Method for evaluating arc fault resistance of key structure of oil-immersed power equipment

Abstract

The application discloses an oil-immersed power equipment key structure arc fault tolerance capacity evaluation method, comprising the following steps: performing impact load test and simulation calculation on each structure of the oil-immersed power equipment, determining the mapping relationship between the test failure characteristic quantity and the simulation failure characteristic quantity of each structure, and constructing a structure failure surface; performing equivalent impact test on a key structure to be evaluated of the oil-immersed power equipment, and obtaining key structure test failure characteristic quantity of the key structure to be evaluated; converting the key structure failure characteristic quantity according to the mapping relationship, and obtaining effective failure characteristic quantity of the key structure to be evaluated; performing arc fault tolerance capacity evaluation on the key structure effective failure characteristic quantity according to the structure failure surface, and determining the tolerance capacity evaluation result of the key structure to be evaluated.

Description

Technical Field

[0001] This invention relates to the field of oil-immersed power equipment technology, and more specifically, to a method for evaluating the arc fault tolerance capability of key structures in oil-immersed power equipment. Background Technology

[0002] Oil-immersed electrical equipment, such as transformers, tap changers, and risers, inevitably suffers from arcing faults. High-energy arcing faults can lead to structural damage to the equipment and uncontrolled leakage of the insulating oil inside. This oil can then cause a fire or explosion upon contact with air. The leaked oil-gas mixture can further endanger surrounding equipment, personnel, and the environment, causing significant losses and adverse effects.

[0003] Currently, oil-immersed power equipment generally does not undergo explosion-proof verification, but only some low static pressure factory tests, such as positive and negative pressure tests. These tests are mainly to check the sealing performance of the oil tank and the oil carrying capacity during normal operation. Some transformer manufacturers at home and abroad have put forward explosion-proof requirements and carried out explosion-proof verification and design for transformers, but they still use iterative methods based on static pressure. The verification criteria are mainly based on structural stress and strain, ignoring the failure and damage caused by impact loads under arc faults.

[0004] In the general mechanical and materials fields, quasi-static and dynamic impact test specifications and standards have been established for materials or structures, such as uniaxial tension, three-point bending, Charpy test, pendulum and drop hammer test, etc. However, most of them require the processing of standard specimens, and the test conditions are different from the impact load conditions of arc faults, and the stress state of transformer structures in arc faults is not considered.

[0005] As voltage levels increase, arc fault energy rises, and impact loads become greater. If existing static verification methods are used, the verification standards are too stringent and cannot effectively guide the design and verification of explosion-proof transformers. Directly assessing explosion resistance based on quasi-static and impact tests of existing materials and structures cannot accurately reflect the stress state of the transformer tank under actual arc fault conditions, nor can it accurately correlate test results with the arc fault tolerance of key transformer structures. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for evaluating the arc fault tolerance capability of key structures in oil-immersed power equipment.

[0007] According to one aspect of the present invention, a method for evaluating the arc fault tolerance capability of key structures in oil-immersed power equipment is provided, comprising:

[0008] Impact load tests and simulation calculations were performed on various structures of oil-immersed power equipment to determine the mapping relationship between the test failure characterization quantities and the simulation failure characterization quantities of each structure and to construct the structural failure surface.

[0009] Equivalent impact tests were conducted on the key structures of the oil-immersed power equipment to be evaluated, and the test failure characterization quantities of the key structures to be evaluated were obtained.

[0010] Based on the mapping relationship, the failure characterization quantities of the key structure are transformed to obtain the effective failure characterization quantities of the key structure to be evaluated.

[0011] The arc fault tolerance capability is assessed based on the effective failure characterization quantity of the key structure according to the structural failure curve, and the tolerance capability assessment result of the key structure to be assessed is determined.

[0012] Optionally, impact load tests and simulation calculations are performed on various structures of the oil-immersed power equipment to determine the mapping relationship between the test failure characterization quantities and the simulation failure characterization quantities of each structure, and to construct the structural failure surface, including:

[0013] Mechanical property tests were conducted on various materials of oil-immersed power equipment, and constitutive models and failure models of each material were constructed.

[0014] Based on the constitutive models of each material, a simulation model of transformer arc fault is constructed, and arc fault simulation is performed. The simulation results are analyzed based on the failure models of each structure to determine the failure structures of the oil-immersed power equipment, as well as the stress state and impact load of each failure structure.

[0015] Equivalent impact tests were conducted on each failed structure based on the stress state and impact load to obtain the test failure characterization quantities of each failed structure.

[0016] Based on the boundary conditions and loads of each failed structure in the transformer arc fault simulation model, establish the failure structure sub-models of each failed structure.

[0017] Simulation calculations are performed on each failure structure sub-model to obtain the simulation failure characterization quantities of each failure structure;

[0018] Based on the experimental and simulated failure characterization quantities of each failed structure, a mapping relationship between the experimental and simulated failure characterization quantities and a structural failure surface are constructed.

[0019] Optionally, the constitutive model expression is:

[0020]

[0021] In the formula, A , B , n , C and m These are the constitutive model parameters, obtained experimentally. For equivalent plastic strain, The equivalent rate of change, For reference strain rate, , T The current temperature. T room For ambient temperature, T melt For melting point, the effect of strain rate is... C =5.94×10⁻⁶+0.019; Equivalent stress;

[0022] The failure model expression is:

[0023]

[0024] In the formula, D 1~ D 5 represents the failure model parameters. For stress triaxiality, For plastic strain, denoted as relative strain rate.

[0025] Optionally, based on the experimental failure characterization parameters and simulated failure characterization parameters of each failed structure, a structural failure surface is constructed for each failed structure, including:

[0026] A sample dataset is constructed based on experimental failure characterization parameters and simulated failure characterization parameters, where both experimental and simulated failure characterization parameters contain n features.

[0027] The feature values ​​in the sample dataset are subjected to infinite hardening and normalization to obtain m failure points;

[0028] The m failure points are plotted on an n-dimensional space and fitted to obtain an n-dimensional structural failure surface.

[0029] Optionally, the formula for calculating the tolerance assessment result is:

[0030]

[0031] In the formula, d critical Let be the vector magnitude of the projection points of the effective failure characterization quantity of the key structure to be evaluated onto the constructed structural failure surface. d This represents the vector magnitude in the failure space of the effective failure characterization quantity of the key structure to be evaluated.

[0032] According to another aspect of the present invention, a device for evaluating the arc fault tolerance capability of key structures in oil-immersed power equipment is provided, comprising:

[0033] The module is used to perform impact load tests and simulation calculations on various structures of oil-immersed power equipment, determine the mapping relationship between the test failure characterization quantities and the simulation failure characterization quantities of each structure, and construct the structural failure surface.

[0034] The test module is used to conduct equivalent impact tests on the key structures of oil-immersed power equipment to be evaluated, and to obtain the test failure characterization quantities of the key structures to be evaluated.

[0035] The conversion module is used to convert the failure characterization quantities of the key structure according to the mapping relationship, and obtain the effective failure characterization quantities of the key structure to be evaluated.

[0036] The evaluation module is used to evaluate the arc fault tolerance of key structures based on the effective failure characterization quantities of the structural failure curve, and to determine the tolerance evaluation results of the key structures to be evaluated.

[0037] According to another aspect of the present invention, a computer-readable storage medium is provided, the storage medium storing a computer program for performing the methods described in any of the above aspects of the present invention.

[0038] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising: a processor; a memory for storing executable instructions of the processor; the processor being configured to read the executable instructions from the memory and execute the instructions to implement the method described in any of the preceding aspects of the present invention.

[0039] Therefore, this invention calculates the impact loads acting on different transformer structures based on a strong fluid-structure interaction algorithm of explicit dynamics; constructs failure criteria regarding strain rate and stress state; conducts mechanical property tests at different strain rates using tests with different structural sizes; and calculates the material failure surface. Based on the stress state of the transformer structure under arc faults, an impact testing fixture is designed to ensure that the test specimens reach the same stress state during the test. The time-varying arc fault impact load is equivalent to the energy and impulse equivalence method. This achieves impact tests that more closely approximate the actual arc fault load conditions. Attached Figure Description

[0040] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0041] Figure 1 This is a flowchart illustrating an exemplary embodiment of the present invention regarding a method for evaluating the arc fault tolerance of key structures in oil-immersed power equipment.

[0042] Figure 2 This is another flowchart illustrating the method for evaluating the arc fault tolerance of key structures in oil-immersed power equipment according to an exemplary embodiment of the present invention.

[0043] Figure 3 This is a schematic diagram of a spatial failure surface provided in an exemplary embodiment of the present invention;

[0044] Figure 4 This is a schematic diagram of the structure of an oil-immersed power equipment key structure arc fault tolerance assessment device provided in an exemplary embodiment of the present invention.

[0045] Figure 5 This is the structure of an electronic device provided in an exemplary embodiment of the present invention. Detailed Implementation

[0046] Hereinafter, exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein.

[0047] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0048] Those skilled in the art will understand that the terms "first," "second," etc., in the embodiments of the present invention are only used to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them.

[0049] It should also be understood that in the embodiments of the present invention, "multiple" can refer to two or more, and "at least one" can refer to one, two or more.

[0050] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more unless explicitly defined or given contrary instructions in the context.

[0051] Furthermore, the term "and / or" in this invention is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this invention generally indicates that the preceding and following related objects have an "or" relationship.

[0052] It should also be understood that the description of the various embodiments in this invention emphasizes the differences between the various embodiments, and the similarities or similarities can be referred to each other. For the sake of brevity, they will not be described in detail.

[0053] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0054] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0055] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0056] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0057] The embodiments of this invention can be applied to electronic devices such as terminal devices, computer systems, and servers, and can operate together with a wide range of other general-purpose or special-purpose computing system environments or configurations. Well-known examples of terminal devices, computing systems, environments, and / or configurations suitable for use with electronic devices such as terminal devices, computer systems, and servers include, but are not limited to: personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputer systems, mainframe computer systems, and distributed cloud computing environments including any of the above systems, etc.

[0058] Electronic devices such as terminal devices, computer systems, and servers can be described in the general context of computer system executable instructions (such as program modules) executed by a computer system. Typically, program modules can include routines, programs, object programs, components, logic, data structures, etc., which perform specific tasks or implement specific abstract data types. Computer systems / servers can be implemented in distributed cloud computing environments, where tasks are executed by remote processing devices linked through communication networks. In distributed cloud computing environments, program modules can reside on local or remote computing system storage media, including storage devices.

[0059] Exemplary methods

[0060] Figure 1 This is a flowchart illustrating a method for evaluating the arc fault tolerance of key structures in oil-immersed power equipment according to an exemplary embodiment of the present invention. This embodiment can be applied to electronic devices, such as... Figure 1 As shown, the method 100 for evaluating the arc fault tolerance capability of key structures in oil-immersed power equipment includes the following steps:

[0061] Step 101: Conduct impact load tests and simulation calculations on each structure of the oil-immersed power equipment to determine the mapping relationship between the test failure characterization quantity and the simulation failure characterization quantity of each structure and to construct the structural failure surface.

[0062] Step 102: Conduct an equivalent impact test on the key structure to be evaluated of the oil-immersed power equipment to obtain the key structure test failure characterization quantity of the key structure to be evaluated.

[0063] Step 103: Convert the failure characterization quantity of the key structure according to the mapping relationship to obtain the effective failure characterization quantity of the key structure to be evaluated.

[0064] Step 104: Evaluate the arc fault tolerance capability of the key structure based on the effective failure characterization quantity of the structural failure curve, and determine the tolerance capability evaluation result of the key structure to be evaluated.

[0065] Specifically, in response to the technical problems existing in the background art, this invention proposes a method for evaluating the arc fault tolerance capability of key structures in oil-immersed power equipment. The specific steps are as follows: Figure 2 As shown:

[0066] Step 1: Material Mechanical Property Testing. Different mechanical property tests are conducted on the transformer tank material to calculate and obtain the material's constitutive model and failure model. The construction of the constitutive model and failure model should consider the effects of strain rate and stress state, such as the Johnson-Cook (JC) constitutive model and Johnson-Cook (JC) failure model. Therefore, different test methods / equipment are needed to achieve different strain rates in the mechanical property tests, such as using uniaxial tension for low-speed and quasi-static tension, and using Hopkinson bars for medium- and high-speed tests. The structure and parameters of the specimen are modified to control the stress state in the effective deformation zone. Based on the test results, the standard constitutive model and failure model equations are fitted, and the equation parameters are solved to obtain the corresponding constitutive model and failure model. When the test results are difficult to fit the standard constitutive model and failure model well, the standard model can be appropriately modified. In addition to constructing constitutive and failure models for the tank material, tests should also be conducted on the weld material and bolt material, and their constitutive and failure models should be constructed. (P.S.: Even with the same material, products from different manufacturers can exhibit differences in mechanical properties, especially in plastic deformation and failure behavior. Therefore, to obtain high-precision evaluations, it is necessary to build models of the specific materials used by the transformer manufacturers. Similarly, the same applies to bolt materials. The properties of welded mechanism materials are also affected by welding processes and other factors, resulting in variability, thus requiring model building.)

[0067] Standard JC constitutive model:

[0068] ;

[0069] Standard JC Failure Model:

[0070] .

[0071] Table 1 Constitutive Model of Fuel Tank Base Material and Welds

[0072] A B n C m 25mm base material 420 858 0.627 0.04922 1.03872 40mm base material 352 646.7 0.5264 0.06 1.17989 Butt weld 429 667.3 0.5556 0.0416 0.7363 T-weld 589 547.6 0.467 0.02305 0.46367 docking thermal impact zone 454 444.1 0.3913 0.04336 0.9293 T-shaped heat-affected zone 639 671.8 0.4882 0.03338 1.2059

[0073] Table 2 Failure Models for Fuel Tank Base Material and Welds

[0074] <![CDATA[D1]]> <![CDATA[D2]]> <![CDATA[D3]]> <![CDATA[D4]]> <![CDATA[D5]]> 25mm base material 0.8152 1.99913 -3.77696 -0.05709 1.47103 40mm base material 0.84647 7.4121 -7.93835 -0.05751 0.10236 Butt weld 0.26265 2.7927 -3.03371 -0.05584 0.11399 T-weld 0.69487 2.2372 -5.7672 -0.054 7.38447 docking thermal impact zone 0.227705 0.27166 -2.9038 -0.02737 0.0674 T-shaped heat-affected zone 0.17021 1.45239 -8.11624 -0.01557 12.85015

[0075] If the standard model does not agree well with the experimental results, the model can be modified. For example, the parameter C (strain rate influence term) in the JC constitutive model can be changed from a constant value to an expression such as C = 5.94 × 10⁻⁶ + 0.019.

[0076] Step 2: Transformer Arc Fault Simulation. This simulation obtains the stress state and load of the structure to be evaluated, as well as the boundary conditions of the sub-model (Step 3). The simulation model is based on the actual transformer structure, and the material properties of each structure are the constitutive model and failure model obtained in Step 1. The established simulation model is used for transient simulation of transformer arc faults, which can simulate the dynamic development process of the arc fault pressure wave and its interaction with the transformer structure. Therefore, the simulation model needs to have strong fluid-structure interaction calculation capabilities between the insulating oil and the transformer structure, while also showing the plastic deformation and failure of the structure well. The simulation model can be modeled and calculated on the LS-Dyna platform. The simulation can provide the impact load curve on each structure to be evaluated, as well as the stress state of the structure (such as tension, compression, shear, bending, or combined states). If the material failure criterion threshold (JC failure model in Step 1) is reached, the simulation can show the failure of the transformer, thereby identifying the potentially failed structure. Furthermore, by simulating the impact effect of arc faults at different high-probability fault locations on various structures of the transformer, the maximum impact load on the structure under a given arc energy is found, and this impact load is used as the equivalent impact test load basis. Because the actual fuel tank structure is large, it is impossible to fully and accurately represent the details of the structure under test in the simulation. Therefore, the failure characteristics are relatively coarse. Therefore, it is necessary to establish a fine sub-model of the structure to be evaluated to more accurately characterize the failure (step 3).

[0077] Step 3: The sub-model features more detailed meshing and structural detail representation, while also characterizing material heterogeneity (non-uniformity of material mechanical properties). The boundary conditions of the sub-model are obtained from the overall transformer model and are consistent with the corresponding parts in the overall model. The sub-model mainly targets high-risk structures in the transformer tank such as welds and bolts. The sub-model can be modeled using a solid model and meticulously set according to various contact and constraint conditions on the actual structure.

[0078] Step 4: Structural Equivalent Impact Test. An equivalent impact test is conducted on the high-risk failure structure obtained from the simulation in Step 2. The equivalent load application in the equivalent test is based on the obtained impact pressure curve, and equivalence is performed from the perspective of energy and impulse equivalence. Corresponding impact test parameters are set, such as the hammer counterweight and height in the drop hammer impact test. Furthermore, based on the stress state of the structure under test obtained from the simulation, corresponding tooling fixtures are designed to ensure that the specimen has the same stress state in the impact test. The failure characteristic quantities of the structural specimen are then obtained and compared with the failure characteristic quantities obtained from the structural sub-model simulation in Step 3.

[0079] Step 5: Construct the structural failure surface. Based on the structural failure characteristic quantities calculated in Step 3, construct the structural failure criteria. The failure criteria can be a single factor, such as the maximum deformation; or a composite factor, such as the maximum deformation and bending angle, to construct a spatial failure surface / plane. The specific failure criteria are selected based on the actual structure. For example, for thin-walled box structures, the maximum deformation and deflection can be used as parameters; for welded structures, bending angle and relative displacement can be used; and for threaded connection structures, screw elongation and bending angle can be used. The selected criteria are dimensionless and normalized to construct failure points (failure characteristic value 1, failure characteristic value 2, ..., failure characteristic value n). All m failure points obtained from simulation and experiment can be plotted in n-dimensional space, and further, an n-dimensional failure surface can be fitted based on these m failure points. When the failure characteristic quantity of the specimen obtained in the equivalent impact test falls on the failure surface or exceeds its range, it is considered a failure. If it is within the range, the ratio of the magnitude of the characteristic quantity vector to the vector magnitude of the point projected on the failure surface is calculated to calculate the failure probability. Figure 3 As shown, taking two failure characteristic values ​​as an example, the construction and evaluation of the criterion are explained.

[0080] Step 6: By comparing the failure characteristics in the simulation with the failure characteristics obtained from the equivalent impact test, a mapping relationship of structural failure characteristic quantities is constructed, such as the relative maximum deformation in the equivalent impact test and the deformation of the corresponding structure in the simulation. Subsequent equivalent impact tests can use this mapping relationship to calculate the structural failure characteristic quantities and conduct explosion-proof capability assessments. The boundary conditions for the critical structural deformation failure in a real-world transformer tank arc fault and the structural deformation failure in the equivalent impact test cannot be completely consistent. For example, in the welded structure of the top cover and sidewalls, the boundary conditions in a real-world tank also include the deformation and displacement of the top cover and sidewalls, while the equivalent impact test cannot simulate this deformation and position, and can only use fixed constraints. Therefore, mapping of failure characteristic quantities is necessary.

[0081] Step 7: Assessment of Structural Arc Fault Tolerance. Using equivalent impact tests and the mapping relationship established in Step 6, the structural failure characteristic quantities are calculated. Comparing these with the failure surface established in Step 5, the structure's arc fault tolerance is assessed. The assessment algorithm is as follows:

[0082]

[0083] Therefore, this invention calculates the impact loads acting on different transformer structures based on a strong fluid-structure interaction algorithm of explicit dynamics; constructs failure criteria regarding strain rate and stress state; conducts mechanical property tests at different strain rates using tests with different structural sizes; and calculates the material failure surface. Based on the stress state of the transformer structure under arc faults, an impact testing fixture is designed to ensure that the test specimens reach the same stress state during the test. The time-varying arc fault impact load is equivalent to the energy and impulse equivalence method. This achieves impact tests that more closely approximate the actual arc fault load conditions.

[0084] Exemplary device

[0085] Figure 4 This is a schematic diagram of the structure of an oil-immersed power equipment key structure arc fault tolerance assessment device provided in an exemplary embodiment of the present invention. Figure 4 As shown, the device 400 includes:

[0086] Module 410 is used to perform impact load tests and simulation calculations on various structures of oil-immersed power equipment, determine the mapping relationship between the test failure characterization quantities and the simulation failure characterization quantities of each structure, and construct the structural failure surface.

[0087] Test module 420 is used to conduct equivalent impact tests on the key structures to be evaluated of oil-immersed power equipment and obtain the test failure characterization quantity of the key structures to be evaluated.

[0088] The conversion module 430 is used to convert the failure characterization quantity of the key structure according to the mapping relationship, and obtain the effective failure characterization quantity of the key structure to be evaluated.

[0089] The evaluation module 440 is used to evaluate the arc fault tolerance of the key structure based on the effective failure characterization quantity of the structural failure curve, and to determine the tolerance evaluation result of the key structure to be evaluated.

[0090] Optionally, module 410 is defined, including:

[0091] The first construction submodule is used to conduct mechanical property tests on various materials of oil-immersed power equipment and to construct constitutive models and failure models for each material.

[0092] The submodule is used to construct a transformer arc fault simulation model based on the constitutive model of each material, perform arc fault simulation, analyze the simulation results based on the failure model of each structure, and determine the failure structure of the oil-immersed power equipment, as well as the stress state and impact load of each failure structure.

[0093] The acquisition submodule is used to perform equivalent impact tests on each failed structure based on the stress state and impact load, and to acquire the test failure characterization quantities of each failed structure.

[0094] Establish a submodule to create a failure structure submodel for each failure structure based on the boundary conditions and loads of each failure structure in the transformer arc fault simulation model;

[0095] The calculation submodule is used to perform simulation calculations on each failure structure sub-model and obtain the simulation failure characterization of each failure structure.

[0096] The second construction submodule is used to construct the mapping relationship between the experimental failure characterization quantity and the simulated failure characterization quantity of each failed structure, as well as the structural failure surface, based on the experimental failure characterization quantity and the simulated failure characterization quantity of each failed structure.

[0097] Optionally, the constitutive model expression is:

[0098]

[0099] In the formula, A , B , n , C and m These are the constitutive model parameters, obtained experimentally. For equivalent plastic strain, The equivalent rate of change, For reference strain rate, , T The current temperature. T room For ambient temperature, T melt For melting point, the effect of strain rate is... C =5.94×10⁻⁶+0.019; Equivalent stress;

[0100] The failure model expression is:

[0101]

[0102] In the formula, D 1~ D 5 represents the failure model parameters. For stress triaxiality, For plastic strain, denoted as relative strain rate.

[0103] Optionally, the second construction submodule constructs the structural failure surface of each failed structure based on the experimental failure characterization and simulation failure characterization of each failed structure, including:

[0104] The construction unit is used to construct a sample dataset based on experimental failure characterization parameters and simulated failure characterization parameters, where both experimental and simulated failure characterization parameters contain n features.

[0105] The processing unit is used to perform infinite hardening and normalization on the feature values ​​in the sample dataset to obtain m failure points;

[0106] The fitting unit is used to plot m failure points in an n-dimensional space and fit them to obtain an n-dimensional structural failure surface.

[0107] Optionally, the formula for calculating the tolerance assessment result is:

[0108]

[0109] In the formula, d critical Let be the vector magnitude of the projection points of the effective failure characterization quantity of the key structure to be evaluated onto the constructed structural failure surface. d This represents the vector magnitude in the failure space of the effective failure characterization quantity of the key structure to be evaluated.

[0110] Exemplary electronic devices

[0111] Figure 5 This is the structure of an electronic device provided in an exemplary embodiment of the present invention. For example... Figure 5 As shown, the electronic device 50 includes one or more processors 51 and memory 52.

[0112] The processor 51 may be a central processing unit (CPU) or other form of processing unit with data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0113] The memory 52 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 51 may execute the program instructions to implement the methods of the software programs of the various embodiments of the present invention described above, and / or other desired functions. In one example, the electronic device may also include an input device 53 and an output device 54, these components being interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0114] In addition, the input device 53 may also include, for example, a keyboard, a mouse, etc.

[0115] The output device 54 can output various information to the outside. The output device 54 may include, for example, a display, a speaker, a printer, and a communication network and its connected remote output devices, etc.

[0116] Of course, for the sake of simplicity, Figure 5 Only some of the components of this electronic device relevant to the present invention are shown, omitting components such as buses, input / output interfaces, etc. In addition, the electronic device may include any other suitable components depending on the specific application.

[0117] Exemplary computer program products and computer-readable storage media

[0118] In addition to the methods and apparatus described above, embodiments of the present invention may also be computer program products, which include computer program instructions that, when executed by a processor, cause the processor to perform the steps in the methods according to various embodiments of the present invention described in the "Exemplary Methods" section above.

[0119] The computer program product can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of the present invention. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0120] Furthermore, embodiments of the present invention may also be computer-readable storage media storing computer program instructions thereon, which, when executed by a processor, cause the processor to perform the steps of the methods according to various embodiments of the present invention described in the "Exemplary Methods" section above.

[0121] The computer-readable storage medium may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, system, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0122] The basic principles of the present invention have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in the present invention are merely examples and not limitations, and should not be considered as essential features of each embodiment of the present invention. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the present invention to the necessity of employing the aforementioned specific details.

[0123] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For system embodiments, since they largely correspond to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0124] The block diagrams of devices, systems, devices, and systems involved in this invention are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, systems, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0125] The methods and systems of the present invention may be implemented in many ways. For example, they may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of the present invention are not limited to the order specifically described above unless otherwise specifically stated. Furthermore, in some embodiments, the present invention may also be implemented as a program recorded on a recording medium, the program comprising machine-readable instructions for implementing the methods according to the present invention. Thus, the present invention also covers recording media storing programs for performing the methods according to the present invention.

[0126] It should also be noted that in the systems, apparatus, and methods of the present invention, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered equivalents of the present invention. The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the invention. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the invention. Therefore, the invention is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0127] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the invention to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for evaluating the arc fault tolerance capability of key structures in oil-immersed power equipment, characterized in that, include: Impact load tests and simulation calculations were performed on various structures of oil-immersed power equipment to determine the mapping relationship between the test failure characterization quantities and the simulation failure characterization quantities of each structure and to construct the structural failure surface. An equivalent impact test was conducted on the key structure to be evaluated of the oil-immersed power equipment to obtain the key structural test failure characterization quantity of the key structure to be evaluated. The failure characterization quantity of the key structure is transformed according to the mapping relationship to obtain the effective failure characterization quantity of the key structure to be evaluated. Based on the structural failure curve, the arc fault tolerance capability of the key structure is evaluated, and the tolerance capability evaluation result of the key structure to be evaluated is determined. Impact load tests and simulation calculations were conducted on various structures of the oil-immersed power equipment to determine the mapping relationship between the test failure characterization quantities and the simulation failure characterization quantities of each structure, and to construct the structural failure surface, including: Mechanical property tests were conducted on various materials of oil-immersed power equipment, and constitutive models and failure models of each material were constructed. A transformer arc fault simulation model was constructed based on the constitutive models of each material, and arc fault simulation was performed. The simulation results were analyzed based on the failure models of each structure to determine the failure structures of the oil-immersed power equipment, as well as the stress state and impact load of each failure structure. Based on the stress state and the impact load, equivalent impact tests are conducted on each failed structure to obtain the test failure characterization quantities of each failed structure. Based on the boundary conditions and loads of each failure structure in the transformer arc fault simulation model, establish a failure structure sub-model for each failure structure. Simulation calculations are performed on each failure structure sub-model to obtain the simulation failure characterization quantities of each failure structure; Based on the experimental failure characterization quantities and the simulated failure characterization quantities of each failed structure, the mapping relationship between the experimental failure characterization quantities and the simulated failure characterization quantities of each failed structure, as well as the structural failure surface, are constructed. Based on the experimental failure characterization parameters and the simulated failure characterization parameters of each failed structure, the structural failure surface of each failed structure is constructed, including: A sample dataset is constructed based on the experimental failure characterization and the simulated failure characterization, wherein both the experimental failure characterization and the simulated failure characterization contain n features. The feature values ​​in the sample dataset are subjected to infinite hardening and normalization to obtain m failure points; The m failure points are plotted on an n-dimensional space and fitted to obtain an n-dimensional failure surface of the structure. The formula for calculating the tolerance assessment result is as follows: In the formula, d critical Let d be the vector magnitude of the projection point of the effective failure characterization quantity of the key structure to be evaluated onto the constructed structural failure surface, and let d be the vector magnitude of the effective failure characterization quantity of the key structure to be evaluated in the failure space. The constitutive model expression is: In the formula, A, B, n, C, and m are constitutive model parameters obtained experimentally. For equivalent plastic strain, The equivalent rate of change, For reference strain rate, T is the current temperature. room For ambient temperature, T melt The melting point is given by the strain rate effect term C = 5.94 × 10⁻⁶ ε. * +0.019; σ eq Equivalent stress; The failure model expression is: In the formula, D1~D5 are failure model parameters, σ * For stress triaxiality, ε f For plastic strain, denoted as relative strain rate.

2. A device for evaluating the arc fault tolerance capability of key structures in oil-immersed power equipment, characterized in that, include: The module is used to perform impact load tests and simulation calculations on various structures of oil-immersed power equipment, determine the mapping relationship between the test failure characterization quantities and the simulation failure characterization quantities of each structure, and construct the structural failure surface. The test module is used to conduct equivalent impact tests on the key structures of the oil-immersed power equipment to be evaluated, and to obtain the key structural test failure characterization quantity of the key structures to be evaluated. The conversion module is used to convert the failure characterization quantity of the key structure according to the mapping relationship, and obtain the effective failure characterization quantity of the key structure to be evaluated. The evaluation module is used to evaluate the arc fault tolerance of the key structure based on the effective failure characterization quantity of the structure failure surface, and to determine the tolerance evaluation result of the key structure to be evaluated. The module to be determined includes: The first construction submodule is used to conduct mechanical property tests on various materials of oil-immersed power equipment and to construct constitutive models and failure models for each material. The submodule is used to construct a transformer arc fault simulation model based on the constitutive model of each material, perform arc fault simulation, analyze the simulation results based on the failure model of each structure, and determine the failure structure of the oil-immersed power equipment, as well as the stress state and impact load of each failure structure. The acquisition submodule is used to perform equivalent impact tests on each failed structure according to the stress state and the impact load, and to acquire the test failure characterization quantity of each failed structure. A submodule is established to create a failure structure submodel for each failure structure based on the boundary conditions and loads of each failure structure in the transformer arc fault simulation model. The calculation submodule is used to perform simulation calculations on each failure structure sub-model and obtain the simulation failure characterization of each failure structure. The second construction submodule is used to construct the mapping relationship between the experimental failure characterization quantity and the simulated failure characterization quantity of each failure structure, as well as the structural failure surface, based on the experimental failure characterization quantity and the simulated failure characterization quantity of each failure structure. The second construction submodule constructs the structural failure surface of each failed structure based on the experimental failure characterization quantity and the simulated failure characterization quantity, including: A construction unit is used to construct a sample dataset based on the experimental failure characterization quantity and the simulated failure characterization quantity, wherein both the experimental failure characterization quantity and the simulated failure characterization quantity contain n feature quantities; The processing unit is used to perform infinite hardening and normalization processing on the feature values ​​in the sample dataset to obtain m failure points; The fitting unit is used to plot m failure points in an n-dimensional space and fit them to obtain an n-dimensional failure surface of the structure. The formula for calculating the tolerance assessment result is as follows: In the formula, d critical Let d be the vector magnitude of the projection point of the effective failure characterization quantity of the key structure to be evaluated onto the constructed structural failure surface, and let d be the vector magnitude of the effective failure characterization quantity of the key structure to be evaluated in the failure space. The constitutive model expression is: In the formula, A, B, n, C, and m are constitutive model parameters obtained experimentally. For equivalent plastic strain, The equivalent rate of change, For reference strain rate, T is the current temperature. room For ambient temperature, T melt The melting point is given by the strain rate effect term C = 5.94 × 10⁻⁶ ε. * +0.019; σ eq Equivalent stress; The failure model expression is: In the formula, D1~D5 are failure model parameters, σ * For stress triaxiality, ε f For plastic strain, denoted as relative strain rate.

3. A computer-readable storage medium, characterized in that, The storage medium stores a computer program for executing the method described in claim 1.

4. An electronic device, characterized in that, The electronic device includes: processor; Memory used to store the processor's executable instructions; The processor is configured to read the executable instructions from the memory and execute the instructions to implement the method of claim 1.

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