard for quantitatively determining the reliability of a transformer's ability to withstand short circuits, and can achieve accurate and unified reliability testing of a transformer's ability to withstand short circuits.

Description

Technical Field

[0001] The present application relates to the technical field of power equipment performance evaluation, and in particular to a method, device, computer equipment, storage medium and computer program product for testing the reliability of transformer short-circuit resistance. Background Art

[0002] At present, the national standard GB1094.5 Power Transformer Part 5 on the ability of power transformers to withstand short circuits provides an appendix theoretical evaluation method for judging the reliability of the transformer's ability to withstand short circuits. However, this standard only provides an algorithm for the allowable value of the transformer's ability to withstand short circuits, but does not specify the actual value of the ability to withstand short circuits under short circuit conditions. At the same time, non-physical parameters such as transformer manufacturing capabilities and quality control systems have a certain impact on this judgment, making it difficult to form a unified algorithm or calculation platform for problems in this field.

[0003] Over the years, the short-circuit capacity of power transformers can be verified by sudden short-circuit tests, but this method has the problem of high resource consumption and the inability to monitor the degree of damage and quickly diagnose and repair it. Therefore, regarding the reliability test method of transformer short-circuit capacity, the industry mostly adopts the method of simultaneous verification of calculation, design and manufacturing, but the corresponding calculation algorithm has not been unified and has not been standardized to a unified platform. Even if the transformers with the same parameters are tested for reliability using different theoretical systems, there are large differences in the conclusions, and even completely different results.

[0004] Therefore, it is necessary to provide a test scheme that can uniformly measure the reliability of the transformer's short-circuit resistance capability. Summary of the invention

[0005] Based on this, it is necessary to provide a transformer short-circuit resistance reliability test method, device, computer equipment, computer-readable storage medium and computer program product that can uniformly measure the reliability of transformer short-circuit resistance in response to the above technical problems.

[0006] In a first aspect, the present application provides a method for testing the reliability of a transformer's short-circuit resistance capability. The method comprises:

[0007] Obtain a transformer finite element simulation model and simulation results of the transformer finite element simulation model under a short-circuit condition;

[0008] According to the transformer finite element simulation model and simulation results, the electromagnetic force of the transformer neutral disc under short-circuit conditions is determined;

[0009] Obtaining the allowable value of the state characteristic quantity of the coil under the short-circuit condition, and obtaining the actual value of the state characteristic quantity of the coil under the short-circuit condition according to the electromagnetic force of the coil under the short-circuit condition, the state characteristic quantity characterizing the short-circuit resistance of the transformer;

[0010] The ratio of the allowable value to the actual value under short-circuit conditions is obtained, and the safety factor of the transformer is determined based on the ratio. The safety factor is positively correlated with the reliability of the transformer's short-circuit resistance.

[0011] In one embodiment, obtaining a transformer finite element simulation model includes:

[0012] Obtaining the structural parameters of the transformer and the electrical parameters of the transformer under short-circuit conditions;

[0013] According to the structural parameters of the transformer and the electrical parameters of the transformer under short-circuit conditions, an initial transformer finite element simulation model is constructed;

[0014] According to different simulation calculation methods, the initial transformer finite element simulation model is simulated and calculated to obtain different simulation results under short-circuit conditions;

[0015] The different simulation results are compared, and according to the comparison results of the different simulation results, the correctness of the electrical parameters of the initial transformer finite element simulation model is verified, and the initial transformer finite element simulation model that has passed the electrical parameter correctness verification is determined as the transformer finite element simulation model.

[0016] In one embodiment, the simulation results include a first simulation result corresponding to the first simulation calculation method and a second simulation result corresponding to the second simulation calculation method;

[0017] Based on the comparison of different simulation results, the electrical parameter correctness verification of the initial transformer finite element simulation model includes:

[0018] Collecting a first short-circuit impedance in the first simulation result and a second short-circuit impedance in the second simulation result;

[0019] determining a deviation between the first short-circuit impedance and the second short-circuit impedance;

[0020] If the impedance deviation between the first short-circuit impedance and the second short-circuit impedance is less than or equal to the preset deviation threshold, it is determined that the initial transformer finite element simulation model passes the electrical parameter correctness verification.

[0021] In one embodiment, the first simulation result includes a static field simulation result, and the second simulation result includes a frequency domain field-circuit coupling simulation mode result.

[0022] In one embodiment, obtaining the allowable value of the state characteristic quantity of the coil under the short circuit condition includes:

[0023] According to the predefined material property data, the preset allowable value calculation rule of the state characteristic quantity and the structural parameters of the transformer, the allowable value of the state characteristic quantity of the coil under the short-circuit condition is obtained;

[0024] According to the electromagnetic force of the coil under the short-circuit condition, the actual value of the state characteristic quantity of the coil under the short-circuit condition is obtained, including:

[0025] According to the electromagnetic force of the coil under the short-circuit condition, the structural parameters of the transformer and the material property data, the actual value of the state characteristic quantity of the coil under the short-circuit condition is obtained.

[0026] In one embodiment, the short-circuit condition includes multiple types of short-circuit conditions; the number of coils is multiple;

[0027] Determining the transformer's safety factor based on the ratio includes:

[0028] The minimum value of the ratio corresponding to each coil under different types of short-circuit conditions is selected respectively to obtain an initial safety factor set;

[0029] The minimum value in the initial safety factor set is selected to obtain the safety factor of the transformer.

[0030] In a second aspect, the present application also provides a transformer short-circuit resistance reliability test device. The device comprises:

[0031] A data acquisition module, used to acquire a transformer finite element simulation model and a simulation result of the transformer finite element simulation model under a short-circuit condition;

[0032] The electromagnetic force determination module is used to determine the electromagnetic force of the transformer neutral disc under the short-circuit condition according to the transformer finite element simulation model and simulation results;

[0033] The state characteristic quantity calculation module is used to obtain the allowable value of the state characteristic quantity of the coil under the short-circuit condition, and obtain the actual value of the state characteristic quantity of the coil under the short-circuit condition according to the electromagnetic force of the coil under the short-circuit condition. The state characteristic quantity represents the short-circuit resistance of the transformer;

[0034] The short-circuit resistance reliability test module is used to obtain the ratio of the allowable value to the actual value under short-circuit conditions, and determine the safety factor of the transformer based on the ratio. The safety factor is positively correlated with the reliability of the transformer's short-circuit resistance.

[0035] In a third aspect, the present application further provides a computer device. The computer device includes a memory and a processor, the memory stores a computer program, and the processor implements the following steps when executing the computer program:

[0036] Obtain a transformer finite element simulation model and simulation results of the transformer finite element simulation model under a short-circuit condition;

[0037] According to the transformer finite element simulation model and simulation results, the electromagnetic force of the transformer neutral disc under short-circuit conditions is determined;

[0038] Obtaining the allowable value of the state characteristic quantity of the coil under the short-circuit condition, and obtaining the actual value of the state characteristic quantity of the coil under the short-circuit condition according to the electromagnetic force of the coil under the short-circuit condition, the state characteristic quantity characterizing the short-circuit resistance of the transformer;

[0039] The ratio of the allowable value to the actual value under short-circuit conditions is obtained, and the safety factor of the transformer is determined based on the ratio. The safety factor is positively correlated with the reliability of the transformer's short-circuit resistance.

[0040] In a fourth aspect, the present application further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the following steps are implemented:

[0041] Obtain a transformer finite element simulation model and simulation results of the transformer finite element simulation model under a short-circuit condition;

[0042] According to the transformer finite element simulation model and simulation results, the electromagnetic force of the transformer neutral disc under short-circuit conditions is determined;

[0043] Obtaining the allowable value of the state characteristic quantity of the coil under the short-circuit condition, and obtaining the actual value of the state characteristic quantity of the coil under the short-circuit condition according to the electromagnetic force of the coil under the short-circuit condition, the state characteristic quantity characterizing the short-circuit resistance of the transformer;

[0044] The ratio of the allowable value to the actual value under short-circuit conditions is obtained, and the safety factor of the transformer is determined based on the ratio. The safety factor is positively correlated with the reliability of the transformer's short-circuit resistance.

[0045] In a fifth aspect, the present application further provides a computer program product. The computer program product includes a computer program, and when the computer program is executed by a processor, the following steps are implemented:

[0046] Obtaining a transformer finite element simulation model and simulation results of the transformer finite element simulation model under each short-circuit condition, wherein the transformer finite element simulation model is a model verified by electrical parameter correctness and is constructed based on structural parameters of the transformer and electrical parameters under each short-circuit condition;

[0047] Based on the transformer finite element simulation model, each simulation result is combined to obtain the electromagnetic force of multiple coils of the transformer under each short-circuit condition;

[0048] For each short-circuit condition, the allowable value of the state characteristic quantity of each coil and the actual value of the state characteristic quantity of each coil obtained based on each electromagnetic force are obtained, and the state characteristic quantity represents the short-circuit resistance of the transformer;

[0049] Determine the ratio of the allowable value to the actual value of the state characteristic quantity of each coil under each short-circuit condition, and determine the safety factor of the transformer based on the ratio. The safety factor is positively correlated with the reliability of the transformer's short-circuit resistance.

[0050] The above-mentioned transformer short-circuit resistance reliability test method, device, computer equipment, storage medium and computer program product construct a transformer finite element simulation model based on mature finite element simulation technology, which can ensure the correctness of the finite element calculation results obtained based on the model. Further, the electromagnetic force of the transformer coil under the short-circuit condition is calculated based on the model, and then the actual value of the state characteristic quantity that characterizes the transformer's ability to withstand short circuit is calculated based on the electromagnetic force, and the allowable value of the state characteristic quantity is calculated, and then the reliability of the transformer's short-circuit resistance is quantitatively judged based on the ratio of the actual value to the allowable value. The above scheme proposes an implementation standard that can quantitatively determine the reliability of the transformer's short-circuit resistance. It accurately tests the stress of the coil under the short-circuit condition, and quantitatively judges the reliability of the transformer's short-circuit resistance based on the stress, so that accurate and unified short-circuit resistance reliability testing of the transformer can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A schematic diagram of a flow chart of a method for testing the reliability of a transformer's short-circuit resistance capability in one embodiment;

[0052] Figure 2 A schematic diagram of a flow chart of steps for constructing a transformer finite element simulation model in one embodiment;

[0053] Figure 3-1 A schematic diagram of a flow chart of a standard platform for determining the reliability of a transformer's short-circuit resistance capability in another embodiment;

[0054] Figure 3-2 A schematic diagram of differences in constructing a transformer finite element simulation model using different modeling methods in one embodiment;

[0055] Figure 3-3 A schematic diagram of key results of finite element simulation calculation in another embodiment;

[0056] Figure 4 A schematic flow chart of a method for testing the reliability of a transformer's short-circuit resistance capability in another embodiment;

[0057] Figure 5 A structural block diagram of a transformer short-circuit resistance reliability testing device in one embodiment;

[0058] Figure 6 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0060] With the development and improvement of computer simulation technology, the accuracy of finite element simulation technology has fully met the conditions for engineering application. Large-scale simulation software has become quite mature in transformer electromagnetic field solution technology. When the same transformer parameters and short-circuit impact loads are used, the results of electromagnetic field calculations and Lorentz force by different simulation software are slightly different, which can meet the accuracy of engineering judgment. Therefore, this application proposes a reliability test scheme for transformer short-circuit resistance based on finite element simulation technology.

[0061] In one embodiment, Figure 1 As shown, a method for testing the reliability of transformer short-circuit resistance is provided. This embodiment uses the method applied to a terminal as an example for illustration. It can be understood that the method can also be applied to a server, and can also be applied to a system including a terminal and a server, and is implemented through the interaction between the terminal and the server. In this embodiment, the method includes the following steps:

[0062] Step 202, obtaining a transformer finite element simulation model and a simulation result of the transformer finite element simulation model under a short-circuit condition.

[0063] In practical applications, mature finite element simulation software, such as ANSYS or COMSOL, can be used to construct a transformer finite element simulation model based on the structural parameters and electrical parameters of the transformer. Among them, the structural parameters of the transformer include core parameters, winding parameters, coil parameters and conductor parameters, and the electrical parameters include current or voltage values. The simulation results can be simulated and calculated for the transformer finite element simulation model under short-circuit conditions to obtain corresponding simulation results. Specifically, the simulation results include magnetic field energy, node voltage, leakage flux, short-circuit impedance, and axial Lorentz force density and radial Lorentz force density of each coil of each winding.

[0064] In another embodiment, the short-circuit condition can be a variety of short-circuit conditions, including normal conditions, maximum conditions, minimum conditions, rated conditions or calibration conditions, etc.). In the specific implementation, it can be for each short-circuit condition, a transformer finite element simulation model is constructed separately, and according to the current short-circuit condition, different currents or voltages are applied to the transformer finite element simulation model, and then the transformer finite element simulation model is simulated and calculated to obtain the simulation results under each short-circuit condition. The transformer finite element simulation model obtained in this embodiment is a model after the electrical parameter correctness verification. Specifically, the electrical parameter correctness verification includes geometric model checking (also known as model checking) and electrical parameter checking (referred to as parameter checking) of the transformer finite element simulation model. The geometric model is checked, including checking whether the size of its core, iron yoke, winding position, and voltage regulating coil position are correct. The electrical parameter check mainly verifies the transformer voltage ratio, ampere-turn balance rate, and short-circuit impedance. The model with incorrect verification needs to modify the parameters or re-fill, and only when the geometric check and electrical parameter check are correct can subsequent operations and calculations be performed. Specifically, the electrical parameter check is performed after the initial transformer finite element simulation model passes the model check. When the model passes the electrical parameter check, the initial transformer finite element simulation model can be considered to be a correct transformer finite element simulation model.

[0065] Step 204, determining the electromagnetic force of the transformer neutral conductor under a short-circuit condition according to the transformer finite element simulation model and the simulation results.

[0066] In this embodiment, the electromagnetic force may be a Lorentz force, and each coil may be used as a basic unit for data calculation and statistics. Specifically, it may be a general method of reference field research, for each short-circuit condition, respectively extract the axial Lorentz force density and radial Lorentz force density of each coil of each winding simulation, and then use the integral algorithm to sum and calculate the electromagnetic force of each coil under each short-circuit condition, and then make subsequent reliability and safety judgments based on this.

[0067] Step 206, obtaining the allowable value of the state characteristic quantity of the coil under the short-circuit condition, and obtaining the actual value of the state characteristic quantity of the coil under the short-circuit condition based on the electromagnetic force of the coil under the short-circuit condition, the state characteristic quantity characterizing the short-circuit resistance of the transformer.

[0068] The state characteristic quantity is a characteristic quantity that characterizes the short-circuit resistance of the transformer based on the national standard, which mainly includes the types of force and stress, see Table 1, which specifically includes the average annular tensile stress of the outer winding, the average compressive stress of the multi-layer winding, the axial end thrust, the conductor paper insulation and radial pad compressive stress, and the common pressure plate compressive stress, etc. In this embodiment, the allowable value refers to the value calculated by the allowable value algorithm of each state characteristic quantity given in the reference national standard. The actual value is the actual value of the state characteristic quantity calculated based on the Lorentz force calculated by the finite element simulation model of the transformer. Similarly, in the specific implementation, the allowable value and actual value of the state characteristic quantity of each coil can be calculated for each short-circuit condition.

[0069] Step 208, obtaining the ratio of the allowable value to the actual value under the short-circuit condition, and determining the safety factor of the transformer according to the ratio, the safety factor is positively correlated with the reliability of the transformer's short-circuit resistance capability.

[0070] After calculating the allowable value and the actual value of the state characteristic quantity of each coil under each short-circuit condition, the ratio of the allowable value and the actual value of the state characteristic quantity of each coil can be used as the safety factor of each coil.

[0071] Specifically, the actual value of the state characteristic quantity is calculated with each wire cake as the unit, and its array expression is:

[0072]

[0073] Wherein: WA, WB represent winding A and winding B, Amn represents the actual value of the nth state characteristic quantity of the mth coil of winding A, and so on.

[0074] The allowable value of the state characteristic quantity is calculated for each coil, and a corresponding database is established corresponding to the actual value. Taking winding A as an example, the array expression is as follows:

[0075]

[0076] Taking winding A as an example, calculate the safety factor of each coil:

[0077] K WA =[A all ] / A act

[0078] Where: K WA , [A all ] and A act All are arrays.

[0079] Specifically, each winding can be used as the main body for safety judgment, and the minimum safety factor of each coil in the winding is taken as the safety factor of this winding. Then, based on the safety factor of each winding, the final safety factor of the transformer is screened out. In this embodiment, if the safety factor is greater than 1, it can be determined that the short-circuit resistance of the transformer is qualified, otherwise, it is determined to be unqualified. It can be understood that in other embodiments, the boundaries of the safety factor can be corrected and improved according to actual conditions, and the values ​​in different projects can also be slightly increased. For example, in nuclear power projects and ultra-high voltage projects, the safety factor can be appropriately increased to 1.2. The specific value can be determined according to actual conditions and is not limited here.

[0080] In the above-mentioned transformer short-circuit resistance reliability test method, a transformer finite element simulation model is constructed based on the mature finite element simulation technology, which can ensure the correctness of the finite element calculation results obtained based on the model. Further, the electromagnetic force of the transformer coil under the short-circuit condition is calculated based on the model, and then the actual value of the state characteristic quantity that characterizes the transformer's ability to withstand short circuits is calculated based on the electromagnetic force, and the allowable value of the state characteristic quantity is calculated, and then the reliability of the transformer's short-circuit resistance is quantitatively judged based on the ratio of the actual value to the allowable value. The above scheme proposes an implementation standard that can quantitatively determine the reliability of the transformer's short-circuit resistance. It accurately tests the stress of the coil under the short-circuit condition, and quantitatively judges the reliability of the transformer's short-circuit resistance based on the stress, so that accurate and unified short-circuit resistance reliability testing of the transformer can be achieved.

[0081] Table 1 Statistics of key state characteristics of transformer short-circuit reliability

[0082]

[0083] like Figure 2 As shown, in one embodiment, obtaining a transformer finite element simulation model includes:

[0084] Step 222, obtaining structural parameters of the transformer and electrical parameters of the transformer under short-circuit conditions;

[0085] Step 242, constructing an initial transformer finite element simulation model according to the structural parameters of the transformer and the electrical parameters of the transformer under a short-circuit condition;

[0086] Step 262, performing simulation calculations on the initial transformer finite element simulation model according to different simulation calculation methods to obtain different simulation results under short-circuit conditions;

[0087] Step 282, comparing different simulation results, verifying the correctness of electrical parameters of the initial transformer finite element simulation model according to the comparison results of the different simulation results, and determining the initial transformer finite element simulation model that passes the electrical parameter correctness verification as the transformer finite element simulation model.

[0088] In actual operation, it is necessary to construct a transformer finite element simulation model for each short-circuit condition in order to obtain the safety factor of the transformer under each short-circuit condition. Specifically, the transformer finite element simulation model can be obtained based on the following methods:

[0089] 1) Collect data. Based on the technical characteristics of the field, reference standards and literature results, establish a characteristic quantity relationship element parameter table that can characterize the transformer's ability to withstand short circuits, and obtain the electrical parameters and structural parameters of the transformer, where the electrical parameters include data such as the current or voltage to be applied, capacity, etc., and the structural parameters include core parameters, winding parameters, coil parameters, and conductor parameters. Specifically, data collection can use a unified parameterized collection system to reduce the differences in the definition of algorithm parameter input. Parameterized input can be in the form of direct input, ECXCEL table import, XML format import, etc.

[0090] 2) Finite element simulation calculation pre-processing. This includes building an initial transformer finite element simulation model based on electrical parameters and structural parameters for each short-circuit condition based on mature finite element simulation software, and then planning the finite element meshing, material property definition, magnetic field and circuit boundary conditions and load settings for the initial transformer finite element simulation model.

[0091] In the specific implementation, COMSOL software is used for simulation. According to the project engineering calculation amount, the pancake-by-pancake modeling method is selected to build the initial transformer finite element simulation model. The electromagnetic module uses a two-dimensional axisymmetric field, and the material properties are defined, including the relative magnetic permeability, relative dielectric constant, and Young's modulus of copper and iron. In addition to the pancake-by-pancake modeling method mentioned in this embodiment, the partition modeling method can also be used to build the initial transformer finite element simulation model according to the project engineering calculation amount. The difference between the two models is shown in the attached Figure 3-2 .

[0092] 3) Finite element simulation calculation. The preset first simulation calculation method and the preset second simulation calculation method are respectively used to simulate the initial transformer finite element simulation model constructed for each short-circuit condition to obtain the first simulation result and the second simulation result under each short-circuit condition. The basic functions of COMSOL software development and use should be used for finite element calculation, including software use, data checking, parameterized input and automatic report generation. The software usage process includes parameter filling, model checking, parameter checking, calculation, result viewing and data saving. The specific usage process of the standard platform for reliability judgment of transformer short-circuit capacity is attached. Figure 3-1 .

[0093] 4) Verification of electrical parameter correctness. Compare the first simulation result with the second simulation result, verify the correctness of the electrical parameters of the initial transformer finite element simulation model according to the comparison result, and determine the initial transformer finite element simulation model that passes the electrical parameter correctness verification as the transformer finite element simulation model.

[0094] In this embodiment, the electrical parameter correctness of the initial transformer finite element simulation model can be verified according to the simulation results obtained in two different simulation calculation methods, which can simply and effectively verify the correctness of the initial transformer finite element simulation model and ensure the correctness of the finite element calculation.

[0095] In one of the embodiments, the simulation results include a first simulation result corresponding to a first simulation calculation method and a second simulation result corresponding to a second simulation calculation method; based on the comparison results of different simulation results, verifying the correctness of electrical parameters of the initial transformer finite element simulation model includes: collecting the first short-circuit impedance in the first simulation result and the short-circuit impedance in the second simulation result, determining the deviation between the first short-circuit impedance and the second short-circuit impedance, and if the impedance deviation between the first short-circuit impedance and the second short-circuit impedance is less than or equal to a preset deviation threshold, then determining that the initial transformer finite element simulation model passes the electrical parameter correctness verification.

[0096] In this embodiment, the short-circuit impedance that is more representative in the simulation results is selected as an indicator to verify the correctness of the electrical parameters of the initial transformer finite element simulation model. Specifically, the deviation of the first short-circuit impedance in the first simulation result and the short-circuit impedance in the second simulation result can be calculated, and the deviation is compared to see whether it is greater than a preset deviation threshold value such as 2%. If the deviation is less than or equal to 2%, it is determined that the initial transformer finite element simulation model passes the electrical parameter correctness verification. At the same time, since the deviation of the short-circuit impedance of the conventional structure transformer solved by the theoretical analytical algorithm can be controlled within the range of 5%, the analytical solution can be used to compare the deviation with the finite element simulation calculation results, but the deviation range should be appropriately enlarged at this time, and 5% can be selected as the correctness standard. It can be understood that in other embodiments, the capacity, node voltage or leakage magnetic flux in the simulation results can also be selected as indicators to verify the correctness of the electrical parameters of the initial transformer finite element simulation model. The specific can be determined according to the actual situation and is not limited here. In this embodiment, the short-circuit impedance is selected as an indicator for judging the initial transformer finite element simulation model, which can be more accurate and more representative.

[0097] In one embodiment, the first simulation result includes a static field simulation result, and the second simulation result includes a frequency domain field-circuit coupling simulation mode result.

[0098] In this embodiment, static field simulation calculation and frequency domain field-circuit coupling simulation calculation can be performed on the initial transformer finite element simulation model to obtain static field simulation results and frequency domain field-circuit coupling simulation results. Further, the first short-circuit impedance of the static field simulation result and the second short-circuit impedance of the frequency domain field-circuit coupling simulation result can be collected, and the first short-circuit impedance and the second short-circuit impedance are compared to calculate the deviation of the short-circuit impedance. If the deviation is less than or equal to 2%, it is determined that the initial transformer finite element simulation model passes the model correctness check. In this embodiment, static field and frequency domain field-circuit coupling are used simultaneously, and the short-circuit impedance of the transformer is used as the verification standard of the electrical parameters, so that the model correctness can be verified more accurately.

[0099] In one embodiment, obtaining the allowable value of the state characteristic quantity of the coil under the short circuit condition includes:

[0100] According to the predefined material property data, the allowable value calculation rule of the preset state characteristic quantity and the structural parameters of the transformer, the allowable value of the state characteristic quantity of the coil under the short-circuit condition is obtained;

[0101] According to the electromagnetic force of the coil under the short-circuit condition, the actual value of the state characteristic quantity of the coil under the short-circuit condition is obtained, including:

[0102] According to the electromagnetic force of the coil under the short-circuit condition, the structural parameters of the transformer and the material property data, the actual value of the state characteristic quantity of the coil under the short-circuit condition is obtained.

[0103] In specific implementation, the allowable value of the state characteristic quantity of each coil can be calculated based on the allowable value algorithm given in the national standard, combined with the material property data of the transformer finite element model and the structural parameters of the transformer, to obtain the allowable value of the state characteristic quantity of each coil. The actual value of the state characteristic quantity of each coil can be calculated based on the electromagnetic force under each short-circuit condition, the structural parameters of the transformer and the material property data to obtain the actual value of the state characteristic quantity of each coil. In this embodiment, a standard solution for calculating the actual value of the state characteristic quantity of each coil is provided based on the electromagnetic force obtained from the finite element model of the transformer.

[0104] In one embodiment, the short-circuit condition includes multiple types of short-circuit conditions; the number of coils is multiple; determining the safety factor of the transformer based on the ratio includes: respectively screening the minimum value of the ratio corresponding to each coil under different types of short-circuit conditions to obtain an initial safety factor set, and selecting the minimum value in the initial safety factor set to obtain the safety factor of the transformer.

[0105] After determining the ratio of the actual value of the state characteristic quantity of each coil to the allowable value under each short-circuit condition, the minimum value of the ratio (safety factor) of the coil under each short-circuit condition is taken as the safety factor of the winding where the coil is located, that is, the initial safety factor, and the initial safety factor set under each short-circuit condition is obtained. Then, the minimum value in the initial safety factor set is collected and taken as the final safety factor, that is, the minimum ratio of all coils under all short-circuit conditions is taken as the safety factor of the transformer. In this embodiment, the minimum safety factor of the coil under all short-circuit conditions is taken as the safety factor of the transformer, which can make a more accurate assessment of the reliability of the transformer's short-circuit resistance.

[0106] In order to clearly illustrate the transformer short-circuit resistance reliability test method provided by the present application, the following is combined with a specific embodiment and the attached Figure 4 To illustrate, this embodiment includes the following steps:

[0107] (1) Collect data. The acquired data include the electrical parameters and structural parameters of the transformer, where the electrical parameters include the current or voltage to be applied, capacity and other data, and the structural parameters include core parameters, winding parameters, coil parameters and conductor parameters. Specifically, data collection can adopt a unified parameterized collection system to reduce the differences caused by the definition of algorithm parameter input. Parameterized input can be in the form of direct input, ECXCEL table import, XML format import, etc.

[0108] (2) Pre-processing of finite element simulation calculations. Use COMSOL software for simulation. According to the amount of engineering calculations for the project, select the pancake-by-pancake modeling method. Combine the structural parameters of the transformer and the electrical parameters under each short-circuit condition to build the corresponding initial transformer finite element simulation model. Then, plan the finite element meshing of the initial transformer finite element simulation model, define material properties, and set magnetic field and circuit boundary conditions and loads. Among them, the electromagnetic module uses a two-dimensional axisymmetric field, and defines material properties including the relative magnetic permeability, relative dielectric constant, and Young's modulus of copper and iron. In addition to the pancake-by-pancake modeling method mentioned in this embodiment, the partition modeling method can also be used to build the initial transformer finite element simulation model according to the amount of engineering calculations for the project. The difference between the two models is shown in the attached figure. Figure 3-2 .

[0109] (3) Finite element simulation calculation. For each short-circuit condition, the initial transformer finite element simulation model is subjected to steady-state field simulation calculation and frequency-domain field-circuit coupling simulation calculation to obtain steady-state field simulation results and frequency-domain field-circuit coupling simulation results. Then, the short-circuit impedance in the above simulation results is collected respectively. For details, the schematic diagram of the key results in the simulation calculation can be referred to Figure 3-3 .

[0110] (4) Verify the correctness of the model. After geometrically checking the model, compare the short-circuit impedance in the simulation results obtained by the static field calculation algorithm and the frequency domain field-circuit coupling algorithm to obtain the impedance deviation result. When the impedance deviation between the two is less than or equal to 2%, the initial transformer finite element simulation model is judged to be correct, and the correct initial transformer finite element simulation model is determined as the transformer finite element simulation model for subsequent use.

[0111] (5) Extract the Lorentz force. According to the general research method in the field, extract the axial Lorentz force density and radial Lorentz force density of each coil of each winding. Calculate the electromagnetic force on the coil under each short-circuit condition through the integral summation algorithm, and make subsequent reliability and safety judgments based on this. When calculating the forces under different short-circuit conditions at the same time, independent modeling and value assignment should be performed to calculate the electromagnetic force.

[0112] (6) Calculate the actual value of the state characteristic quantity. For each short-circuit condition, take each coil as the basic unit for data statistics, and calculate the actual value of the state characteristic quantity of each coil based on the calculated Lorentz force, combined with the structural parameters and material property data of the transformer.

[0113] (7) Calculate the allowable value of the state characteristic quantity. For each short-circuit condition, take each coil as a unit, calculate the allowable value corresponding to each coil and the state characteristic quantity according to national standards, material property data and structural parameters of the transformer, and further establish a database corresponding to the actual value.

[0114] (8) Determine the safety factor. The ratio of the allowable value to the actual value is determined as the safety factor. Each winding is used as the safety judgment subject, and the minimum safety factor of each coil in the winding is taken as the safety factor of this winding. Then, the safety factors of each winding under each short-circuit condition are aggregated, and the minimum safety factor of the winding under all short-circuit conditions is selected as the safety factor of the transformer. Specifically, if the safety factor is greater than 1, it is determined that the transformer's short-circuit resistance is qualified. The safety factor can be modified according to actual conditions, and the value can be slightly increased in different projects. Furthermore, the safety factor can be converted into a withstand current according to needs and concerns to judge the safety of the transformer.

[0115] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0116] Based on the same inventive concept, the embodiment of the present application also provides a transformer short-circuit capability reliability test device for implementing the above-mentioned transformer short-circuit capability reliability test method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above-mentioned method, so the specific limitations in one or more transformer short-circuit capability reliability test device embodiments provided below can refer to the limitations of the transformer short-circuit capability reliability test method above, and will not be repeated here.

[0117] In one embodiment, Figure 5 As shown, a transformer short-circuit resistance reliability test device is provided, comprising: a data acquisition module 510, an electromagnetic force determination module 520, a state characteristic quantity calculation module 530 and a short-circuit resistance reliability test module 540, wherein:

[0118] The data acquisition module 510 is used to acquire the transformer finite element simulation model and the simulation results of the transformer finite element simulation model under a short-circuit condition.

[0119] The electromagnetic force determination module 520 is used to determine the electromagnetic force of the transformer neutral conductor under a short-circuit condition according to the transformer finite element simulation model and simulation results.

[0120] The state characteristic quantity calculation module 530 is used to obtain the allowable value of the state characteristic quantity of the coil under the short-circuit condition, and obtain the actual value of the state characteristic quantity of the coil under the short-circuit condition based on the electromagnetic force of the coil under the short-circuit condition. The state characteristic quantity represents the short-circuit resistance of the transformer.

[0121] The short-circuit resistance reliability test module 540 is used to obtain the ratio of the allowable value to the actual value under the short-circuit condition, and determine the safety factor of the transformer according to the ratio. The safety factor is positively correlated with the reliability of the transformer's short-circuit resistance.

[0122] The above-mentioned transformer short-circuit resistance reliability test device constructs a transformer finite element simulation model based on mature finite element simulation technology, which can ensure the correctness of the finite element calculation results obtained based on the model. Further, the electromagnetic force of the transformer coil under the short-circuit condition is calculated based on the model, and then the actual value of the state characteristic quantity that characterizes the transformer's ability to withstand short circuits is calculated based on the electromagnetic force, and the allowable value of the state characteristic quantity is calculated, and then the reliability of the transformer's short-circuit resistance is quantitatively judged based on the ratio of the actual value to the allowable value. The above scheme proposes an implementation standard that can quantitatively determine the reliability of the transformer's short-circuit resistance. It accurately tests the stress of the coil under the short-circuit condition, and quantitatively judges the reliability of the transformer's short-circuit resistance based on the stress, so that accurate and unified short-circuit resistance reliability testing of the transformer can be achieved.

[0123] In one of the embodiments, the data acquisition module 510 is also used to obtain the structural parameters of the transformer and the electrical parameters of the transformer under short-circuit conditions, and construct an initial transformer finite element simulation model based on the structural parameters of the transformer and the electrical parameters of the transformer under short-circuit conditions. The initial transformer finite element simulation model is simulated and calculated according to different simulation calculation methods to obtain different simulation results under short-circuit conditions, and the different simulation results are compared. Based on the comparison results of the different simulation results, the electrical parameter correctness of the initial transformer finite element simulation model is verified, and the initial transformer finite element simulation model that has passed the electrical parameter correctness verification is determined as the transformer finite element simulation model.

[0124] In one of the embodiments, the data acquisition module 510 is also used to collect the first short-circuit impedance in the first simulation result and the short-circuit impedance in the second simulation result, determine the deviation between the first short-circuit impedance and the second short-circuit impedance, and if the impedance deviation between the first short-circuit impedance and the second short-circuit impedance is less than or equal to a preset deviation threshold, it is determined that the initial transformer finite element simulation model has passed the electrical parameter correctness verification.

[0125] In one of the embodiments, the state characteristic quantity calculation module 530 is also used to obtain the allowable value of the state characteristic quantity of the coil under the short-circuit condition based on the predefined material property data of the transformer finite element model, the preset allowable value calculation rules of the state characteristic quantity and the structural parameters of the transformer, and to obtain the allowable value of the state characteristic quantity of the coil under the short-circuit condition based on the electromagnetic force, the structural parameters of the transformer and the material property data.

[0126] In one embodiment, the short-circuit resistance reliability test module 540 is also used to screen the minimum value of the ratio corresponding to each coil under different types of short-circuit conditions, obtain an initial safety factor set, select the minimum value in the initial safety factor set, and obtain the safety factor of the transformer.

[0127] Each module in the above transformer short-circuit resistance reliability test device can be implemented in whole or in part by software, hardware and their combination. Each module can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to each module above.

[0128] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Figure 6 As shown. The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer 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 computer 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 testing the reliability of the transformer's short-circuit resistance is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the computer device housing, or an external keyboard, touchpad or mouse, etc.

[0129] Those skilled in the art will understand that Figure 6 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0130] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned transformer short-circuit resistance reliability test method when executing the computer program.

[0131] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned transformer short-circuit resistance reliability test method are implemented.

[0132] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above-mentioned transformer short-circuit resistance reliability testing method when executed by a processor.

[0133] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0134] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0135] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for testing the reliability of transformer short-circuit resistance, characterized in that: The method comprises: Obtaining structural parameters of the transformer and electrical parameters of the transformer under short-circuit conditions; Constructing an initial transformer finite element simulation model according to the structural parameters of the transformer and the electrical parameters of the transformer under a short-circuit condition; According to different simulation calculation methods, the initial transformer finite element simulation model is simulated and calculated to obtain different simulation results under short-circuit conditions, wherein the simulation results include a first simulation result corresponding to the first simulation calculation method and a second simulation result corresponding to the second simulation calculation method; Comparing the different simulation results, collecting a first short-circuit impedance in the first simulation result and a second short-circuit impedance in the second simulation result, and determining a deviation between the first short-circuit impedance and the second short-circuit impedance; If the impedance deviation is less than or equal to the preset deviation threshold, it is determined that the initial transformer finite element simulation model passes the electrical parameter correctness verification, and the initial transformer finite element simulation model is determined as the transformer finite element simulation model; Determine the electromagnetic force of the transformer neutral disc under the short-circuit condition according to the transformer finite element simulation model and the simulation result of the transformer finite element simulation model under the short-circuit condition; Obtaining an allowable value of a state characteristic quantity of the coil under a short-circuit condition, and obtaining an actual value of a state characteristic quantity of the coil under a short-circuit condition based on the electromagnetic force of the coil under the short-circuit condition, wherein the state characteristic quantity represents the short-circuit resistance of the transformer; The ratio of the allowable value to the actual value under the short-circuit condition is obtained, and the safety factor of the transformer is determined according to the ratio, wherein the safety factor is positively correlated with the reliability of the short-circuit resistance capability of the transformer.

2. The transformer short-circuit resistance reliability testing method according to claim 1 is characterized in that: The first simulation result includes a static field simulation result, and the second simulation result includes a frequency domain field-circuit coupling simulation mode result.

3. The transformer short-circuit resistance reliability testing method according to claim 1 is characterized in that: The obtaining of the allowable value of the state characteristic quantity of the coil under the short-circuit condition includes: According to predefined material property data, preset allowable value calculation rules of the state characteristic quantity and structural parameters of the transformer, obtain the allowable value of the state characteristic quantity of the coil under the short-circuit condition; According to the electromagnetic force of the coil under the short-circuit condition, obtaining the actual value of the state characteristic quantity of the coil under the short-circuit condition includes: According to the electromagnetic force of the coil under the short-circuit condition, the structural parameters of the transformer and the material property data, the actual value of the state characteristic quantity of the coil under the short-circuit condition is obtained.

4. The transformer short-circuit resistance reliability testing method according to any one of claims 1 to 3, characterized in that: The short-circuit working condition includes various types of short-circuit working conditions; The number of the wire cakes is multiple; Determining the safety factor of the transformer according to the ratio includes: The minimum values ​​of the ratios corresponding to the coils under different types of short-circuit conditions are respectively selected to obtain an initial safety factor set; The minimum value in the initial safety factor set is selected to obtain the safety factor of the transformer.

5. A transformer short-circuit resistance reliability test device, characterized in that: The device comprises: A data acquisition module, used to acquire structural parameters of a transformer and electrical parameters of the transformer under a short-circuit condition, construct an initial transformer finite element simulation model according to the structural parameters of the transformer and the electrical parameters of the transformer under a short-circuit condition, perform simulation calculations on the initial transformer finite element simulation model according to different simulation calculation methods, and obtain different simulation results under a short-circuit condition, wherein the simulation results include a first simulation result corresponding to a first simulation calculation method and a second simulation result corresponding to a second simulation calculation method, compare the different simulation results, collect a first short-circuit impedance in the first simulation result and a second short-circuit impedance in the second simulation result, determine a deviation between the first short-circuit impedance and the second short-circuit impedance, and if the impedance deviation is less than or equal to a preset deviation threshold, determine that the initial transformer finite element simulation model passes the electrical parameter correctness verification, and determine the initial transformer finite element simulation model as a transformer finite element simulation model; An electromagnetic force determination module, used to determine the electromagnetic force of the transformer neutral disk under the short-circuit condition according to the transformer finite element simulation model and the simulation result of the transformer finite element simulation model under the short-circuit condition; A state characteristic quantity calculation module is used to obtain an allowable value of the state characteristic quantity of the coil under a short-circuit condition, and obtain an actual value of the state characteristic quantity of the coil under a short-circuit condition according to the electromagnetic force of the coil under the short-circuit condition, wherein the state characteristic quantity represents the short-circuit resistance of the transformer; The short-circuit resistance reliability test module is used to obtain the ratio of the allowable value to the actual value under short-circuit conditions, and determine the safety factor of the transformer according to the ratio, wherein the safety factor is positively correlated with the reliability of the short-circuit resistance of the transformer.

6. The device according to claim 5, characterized in that The state characteristic quantity calculation module is also used to obtain the allowable value of the state characteristic quantity of the coil under the short-circuit condition according to predefined material property data, preset allowable value calculation rules of the state characteristic quantity and the structural parameters of the transformer, and to obtain the actual value of the state characteristic quantity of the coil under the short-circuit condition according to the electromagnetic force of the coil under the short-circuit condition, the structural parameters of the transformer and the material property data.

7. The device according to claim 5 or 6, characterized in that The short-circuit conditions include multiple types of short-circuit conditions; the number of the coils is multiple; the short-circuit resistance reliability test module is also used to screen the minimum value of the ratio corresponding to each coil under different types of short-circuit conditions, obtain an initial safety factor set, select the minimum value in the initial safety factor set, and obtain the safety factor of the transformer.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 4 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

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