Method for acquiring equivalent resistance of transformer winding and related equipment

Abstract

The embodiment of the invention discloses a method for obtaining equivalent resistance of a transformer winding and related equipment. The method comprises the following steps: constructing an equivalent circuit model of the transformer winding; taking a wire turn of the transformer winding as a conductor unit, and obtaining conductor current density of the equivalent circuit model under alternating current with different frequencies by using a finite element method; and obtaining the conductor equivalent resistance of the transformer winding according to the conductor current density, the alternating current and the cross sectional area of the conductor unit. According to the method, the influence of frequency change and current distribution on winding resistance is considered, the conductor current density of the equivalent circuit model under alternating current of different frequencies is obtained, and the corresponding conductor equivalent resistance is obtained based on the conductor current density, so that the error of the conductor equivalent resistance obtained under the specific frequency is relatively small.

Description

[Technical field]

[0001] The present invention relates to the technical field of winding analysis and testing, and in particular to a method for obtaining equivalent resistance of a transformer winding and related equipment. [Background technology]

[0002] As an indispensable key equipment in the power system, the transformer not only ensures the efficient transmission and distribution of electricity, but also plays a positive role in the sustainable development of the entire social economy, the improvement of people's living standards and social stability. The transformer winding is the key core component of the transformer to achieve voltage and current conversion, energy distribution and transmission. Its safe and stable operation is directly related to the reliable power supply of the power system. However, due to the complex structure and long-term working state of the transformer winding, coupled with the influence of various factors such as long-term heavy load and overload operation of the transformer and the complex working environment in which it is located, the performance parameters of the transformer winding will deteriorate, and even winding deformation, turn-to-turn short circuit and other faults will occur, causing the transformer to stop operating, causing substation pressure loss, and large-scale regional power outages, greatly reducing the reliability of the power system, seriously affecting the normal power consumption of industrial production and public service facilities, causing serious economic losses, and threatening the sustainable and healthy development of society. At the same time, winding faults may cause internal short circuits or partial discharges in the transformer, thereby aggravating the damage of the transformer, and even causing fires or explosions, threatening the safety of personnel and property. In addition, winding faults may cause the performance of the transformer to decline, increase the load of the power system, and thus affect the stable operation of the power system. Therefore, the performance parameters of transformer windings are of great significance to the operation of the power system, and the monitoring, accurate calculation and comparative analysis of the equivalent resistance of transformer windings are particularly important.

[0003] Equivalent resistance parameters are important indicators for evaluating transformer winding performance. Traditional methods for calculating equivalent resistance parameters often ignore the impact of frequency changes on winding resistance and do not carefully consider the current distribution. Instead, they give equivalent resistance based on the geometric dimensions and electromagnetic properties of the conductor, resulting in large errors in the calculation results at specific frequencies. [Summary of the invention]

[0004] In view of this, the present invention provides a method for obtaining the equivalent resistance of a transformer winding and related equipment.

[0005] The specific technical solution of the first embodiment of the present invention is: a method for obtaining the equivalent resistance of a transformer winding, the method comprising: constructing an equivalent circuit model of the transformer winding; using the turns of the transformer winding as conductor units, and using the finite element method to obtain the conductor current density of the equivalent circuit model under alternating currents of different frequencies; and obtaining the conductor equivalent resistance of the transformer winding based on the conductor current density, the alternating current and the cross-sectional area of ​​the conductor unit.

[0006] Preferably, constructing the equivalent circuit model of the transformer winding includes: constructing the equivalent circuit model according to the winding shape, size, material and connection method of the transformer winding.

[0007] Preferably, constructing the equivalent circuit model according to the winding shape, size, material and connection method of the transformer winding includes: modeling the transformer winding based on the winding shape, size and material and using electromagnetic field simulation software; analyzing the electromagnetic field distribution characteristics of the transformer winding by using the modeled model simulation; extracting the simulated inductance and simulated capacitance of the transformer winding according to the electromagnetic field distribution characteristics, and correcting the simulated inductance according to the actual inductance of the transformer winding, and correcting the simulated capacitance according to the actual capacitance of the transformer winding; constructing the equivalent circuit model using the corrected simulated inductance, corrected simulated capacitance and the connection method of the winding.

[0008] Preferably, the method of using the finite element method to obtain the conductor current density of the equivalent circuit model under alternating currents of different frequencies includes: setting boundary conditions for the current and voltage of the transformer winding; using finite element software to mesh the equivalent circuit model, dividing the transformer winding into a finite number of units; setting material properties for each unit; the material properties include electrical conductivity and magnetic permeability; constructing finite element equations based on Maxwell's equations, the boundary conditions and the material properties of each unit; and solving the finite element equations to obtain the conductor current density of each unit.

[0009] Preferably, obtaining the conductor equivalent resistance of the transformer winding according to the conductor current density, the alternating current and the cross-sectional area of ​​the conductor unit comprises: obtaining the conductor equivalent resistance in a field calculator according to the conductor current density, the alternating current, the cross-sectional area of ​​the conductor unit and the conductor conductivity.

[0010] Preferably, the conductor equivalent resistance is obtained using the following formula:

[0011] I 2 R eq =∫ S J 2 σ -1 dS

[0012] Where, |I| is the effective value of the AC current, R eq is the conductor equivalent resistance, S is the cross-sectional area of ​​the conductor unit, J is the conductor current density, and σ is the conductor conductivity.

[0013] Preferably, the effective value of the alternating current is obtained according to the waveform data of the alternating current and the cycle length of the alternating current.

[0014] The specific technical solution of the second embodiment of the present invention is: a system for acquiring an equivalent resistance of a transformer winding, characterized in that the system includes: an equivalent model construction module, a conductor current density acquisition module and a conductor equivalent resistance acquisition module; the equivalent model construction module is used to construct an equivalent circuit model of the transformer winding; the conductor current density acquisition module is used to use the turns of the transformer winding as conductor units, and use the finite element method to obtain the conductor current density of the equivalent circuit model under alternating currents of different frequencies; the conductor equivalent resistance acquisition module is used to obtain the conductor equivalent resistance of the transformer winding according to the conductor current density, the alternating current and the cross-sectional area of ​​the conductor unit.

[0015] The specific technical solution of the third embodiment of the present invention is: an equivalent resistance acquisition device for a transformer winding, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method described in any one of the first embodiments of the present application.

[0016] The specific technical solution of the fourth embodiment of the present invention is: a computer-readable storage medium storing a computer program, which, when executed by a processor, enables the processor to perform the steps of the method described in any one of the first embodiments of the present application.

[0017] Implementing the embodiments of the present invention will have the following beneficial effects:

[0018] The present invention constructs an equivalent circuit model of a transformer winding; uses the turns of the transformer winding as conductor units, and uses the finite element method to obtain the conductor current density of the equivalent circuit model under alternating currents of different frequencies; and obtains the conductor equivalent resistance of the transformer winding according to the conductor current density, the alternating current, and the cross-sectional area of ​​the conductor unit. Considering the influence of frequency change and current distribution on the winding resistance, the present application obtains the conductor current density of the equivalent circuit model under alternating currents of different frequencies, and obtains the corresponding conductor equivalent resistance based on the conductor current density, so that the error of the conductor equivalent resistance obtained at a specific frequency is small.

Brief Description of the Drawings

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A flowchart of a method for obtaining the equivalent resistance of a transformer winding;

[0021] Figure 2 is a schematic diagram of the equivalent circuit model of the transformer winding;

[0022] Figure 3a This is a schematic diagram of the current density distribution of the conductor at a frequency of 1kHz;

[0023] Figure 3b It is a schematic diagram of the current density distribution of the conductor at a frequency of 100kHz;

[0024] Figure 3c Schematic diagram of the current density distribution of the conductor at a frequency of 600kHz;

[0025] Figure 3d It is a schematic diagram of the current density distribution of the conductor at a frequency of 1000kHz;

[0026] Figure 4 It is a structural schematic diagram of a system for obtaining equivalent resistance of a transformer winding;

[0027] Figure 5 It is a diagram of the internal structure of a computer device;

[0028] Among them, 201 is an equivalent model building module; 202 is a conductor current density acquisition module; 203 is a conductor equivalent resistance acquisition module. [Specific implementation method]

[0029] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] The terms "first", "second", etc. in the specification, claims and drawings of this application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or modules is not limited to the listed steps or modules, but optionally includes steps or modules that are not listed, or optionally includes other steps or modules that are inherent to these processes, methods, products or devices.

[0031] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0032] See also Figure 1 , is a flowchart of a method for obtaining an equivalent resistance of a transformer winding in the first embodiment of the present application, so that the error of the conductor equivalent resistance obtained at a specific frequency is small, and the method includes:

[0033] Step 101, constructing an equivalent circuit model of a transformer winding;

[0034] Step 102: using the turns of the transformer winding as conductor units, and using the finite element method to obtain the conductor current density of the equivalent circuit model under alternating currents of different frequencies;

[0035] Step 103: Obtain the conductor equivalent resistance of the transformer winding according to the conductor current density, the alternating current and the cross-sectional area of ​​the conductor unit.

[0036] The method in this embodiment constructs an equivalent circuit model of the transformer winding; uses the turns of the transformer winding as conductor units, and uses the finite element method to obtain the conductor current density of the equivalent circuit model under alternating currents of different frequencies; and obtains the conductor equivalent resistance of the transformer winding according to the conductor current density, the alternating current, and the cross-sectional area of ​​the conductor unit. Considering the influence of frequency changes and current distribution on the winding resistance, the present application obtains the conductor current density of the equivalent circuit model under alternating currents of different frequencies, and obtains the corresponding conductor equivalent resistance based on the conductor current density, so that the error of the conductor equivalent resistance obtained at a specific frequency is small.

[0037] Specifically, since the equivalent resistance parameter measurement and port response test analysis of the winding are mainly carried out in the high frequency band, the skin effect and proximity effect are significantly affected. The current will be concentrated on the surface of the winding conductor or the edge of the cross section under the influence of the rising frequency, which will cause the current density in the conductor path to change, further affecting the winding resistance value. For a schematic diagram of the equivalent circuit model of the transformer winding, please refer to Figure 2 The resistance in the equivalent circuit model of the transformer winding is divided into two parts. One part is the resistance in series with the inductance, which represents the variable loss caused by the copper conductor in the winding; the other part is the conductance in parallel with the capacitor, which represents the capacitive loss caused by the leakage current.

[0038] Based on the winding turns as conductor units, the current density distribution of the conductor at different frequencies was analyzed by using the two-dimensional finite element eddy current field of ANSYS Maxwell. Figure 3a , Figure 3b , Figure 3c and Figure 3d As shown in the conductor current density distribution diagram, the distribution of current density is greatly affected by frequency. Figure 3a It can be seen that at 1kHz, the current density distribution has shown a trend of gradually concentrating from the center to the edge, but the overall difference is not large; according to Figure 3b It can be seen that at 100kHz, the current density is obviously distributed at the edge of the conductor cross section, with the highest reaching 8.1715e+7A / m2, and the current density in the central area is close to 0A / m2; according to Figure 3c It can be seen that when the frequency is greater than 600kHz, the current density distribution is basically concentrated at the four corners of the conductor cross section, with the highest reaching 4.0339e+8A / m2, and the current density in the middle of the turn is 0A / m2. Figure 3d It can be seen that as the frequency increases, the winding is more significantly affected by the skin effect and proximity effect, the current carrying capacity of the conductor gradually decreases, and the winding resistance value increases. Therefore, the calculation methods for the resistance of copper conductors include the finite element method and the formula method. The finite element method calculates the current density distribution in the conductor at different frequencies based on the eddy current field, and then uses the field calculator to calculate the equivalent resistance of the conductor.

[0039] In a specific embodiment, constructing the equivalent circuit model of the transformer winding includes: constructing the equivalent circuit model according to the winding shape, size, material and connection method of the transformer winding.

[0040] Specifically, the winding can be wound in various forms, such as spiral, disc, cylinder, cross, etc., and windings of different shapes will affect the inductance, capacitance, and resistance of the winding. The size of the winding (such as diameter, length, number of turns, etc.) will affect its electrical performance. An increase in the number of turns usually increases the inductance, while changes in the diameter and length of the winding will affect the resistance and capacitance. The conductivity and magnetic permeability of the winding material will affect the resistance and inductance of the winding. Commonly used winding materials include conductive materials such as copper and aluminum, and core materials (such as silicon steel sheets) to enhance magnetic permeability. The windings can be connected in series or in parallel, which will affect the total resistance, total inductance, and total capacitance of the circuit. When connected in series, the current of each winding is the same; when connected in parallel, the voltage across each winding is the same. Ideally, the transformer has no energy loss, and all magnetic fluxes are perfectly coupled between the windings. At this time, the equivalent circuit model only includes an ideal transformer with a turns ratio of n=N2 / N1, where N1 and N2 are the turns of the primary and secondary windings, respectively. In actual situations, transformers have various non-ideal factors, such as resistance, inductance, capacitance, and magnetic leakage.

[0041] The equivalent circuit model needs to include these non-ideal factors:

[0042] 1. Resistance: includes the resistance of the primary and secondary windings (Rp, Rs), as well as possible parallel resistance (such as the resistance equivalent to the core loss Rc).

[0043] 2. Inductance: includes the self-inductance of the primary and secondary windings (Llp, Lls), as well as the inductance caused by mutual inductance.

[0044] 3. Capacitance: includes the capacitance between windings (Cww) and the distributed capacitance of primary and secondary windings (CDP, CDS).

[0045] 4. Leakage magnetic field: simulated by leakage inductance (inductance in series with ideal self-inductance).

[0046] Construct an equivalent circuit model based on the winding shape, size, material, and connection method of the winding, and clearly mark the parameters of each component (such as resistance, inductance, capacitance, etc.) and their connection methods. Use circuit simulation software (such as Multisim, PSpice, etc.) to simulate and verify the equivalent circuit model. By comparing the simulation results with the performance parameters of the actual transformer, the accuracy of the equivalent circuit model can be evaluated. According to the simulation results, adjust and optimize the parameters in the equivalent circuit model. Repeat the simulation verification process until satisfactory model accuracy is obtained.

[0047] In a specific embodiment, the equivalent circuit model is constructed according to the winding shape, size, material and connection method of the transformer winding, including: modeling the transformer winding based on the winding shape, size and material and using electromagnetic field simulation software; using the modeled model to simulate and analyze the electromagnetic field distribution characteristics of the transformer winding; extracting the simulated inductance and simulated capacitance of the transformer winding according to the electromagnetic field distribution characteristics, and correcting the simulated inductance according to the actual inductance of the transformer winding, and correcting the simulated capacitance according to the actual capacitance of the transformer winding; and constructing the equivalent circuit model using the corrected simulated inductance, corrected simulated capacitance and the connection method of the winding.

[0048] Specifically, through simulation analysis and correction, the equivalent circuit model can more accurately reflect the electromagnetic characteristics of the transformer winding, including key parameters such as inductance and capacitance. Compared with direct measurement, using the corrected simulation value to build the model can reduce errors caused by measurement errors, instrument accuracy and other factors. An accurate equivalent circuit model can provide strong support for the optimal design of the transformer. By adjusting the parameters in the model, the performance under different design schemes can be predicted, so as to select the optimal scheme. During the operation of the transformer, the equivalent circuit model can be used to evaluate its performance, including key indicators such as voltage fluctuations, current distribution, and losses. This helps to detect potential problems in a timely manner and make optimization adjustments.

[0049] In a specific embodiment, the method of using the finite element method to obtain the conductor current density of the equivalent circuit model under alternating current of different frequencies includes: setting boundary conditions of current and voltage of the transformer winding; using finite element software to mesh the equivalent circuit model and divide the transformer winding into a finite number of units; setting material properties for each unit; the material properties include conductivity and magnetic permeability; constructing a finite element equation based on Maxwell's equations, the boundary conditions and the material properties of each unit; and solving the finite element equation to obtain the conductor current density of each unit.

[0050] Specifically, according to the actual operation of the transformer and the analysis requirements, determine the boundary condition type of current and voltage. Common boundary conditions include current source, voltage source, grounding, etc.; set the current source at the input or output end of the winding to specify the magnitude and direction of the current. If the AC current is analyzed, the amplitude and phase of the current need to be specified; set the voltage source or grounding condition at the other end of the winding or at a specific position. The voltage source can specify the magnitude and phase of the voltage, while the grounding condition means that the potential at this point is zero. Import the equivalent circuit model of the transformer into the finite element software. In the finite element software, mesh the transformer winding. The density of the mesh should be reasonably selected according to the analysis accuracy and computing resources. The mesh can be appropriately encrypted in areas where the current density changes greatly (such as winding ends, joints, etc.). In the finite element software, define the type of material used for the winding. This usually includes conductive materials such as copper and aluminum. According to the physical properties of the material, set its conductivity and magnetic permeability. These parameters will affect the current distribution and electromagnetic field distribution in the winding. In the finite element software, select the electromagnetic field as the physical field for analysis. This typically includes options such as electric, magnetic, or coupled electromagnetic analysis. The finite element equations are constructed based on Maxwell's equations, boundary conditions, and material properties for each element. These equations will describe the electromagnetic field distribution and current density distribution in the winding. In the finite element software, the solver type and solution parameters are set. This includes selecting an iterative solver or a direct solver, and setting convergence criteria and number of iterations. Run the solver to solve the finite element equations. This typically requires a certain amount of computing time and resources, depending on the complexity of the model and the density of the mesh. After the solution is completed, extract the results of the conductor current density from the finite element software. This can be done by viewing the result file or using post-processing tools. The results are usually presented in the form of graphs or data tables, which can intuitively show the current density distribution in the winding.

[0051] In a specific embodiment, the obtaining of the conductor equivalent resistance of the transformer winding according to the conductor current density, the alternating current and the cross-sectional area of ​​the conductor unit comprises: obtaining the conductor equivalent resistance according to the conductor current density, the alternating current, the cross-sectional area of ​​the conductor unit and the electrical conductivity of the conductor in a field calculator. Specifically, by considering the conductor current density, cross-sectional area and electrical conductivity, the local resistance of each conductor unit can be accurately calculated. This method can better reflect the resistance distribution inside the conductor than the traditional overall resistance calculation method. Field calculators are generally capable of handling complex geometries and boundary conditions. Therefore, this method can be applied to conductors with complex geometries without simplification or approximation.

[0052] In a specific embodiment, the conductor equivalent resistance is obtained using the following formula:

[0053] I 2 Req =∫ S J 2 σ -1 dS

[0054] Where, |I| is the effective value of the AC current, R eq is the conductor equivalent resistance, S is the cross-sectional area of ​​the conductor unit, J is the conductor current density, and σ is the conductor conductivity.

[0055] In a specific embodiment, the effective value of the alternating current is obtained according to the waveform data of the alternating current and the cycle length of the alternating current. Specifically, the waveform data of the alternating current is obtained by measurement or simulation, including the instantaneous value of the current changing with time. The cycle length of the alternating current, that is, the time required for a complete waveform, is determined according to the waveform data. Each instantaneous value in the waveform data is squared to obtain a square sequence of instantaneous values. The square sequence of instantaneous values ​​is integrated within a cycle (or summed and divided by the cycle length) to obtain the average value of the square of the instantaneous value. The square root of the average value of the square of the instantaneous value is taken to obtain the effective value of the alternating current.

[0056] In a specific embodiment, the existing technical solution is to use a formula method to obtain the equivalent resistance. Specifically, the formula method does not carefully consider the distribution of the current, but gives a solution expression for the equivalent resistance based on the geometric size and electromagnetic characteristics of the conductor, as shown below:

[0057]

[0058] Among them, n z is the number of turns of the coil unit, d b is the winding coil diameter, h a and h r are the axial height and radial width of the turns, respectively, f is the frequency of the excitation signal, μ is the magnetic permeability of the conductor, and σ is the electrical conductivity of the conductor.

[0059]

[0060] Table 1: Conductor resistance values ​​at frequency points

[0061] Table 1 shows the comparison of copper conductor resistance parameters calculated at the main frequency points using the finite element method and the formula method, where HV is the high voltage winding, MV is the medium voltage winding, and LV is the low voltage winding. It can be seen from the table that the finite element method and the formula method have a high degree of agreement in the calculation of resistance parameters in the medium and high frequency bands. The two calculation methods verify that the conductor resistance shows an increasing trend with increasing frequency. The MV winding is calculated to be 0.549Ω by the finite element method at 1MHz, and the LV winding maintains a small value in the entire frequency band. At 1MHz, the finite element method and the formula method are calculated to be 0.150Ω and 0.147Ω respectively. Therefore, when the equivalent resistance value of the transformer winding is measured and calculated, the equivalent resistance value obtained by the finite element method is more accurate.

[0062] In the specific embodiments, see Figure 4 , is a schematic diagram of the structure of an equivalent resistance acquisition system for a transformer winding in the second embodiment of the present application, the system comprising: an equivalent model construction module 201, a conductor current density acquisition module 202 and a conductor equivalent resistance acquisition module 203; the equivalent model construction module 201 is used to construct an equivalent circuit model of the transformer winding; the conductor current density acquisition module 202 is used to use the turns of the transformer winding as conductor units, and use the finite element method to obtain the conductor current density of the equivalent circuit model under alternating currents of different frequencies; the conductor equivalent resistance acquisition module 203 is used to obtain the conductor equivalent resistance of the transformer winding according to the conductor current density, the alternating current and the cross-sectional area of ​​the conductor unit. The system in this embodiment constructs an equivalent circuit model of the transformer winding; uses the turns of the transformer winding as conductor units, and uses the finite element method to obtain the conductor current density of the equivalent circuit model under alternating currents of different frequencies; and obtains the conductor equivalent resistance of the transformer winding according to the conductor current density, the alternating current and the cross-sectional area of ​​the conductor unit. Taking into account the influence of frequency change and current distribution on winding resistance, the present application obtains the conductor current density of the equivalent circuit model under alternating current of different frequencies, and obtains the corresponding conductor equivalent resistance based on the conductor current density, so that the error of the conductor equivalent resistance obtained at a specific frequency is small.

[0063] In a specific embodiment, the third embodiment of the present application provides an equivalent resistance acquisition device for a transformer winding, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of the method described in any one of the first embodiments of the present application. The device in this embodiment takes into account the influence of frequency change and current distribution on the winding resistance. The present application obtains the conductor current density of the equivalent circuit model under alternating current of different frequencies, and obtains the corresponding conductor equivalent resistance based on the conductor current density, so that the error of the conductor equivalent resistance obtained at a specific frequency is small.

[0064] In a specific embodiment, the fourth embodiment of the present application provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the processor executes the steps of the method described in any one of the first embodiments of the present application. The storage medium in this embodiment takes into account the influence of frequency change and current distribution on winding resistance. The present application obtains the conductor current density of the equivalent circuit model under alternating current of different frequencies, and obtains the corresponding conductor equivalent resistance based on the conductor current density, so that the error of the conductor equivalent resistance obtained at a specific frequency is small.

[0065] Figure 5 The internal structure of a computer device in one embodiment is shown. The computer device can be a terminal or a server. Figure 5 The computer device includes a processor, a memory, etc. connected via a system bus. The memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system and may also store a computer program. When the computer program is executed by the processor, the processor can implement the method in this embodiment. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor can implement the method in this embodiment. Those skilled in the art can understand that Figure 5 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0066] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

[0067] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for obtaining the equivalent resistance of a transformer winding, characterized in that: The method comprises: Construct an equivalent circuit model of the transformer winding; The turns of the transformer winding are used as conductor units, and the conductor current density of the equivalent circuit model under alternating currents of different frequencies is obtained by using a finite element method; The conductor equivalent resistance of the transformer winding is obtained according to the conductor current density, the alternating current and the cross-sectional area of ​​the conductor unit.

2. The method for obtaining the equivalent resistance of a transformer winding according to claim 1, characterized in that: The constructing of the equivalent circuit model of the transformer winding comprises: The equivalent circuit model is constructed according to the winding shape, size, material and connection mode of the transformer winding.

3. The method for obtaining the equivalent resistance of a transformer winding according to claim 2, characterized in that: The equivalent circuit model is constructed according to the winding shape, size, material and connection mode of the transformer winding, including: Modeling the transformer winding based on the winding shape, the size, and the material using electromagnetic field simulation software; Utilizing the model after modeling to simulate and analyze the electromagnetic field distribution characteristics of the transformer winding; Extracting the simulated inductance and simulated capacitance of the transformer winding according to the electromagnetic field distribution characteristics, and correcting the simulated inductance according to the actual inductance of the transformer winding, and correcting the simulated capacitance according to the actual capacitance of the transformer winding; The equivalent circuit model is constructed by using the modified simulated inductance, the modified simulated capacitance and the connection mode of the winding.

4. The method for obtaining the equivalent resistance of a transformer winding according to claim 1, characterized in that: The method of using the finite element method to obtain the conductor current density of the equivalent circuit model under alternating currents of different frequencies includes: Set boundary conditions for current and voltage of transformer windings; Using finite element software to mesh the equivalent circuit model, dividing the transformer winding into a finite number of units; Setting material properties for each unit; the material properties include electrical conductivity and magnetic permeability; constructing finite element equations based on Maxwell's equations, the boundary conditions and the material properties of each element; The finite element equation is solved to obtain the conductor current density of each unit.

5. The method for obtaining the equivalent resistance of a transformer winding according to claim 1, characterized in that: The obtaining of the conductor equivalent resistance of the transformer winding according to the conductor current density, the alternating current and the cross-sectional area of ​​the conductor unit comprises: The conductor equivalent resistance is obtained in a field calculator according to the conductor current density, the alternating current, the cross-sectional area of ​​the conductor unit and the conductor conductivity.

6. The method for obtaining the equivalent resistance of a transformer winding according to claim 1, characterized in that: The conductor equivalent resistance is obtained using the following formula: I 2 R eq =∫ S J 2 σ -1 dS Where, |I| is the effective value of the AC current, R eq is the conductor equivalent resistance, S is the cross-sectional area of ​​the conductor unit, J is the conductor current density, and σ is the conductor conductivity.

7. The method for obtaining the equivalent resistance of a transformer winding according to claim 6, characterized in that: The effective value of the alternating current is obtained according to the waveform data of the alternating current and the cycle length of the alternating current.

8. A system for obtaining equivalent resistance of transformer windings, characterized in that: The system comprises: an equivalent model building module, a conductor current density acquisition module and a conductor equivalent resistance acquisition module; The equivalent model building module is used to build an equivalent circuit model of the transformer winding; The conductor current density acquisition module is used to use the turns of the transformer winding as conductor units and use the finite element method to obtain the conductor current density of the equivalent circuit model under alternating currents of different frequencies; The conductor equivalent resistance acquisition module is used to obtain the conductor equivalent resistance of the transformer winding according to the conductor current density, the alternating current and the cross-sectional area of ​​the conductor unit.

9. A device for obtaining equivalent resistance of a transformer winding, comprising a memory and a processor, characterized in that: The memory stores a computer program, and when the computer program is executed by the processor, the processor is caused to perform the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the processor is caused to perform the steps of the method according to any one of claims 1 to 7.

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