A dynamic checking and evaluating method and device for short-circuit resistance of a transformer

Abstract

The application discloses a transformer anti-short-circuit capability dynamic checking and evaluating method and device. The method comprises the following steps: real-time calculation of dynamic winding impedance and winding dynamic axial pre-tightening force of a coil structure according to coil structure parameters of a transformer; calculation of inter-pie short-circuit stress based on axial vibration displacement of pie short-circuit of the coil structure; determination of the anti-short-circuit capability of the transformer based on the dynamic winding impedance, the winding dynamic axial pre-tightening force, the inter-pie short-circuit stress and a preset anti-short-circuit capability dynamic criterion.

Description

Technical Field

[0001] This invention relates to the field of electrical engineering technology, and more specifically, to a method and apparatus for dynamic verification and evaluation of transformer short-circuit withstand capability. Background Technology

[0002] Power transformers are core equipment in power grids, and their insufficient short-circuit withstand capability is the primary cause of transformer failures. When a transformer experiences a short circuit, the windings experience a short-circuit current tens of times its rated value, causing a sharp increase in internal leakage flux. This generates enormous electrodynamic forces acting on the coils and other structures. Instability in this process can lead to a series of changes, including insulation material damage and altered insulation distances, resulting in internal discharge and unplanned transformer outages. This threatens the reliability of the power supply system and, in severe cases, can cause serious malfunctions such as equipment explosions and fires, potentially even directly impacting other equipment within the substation and endangering personnel safety. Therefore, a rapid and accurate method for dynamically assessing the short-circuit withstand capability of power transformers is urgently needed. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a method and apparatus for dynamic verification and evaluation of transformer short-circuit withstand capability.

[0004] According to one aspect of the present invention, a method for dynamic verification and evaluation of the short-circuit withstand capability of a transformer is provided, comprising:

[0005] The dynamic winding impedance and dynamic axial preload of the winding structure are calculated in real time based on the transformer's coil structure parameters.

[0006] Calculation of short-circuit stress between coil discs based on axial vibration displacement during short-circuit short-circuit of coil discs;

[0007] The transformer's short-circuit withstand capability is determined based on dynamic winding impedance, dynamic axial preload of the winding, short-circuit stress between the winding discs, and a preset dynamic criterion for short-circuit withstand capability.

[0008] Optionally, the expression for calculating the dynamic winding impedance is:

[0009]

[0010] In the formula, μ 0 is the permeability of free space. N The number of coil turns. S coil The cross-sectional area of ​​the coil is... L This represents the length of the winding wire.

[0011] Optionally, the dynamic axial preload of the coil structure is calculated in real time based on the transformer coil structure parameters, including:

[0012] The cumulative coefficient of dynamic stability peak value of the transformer is obtained based on the number of historical short-circuit impacts and the number of short-circuit impacts.

[0013] The dynamic axial preload of the winding is calculated based on the force accumulation coefficient and the transformer coil structural parameters.

[0014] Optionally, the calculation expression for the dynamic axial preload of the winding is:

[0015]

[0016] In the formula, F 0 represents the initial preload of the coil winding. H n for n Coil geometry height after the second short-circuit impact H s After the coil has experienced multiple short-circuit faults, E n The elastic modulus of the coil, δ n for n The magnitude of the short-circuit force of the secondary short-circuit impact k f This is the force accumulation coefficient.

[0017] Optionally, the calculation of the short-circuit stress between the coil discs based on the axial vibration displacement during short-circuit operation of the coil structure includes:

[0018] The heat accumulation coefficient is obtained based on the transformer's service life and average operating temperature;

[0019] The cumulative coefficient of dynamic stability peak value of the transformer is obtained based on the number of historical short-circuit impacts and the number of short-circuit impacts.

[0020] The mechanical property parameters of the material are obtained based on the thermal accumulation coefficient and the force accumulation coefficient.

[0021] Short-circuit current is obtained based on transformer short-circuit parameters or short-circuit current waveform recording;

[0022] Based on the short-circuit current and the electromagnetic spatial distribution of the transformer windings under short-circuit conditions, the short-circuit electromagnetic force is calculated.

[0023] Based on the simplified mass-spring-damping model of the winding, the short-circuit electromagnetic force, and the mechanical property parameters of the material, the spatial vibration displacement of the coil is calculated to obtain the short-circuit axial vibration displacement of the coil.

[0024] Calculate the short-circuit stress between discs based on the axial vibration displacement of the discs during short circuit.

[0025] Optionally, based on the short-circuit current and the electromagnetic spatial distribution of the transformer windings under short-circuit conditions, the short-circuit electromagnetic force is calculated, including:

[0026] Calculate the current density of the coil unit based on the short-circuit current;

[0027] The electromagnetic spatial distribution of the transformer winding under short-circuit conditions is calculated based on the winding design parameters and core design parameters constructed using a winding short-circuit electromagnetic simulation model.

[0028] The short-circuit electromagnetic force is calculated based on the current density of the coil unit and the electromagnetic spatial distribution.

[0029] Optionally, the calculation expression for the axial vibration displacement of the wire disc during short circuit is:

[0030]

[0031] In the formula, z n For the first n Axial vibration displacement of the disc under short circuit; z n+1 For the first n+ Axial vibration displacement of disc 1 during short circuit; m For the quality of the thread cake; K The elastic modulus of the inter-panel insulation material; f ( t ) represents the short-circuit electromagnetic force at time t; g represents the gravitational acceleration; c represents the inter-disc damping coefficient;

[0032] The formula for calculating the short-circuit stress between discs is:

[0033]

[0034] In the formula, h n0 For the first n cake and the n+ The initial height between the two discs, E The Young's modulus of the inter-panel insulation material. σ n For the first n cake and n+1 Short-circuit stress between the cakes.

[0035] Optionally, the transformer's short-circuit withstand capability is determined based on dynamic winding impedance, dynamic axial preload of the winding, inter-disc short-circuit stress, and a preset dynamic criterion for short-circuit withstand capability, including:

[0036] The winding impedance change is determined based on the dynamic winding impedance and the initial winding impedance.

[0037] The axial preload loss of the winding is determined based on the dynamic axial preload of the winding and the initial axial preload of the winding.

[0038] If the winding impedance change meets the first criterion, or the winding axial preload loss meets the second criterion, or the inter-disc short-circuit stress meets the third criterion, the transformer winding is deemed to have a short-circuit failure risk.

[0039] Optionally, the first criterion is that the change in winding impedance reaches a first threshold; the second criterion is that the loss of axial preload in the winding reaches a second threshold; and the third criterion is that the short-circuit stress between the discs is greater than the allowable value of dynamic stress of the insulation material.

[0040] According to another aspect of the present invention, a dynamic verification and evaluation device for the short-circuit withstand capability of a transformer is provided, comprising:

[0041] The first calculation module is used to calculate the dynamic winding impedance and dynamic axial preload of the winding structure in real time based on the transformer's coil structure parameters.

[0042] The second calculation module is used to calculate the short-circuit stress between coil discs based on the axial vibration displacement of the coil discs during short circuits.

[0043] The determination module is used to determine the transformer's short-circuit withstand capability based on dynamic winding impedance, dynamic axial preload of the winding, short-circuit stress between the winding discs, and preset dynamic criteria for short-circuit withstand capability.

[0044] 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.

[0045] 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.

[0046] Therefore, this invention proposes a mathematical model and mechanical parameter variation law for quantifying the cumulative effect of materials, which is applied to dynamic calculation to improve the accuracy and simulation of transformer short-circuit dynamic calculation, and the calculation is more consistent with the actual situation of external short-circuit faults in transformers. At the same time, it proposes a number of dynamic failure criteria for transformer short circuits, forming a complete dynamic evaluation method system that takes into account the cumulative effect, which has higher practicality and flexibility. Attached Figure Description

[0047] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0048] Figure 1 This is a flowchart illustrating the dynamic verification and evaluation method for transformer short-circuit withstand capability provided in an exemplary embodiment of the present invention.

[0049] Figure 2 This is a schematic diagram of the structure of a transformer short-circuit withstand capability dynamic verification and evaluation device provided in an exemplary embodiment of the present invention;

[0050] Figure 3 This is the structure of an electronic device provided in an exemplary embodiment of the present invention. Detailed Implementation

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] Exemplary methods

[0065] Figure 1 This is a schematic flowchart of a dynamic verification and evaluation method for transformer short-circuit withstand capability provided in an exemplary embodiment of the present invention. This embodiment can be applied to electronic devices, such as... Figure 1 As shown, the dynamic verification and evaluation method 100 for transformer short-circuit withstand capability includes the following steps:

[0066] Step 101: Calculate the dynamic winding impedance and dynamic axial preload of the winding structure in real time based on the transformer's coil structure parameters.

[0067] Step 102: Calculate the short-circuit stress between coil discs based on the axial vibration displacement of the coil discs during short circuit;

[0068] Step 103: Determine the transformer's short-circuit withstand capability based on dynamic winding impedance, dynamic axial preload of the winding, short-circuit stress between the winding discs, and a preset dynamic criterion for short-circuit withstand capability.

[0069] Specifically, this invention, based on coil materials and simulated dynamic short-circuit impact tests, proposes a mathematical model for quantifying the cumulative effect of materials and the variation law of mechanical parameters, which is applied to dynamic calculations. Simultaneously, it proposes multiple dynamic failure criteria for transformers under short-circuit conditions, forming a complete dynamic evaluation method system that considers cumulative effects. This addresses the problem of how to quickly and accurately determine the short-circuit withstand capability of power transformers. The specific implementation process is as follows:

[0070] I. Obtain the design parameters, service life, and historical short-circuit conditions of the power transformer equipment, specifically including the equipment's electrical parameters and short-circuit impact factor. S Rated voltage U Transformer short-circuit impedance and system short-circuit impedance Z t and Z s Winding design parameters, core design parameters, service life y Average annual operating temperature T Historical short circuit count n and the stable peak value of each short circuit impact F And so on, and process the collected parameters to obtain a model for short-circuit dynamic calculation.

[0071] II. Quantitative measurement of the cumulative state and mechanical parameters of key materials. This includes the following steps:

[0072] (1): Determining the thermal accumulation coefficient based on key information parameters from the data acquisition module k t ( y , T ) and force accumulation factor k f ( n , F As shown in equations (1) and (2), where y For the number of years of operation, T The average annual operating temperature, n This refers to the number of short-circuit impacts in history. F This represents the peak value of dynamic stability during each short-circuit impact.

[0073] (1)

[0074] (2)

[0075] (2) Calculate the axial preload of the winding based on the cumulative coefficient. fP ( k f Peak short-circuit current I s ( k f and key mechanical performance parameters K ( k t , k f ),in f P For the dynamic axial preload of the winding, I s This is the calculated peak value of the short-circuit current. K These are the mechanical property parameters of the material, all of which are determined by the cumulative coefficient. They are adjusted according to the degree of cumulative effect of individual products to form a differentiated calculation method, and output the calculation results of the coil displacement, inter-coil stress and structural short-circuit stress under short-circuit impact; the calculation of the dynamic axial preload of the winding is shown in equation (3), where F 0 represents the initial preload of the coil winding. H n for n Coil geometry height after the second short-circuit impact H s The height of the equivalent elastic structure of the coil in the direction parallel to the pressure plate after experiencing multiple short-circuit faults. E n The elastic modulus of the coil, δ n for n The magnitude of the short-circuit force of the secondary short-circuit impact; the calculation of the short-circuit current is shown in equation (4), where S This is the short-circuit impact factor. U Rated voltage, Z t and Z s These are the transformer short-circuit impedance and the system short-circuit impedance, respectively. The calculation of the elastic coefficient is related to the thermal accumulation coefficient and the force accumulation coefficient. The corresponding Young's modulus fitting curve of the material is selected according to the corresponding accumulation coefficient for calculation.

[0076] (3)

[0077] (4)

[0078] III. Calculation of Short-Circuit Electromagnetic Force Based on Collected Equipment Electrical Parameters f As shown in equations (5)-(9), where i s This is the short-circuit current. t For time, ω Angular frequency, Φ It is the impedance angle. α The initial phase angle of the short-circuit voltage. τ The decay time constant, J seg The current density of the coil unit. N seg This refers to the actual number of turns in the coil unit. S seg The area of ​​the coil unit. A For magnetic vector potential, μ Permeability, J The current density is [value] in the coil region. J seg In other regions, it is 0. B It represents the magnetic flux density. r The average radial radius of the coil.

[0079] Based on the collected winding design parameters and core design parameters, a short-circuit electromagnetic simulation model of the winding is constructed to calculate the electromagnetic spatial distribution of the transformer winding under short-circuit conditions (Equations 7 and 8). The spatial vibration displacement of the coil is calculated based on the simplified mass-spring-damping model of the winding, and then the short-circuit stress between the coils is calculated based on the spatial vibration displacement. The calculation process considers the actual short-circuit current waveform and the dynamic deformation-electromagnetic coupling process of the coils. The calculation process is shown in Equations (10) and (11), where... m For the quality of the thread cake, z n For the first n The disc-shaped spatial vibration displacement h n0 For the first n cake and the n+1 The initial height between the pie discs, E The Young's modulus of the inter-panel insulation material. σ n For the first n cake and n+1 The short-circuit stress between the discs is given by g, where g is the acceleration due to gravity, and c is the damping coefficient between the discs, which is usually taken as an empirical value of 0.02-0.04.

[0080] (5)

[0081] (6)

[0082] (7)

[0083] (8)

[0084] (9)

[0085] (10)

[0086] (11)

[0087] IV. Evaluating the short-circuit force withstand capability of the coil structure includes the following steps.

[0088] (1) The dynamic Z-method for calculating winding impedance is related to the warping deformation, axial bending deformation, and radial bending deformation of the winding wire, as shown in equation (12). μ 0 is the permeability of free space. N The number of coil turns. S coil The cross-sectional area of ​​the coil is... L This refers to the winding length;

[0089] (12)

[0090] (2) When the change in the macroscopic impedance of the coil winding reaches 1%, the short-circuit withstand capability is warned, and when it reaches 2%, the short-circuit withstand capability is considered to be ineffective;

[0091] (3) Axial preload of winding f P The calculation method is related to the cumulative plastic deformation of the insulating pad and the insulating paper, forming a model for the loss and redistribution of the preload, as shown in Equation (3);

[0092] (4) When the axial preload of the winding is lost by 15%, the short-circuit withstand capability is warned; when the axial preload of the winding is lost by 25%, the short-circuit withstand capability is considered to be ineffective.

[0093] (5) Calculate the short-circuit stress between coils based on the axial displacement of the coils. When the stress between coils is greater than the allowable value of the dynamic stress of the insulation material, it is determined that the winding stability has failed.

[0094] (6) The above criteria are OR relationships, that is, when a certain failure exists, the transformer windings as a whole are judged to have a large risk of short circuit failure.

[0095] Therefore, this invention proposes a mathematical model and mechanical parameter variation law for quantifying the cumulative effect of materials, which is applied to dynamic calculations to improve the accuracy and simulation of transformer short-circuit dynamic calculations, making the calculations more consistent with the actual external short-circuit faults of transformers. Simultaneously, it proposes multiple dynamic failure criteria for transformer short circuits, forming a complete dynamic evaluation method system that considers cumulative effects, possessing higher practicality and flexibility. This invention guides transformer manufacturers in improving the short-circuit withstand capability of transformers, promoting improvements in transformer manufacturing quality and operational reliability.

[0096] Exemplary device

[0097] Figure 2This is a schematic diagram of the structure of a transformer short-circuit withstand capability dynamic verification and evaluation device provided in an exemplary embodiment of the present invention. Figure 2 As shown, the device 200 includes:

[0098] The first calculation module 210 is used to calculate the dynamic winding impedance and dynamic axial preload of the winding structure in real time based on the coil structure parameters of the transformer.

[0099] The second calculation module 220 is used to calculate the short-circuit stress between the coil discs based on the short-circuit axial vibration displacement of the coil discs in the coil structure.

[0100] The determination module 230 is used to determine the short-circuit withstand capability of the transformer based on the dynamic winding impedance, the dynamic axial preload of the winding, the short-circuit stress between the discs, and a preset dynamic criterion for short-circuit withstand capability.

[0101] Exemplary electronic devices

[0102] Figure 3 This is the structure of an electronic device provided in an exemplary embodiment of the present invention. For example... Figure 3 As shown, the electronic device 30 includes one or more processors 31 and memory 32.

[0103] The processor 31 may be a central processing unit (CPU) or other form of processing unit with data processing and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0104] The memory 32 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 31 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 33 and an output device 34, these components being interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0105] In addition, the input device 33 may also include, for example, a keyboard, a mouse, etc.

[0106] The output device 34 can output various information to the outside. The output device 34 may include, for example, a display, a speaker, a printer, and a communication network and its connected remote output devices, etc.

[0107] Of course, for the sake of simplicity, Figure 3 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.

[0108] Exemplary computer program products and computer-readable storage media

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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 dynamic verification and evaluation of a transformer's short-circuit withstand capability, characterized in that, include: The dynamic winding impedance and dynamic axial preload of the winding structure are calculated in real time based on the transformer's coil structure parameters. Calculate the short-circuit stress between coil discs based on the axial vibration displacement of the coil discs in the above coil structure. The short-circuit withstand capability of the transformer is determined based on the dynamic winding impedance, the dynamic axial preload of the winding, the short-circuit stress between the discs, and the preset dynamic criteria for short-circuit withstand capability. The calculation of the short-circuit stress between the coil discs based on the axial vibration displacement of the coil discs during short circuit includes: The heat accumulation coefficient is obtained based on the transformer's service life and average operating temperature; The cumulative coefficient of dynamic stability peak value of the transformer is obtained based on the number of historical short-circuit impacts and the number of short-circuit impacts. The material mechanical property parameters are obtained based on the thermal accumulation coefficient and the force accumulation coefficient. The short-circuit current is obtained based on the short-circuit parameters or short-circuit current waveform of the transformer. Based on the short-circuit current and the electromagnetic spatial distribution of the transformer windings under short-circuit conditions, the short-circuit electromagnetic force is calculated. Based on the simplified mass-spring-damping model of the winding, the short-circuit electromagnetic force, and the mechanical property parameters of the material, the spatial vibration displacement of the coil is calculated to obtain the short-circuit axial vibration displacement of the coil. The short-circuit stress between the discs is calculated based on the axial vibration displacement of the discs during short circuit. The calculation expression for the inter-disc short-circuit stress is as follows: In the formula, z n For the first n Axial vibration displacement of the disc under short circuit; z n+1 For the first n+ Axial vibration displacement of disc 1 during short circuit; h n0 For the first n cake and the n+ The initial height between the two discs, E The Young's modulus of the inter-panel insulation material. σ n For the first n cake and n+1 Short-circuit stress between the cakes.

2. The method according to claim 1, characterized in that, The formula for calculating the dynamic winding impedance is as follows: In the formula, μ 0 is the permeability of free space. N The number of coil turns. S coil The cross-sectional area of ​​the coil is... L This represents the length of the winding wire.

3. The method according to claim 1, characterized in that, The dynamic axial preload of the coil structure is calculated in real time based on the transformer coil structure parameters, including: The cumulative coefficient of dynamic stability peak value of the transformer is obtained based on the number of historical short-circuit impacts and the number of short-circuit impacts. The dynamic axial preload of the winding is calculated based on the force accumulation coefficient and the transformer coil structural parameters.

4. The method according to claim 3, characterized in that, The calculation expression for the dynamic axial preload of the winding is: In the formula, F 0 represents the initial preload of the coil winding. H n for n Coil geometry height after the second short-circuit impact H s After the coil has experienced multiple short-circuit faults, E n The elastic modulus of the coil, δ n for n The magnitude of the short-circuit force of the secondary short-circuit impact k f This is the force accumulation coefficient.

5. The method according to claim 1, characterized in that, Based on the short-circuit current and the electromagnetic spatial distribution of the transformer windings under short-circuit conditions, the short-circuit electromagnetic force is calculated, including: Calculate the coil unit current density based on the short-circuit current; The electromagnetic spatial distribution of the transformer winding under short-circuit conditions is calculated based on the winding design parameters and core design parameters constructed using a winding short-circuit electromagnetic simulation model. The short-circuit electromagnetic force is calculated based on the current density of the coil unit and the electromagnetic spatial distribution.

6. The method according to claim 1, characterized in that, The calculation expression for the axial vibration displacement of the short-circuit coil is as follows: In the formula, m For the quality of the thread cake; K The elastic modulus of the inter-panel insulation material; f ( t ) represents the short-circuit electromagnetic force at time t; g represents the gravitational acceleration; and c represents the inter-disc damping coefficient.

7. The method according to claim 1, characterized in that, The short-circuit withstand capability of the transformer is determined based on the dynamic winding impedance, the dynamic axial preload of the winding, the short-circuit stress between the winding discs, and a preset dynamic criterion for short-circuit withstand capability, including: The winding impedance change is determined based on the dynamic winding impedance and the initial winding impedance. The winding axial preload loss is determined based on the dynamic axial preload of the winding and the initial axial preload of the winding. The judgment results are obtained by determining whether the change in winding impedance satisfies the first criterion, whether the axial preload loss of winding satisfies the second criterion, and whether the short-circuit stress between discs satisfies the third criterion. Based on the judgment result, it is determined that the windings of the transformer are at risk of short-circuit failure.

8. The method according to claim 7, characterized in that, The first criterion is that the change in winding impedance reaches a first threshold; the second criterion is that the loss of axial preload in the winding reaches a second threshold; and the third criterion is that the short-circuit stress between the discs is greater than the allowable value of dynamic stress of the insulating material.

9. A dynamic verification and evaluation device for the short-circuit withstand capability of a transformer, characterized in that, include: The first calculation module is used to calculate the dynamic winding impedance and dynamic axial preload of the winding structure in real time based on the coil structure parameters of the transformer. The second calculation module is used to calculate the short-circuit stress between the coil discs based on the short-circuit axial vibration displacement of the coil discs in the coil structure. The determination module is used to determine the short-circuit withstand capability of the transformer based on the dynamic winding impedance, the dynamic axial preload of the winding, the short-circuit stress between the discs, and a preset dynamic criterion for short-circuit withstand capability. The second calculation module includes: The heat accumulation coefficient is obtained based on the transformer's service life and average operating temperature; The cumulative coefficient of dynamic stability peak value of the transformer is obtained based on the number of historical short-circuit impacts and the number of short-circuit impacts. The material mechanical property parameters are obtained based on the thermal accumulation coefficient and the force accumulation coefficient. The short-circuit current is obtained based on the short-circuit parameters or short-circuit current waveform of the transformer. Based on the short-circuit current and the electromagnetic spatial distribution of the transformer windings under short-circuit conditions, the short-circuit electromagnetic force is calculated. Based on the simplified mass-spring-damping model of the winding, the short-circuit electromagnetic force, and the mechanical property parameters of the material, the spatial vibration displacement of the coil is calculated to obtain the short-circuit axial vibration displacement of the coil. The short-circuit stress between the discs is calculated based on the axial vibration displacement of the discs during short circuit. The calculation expression for the inter-disc short-circuit stress is as follows: In the formula, z n For the first n Axial vibration displacement of the disc under short circuit; z n+1 For the first n+ Axial vibration displacement of disc 1 during short circuit; h n0 For the first n cake and the n+ The initial height between the two discs, E The Young's modulus of the inter-panel insulation material. σ n For the first n cake and n+1 Short-circuit stress between the cakes.

10. The apparatus according to claim 9, characterized in that, The formula for calculating the dynamic winding impedance is as follows: In the formula, μ 0 is the permeability of free space. N The number of coil turns. S coil The cross-sectional area of ​​the coil is... L This represents the length of the winding wire.

11. The apparatus according to claim 9, characterized in that, The first calculation module calculates the dynamic axial preload of the coil winding in real time based on the transformer coil structure parameters, including: The cumulative coefficient of dynamic stability peak value of the transformer is obtained based on the number of historical short-circuit impacts and the number of short-circuit impacts. The dynamic axial preload of the winding is calculated based on the force accumulation coefficient and the transformer coil structural parameters.

12. The apparatus according to claim 11, characterized in that, The calculation expression for the dynamic axial preload of the winding is: In the formula, F 0 represents the initial preload of the coil winding. H n for n Coil geometry height after the second short-circuit impact H s After the coil has experienced multiple short-circuit faults, E n The elastic modulus of the coil, δ n for n The magnitude of the short-circuit force of the secondary short-circuit impact k f This is the force accumulation coefficient.

13. The apparatus according to claim 9, characterized in that, Based on the short-circuit current and the electromagnetic spatial distribution of the transformer windings under short-circuit conditions, the short-circuit electromagnetic force is calculated, including: Calculate the coil unit current density based on the short-circuit current; The electromagnetic spatial distribution of the transformer winding under short-circuit conditions is calculated based on the winding design parameters and core design parameters constructed using a winding short-circuit electromagnetic simulation model. The short-circuit electromagnetic force is calculated based on the current density of the coil unit and the electromagnetic spatial distribution.

14. The apparatus according to claim 9, characterized in that, The calculation expression for the axial vibration displacement of the short-circuit coil is as follows: In the formula, m For the quality of the thread cake; K The elastic modulus of the inter-panel insulation material; f ( t ) represents the short-circuit electromagnetic force at time t; g represents the gravitational acceleration; and c represents the inter-disc damping coefficient.

15. The apparatus according to claim 9, characterized in that, The module to be determined includes: The winding impedance change is determined based on the dynamic winding impedance and the initial winding impedance. The winding axial preload loss is determined based on the dynamic axial preload of the winding and the initial axial preload of the winding. The judgment results are obtained by determining whether the change in winding impedance satisfies the first criterion, whether the axial preload loss of winding satisfies the second criterion, and whether the short-circuit stress between discs satisfies the third criterion. Based on the judgment result, it is determined that the windings of the transformer are at risk of short-circuit failure.

16. The apparatus according to claim 15, characterized in that, The first criterion is that the change in winding impedance reaches a first threshold; the second criterion is that the loss of axial preload in the winding reaches a second threshold; and the third criterion is that the short-circuit stress between the discs is greater than the allowable value of dynamic stress of the insulating material.

17. A computer-readable storage medium, characterized in that, The storage medium stores a computer program for performing the method described in any one of claims 1-8.

18. 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 described in any one of claims 1-8.

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