Method and System for Obtaining Critical Stress Test Results for Radial Stability of Power Transformer Windings

Abstract

This invention discloses a method and system for obtaining the critical stress test results for the radial stability of power transformer windings, comprising: designing the winding to be studied and its matching winding pair, and constructing the transformer body structure based on the winding pair; calculating the critical test current of the winding pair of the power transformer; based on the critical test current, using a short-circuit test method to obtain the applied load when the power transformer undergoes radial deformation or radial instability, and analyzing the state of the winding pair after impact; disassembling the power transformer and measuring the radial deformation of the winding pair of the power transformer; based on the radial deformation, establishing a relationship curve between the simulated stress distribution and the measured deformation to obtain the critical point of the radial stability critical stress of the power transformer windings; and extracting the stress value and critical withstand current of the radial stability critical stress of the power transformer windings based on the critical point and the relationship curve. This invention solves the problem of accurately confirming the radial stability critical stress in transformer short-circuit impact resistance technology.

Description

Technical Field

[0001] This invention relates to the field of short-circuit withstand capability technology for power transformers, specifically to a method and system for obtaining critical stress test results for radial stability of power transformer windings. Background Technology

[0002] Short-circuit impacts at the power transformer outlet can cause stress failure of the winding coils, damaging the windings and the transformer itself. Radial stability failure is a common and typical form of damage. On one hand, the radial stability of the winding is affected by factors such as conductor type, conductor size, and coil diameter; on the other hand, the internal support conditions and axial clamping force manufactured also affect its radial stability. Due to the aforementioned calculation deviations and manufacturing differences, the critical stress conditions for the radial stability of the winding are difficult to obtain accurately. Values ​​obtained through simulation calculations can guide design verification and operational reliability assessment, but their accuracy is poor. Since short-circuit tests are mostly designed to pass the test and retain sufficient margin, they cannot guide this research.

[0003] Determining the critical value of radial stress on the winding is a bottleneck limiting structural and performance optimization in this field. The industry lacks effective methods for tracking and researching this issue, ultimately leading to difficulties in accurately understanding the state of transformers after short-circuit impacts. Summary of the Invention

[0004] The technical problem this invention aims to solve is the difficulty in accurately determining the radial stability (i.e., the critical stress stability boundary under radial stress) in transformer short-circuit impact resistance technology. The purpose is to provide a method and system for obtaining the critical stress test results for the radial stability of power transformer windings. This primarily addresses the difficulty in knowing the stability of the inner winding under radial stress during a transformer short-circuit impact, resulting in an unclear transformer state. Based on existing research methods, this invention accurately obtains the stress characteristics of the winding under short-circuit conditions through experimental methods. This invention achieves full-process control of the winding's design and testing by using feedback data from full-scale tests and simulation modeling analysis to determine the stress value and critical withstand current value of the critical stress the winding can withstand.

[0005] The research method of this invention takes an actual transformer as the research object and belongs to experimental research. It is applicable to the radial stability field in the analysis of the short-circuit withstand capability of the inner winding of copper conductor power transformers. The technology is highly targeted and has a wide range of applications.

[0006] This invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides a method for obtaining the critical stress test results for the radial stability of power transformer windings, the method comprising:

[0008] Design the winding to be studied and the matching winding pair, and construct the power transformer body structure based on the winding pair;

[0009] Preliminary calculation of the critical test current for the winding pairs of the power transformer;

[0010] Based on the critical test current, the short-circuit test method is used to obtain the applied load when the power transformer undergoes radial deformation or radial instability, and to analyze the state of the winding after the impact.

[0011] Disassemble the power transformer and measure the radial deformation of the winding pairs of the power transformer;

[0012] Based on radial deformation, a relationship curve between simulated force distribution and measured deformation is established to obtain the critical point of radial stability of power transformer windings under critical force.

[0013] Based on the critical point and the relationship curve, the stress value and critical withstand current of the radial stability of the power transformer winding are extracted.

[0014] Furthermore, the design of the winding to be studied and its matching winding pair includes:

[0015] The characteristic quantities that characterize the radial stability of the power transformer windings are extracted. These characteristic quantities include winding form, conductor type, conductor size, conductor yield strength, and the number of supporting struts.

[0016] Based on the characteristic quantities and the strength and stiffness of the matching winding, the winding to be studied and the matching winding pair are designed.

[0017] Furthermore, the critical test current of the winding pair of the power transformer is preliminarily calculated, including:

[0018] The critical test current of the winding pairs of the power transformer is calculated by simulating using the finite element method or the national standard theoretical method.

[0019] Furthermore, the short-circuit test method adopts a short-circuit test method based on gradually increasing current.

[0020] Furthermore, the short-circuit test method based on gradually increasing current includes:

[0021] During a short-circuit impact: Measure the voltage and current waveforms of the winding pairs of the power transformer;

[0022] During a short-circuit impact: measure the vibration and oil pressure changes of the power transformer;

[0023] After the short-circuit impulse test: Measure parameters such as the impedance change and capacitance change of the winding pairs of the power transformer;

[0024] Based on parameters such as voltage and current waveforms, vibration and oil pressure changes, impedance changes and capacitance changes, the state of the winding after impact is comprehensively analyzed and evaluated.

[0025] Furthermore, if it is determined that the state of the winding after the impact has not changed or is within the acceptable range of the standard, the short-circuit test will continue to be performed, and the test current will remain unchanged or increase according to the preset result based on the result of the previous test.

[0026] If the condition of the winding after impact exceeds the judgment criteria, then the short-circuit test should be stopped.

[0027] Furthermore, the power transformer is disassembled, and the radial deformation of the winding pairs of the power transformer is measured, including:

[0028] Disassemble the power transformer, observe the radial deformation of the winding pairs, and measure the deformation values ​​at different heights;

[0029] The measurement of deformation values ​​at different heights includes: using the same gear setting, i.e., measuring data at different height positions of the same circumference angle; and using different gear settings to observe or measure obvious deformation.

[0030] Furthermore, the critical withstand current I sc The calculation formula is:

[0031]

[0032] In the formula, K s K is the threshold coefficient. s The value can range from 1.10 to 1.30, with 1.15 being preferred; σ act I represents the critical stress value for radial stability of the power transformer winding. sc0 σ is the critical test current for the winding pair of the power transformer. cr0 This represents the maximum stress experienced by the windings of a power transformer.

[0033] Secondly, the present invention provides a system for obtaining the critical stress test results for the radial stability of power transformer windings, the system using the aforementioned method for obtaining the critical stress test results for the radial stability of power transformer windings; the system includes:

[0034] The transformer and winding design unit is used to design the winding to be studied and the matching winding pairs, and to construct the power transformer body structure based on the winding pairs.

[0035] The critical test current calculation unit is used to initially calculate the critical test current of the winding pairs of the power transformer;

[0036] The short-circuit test unit is used to obtain the applied load when the power transformer is deformed or instable radially according to the critical test current and the short-circuit test method, and to analyze the state of the winding after the impact.

[0037] The disassembly and deformation measurement unit is used to disassemble power transformers and measure the radial deformation of the winding pairs of power transformers.

[0038] The relationship curve establishment unit is used to establish the relationship curve between the simulated force distribution and the measured deformation based on radial deformation, so as to obtain the critical point of the radial stability critical force of the power transformer winding.

[0039] The critical stress calculation unit extracts the stress value and critical withstand current of the radial stability critical force of the power transformer winding based on the critical point and the relationship curve.

[0040] Furthermore, the critical withstand current I sc The calculation formula is:

[0041]

[0042] In the formula, K s K is the threshold coefficient. s The value can range from 1.10 to 1.30, with 1.15 being preferred; σ act I represents the critical stress value for radial stability of the power transformer winding. sc0 σ is the critical test current for the winding pair of the power transformer. cr0 This represents the maximum stress experienced by the windings of a power transformer.

[0043] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0044] This invention relates to a method and system for obtaining critical stress values ​​for the radial stability of power transformer windings. It primarily addresses the challenge of determining the stability of the inner windings under radial stress during short-circuit impacts, leading to unclear transformer conditions. Building upon existing research methods, this invention accurately obtains the stress characteristics of the windings under short-circuit conditions through experimental methods. Specifically, the winding pairs to be designed and tested are modeled using simulation analysis. Simulation modeling analysis yields the radial stress distribution and corresponding current magnitude that the designed winding pairs can withstand, guiding the selection of short-circuit current values ​​in subsequent full-scale tests. The simulation modeling and local structural reinforcement are optimized based on the current values ​​from the full-scale tests and the electrical quantity detection results of the winding pairs after the tests, enhancing the simulation modeling's support for the full-scale tests and improving the accuracy of simulation analysis. Through feedback from the full-scale test results and simulation modeling analysis, the stress values ​​and critical withstand current values ​​that the winding pairs can withstand are determined, achieving full-process control of the winding pair design and testing. Attached Figure Description

[0045] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0046] Figure 1 This is a flowchart of the method for obtaining the critical stress test results for the radial stability of power transformer windings according to the present invention;

[0047] Figure 2 This is a schematic diagram showing the direction of force on the winding of the present invention;

[0048] Figure 3 This is a flowchart of the short-circuit test research process for this invention;

[0049] Figure 4 This is a schematic diagram of the deformation of the transformer windings in the present invention.

[0050] Figure 5 This is a schematic diagram of the radial force on the winding of the present invention; the vertical axis represents the height of the winding; the horizontal axis represents the force on the winding, where negative values ​​indicate inward force and positive values ​​indicate outward force; each point represents a coil.

[0051] Figure 6 This is a comparison chart of the calculated compressive stress and the actual measured deformation of the winding in this invention;

[0052] Figure 7 This is a block diagram of the system structure for obtaining the critical stress test results of the radial stability of the power transformer windings according to the present invention. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0054] Existing methods for obtaining the critical stress conditions for the radial stability of power transformer windings rely on simulation calculations to guide design verification and operational reliability assessments, but their accuracy is poor. Since short-circuit tests primarily aim to pass the test and leave sufficient margins, they cannot guide this research. Therefore, obtaining the critical value of the radial stress on the windings is a bottleneck limiting structural and performance optimization in this field. The industry lacks effective methods for tracking and researching this issue, ultimately leading to difficulties in accurately understanding the state of transformers after short-circuit impacts.

[0055] Therefore, addressing the difficulty in accurately confirming radial stability (i.e., the critical stress stability boundary under radial stress) in the above-mentioned transformer short-circuit impact resistance technologies, this invention designs a method and system for obtaining the critical stress test results of the radial stability of power transformer windings. This primarily solves the problem of difficulty in knowing the stability of the inner windings after radial stress during a transformer short-circuit impact, resulting in unclear transformer conditions. Based on existing research methods, this invention accurately obtains the stress characteristics of the windings under short-circuit conditions through experimental methods.

[0056] Specifically, the winding pairs to be designed and tested are modeled using simulation analysis. Through simulation modeling analysis, the radial stress distribution and corresponding current magnitude that the designed winding pairs can withstand are obtained, which guides the selection of short-circuit current values ​​in subsequent full-scale tests. The simulation modeling and local structural reinforcement are optimized by referring to the current values ​​of the full-scale tests and the electrical quantity detection results of the winding pairs after the tests, so as to improve the assistance of simulation modeling to the full-scale tests and improve the accuracy of simulation modeling analysis. Through the feedback of the results data of the full-scale tests and simulation modeling analysis, the stress values ​​and critical withstand current values ​​that the winding pairs can withstand are realized, achieving full-process control of the winding pair design and testing.

[0057] The research method of this invention takes an actual transformer as the research object and belongs to experimental research. It is applicable to the radial stability field in the analysis of the short-circuit withstand capability of the inner winding of copper conductor power transformers. The technology is highly targeted and has a wide range of applications.

[0058] Example 1

[0059] like Figure 1 As shown, the present invention provides a method for obtaining the critical stress test results for the radial stability of power transformer windings. The method includes:

[0060] Step 1: Design the winding to be studied and the matching winding pair, and construct the power transformer body structure based on the winding pair;

[0061] In this embodiment, step 1, designing the winding to be studied and its matching winding pair, includes:

[0062] Characteristic quantities that characterize the radial stability of power transformer windings are extracted. These characteristic quantities include winding form, conductor type, conductor size, conductor yield strength, and the number of supporting struts.

[0063] Based on the characteristic quantities and the strength and stiffness of the matching winding, the winding to be studied and the matching winding pair are designed.

[0064] Specifically, the design of the winding to be studied should be sufficiently representative or have research value, and should be able to characterize the main influencing factors of the radial stability of the winding.

[0065] Specifically, the matching winding should have sufficient strength, such as Figure 2 The diagram shown illustrates the forces acting on the winding. Research results should not present a situation where the matching winding fails while the winding under investigation remains undamaged.

[0066] Common methods for enhancing the strength and stiffness of matching windings include reducing winding current density, using self-adhesive transposed conductors, and increasing conductor yield strength.

[0067] As a further preferred embodiment, this invention constructs a two-phase or three-phase transformer to obtain more data sources. Optionally, in a multi-phase transformer, the characteristic quantities of the winding under study are locally changed to achieve the research objective of multiple parameters and multiple data.

[0068] Step 2: Preliminary calculation of the critical test current for the winding pairs of the power transformer;

[0069] Based on the power transformer winding structure constructed in step 1, the critical withstand current capability of the winding pair is calculated using national standard theoretical methods, finite element simulation, or effective methods that have been proven in engineering.

[0070] Since radial stability involves less dynamic stress on the windings, static calculation methods can be used for specific calculations.

[0071] Assuming the test current I sc0 Under these conditions, the maximum stress on the winding is σ. cr0 .

[0072] In theory, the critical withstand current refers to the current that causes irreversible permanent damage or failure to the winding after three impacts. The specific criteria for determining the damage are based on the national standard GB1094.5-2008.

[0073] For the convenience of the subsequent description of the present invention, the above-mentioned critical test current is denoted as I. sc0 .

[0074] Step 3: Based on the critical test current, use the short-circuit test method to obtain the applied load when the power transformer experiences radial deformation or radial instability, and analyze the winding's state after the impact; the short-circuit test research process in Step 3 is as follows: Figure 3 As shown.

[0075] The short-circuit test of a transformer should differ from the traditional short-circuit test verification method, and should adopt a method of gradually increasing the current.

[0076] Before the short-circuit test, data such as short-circuit impedance, capacitance, DC resistance, and winding deformation are measured to provide data for comparative analysis of the short-circuit test.

[0077] Specifically, the short-circuit test method employs a method based on gradually increasing current, and can utilize research methods that reduce the initial impact current, such as using 50% of I. sc0 The first test was conducted, and then the current was gradually increased.

[0078] In this embodiment, the short-circuit test method based on gradually increasing current includes:

[0079] During a short-circuit impact: Measure the voltage and current waveforms of the winding pairs of the power transformer;

[0080] During a short-circuit impact: measure the vibration and oil pressure changes of the power transformer;

[0081] After the short-circuit impulse test: Measure parameters such as the impedance change and capacitance change of the winding pairs of the power transformer;

[0082] Based on parameters such as voltage and current waveforms, vibration and oil pressure changes, impedance changes and capacitance changes, the state of the winding after impact is comprehensively analyzed and evaluated.

[0083] Specifically, after comprehensive analysis and evaluation of the state of the winding after the impact, if it is determined that the state of the winding after the impact has not changed or is within the acceptable range of the standard, the short circuit test will continue, and the test current will remain unchanged or increase according to the preset result based on the previous test result; if it is determined that the state of the winding after the impact exceeds the judgment criteria, the short circuit test will be stopped.

[0084] The above analysis and evaluation of the winding's condition after impact are based on the national standard GB1094.5-2008. Optionally, more mature technologies and widely accepted academic findings can be used for the assessment.

[0085] After all phase tests are completed, the transformer is retested for short-circuit impedance, capacitance, DC resistance, and winding deformation. Once all tests are confirmed to meet the requirements, the transformer is returned to the factory for disassembly and inspection.

[0086] Step 4: Disassemble the power transformer and measure the radial deformation of the winding pairs of the power transformer;

[0087] Step 4 specifically includes:

[0088] Disassemble the power transformer, observe the radial deformation of the winding pairs, and measure the deformation values ​​at different heights;

[0089] The measurement of deformation values ​​at different heights includes: using the same gear setting, i.e., measuring data at different height positions of the same circumference angle; and using different gear settings to observe or measure obvious deformation.

[0090] The difference in radial force on the winding along the circumference is not within the scope of the method proposed in this invention.

[0091] When this invention is implemented, the transformer winding images observed during disassembly are used as an example. Figure 4 As shown.

[0092] Step 5: Based on radial deformation, establish the relationship curve between simulated force distribution and measured deformation to obtain the critical point of radial stability of the power transformer winding.

[0093] The difference in radial force on the winding at different heights mainly stems from variations in axial leakage flux. Furthermore, the force is greater in the middle and smaller at both ends. A typical example of this force is... Figure 5 As shown.

[0094] Figure 5 The gradually changing forces within the two dashed boxes will cause a gradual change in deformation, and this change is directly proportional to the change in force. This is the key to obtaining the critical force in this invention.

[0095] Because multiple short-circuit tests are used, deformation will accumulate after reaching the critical point. Correspondingly, no accumulation will occur at locations below the critical stress level; therefore, the location of the abrupt change in deformation is the critical stress point.

[0096] The compressive stress of each winding is calculated based on the short-circuit impact current and compared with the deformation measured in step 4 in the same diagram, such as... Figure 6 As shown.

[0097] Figure 6 The abrupt change at the dashed line represents the critical boundary where deformation transitions from stability to instability. The stress at this location is the point of abrupt change in the winding. Extracting this stress is the critical force (i.e., the critical stress value) of the winding, denoted as σ. act .

[0098] Step 6: Based on the critical point and the relationship curve, extract the stress value and critical withstand current of the radial stability of the power transformer winding.

[0099] Based on step 5, considering the dispersion of materials and manufacturing processes, a certain safety margin K is taken. s The above K was obtained by reverse calculation. s *σ act The impact current (i.e., the critical withstand current) I sc .

[0100] The calculation expression is:

[0101]

[0102] In the formula, K s K is the threshold coefficient. s The value can range from 1.10 to 1.30, with 1.15 being preferred; σ act I represents the critical stress value for radial stability of the power transformer winding. sc0 σ is the critical test current for the winding pair of the power transformer. cr0 This represents the maximum stress experienced by the windings of a power transformer.

[0103] Theoretically, the aforementioned impact current I sc The corresponding winding damage will occur in the middle of the winding, i.e. Figure 5 The stable position under force in the image is different from the position obtained in this invention, but it is within the range of the position obtained in this invention.

[0104] Example 2

[0105] like Figure 7 As shown, the difference between this embodiment and Embodiment 1 is that this embodiment provides a system for obtaining the critical stress test results for the radial stability of power transformer windings. This system uses the method for obtaining the critical stress test results for the radial stability of power transformer windings from Embodiment 1. The system includes:

[0106] The transformer and winding design unit is used to design the winding to be studied and the matching winding pairs, and to construct the power transformer body structure based on the winding pairs.

[0107] The critical test current calculation unit is used to initially calculate the critical test current of the winding pairs of the power transformer;

[0108] The short-circuit test unit is used to obtain the applied load when the power transformer is deformed or instable radially according to the critical test current and the short-circuit test method, and to analyze the state of the winding after the impact.

[0109] The disassembly and deformation measurement unit is used to disassemble power transformers and measure the radial deformation of the winding pairs of power transformers.

[0110] The relationship curve establishment unit is used to establish the relationship curve between the simulated force distribution and the measured deformation based on radial deformation, so as to obtain the critical point of the radial stability critical force of the power transformer winding.

[0111] The critical stress calculation unit extracts the stress value and critical withstand current of the radial stability critical force of the power transformer winding based on the critical point and the relationship curve.

[0112] In this embodiment, the critical withstand current I sc The calculation formula is:

[0113]

[0114] In the formula, K s K is the threshold coefficient. s The value can range from 1.10 to 1.30, with 1.15 being preferred; σ act I represents the critical stress value for radial stability of the power transformer winding. sc0 σ is the critical test current for the winding pair of the power transformer. cr0 This represents the maximum stress experienced by the windings of a power transformer.

[0115] The execution process of each unit can be carried out according to the procedure of the power transformer winding radial stability critical stress test method in Example 1, and will not be described in detail in this example.

[0116] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0117] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0118] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0119] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable apparatus for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0120] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for obtaining the critical stress test results for the radial stability of power transformer windings, characterized in that, The method includes: Design the winding to be studied and the matching winding pair, and construct the power transformer body structure based on the winding pair; Preliminary calculation of the critical test current for the winding pairs of the power transformer; Based on the critical test current, the short-circuit test method is used to obtain the applied load when the power transformer undergoes radial deformation or radial instability, and the state of the winding after the impact is analyzed. Disassemble the power transformer and measure the radial deformation of the winding pairs of the power transformer; Based on the radial deformation, a relationship curve between the simulated force distribution and the measured deformation is established to obtain the critical point of the radial stability critical force of the power transformer winding. Based on the critical point and the relationship curve, extract the stress value and critical withstand current of the radial stability critical force of the power transformer winding. Preliminary calculation of the critical test current for the winding pairs of the power transformer includes: The critical test current of the winding pairs of the power transformer is calculated using either the finite element method or the national standard theoretical method; the static calculation method is used in the specific simulation calculation. The critical withstand current I sc The calculation formula is: ； In the formula, K s K is the threshold coefficient. s The value ranges from 1.10 to 1.30; σ act I represents the critical stress value for radial stability of the power transformer winding. sc0 σ is the critical test current for the winding pair of the power transformer. cr0 This represents the maximum stress experienced by the winding pair of a power transformer. Based on the radial deformation, a relationship curve between the simulated force distribution and the measured deformation is established to obtain the critical point of the radial stability of the power transformer winding, including: The location of the actual deformation abrupt change in the curve of the relationship between simulated stress distribution and measured deformation is the critical boundary between stability and instability. The stress at this location is the location of the winding abrupt change, and extracting the stress at this location is the critical stress for radial stability of the power transformer winding.

2. The method for obtaining the critical stress test for radial stability of power transformer windings according to claim 1, characterized in that, Design the winding to be studied and the matching winding pair, including: The characteristic quantities characterizing the radial stability of the power transformer windings are extracted. These characteristic quantities include winding form, conductor type, conductor size, conductor yield strength, and the number of supporting struts. Based on the aforementioned characteristic quantities and the strength and stiffness of the matching winding, the winding to be studied and its matching winding pair are designed.

3. The method for obtaining the critical stress test for radial stability of power transformer windings according to claim 1, characterized in that, The short-circuit test method is based on gradually increasing the current.

4. The method for obtaining the critical stress test for radial stability of power transformer windings according to claim 3, characterized in that, The short-circuit test method based on gradually increasing current includes: During a short-circuit impact: Measure the voltage and current waveforms of the winding pairs of the power transformer; During the short-circuit impact: Measure the vibration and oil pressure changes of the power transformer; After the short-circuit impulse test: Measure the impedance and capacitance changes of the winding pairs of the power transformer. Based on the voltage and current waveforms, vibration and oil pressure changes, impedance changes and capacitance changes, the state of the winding after the impact is comprehensively analyzed and evaluated.

5. The method for obtaining the critical stress test for radial stability of power transformer windings according to claim 4, characterized in that, If it is determined that the state of the winding after the impact has not changed or is within the acceptable range of the standard, then the short-circuit test will continue to be performed, and the test current will remain unchanged or increase according to the preset result based on the result of the previous test. If the condition of the winding after impact exceeds the judgment criteria, then the short-circuit test should be stopped.

6. The method for obtaining the critical stress test for radial stability of power transformer windings according to claim 1, characterized in that, Disassembling the power transformer and measuring the radial deformation of the winding pairs of the power transformer includes: The power transformer was disassembled, the radial deformation of the winding pairs was observed, and the deformation values ​​at different heights were measured. The measurement of deformation values ​​at different heights includes: measuring data at different heights using the same gear setting, i.e., the same circumferential angle; and observing or measuring deformation using different gear settings.

7. A system for obtaining critical stress test data on radial stability of power transformer windings, characterized in that the system uses the method for obtaining critical stress test data on radial stability of power transformer windings as described in any one of claims 1 to 6; the system comprises: The transformer and winding design unit is used to design the winding to be studied and the matching winding pair, and to construct the power transformer body structure based on the winding pair. The critical test current calculation unit is used to preliminarily calculate the critical test current of the winding pairs of the power transformer; The short-circuit test unit is used to obtain the applied load when the power transformer undergoes radial deformation or radial instability, based on the critical test current and the short-circuit test method, and to analyze the state of the winding after the impact. The disassembly and deformation measurement unit is used to disassemble the power transformer and measure the radial deformation of the winding pairs of the power transformer. The relationship curve establishment unit is used to establish a relationship curve between the simulated force distribution and the measured deformation based on the radial deformation, and to obtain the critical point of the radial stability critical force of the power transformer winding. The critical stress calculation unit extracts the stress value and critical withstand current of the radial stability critical stress of the power transformer winding based on the critical point and the relationship curve. Preliminary calculation of the critical test current for the winding pairs of the power transformer includes: The critical test current of the winding pairs of the power transformer is calculated using either the finite element method or the national standard theoretical method; the static calculation method is used in the specific simulation calculation. The critical withstand current I sc The calculation formula is: ； In the formula, K s K is the threshold coefficient. s The value ranges from 1.10 to 1.30; σ act I represents the critical stress value for radial stability of the power transformer winding. sc0 σ is the critical test current for the winding pair of the power transformer. cr0 This represents the maximum stress experienced by the winding pair of a power transformer. Based on the radial deformation, a relationship curve between the simulated force distribution and the measured deformation is established to obtain the critical point of the radial stability of the power transformer winding, including: The location of the actual deformation abrupt change in the curve of the relationship between simulated stress distribution and measured deformation is the critical boundary between stability and instability. The stress at this location is the location of the winding abrupt change, and extracting the stress at this location is the critical stress for radial stability of the power transformer winding.

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