Transformer short-circuit withstand capacity detection method, system, terminal, medium and program

Abstract

The present invention discloses a method, system, terminal, medium and program for detecting the short-circuit withstand ability of a transformer. By obtaining the design parameters of the transformer and the operating conditions of the power system where the transformer is located, then according to the design parameters of the transformer and the operating conditions of the power system where the transformer is located, the maximum through short-circuit current value of the transformer winding is obtained, and then the maximum through short-circuit current value of the transformer winding is input into the first pre-designed calculation model to obtain the first stress value of each disk of the transformer winding. The second stress value of each disk of the transformer winding is obtained by using the second preset method, and then the second current value of the transformer winding is obtained by using the third preset method. Finally, the safety margin of the transformer is obtained to determine the short-circuit withstand ability of the transformer, so as to realize accurate detection of the short-circuit withstand ability of the transformer even under the condition that the radial support is invalid.

Description

Technical Field

[0001] The present invention relates to the field of transformer detection, and particularly to a method, system, terminal, medium and program for detecting the short-circuit resistance ability of a transformer. Background Art

[0002] The reliable operation of power transformers plays a key role in the safety and stability of power systems. When a short circuit occurs in the near area outside the transformer, the huge short-circuit electrodynamic force may damage the wire insulation or structural components. In severe cases, it may cause the winding to loosen, twist and deform, or even the entire winding to collapse or burn, resulting in immeasurable economic losses and social impacts.

[0003] Currently, there are mainly three methods for detecting the short-circuit resistance ability of power transformers: one is to directly conduct short-circuit test detection on the transformer body, but the test conditions and costs are extremely high, which is not conducive to large-scale promotion and application; the second is to conduct short-circuit test detection by sampling, although this method reduces the detection cost to a certain extent, the coverage is limited and there are relatively large potential risks; the third is to conduct short-circuit resistance ability verification detection on the transformer. The traditional method for verifying the short-circuit resistance ability of transformers is based on the effective radial support method for detection.

[0004] However, in the actual design and manufacturing process of transformers, there are certain sleeving clearances in the windings themselves, and shrinkage inevitably occurs during the drying process of insulating materials. Therefore, for transformers in actual operation, the spacers used for radial support and insulation cannot achieve effective support effects, resulting in large deviations in the results of the traditional short-circuit resistance ability verification method based on the effective radial support method, and the accuracy of judging the short-circuit resistance ability of transformers is not high, bringing relatively large risks to the quality control of transformer equipment and the reliable operation of power systems. Summary of the Invention

[0005] [[ID=,19]]The present invention provides a method, system, terminal, medium and program for detecting the short-circuit resistance ability of a transformer to solve the technical problem of large deviations in the results of the existing technology using the short-circuit resistance ability verification detection method based on effective radial support.

[0006] To solve the above technical problem, an embodiment of the present invention provides a method, system, terminal, medium and program for detecting the short-circuit resistance ability of a transformer, including:

[0007] Obtain the design parameters of the transformer and the operating conditions of the power system where the transformer is located;

[0008] According to the design parameters of the transformer and the operating conditions of the power system where the transformer is located, obtain the maximum through short-circuit current value of the transformer winding;

[0009] Input the maximum through - short - circuit current value of the transformer winding into the first pre - designed calculation model to obtain the first stress value of each disk of the transformer winding; wherein, the first pre - designed calculation model is determined by the transformer design parameters;

[0010] According to the transformer design parameters, obtain the second stress value of each disk of the transformer winding by using a second preset method;

[0011] According to the first stress value of each disk of the transformer winding and the second stress value of each disk of the transformer winding, obtain the second current value of the transformer winding in a third preset way;

[0012] According to the second current value of the transformer winding and the maximum through - short - circuit current value of the transformer winding, obtain the safety margin of the transformer;

[0013] Determine the short - circuit resistance ability of the transformer according to the safety margin of the transformer.

[0014] In this way, by obtaining the transformer design parameters and the operating conditions of the power system where the transformer is located to get the maximum through - short - circuit current value of the transformer winding, it is possible to obtain the maximum through - short - circuit current value of the transformer according to the specific design parameters of the transformer and the voltage, current and impedance of the power system where the transformer is located, making the detection of the short - circuit resistance ability of the transformer more accurate. Then, input the obtained maximum through - short - circuit current value of the transformer winding into the first pre - designed calculation model, that is, the finite - element electromagnetic model, to obtain the first stress value of each disk of the corresponding transformer winding, improving the calculation accuracy, reducing the calculation error and improving the calculation efficiency. Then, obtain the second stress value of each disk of the transformer winding by a second preset method, so as to effectively detect the short - circuit resistance ability of the transformer. Obtain the second current value by a third preset method, and then obtain the safety margin of the transformer. Then, by checking whether the safety margin exceeds the first threshold, detect whether the short - circuit resistance ability of the transformer is qualified. In this way, it is possible to judge the short - circuit resistance ability of the transformer at low cost and high efficiency, thus effectively reducing the risk of power system operation failures.

[0015] As a preferred solution, the transformer design parameters include the rated current of the transformer winding and the per - unit value of the transformer short - circuit impedance; the operating conditions of the power system where the transformer is located include the per - unit value of the short - circuit impedance of the power grid system; the maximum through - short - circuit current value of the transformer winding is obtained by the following method:

[0016]

[0017] Where, I m is the maximum through - short - circuit current value of the transformer winding, I N is the rated current of the transformer winding, Z T is the per - unit value of the transformer short - circuit impedance, ZS is the per-unit value of the short-circuit impedance of the power grid system.

[0018] In this way, based on the per-unit value of the short-circuit impedance of the power grid system, the rated current of the transformer winding, and the per-unit value of the short-circuit impedance of the transformer, obtaining the maximum through-current value suffered by the transformer winding under short-circuit conditions can specifically analyze the short-circuit resistance ability of the transformer according to specific conditions and improve the calculation accuracy.

[0019] As a preferred solution, the transformer design parameters include core structure parameters, winding structure parameters based on ineffective radial support, pressing structure parameters, and tank parameters; the first pre-design calculation model is a finite element electromagnetic model;

[0020] Establish a finite element electromagnetic model according to the core structure parameters, winding structure parameters based on ineffective radial support, pressing structure parameters, and tank parameters;

[0021] Input the maximum through-short-circuit current value of the transformer winding into the finite element electromagnetic model to obtain the first stress value of each turn of the transformer winding.

[0022] In this way, according to the core structure parameters of the transformer, winding structure parameters based on ineffective radial support, pressing structure parameters, and tank parameters, establishing the corresponding finite element electromagnetic model can accurately calculate the first stress value by relying on relevant finite element computer software, reduce the calculation time, improve work efficiency, and improve the accuracy of the detection results.

[0023] As a preferred solution, the transformer design parameters include the yield strength and thickness of the transformer wire; determine the second stress value of each turn of the transformer winding through the following method:

[0024] σ l =(Aσ 0.2 +B)lnb eq +C

[0025] σ l is the second stress value of each turn of the transformer winding, σ 0.2 is the yield strength of the wire, b eq is the thickness of the wire, and A, B, and C are preset coefficients.

[0026] In this way, according to the yield strength and thickness of the transformer wire and the preset coefficients, the corresponding stress value can be calculated more accurately.

[0027] As a preferred solution, the numerical range of the preset coefficient A includes 0.13 - 0.15; the numerical range of the preset coefficient B includes 6 - 8; the numerical range of the preset coefficient C includes 12 - 15.

[0028] In this way, corresponding calculations are performed on the preset coefficients within a certain numerical range, making the detection of the short-circuit withstand ability of the transformer more accurate.

[0029] As a preferred solution, obtaining the second current value of the transformer winding in a third preset manner according to the first stress value of each turn of the transformer winding and the second stress value of each turn of the transformer winding, specifically:

[0030] Obtaining the estimated range of the second current value according to the first stress value of each turn of the transformer winding and the second stress value of each turn of the transformer winding;

[0031] Obtaining the second current value according to the estimated range of the second current value and the second stress value of each turn of the transformer winding.

[0032] In this way, through the range of the first stress value, the corresponding range of the current value is obtained, and then through the first preset calculation model, the accurate current value is obtained, reducing the user's calculation time and improving work efficiency.

[0033] As a preferred solution, obtaining the safety margin of the transformer according to the second current value of the transformer winding and the maximum through short-circuit current value of the transformer winding, specifically:

[0034]

[0035] [[ID=2,1]]Where K is the safety margin, I2 is the second current value, and I m is the maximum through short-circuit current value of the winding.

[0036] In this way, the safety margin can be expressed more accurately, reducing the errors caused by simulation and calculation.

[0037] As a preferred solution, determining the short-circuit withstand ability of the transformer according to the safety margin of the transformer, specifically:

[0038] When the safety margin of the transformer is greater than the first threshold, the short-circuit withstand ability of the transformer is qualified;

[0039] When the safety margin of the transformer is less than the first threshold, the short-circuit withstand ability of the transformer is unqualified.

[0040] In this way, the higher the safety margin value of the transformer, the stronger the short-circuit withstand ability of the transformer and the higher the safety factor. Reflecting the safety margin in the form of a numerical value can give users a more intuitive feeling.

[0041] The embodiment of the present invention also provides a system for detecting the short-circuit withstand ability of a transformer, including: an acquisition module, a first calculation module, a second calculation module, a third calculation module, a fourth calculation module, a fifth calculation module, and a judgment module;

[0042] Among them, the obtaining module is used to obtain the transformer design parameters and the operating conditions of the power system where the transformer is located;

[0043] The first calculation module is used to obtain the maximum through - short - circuit current value of the transformer winding according to the transformer design parameters and the operating conditions of the power system where the transformer is located;

[0044] The second calculation module is used to input the maximum through - short - circuit current value of the transformer winding into the first pre - designed calculation model to obtain the first stress value of each disk of the transformer winding; among them, the first pre - designed calculation model is determined by the transformer design parameters;

[0045] The third calculation module is used to obtain the second stress value of each disk of the transformer winding according to the transformer design parameters by using a second preset method;

[0046] The fourth calculation module is used to obtain the second current value of the transformer winding in a third preset manner according to the first stress value of each disk of the transformer winding and the second stress value of each disk of the transformer winding;

[0047] The fifth calculation module is used to obtain the safety margin of the transformer according to the second current value of the transformer winding and the maximum through - short - circuit current value of the transformer winding;

[0048] The judgment module is used to determine the short - circuit resistance ability of the transformer according to the safety margin of the transformer.

[0049] In this way, the obtaining module is used to obtain the transformer design parameters and the operating conditions of the power system where the transformer is located. By using the first calculation module to obtain the maximum through - short - circuit current value of the transformer winding, the maximum through - short - circuit current value of the transformer can be obtained according to the specific design parameters of the transformer and the voltage, current and impedance of the power system where the transformer is located, making the detection of the short - circuit resistance ability of the transformer more accurate. Then, the second calculation module inputs the obtained maximum through - short - circuit current value of the transformer winding into the first pre - designed calculation model, that is, the finite - element electromagnetic model, to obtain the corresponding first stress value of each disk of the transformer winding, improving the calculation accuracy, reducing the calculation error and improving the calculation efficiency. The third calculation module is used to obtain the second stress value of each disk of the transformer winding, so as to effectively detect the short - circuit resistance ability of the transformer. The fourth calculation module is used to obtain the second current value, and then the fifth calculation module is used to obtain the safety margin of the transformer. By using the judgment module to determine whether the safety margin exceeds the first threshold value to detect whether the short - circuit resistance ability of the transformer is qualified, the short - circuit resistance ability of the transformer can be judged at low cost and high efficiency, thus effectively reducing the risk of power system operation failures.

[0050] An embodiment of the present invention further provides a terminal device, which is characterized by including a processor, a memory, and a computer program running on the memory. When the processor executes the computer program, the steps of any one of the transformer short-circuit resistance detection methods as described in the present invention are implemented.

[0051] An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. The computer program is characterized in that when the computer program is executed by the processor, the steps of any one of the transformer short-circuit resistance detection methods as described in the present invention are implemented.

[0052] An embodiment of the present invention further provides a computer program product, including a computer program. The computer program is characterized in that when the computer program is executed by the processor, the steps of any one of the transformer short-circuit resistance detection methods as described in the present invention are implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 : A flowchart showing an embodiment of a transformer short-circuit resistance detection method provided by the present invention;

[0054] Figure 2 : A structural diagram showing an embodiment of a transformer short-circuit resistance detection system provided by the present invention;

[0055] Figure 3 : A numerical curve diagram of the radial critical stress based on the invalidation of the radial support in an embodiment of a transformer short-circuit resistance detection method provided by the present invention;

[0056] Figure 4 : A critical state diagram of a transformer winding after withstanding a short-circuit current in an embodiment of a transformer short-circuit resistance detection method provided by the present invention.

[0057] Among them, the reference numerals of the drawings in the specification are as follows: 100, acquisition module; 200, first calculation module; 300, second calculation module; 400, third calculation module; 500, fourth calculation module; 600, fifth calculation module; 700, judgment module. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0058] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0059] Embodiment 1

[0060] Please refer toFigure 1 , which is a schematic flow diagram of an embodiment of a method for detecting the short - circuit resistance of a transformer provided by the present invention, includes: steps S1 to S7, and the specific steps are as follows:

[0061] Step S1: Obtain the design parameters of the transformer and the operating conditions of the power system where the transformer is located;

[0062] In this embodiment, by obtaining the design parameters of the transformer and the operating conditions of the power system where the transformer is located, it is possible to specifically analyze the specific parameters of the specific transformer, improve the accuracy of the short - circuit resistance detection, and combined with the operating conditions of the power system where the transformer is located, it provides a practical basis for the accuracy of the short - circuit resistance detection, ensuring that the calculation results are targeted and of practical significance.

[0063] In a specific embodiment, taking a transformer of model SSZ - 40000 / 110 as an example, the rated voltage of the transformer is 121 / 40.5 / 10.5 kV, the connection group is YNyn0d11, the short - circuit impedance is HV - MV: 9.75%, the winding arrangement is LV - MV - HV - TV, the yield strength of the medium - voltage winding is 90 MPa, the wire gauge of the medium - voltage winding is 2.24*12.5 mm, the reactance height of the medium - voltage winding is 1280 mm, and the number of spacers of the medium - voltage winding is 20.

[0064] Step S2: Obtain the maximum through - fault short - circuit current value of the transformer winding according to the transformer design parameters and the operating conditions of the power system where the transformer is located;

[0065] In this embodiment, the transformer design parameters include the rated current of the transformer winding and the per - unit value of the transformer short - circuit impedance; the operating conditions of the power system where the transformer is located include the per - unit value of the short - circuit impedance of the power grid system; the maximum through - fault short - circuit current value of the transformer winding is obtained by the following method:

[0066]

[0067] where, I m is the maximum through - fault short - circuit current value of the transformer winding, I N is the rated current of the transformer winding, Z T is the per - unit value of the transformer short - circuit impedance, Z S is the per - unit value of the short - circuit impedance of the power grid system.

[0068] Furthermore, the short - circuit conditions corresponding to different types of transformers are also different. For two - winding transformers, the short - circuit condition is high - voltage - low - voltage; for three - winding transformers, the short - circuit conditions are divided into four types: high - voltage - low - voltage, high - voltage - medium - voltage, medium - voltage - low - voltage, and high - voltage + medium - voltage - low - voltage; corresponding to different conditions, the obtained maximum through - fault short - circuit current value of the transformer will also be different accordingly.

[0069] In a specific embodiment, the maximum through - short - circuit current value of the transformer winding is 5.6 kA.

[0070] In this way, according to the per - unit value of the short - circuit impedance of the power grid system, the rated current of the transformer winding, and the per - unit value of the short - circuit impedance of the transformer, obtaining the maximum through - current value suffered by the transformer winding under short - circuit conditions can specifically analyze the short - circuit resistance ability of the transformer according to specific conditions and improve the calculation accuracy.

[0071] Step S3: Input the maximum through - short - circuit current value of the transformer winding into the first pre - designed calculation model to obtain the first stress value of each turn of the transformer winding; wherein, the first pre - designed calculation model is determined by the transformer design parameters;

[0072] In this embodiment, the transformer design parameters include core structure parameters, winding structure parameters based on ineffective radial support, pressing structure parameters, and tank parameters; the first pre - designed calculation model is a finite - element electromagnetic model;

[0073] Establish a finite - element electromagnetic model according to the core structure parameters, winding structure parameters based on ineffective radial support, pressing structure parameters, and tank parameters;

[0074] Input the maximum through - short - circuit current value of the transformer winding into the finite - element electromagnetic model to obtain the first stress value of each turn of the transformer winding.

[0075] In a specific embodiment, according to the core structure parameters, winding structure parameters based on ineffective radial support, pressing structure parameters, and tank parameters, a finite - element electromagnetic model is established. The magnitude of the leakage magnetic field B at different positions of the winding is calculated by using finite - element electromagnetic software. The magnitude of the electrodynamic force F of different turns can be obtained through the Lorentz force formula. Then, according to the cross - section parameters of the winding conductor, through the material mechanics formula, finally, the stress value of each turn of the transformer winding is calculated. Considering the transmission characteristics of the electrodynamic force of the turns, the average leakage magnetic field is used for calibration detection during calculation, that is, the electrodynamic force and stress for calibration detection are the average electrodynamic force and average stress values of different turns. Finally, the first stress value of each turn of the transformer winding is calculated as 61.2 MPa.

[0076] In this way, according to the core structure parameters, winding structure parameters based on ineffective radial support, pressing structure parameters, and tank parameters of the transformer, a corresponding finite - element electromagnetic model is established, which can accurately calculate the first stress value by relying on relevant finite - element computer software, reduce the calculation time, improve the work efficiency, and improve the accuracy of the detection results.

[0077] Step S4: Obtain the second stress value of each turn of the transformer winding by using a second preset method according to the transformer design parameters;

[0078] Please refer to Figure 3 , which is a numerical curve graph of the radial critical stress based on the invalidation of radial support in an embodiment of a method for detecting the short-circuit withstand capacity of a transformer provided by the present invention. In this embodiment, the design parameters of the transformer include the yield strength and thickness of the transformer wire; the second stress value of each disk of the transformer winding is determined by the following method:

[0079] σ l =(Aσ 0.2 +B)lnb eq +C

[0080] σ l is the second stress value of each disk of the transformer winding, σ 0.2 is the yield strength of the wire, b eq is the thickness of the wire, and A, B, and C are preset coefficients.

[0081] In a specific embodiment, the numerical range of the preset coefficient A includes 0.13 - 0.15; the numerical range of the preset coefficient B includes 6 - 8; the numerical range of the preset coefficient C includes 12 - 15.

[0082] In a specific embodiment, the second stress value is 26.3 - 32.3 MPa.

[0083] In this way, by performing corresponding calculations on the preset coefficients within a certain numerical range, the detection of the short-circuit withstand capacity of the transformer is made more accurate.

[0084] Step S5: Obtain the second current value of the transformer winding in a third preset manner according to the first stress value of each disk of the transformer winding and the second stress value of each disk of the transformer winding;

[0085] In this embodiment, obtaining the second current value of the transformer winding in a third preset manner according to the first stress value of each disk of the transformer winding and the second stress value of each disk of the transformer winding specifically means:

[0086] Obtain the estimated range of the second current value according to the first stress value of each disk of the transformer winding and the second stress value of each disk of the transformer winding;

[0087] Obtain the second current value according to the estimated range of the second current value and the second stress value of each disk of the transformer winding.

[0088] In a specific embodiment, first, based on the first stress values of each turn of the transformer winding and the second stress values of each turn of the transformer winding, the estimated range of the second current value is obtained. Then, two values within the estimated range of the second current value are randomly selected and substituted into the first pre-designed calculation model to obtain the corresponding stress values. The magnitudes of the corresponding stress values are compared with the second stress value, and an iterative method is used to continuously obtain the corresponding stress values. Finally, when the corresponding stress value is equal to the second stress value, the second current value is determined at this time.

[0089] In a specific embodiment, the second current value is the withstand current value of 3.7 - 4.1 kA, and the second stress value is the radial critical stress value of 26.3 - 32.3 MPa.

[0090] In this way, through the range of the first stress value, the corresponding range of the current value is obtained. Then, through the first pre-designed calculation model, the accurate current value is obtained, reducing the user's calculation time and improving work efficiency.

[0091] Step S6: Obtain the safety margin of the transformer according to the second current value of the transformer winding and the maximum through - short - circuit current value of the transformer winding;

[0092] In a specific embodiment, the obtaining of the safety margin of the transformer according to the second current value of the transformer winding and the maximum through - short - circuit current value of the transformer winding is specifically as follows:

[0093]

[0094] where K is the safety margin, I2 is the second current value, and I m is the maximum through - short - circuit current value of the winding.

[0095] In a specific embodiment, the safety margin is 0.66 - 0.73. Reflecting the safety margin value through the ratio of current values can obtain more accurate evaluation data, so that the safety margin can be expressed more accurately, reducing the errors caused by simulation and calculation.

[0096] Step S7: Determine the short - circuit resistance ability of the transformer according to the safety margin of the transformer;

[0097] In this embodiment, the determining of the short - circuit resistance ability of the transformer according to the safety margin of the transformer is specifically as follows:

[0098] When the safety margin of the transformer is greater than the first threshold, the short - circuit resistance ability of the transformer is qualified;

[0099] When the safety margin of the transformer is less than the first threshold, the short - circuit resistance ability of the transformer is unqualified.

[0100] In a specific embodiment, when the safety margin value is greater than 1.0, it indicates that the short-circuit resistance ability of the transformer is qualified; when the safety margin value of the transformer is less than 1.0, it indicates that the short-circuit resistance ability of the transformer is unqualified.

[0101] Please refer to Figure 4 , which is a critical state diagram of a transformer winding after suffering a withstand short-circuit current in an embodiment of a method for detecting the short-circuit resistance ability of a transformer provided by the present invention. In this embodiment, the safety margin value is 0.66 - 0.73, which is much lower than the first threshold value of 1.0. Therefore, it is determined that the short-circuit resistance ability of the transformer is insufficient.

[0102] In this way, by obtaining the design parameters of the transformer and the operating conditions of the power system where the transformer is located, the maximum through short-circuit current value of the transformer winding can be obtained. According to the specific design parameters of the transformer and the voltage, current, and impedance of the power system where the transformer is located, the maximum through short-circuit current value of the transformer can be calculated, making the detection of the short-circuit resistance ability of the transformer more accurate. Then, by inputting the obtained maximum through short-circuit current value of the transformer winding into the first pre-designed calculation model, that is, the finite element electromagnetic model, the first stress value of each turn of the transformer winding can be obtained, improving the calculation accuracy, reducing the calculation error, and improving the calculation efficiency. By obtaining the second stress value of each turn of the transformer winding through the second preset method, the short-circuit resistance ability of the transformer can be effectively detected. By obtaining the second current value through the third preset method, and then obtaining the safety margin of the transformer. By checking whether the safety margin exceeds the first threshold value, it can be detected whether the short-circuit resistance ability of the transformer is qualified. In this way, it is possible to judge the short-circuit resistance ability of the transformer at low cost and high efficiency, thus effectively reducing the risk of power system operation failures.

[0103] Embodiment 2

[0104] Please refer to Figure 2 , which is a schematic structural diagram of an embodiment of a system for detecting the short-circuit resistance ability of a transformer provided by the present invention, including: an acquisition module 100, a first calculation module 200, a second calculation module 300, a third calculation module 400, a fourth calculation module 500, a fifth calculation module 600, and a judgment module 700;

[0105] Among them, the acquisition module 100 is used to obtain the design parameters of the transformer and the operating conditions of the power system where the transformer is located;

[0106] In this embodiment, by using the acquisition module 100 to obtain the design parameters of the transformer and the operating conditions of the power system where the transformer is located, the specific parameters of the specific transformer can be specifically analyzed, improving the accuracy of the short-circuit resistance ability detection. Combining with the operating conditions of the power system where the transformer is located provides a practical basis for the accuracy of the short-circuit resistance ability detection, ensuring that the calculation results are targeted and have practical significance.

[0107] In a specific embodiment, taking a transformer with a model number of SSZ-40000 / 110 as an example, the rated voltage of the transformer is 121 / 40.5 / 10.5 kV, the connection group is YNyn0d11, the short-circuit impedance is HV-MV: 9.75%, the winding arrangement is LV-MV-HV-TV, the yield strength of the medium-voltage winding is 90 MPa, the wire gauge of the medium-voltage winding is 2.24*12.5 mm, the reactance height of the medium-voltage winding is 1280 mm, and the number of spacers in the medium-voltage winding is 20.

[0108] The first calculation module 200 is used to obtain the maximum through-short-circuit current value of the transformer winding according to the transformer design parameters and the operating conditions of the power system where the transformer is located.

[0109] In this embodiment, the transformer design parameters include the rated current of the transformer winding and the per-unit value of the transformer short-circuit impedance; the operating conditions of the power system where the transformer is located include the per-unit value of the short-circuit impedance of the power grid system; the maximum through-short-circuit current value of the transformer winding is obtained in the first calculation module 200 through the following method:

[0110]

[0111] where, I m is the maximum through-short-circuit current value of the transformer winding, I N is the rated current of the transformer winding, Z T is the per-unit value of the transformer short-circuit impedance, and Z S is the per-unit value of the short-circuit impedance of the power grid system.

[0112] Furthermore, the short-circuit conditions corresponding to different types of transformers are also different. For a two-winding transformer, the short-circuit condition is high voltage - low voltage; for a three-winding transformer, the short-circuit conditions are divided into four types: high voltage - low voltage, high voltage - medium voltage, medium voltage - low voltage, and high voltage + medium voltage - low voltage; corresponding to different conditions, the maximum through-short-circuit current values obtained for the transformer will also be different accordingly.

[0113] In a specific embodiment, the maximum through-short-circuit current value of the transformer winding is 5.6 kA.

[0114] In this way, through the first calculation module 200, according to the per-unit value of the short-circuit impedance of the power grid system, the rated current of the transformer winding, and the per-unit value of the transformer short-circuit impedance, obtaining the maximum through-current value suffered by the transformer winding under short-circuit conditions can specifically analyze the short-circuit resistance ability of the transformer according to specific conditions and improve the calculation accuracy.

[0115] The second calculation module 300 is configured to input the maximum through - short - circuit current value of the transformer winding into a first pre - designed calculation model to obtain the first stress value of each disk of the transformer winding; wherein, the first pre - designed calculation model is determined by transformer design parameters;

[0116] In this embodiment, the transformer design parameters include iron - core structure parameters, winding structure parameters based on ineffective radial support, pressing structure parameters, and oil - tank parameters; the first pre - designed calculation model is a finite - element electromagnetic model;

[0117] Establish a finite - element electromagnetic model according to the iron - core structure parameters, winding structure parameters based on ineffective radial support, pressing structure parameters, and oil - tank parameters;

[0118] Input the maximum through - short - circuit current value of the transformer winding into the finite - element electromagnetic model to obtain the first stress value of each disk of the transformer winding.

[0119] In a specific embodiment, establish a finite - element electromagnetic model according to the iron - core structure parameters, winding structure parameters based on ineffective radial support, pressing structure parameters, and oil - tank parameters. Use finite - element electromagnetic software to calculate the magnitude of the leakage magnetic field B at different positions of the winding. The magnitude of the electrodynamic force F of different disks can be obtained through the Lorentz force formula. Then, according to the cross - sectional parameters of the winding conductor, through the material mechanics formula, finally calculate the stress value of each disk of the transformer winding. Considering the transmission characteristics of the electrodynamic force of the disk, the average leakage magnetic field is used for calibration detection during calculation, that is, the electrodynamic force and stress for calibration detection are the average electrodynamic force and average stress values of different disks. Finally, the first stress value of each disk of the transformer winding is calculated as 61.2 MPa.

[0120] Thus, in the second calculation module 300, according to the iron - core structure parameters, winding structure parameters based on ineffective radial support, pressing structure parameters, and oil - tank parameters of the transformer, establish a corresponding finite - element electromagnetic model, which can rely on finite - element computer - related software to accurately calculate the first stress value, reduce the calculation time, improve work efficiency, and improve the accuracy of the detection result.

[0121] The third calculation module 400 is configured to obtain the second stress value of each disk of the transformer winding by using a second preset method according to the transformer design parameters;

[0122] Please refer to Figure 3 , the numerical curve graph of the radial critical stress based on ineffective radial support provided by the present invention. In this embodiment, the transformer design parameters include the yield strength and thickness of the transformer wire; determine the second stress value of each disk of the transformer winding through the following method:

[0123] σ l =(Aσ0.2 (+B)lnb eq +C

[0124] σ l is the second stress value of each turn of the transformer winding, σ 0.2 is the yield strength of the conductor, b eq is the thickness of the conductor, and A, B, and C are preset coefficients.

[0125] In a specific embodiment, the numerical range of the preset coefficient A includes 0.13 - 0.15; the numerical range of the preset coefficient B includes 6 - 8; the numerical range of the preset coefficient C includes 12 - 15.

[0126] In a specific embodiment, the second stress value is 26.3 - 32.3 MPa.

[0127] In this way, through the third calculation module 400, corresponding calculations are performed on the preset coefficients within a certain numerical range, making the detection of the short - circuit resistance of the transformer more accurate.

[0128] The fourth calculation module 500 is used to obtain the second current value of the transformer winding in a third preset manner according to the first stress value and the second stress value of each turn of the transformer winding;

[0129] In this embodiment, obtaining the second current value of the transformer winding in a third preset manner according to the first stress value and the second stress value of each turn of the transformer winding specifically means:

[0130] Obtain the estimated range of the second current value according to the first stress value and the second stress value of each turn of the transformer winding;

[0131] Obtain the second current value according to the estimated range of the second current value and the second stress value of each turn of the transformer winding.

[0132] In a specific embodiment, first obtain the estimated range of the second current value according to the first stress value and the second stress value of each turn of the transformer winding, then randomly select two values within the estimated range of the second current value and substitute them into the first preset calculation model to obtain the corresponding stress values. Compare the magnitudes of the corresponding stress values with the second stress value and use an iterative method to continuously obtain the corresponding stress values. Finally, when the corresponding stress value is equal to the second stress value, the second current value is determined at this time.

[0133] In a specific embodiment, the second current value is the withstand current value of 3.7 - 4.1 kA, and the second stress value is the radial critical stress value of 26.3 - 32.3 MPa.

[0134] In this way, the range of the first stress value is obtained through the fourth calculation module 500, and correspondingly, the range of the corresponding current value is obtained. Then, through the first pre-designed calculation model, an accurate current value is obtained, reducing the user's calculation time and improving work efficiency.

[0135] The fifth calculation module 600 is used to obtain the safety margin of the transformer according to the second current value of the transformer winding and the maximum through-short-circuit current value of the transformer winding;

[0136] In a specific embodiment, obtaining the safety margin of the transformer according to the second current value of the transformer winding and the maximum through-short-circuit current value of the transformer winding is specifically as follows:

[0137]

[0138] where K is the safety margin, I2 is the second current value, and I m is the maximum through-short-circuit current value of the winding.

[0139] In a specific embodiment, the safety margin obtained through the fifth calculation module 600 is 0.66 - 0.73. By reflecting the safety margin value through the ratio of current values, more accurate evaluation data can be obtained, which can more accurately express the safety margin and reduce the errors caused by simulation and calculation.

[0140] The judgment module 700 is used to determine the short-circuit resistance ability of the transformer according to the safety margin of the transformer;

[0141] In this embodiment, determining the short-circuit resistance ability of the transformer according to the safety margin of the transformer is specifically as follows:

[0142] When the safety margin of the transformer is greater than the first threshold, the short-circuit resistance ability of the transformer is qualified;

[0143] When the safety margin of the transformer is less than the first threshold, the short-circuit resistance ability of the transformer is unqualified.

[0144] In a specific embodiment, when the safety margin value is greater than 1.0, it indicates that the short-circuit resistance ability of the transformer is qualified, and when the safety margin value of the transformer is less than 1.0, it indicates that the short-circuit resistance ability of the transformer is unqualified.

[0145] Please refer to Figure 4 , which is the critical state diagram of the transformer winding after suffering from the withstand short-circuit current in an embodiment of a method for detecting the short-circuit resistance ability of a transformer provided by the present invention. In this embodiment, the safety margin value is 0.66 - 0.73, which is much lower than the first threshold of 1.0. Therefore, it is determined that the short-circuit resistance ability of the transformer is insufficient.

[0146] In this way, the transformer design parameters and the operating conditions of the power system where the transformer is located are obtained through the acquisition module 100. Then, the maximum through-fault short-circuit current value of the transformer winding is obtained through the first calculation module 200. The maximum through-fault short-circuit current value of the transformer can be calculated based on the specific design parameters of the transformer and the voltage, current, and impedance of the power system where the transformer is located, making the detection of the transformer's short-circuit resistance more accurate. Then, through the second calculation module 300, the maximum through-fault short-circuit current value of the obtained transformer winding is input into the first pre-designed calculation model, that is, the finite element electromagnetic model, to obtain the first stress value of each turn of the corresponding transformer winding, improving the calculation accuracy, reducing the calculation error, and improving the calculation efficiency. The second stress value of each turn of the transformer winding is obtained by using the third calculation module 400. In this way, the short-circuit resistance of the transformer can be effectively detected. The second current value is obtained through the fourth calculation module 500, and then the safety margin of the transformer is obtained through the fifth calculation module 600. By determining whether the safety margin exceeds the first threshold through the judgment module 700, it is detected whether the short-circuit resistance of the transformer is qualified. In this way, the short-circuit resistance of the transformer can be judged at low cost and high efficiency, effectively reducing the risk of power system operation failures.

[0147] Embodiment III

[0148] [[ID=⑥]]The embodiment of the present invention also provides a terminal device, including a processor, a memory, and a computer program running on the memory. When the processor executes the computer program, the steps of any one of the methods for detecting the short-circuit resistance of a transformer as described in the present invention are implemented.

[0149] Embodiment IV

[0150] The embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by the processor, the steps of any one of the methods for detecting the short-circuit resistance of a transformer as described in the present invention are implemented.

[0151] Embodiment V

[0152] The embodiment of the present invention also provides a computer program product, including a computer program, characterized in that when the computer program is executed by a processor, the steps of any one of the methods for detecting the short-circuit resistance of a transformer as described in the present invention are implemented.

[0153] The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0154] Those of ordinary skill in the art will understand that all or some of the steps and systems disclosed above can be implemented as software, firmware, hardware, and their appropriate combinations. Some physical components or all physical components can be implemented as software executed by a processor, such as a central processing unit, a digital signal processor, or a microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include a computer storage medium (or non-transitory medium) and a communication medium (or transitory medium). As is well known to those of ordinary skill in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory, or other memory technologies, CD-ROM, digital versatile disk (DVD), or other optical disk storage, magnetic cassettes, tapes, magnetic disk storage, or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, as is well known to those of ordinary skill in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave or other transmission mechanism, and can include any information delivery medium.

[0155] In the description of this specification, the description of reference terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0156] In addition, the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of these features. In the description of this application, "plural" means two or more, unless otherwise specifically defined.

[0157] Any process or method description represented in a flowchart or otherwise described herein can be understood to represent a module, segment, or portion of code including one or more executable instructions for implementing a specific logical function or process. The scope of the preferred embodiments of the present application includes additional implementations in which functions may be executed not in the order shown or discussed, including in a substantially simultaneous manner or in the reverse order according to the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application pertain.

[0158] The logic and / or steps represented in a flowchart or otherwise described herein, for example, can be considered a sequenced list of executable instructions for implementing a logical function and can be embodied specifically in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device or in connection with these instruction execution systems, apparatus, or devices.

[0159] The specific embodiments described above have further elaborated on the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above description is only for the specific embodiments of the present invention and is not intended to limit the scope of protection of the present invention. In particular, it is pointed out that for those skilled in the art, any modifications, equivalent replacements, 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 detecting the short-circuit resistance of a transformer, characterized in that: include: Obtain transformer design parameters and operating conditions of the power system where the transformer is located; Obtaining a maximum short-circuit current value of the transformer winding according to the transformer design parameters and the operating conditions of the power system in which the transformer is located; Inputting the maximum short-circuit current value of the transformer winding into a first preset calculation model to obtain a first stress value of each coil of the transformer winding; wherein the first preset calculation model is determined by the transformer design parameters; According to the transformer design parameters, a second stress value of each coil of the transformer winding is obtained using a second preset method; Obtaining a second current value of the transformer winding in a third preset manner according to the first stress value of each coil of the transformer winding and the second stress value of each coil of the transformer winding; Obtaining a safety margin of the transformer according to the second current value of the transformer winding and the maximum short-circuit current value of the transformer winding; The short-circuit resistance of the transformer is determined based on the safety margin of the transformer.

2. A method for detecting the short-circuit resistance of a transformer according to claim 1, characterized in that: The transformer design parameters include the transformer winding rated current and the transformer short-circuit impedance per unit value; the operating status of the power system where the transformer is located includes the power grid system short-circuit impedance per unit value; The maximum short-circuit current value of the transformer winding is obtained by: Among them, I m is the maximum short-circuit current of the transformer winding, I N is the rated current of the transformer winding, Z T is the per-unit short-circuit impedance of the transformer, Z S It is the per-unit value of the short-circuit impedance of the power grid system.

3. A method for detecting the short-circuit resistance of a transformer according to claim 1, characterized in that: The transformer design parameters include core structure parameters, winding structure parameters based on ineffective radial support, compression structure parameters, and oil tank parameters; the first preset calculation model is a finite element electromagnetic model; Establishing a finite element electromagnetic model based on the core structure parameters, the winding structure parameters based on the invalid radial support, the compression structure parameters and the oil tank parameters; The maximum short-circuit current value of the transformer winding is input into the finite element electromagnetic model to obtain the first stress value of each coil of the transformer winding.

4. A method for detecting the short-circuit resistance of a transformer according to claim 1, characterized in that: The transformer design parameters include the yield strength and thickness of the transformer conductor; The second stress value of each coil of the transformer winding is determined by: s l =(Aσ 0.2 +B)lnb eq +C σ l is the second stress value of each coil of the transformer winding, σ 0.2 is the conductor yield strength, b eq is the thickness of the wire, and A, B and C are preset coefficients.

5. A method for detecting the short-circuit resistance of a transformer according to claim 4, characterized in that: The numerical range of the preset coefficient A includes 0.13-0.15; the numerical range of the preset coefficient B includes 6-8; and the numerical range of the preset coefficient C includes 12-15.

6. A method for detecting the short-circuit resistance of a transformer according to claim 1, characterized in that: The second current value of the transformer winding is obtained in a third preset manner according to the first stress value of each coil of the transformer winding and the second stress value of each coil of the transformer winding, specifically: Obtaining an estimated range of a second current value according to a first stress value of each coil of the transformer winding and a second stress value of each coil of the transformer winding; The second current value is obtained according to the estimated range of the second current value and the second stress value of each coil of the transformer winding.

7. A method for detecting the short-circuit resistance of a transformer according to claim 1, characterized in that: The safety margin of the transformer is obtained according to the second current value of the transformer winding and the maximum short-circuit current value of the transformer winding, specifically: Among them, K is the safety margin, I2 is the second current value, I m It is the maximum short-circuit current value of the winding.

8. A method for detecting the short-circuit resistance of a transformer according to claim 1, characterized in that: The short-circuit resistance of the transformer is determined according to the safety margin of the transformer, specifically: When the safety margin of the transformer is greater than the first threshold, the short-circuit resistance of the transformer is qualified; When the safety margin of the transformer is less than the first threshold, the short-circuit resistance of the transformer is unqualified.

9. A transformer short-circuit resistance detection system, characterized in that: include: an acquisition module, a first calculation module, a second calculation module, a third calculation module, a fourth calculation module, a fifth calculation module, and a judgment module; The acquisition module is used to obtain the transformer design parameters and the operating status of the power system where the transformer is located; The first calculation module is used to obtain the maximum short-circuit current value of the transformer winding according to the transformer design parameters and the operating status of the power system where the transformer is located; The second calculation module is used to input the maximum short-circuit current value of the transformer winding into a first preset calculation model to obtain a first stress value of each coil of the transformer winding; wherein the first preset calculation model is determined by the transformer design parameters; The third calculation module is used to obtain the second stress value of each coil of the transformer winding using a second preset method according to the transformer design parameters; The fourth calculation module is used to obtain a second current value of the transformer winding in a third preset manner according to the first stress value of each coil of the transformer winding and the second stress value of each coil of the transformer winding; The fifth calculation module is used to obtain a safety margin of the transformer according to the second current value of the transformer winding and the maximum short-circuit current value of the transformer winding; The judgment module is used to determine the short-circuit resistance capability of the transformer according to the safety margin of the transformer.

10. A terminal device, characterized in that: The method comprises a processor, a memory and a computer program stored and running on the memory, wherein when the processor executes the computer program, the steps of the method for detecting the short-circuit resistance capability of a transformer according to any one of claims 1 to 8 are implemented.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for detecting the short-circuit withstand capability of a transformer as claimed in any one of claims 1 to 8 are implemented.

12. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method for detecting the short-circuit withstand capability of a transformer as claimed in any one of claims 1 to 8 are implemented.

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