Power transformer winding deformation analysis method considering electromagnetic field model updating

Abstract

The invention discloses a power transformer winding deformation analysis method considering electromagnetic field model updating, which comprises the following steps: acquiring parameter information of a first object, and constructing a physical simulation model of the first object; acquiring a first operation parameter of the first object for simulation; and realizing deformation analysis by circularly updating the physical simulation model and the first operation parameter. The electromagnetic field model can be updated after each short circuit impact, the magnitude and distribution operation of the electromagnetic force is carried out again, and high-precision magnetic-structure multi-physics field coupling is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of power transformer winding deformation calculation, in particular to a power transformer winding deformation analysis method taking electromagnetic field model updating into account. Background Art

[0002] The operation of power transformers is accompanied by various types of sudden short-circuit accidents. When a short circuit occurs, the corresponding winding generates a short-circuit current, thereby generating a huge short-circuit electromotive force on the coil, causing irreversible plastic deformation of the windings, struts and pads of the power transformer. This deformation accumulates continuously inside the power transformer, causing the transformer structure to continuously deform, and the short-circuit impact force it receives becomes increasingly uneven, further aggravating the deformation caused by the next short-circuit impact. After repeated accumulation, the power transformer winding becomes completely unstable, and the transformer as a whole is damaged and cannot be used any longer.

[0003] In order to avoid damage to power transformers during operation and to improve the stability of power grid operation, it is necessary to invent a technology for actual measurement or theoretical calculation of the deformation size of power transformers after short-circuit impact. The relevant technical personnel of the power grid can replace transformers with high deformation degrees in time according to the obtained deformation size to improve the stability of power grid operation. However, the current deformation measurement technology has many problems in practical application. Most of its measurements are qualitative measurements with low accuracy and difficult to detect in operation. In contrast, deformation calculation technology is mature, high-precision, can be used in operation, and has higher engineering significance.

[0004] The idea of ​​existing deformation calculation technology is to first record the short-circuit current waveform generated by the transformer, and then use multi-physics field software to simulate the short-circuit electromotive force to calculate the deformation size. However, the electromagnetic field model is not updated in the current multi-physics field simulation calculation. The electromagnetic field model at the beginning of the deformation process is only used to calculate the electromagnetic force distribution once, and then the electromagnetic field model and electromagnetic force distribution are no longer updated. In fact, after the winding is deformed by the electromagnetic force, not only will the mapping relationship between the winding model surface and the electromagnetic force be distorted, but the distribution of the electromagnetic force itself will also change. This makes the calculation method produce huge errors when there are multiple short-circuit shocks or the winding has a large deformation, and it cannot be used in engineering. Summary of the invention

[0005] In view of the above-mentioned problems, the present invention is proposed.

[0006] Therefore, the technical problem solved by the present invention is that the existing deformation analysis method has the problem of one-way coupling distortion and optimization problems such as large errors.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for analyzing the deformation of a power transformer winding taking into account the updating of an electromagnetic field model, comprising:

[0008] Acquire parameter information of a first object and construct a physical simulation model of the first object;

[0009] Acquire a first operating parameter of the first object for simulation;

[0010] Deformation analysis is achieved by cyclically updating the physical simulation model and the first operating parameters.

[0011] As a preferred solution of the power transformer winding deformation analysis method taking into account the updating of the electromagnetic field model described in the present invention, the parameter information of the first object includes physical quantities for 3D modeling of the first object.

[0012] As a preferred solution of the power transformer winding deformation analysis method taking into account the electromagnetic field model update described in the present invention, the physical simulation model includes 3D modeling of the first object and recording excitation in the actual engineering application of the first object for testing.

[0013] As a preferred solution of the power transformer winding deformation analysis method taking into account the electromagnetic field model update described in the present invention, wherein: the first operating parameter includes a physical quantity that affects the deformation of the first object during operation.

[0014] As a preferred solution of the power transformer winding deformation analysis method taking into account the electromagnetic field model update described in the present invention, obtaining the first operating parameter of the first object for simulation includes using simulation software to apply the first operating parameter to the first object to simulate the deformation.

[0015] As a preferred solution of the power transformer winding deformation analysis method taking into account the electromagnetic field model update of the present invention, wherein: the cyclic update includes, through bidirectional coupling, while applying the first operating parameter to the first object, feeding back the deformation amount to the first operating parameter, and updating the first operating parameter;

[0016] After completing the update of the first operating parameter, the 3D modeling of the first object is re-acted, and the bidirectional coupling process is continuously repeated to complete the cyclic update.

[0017] As a preferred solution of the power transformer winding deformation analysis method taking into account the electromagnetic field model update of the present invention, the 3D modeling includes but is not limited to, before updating, the winding of the power transformer is equivalent to a cylinder, and 3D modeling of three-phase three-winding is performed;

[0018] After the update, the undeformed winding is replaced with the deformed winding, and it is checked to confirm that there is no rigid overlap between the deformed winding and the iron core; the material parameters of the deformed winding are set, the interface and current are added, and the distribution and magnitude of the electromagnetic force are analyzed and calculated again.

[0019] A power transformer winding deformation analysis system taking into account the electromagnetic field model update using any method as described in the present invention, characterized in that:

[0020] A model building unit, which obtains parameter information of a first object and builds a physical simulation model of the first object;

[0021] A simulation unit, which obtains a first operating parameter of the first object for simulation;

[0022] The analysis unit implements deformation analysis by cyclically updating the physical simulation model and the first operating parameter.

[0023] A computer device comprises: a memory and a processor; the memory stores a computer program, wherein: the processor implements the steps of any one of the methods of the present invention when executing the computer program.

[0024] A computer-readable storage medium stores a computer program, wherein: when the computer program is executed by a processor, the steps of any one of the methods of the present invention are implemented.

[0025] Beneficial effects of the present invention: The present invention provides a method for analyzing the deformation of power transformer windings that takes into account the update of the electromagnetic field model. The electromagnetic field model will be updated after each short-circuit impact, and the magnitude and distribution of the electromagnetic force will be recalculated to achieve high-precision magnetic-structural multi-physics field coupling. This solves the problem that the traditional method for calculating the deformation of power transformer short-circuit impact does not update the electromagnetic field model, resulting in distortion of the electromagnetic force mapping, which ultimately leads to insufficient calculation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0027] Figure 1 An overall flow chart of a method for analyzing deformation of a power transformer winding taking into account the updating of an electromagnetic field model provided by the first embodiment of the present invention;

[0028] Figure 2A simplified model of a three-phase three-winding power transformer in a power transformer winding deformation analysis method taking into account the updating of an electromagnetic field model provided in a third embodiment of the present invention;

[0029] Figure 3 A Simulink circuit design for simulating short-circuit conditions in a power transformer winding deformation analysis method taking into account electromagnetic field model update provided in a third embodiment of the present invention;

[0030] Figure 4 The calculation results of the Maxwell module in the power transformer winding deformation analysis method taking into account the electromagnetic field model update provided by the third embodiment of the present invention;

[0031] Figure 5 The calculation results of the Structure module in the power transformer winding deformation analysis method taking into account the electromagnetic field model update provided by the third embodiment of the present invention;

[0032] Figure 6 A Spaceclaim module updates the model results in a power transformer winding deformation analysis method taking into account the electromagnetic field model update provided in a third embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0034] Example 1, reference Figure 1 , which is an embodiment of the present invention, provides a method for analyzing deformation of a power transformer winding taking into account the updating of an electromagnetic field model, comprising:

[0035] S1: Acquire parameter information of a first object and construct a physical simulation model of the first object.

[0036] The parameter information of the first object includes physical quantities for 3D modeling of the first object. The physical simulation model includes 3D modeling of the first object and recording excitations in actual engineering applications of the first object for testing.

[0037] In an embodiment of the present invention, the first object is a power transformer, and the 3D modeling process is: the winding of the power transformer is equivalent to a cylinder, and a three-phase three-winding 3D modeling is performed. This simulation model is selected in consideration of the high symmetry of the overall structure of the transformer, and the balance between simulation efficiency and simulation accuracy. A relatively representative transformer is selected as a simulation case, with a capacity of 50000KVA, a voltage ratio of 110KV / 35KV / 10KV, and a total of 102 coils.

[0038] In an optional embodiment, the first object may also be a high-voltage circuit breaker, in particular a vacuum circuit breaker or SF6 circuit breaker for power grid protection. In this context, a physical simulation model of the high-voltage circuit breaker is constructed to analyze the performance and reliability of the circuit breaker under high-voltage operation by simulating its electromagnetic field, mechanical stress and thermal characteristics.

[0039] S2: Obtain first operating parameters of the first object for simulation.

[0040] The first operating parameter is a physical quantity that affects the deformation of the first object during operation. The first operating parameter is applied to the first object using simulation software to simulate the deformation.

[0041] Specifically, for the simulation of the winding, the first parameter refers to calculating the electromagnetic field through the Maxwell module to obtain the distribution of the Lorentz force on the model. The deformation of the model after the Lorentz force is calculated through the Structure module, and the deformed model mesh is exported in stl format. The deformed model mesh is converted into a solid through the Spaceclaim module, and the necessary positions on the surface of the solid are merged.

[0042] In actual working conditions, the Lorentz force cannot be directly measured, but the simulation of the first operating parameter can be achieved by analyzing the current. Specifically, it includes:

[0043] In actual engineering applications, it is necessary to use the actual recorded transformer short-circuit current waveform as short-circuit current excitation. In order to demonstrate the use of this technology, a simulation model of a three-winding transformer in a step-up working state is built through Simulink, and the corresponding circuit breaker opening and closing time is added. A single-phase ground short circuit occurs at the selected time to obtain the short-circuit current waveform for testing.

[0044] The obtained short-circuit current waveform is sampled through Simulink to obtain an Excel file containing discrete values ​​of time and current magnitude, which is converted into a tab worksheet format and imported into Structure and named SC. Add excitation SC to the two sections of the corresponding short-circuit end winding, and ensure that the excitation directions of the two sections are opposite to form a loop.

[0045] Maxwell module settings and calculations: After importing the model, set the excitation according to the previous step. Select the corresponding solution type, and set a region around the model to determine the solution space range. Use Maxwell's automatic meshing function to mesh the model. Create a new Analysis, set its step size to 0.01s, the total solution time length to 0.3s, and a total of 300 time steps.

[0046] Setting and calculation of the Structure module: Suppress the structural parts that do not need to be analyzed, leaving only the windings that need to be solved. Simulate the situation where the upper and lower pressure plates are working normally, and add fixed constraints to their upper and lower ports. Select the mesh size as 0.05mm and the mesh type as tetrahedron (because Maxwell uses tetrahedrons). Create a new Analysis, set the step size to 0.01s, and a total of 300 steps. Add a surface force input in the ImportLoad interface and load it. Set the deformation multiplier to 1, and export the mesh distribution after the winding deformation in stl format from the solution interface.

[0047] The processing steps of the Spaceclaim module are as follows: Import the mesh distribution after the winding deformation, and generate the corresponding winding entity according to the mesh. Merge the upper and lower ends of the winding and the inner and outer cylindrical surfaces so that the separated mesh surfaces form a continuous and unified surface. Export the processed winding entity in stp format.

[0048] In an optional embodiment, the first operating parameter may also be a physical quantity of deformation caused by thermal stress. In high-power equipment (such as power transformers), the windings are affected by the heat generated by the current during operation, resulting in thermal expansion or stress concentration, which in turn affects their deformation. In this embodiment, thermal stress can be used as the first operating parameter to perform simulation analysis of thermally induced deformation.

[0049] S3: Implement deformation analysis by cyclically updating the physical simulation model and the first operating parameters.

[0050] The cyclic update includes, through bidirectional coupling, while applying the first operating parameter to the first object, feeding back the deformation variable to the first operating parameter, and updating the first operating parameter; after completing the update of the first operating parameter, re-acting on the 3D modeling of the first object, and continuously repeating the bidirectional coupling process to complete the cyclic update.

[0051] Specifically, replace the undeformed winding with the deformed winding, and check to make sure that the deformed winding does not overlap with the core. Set material parameters for the deformed winding, add interfaces and currents. Perform electromagnetic force distribution and magnitude analysis and calculations again to achieve an overall update of the Maxwell module.

[0052] Embodiment 2 is an embodiment of the present invention, which provides a power transformer winding deformation analysis system taking into account the electromagnetic field model update, comprising:

[0053] The model building unit obtains parameter information of the first object and builds a physical simulation model of the first object.

[0054] The simulation unit obtains the first operating parameter of the first object to perform simulation, and calculates the electromagnetic field through the Maxwell module to obtain the distribution of the Lorentz force on the model.

[0055] The analysis unit realizes deformation analysis by cyclically updating the physical simulation model and the first operating parameters. The deformation state of the model after being subjected to the Lorentz force is calculated by the Structure module, and the deformation model mesh is exported in the stl format. The deformation model mesh is converted into a solid by the Spaceclaim module, and the necessary positions on the surface of the solid are merged. Return to the Maxwell module to assemble the deformed model entity with the undeformed model entity. Through the cycle between the above modules, the electromagnetic field model update in the deformation calculation of the power transformer winding is realized.

[0056] If the above functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0057] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0058] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0059] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0060] Example 3, reference Figure 2-6 , which is an embodiment of the present invention, provides a deformation analysis method for power transformer windings taking into account the updating of electromagnetic field models. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0061] See also Figure 2 :Simplified model of three-phase three-winding power transformer

[0062] Solidworks and other software are used for modeling and simulation. Considering that the transformer support pads used in actual projects are symmetrical and each turn of the coil is closely adjacent, the winding is simplified into a cylinder in order to shorten the simulation time. As shown in the figure, the brown part is the iron core made of 30Q130 silicon carbon steel material stacked and pressed; the blue part is the low-voltage winding, the yellow part is the medium-voltage winding, and the red part is the high-voltage winding, and the winding material is copper. Two sections are added to each winding, which are shown as two vertical lines on the surface in the figure. These two sections are used to apply two excitation sources of equal size and opposite direction, thereby forming a spiral short-circuit current for generating a magnetic field.

[0063] (2) See Figure 3 :Simulink circuit design for simulating short-circuit conditions

[0064] In this circuit design, a three-phase three-winding transformer is selected as the core. The option of ignoring the medium-voltage winding is checked in the figure, so there are only two windings. A power supply is set on the far left to represent the primary input of the power grid, and a group of loads is set on the far right to represent the secondary output. A circuit breaker is set between the primary input and the transformer to simulate the opening and reclosing of the transformer automatically generated by the protection device after a short circuit. A short-circuit unit is set between the secondary output and the transformer. Through the settings in the unit, the four short-circuit conditions specified in GB1094.5 can be simulated, namely single-phase ground short circuit, double-phase ground short circuit, three-phase ground short circuit and turn-to-turn short circuit. Run the circuit, read the short-circuit current waveform through the Scope unit, and use Subtract to discretize and sample it and export it to obtain the short-circuit current waveform for testing.

[0065] (3) See Figure 4 : Maxwell module calculation results

[0066] Assuming that the three-phase three-winding power transformer is connected to the power supply with high voltage, and the medium and low voltage are loaded, the Maxwell module can be used to calculate the electric force distribution as shown in the figure. The left winding is the electric force exerted on the medium and low voltage windings, and the right side is the electric force exerted on the high voltage windings. As can be seen from the figure, the directions of the electric forces exerted on the two types of windings are completely opposite. The low and medium voltage windings are forced to shrink inward, and the high voltage windings are forced to expand outward.

[0067] According to the set step size, the Maxwell module will output the calculated results and import them into the Structure module as the electromotive force input of the surface density.

[0068] (4) See Figure 5 : Calculation results of Structure module

[0069] The winding in the figure is a low-voltage winding, which is subjected to an inward contraction of electric force, resulting in contraction deformation. In order to make the result more intuitive, the deformation has been magnified by an appropriate multiple. Due to the defects of the transformer itself, the electric force it receives is not completely balanced. Unbalanced electric force is bound to lead to unbalanced deformation, resulting in local deformity, as shown in the protrusion in the figure.

[0070] The mesh distribution model of the winding after deformation is extracted and imported into the Spaceclaim module as input.

[0071] (5) See Figure 6 : Spaceclaim module updates model results

[0072] In Spaceclaim settings, set the import method of the stl file to solid and the unit to meter. After importing the deformed winding mesh in stl format, generate a deformed winding entity, and then integrate the winding surface through face merging. After ensuring that the surface has no distortion or sharp corners, export the winding in stp format.

[0073] The model without the deformed winding is exported and merged with the deformed winding in Maxwell. The result is shown in the figure. The deformed winding in the figure is assigned materials, the winding is constructed, and the coil terminal is set. The electromagnetic field calculation is performed again to update the electromagnetic field model of Maxwell.

[0074] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for analyzing deformation of power transformer windings taking into account the updating of electromagnetic field models, characterized in that: include: Acquire parameter information of a first object and construct a physical simulation model of the first object; Acquire a first operating parameter of the first object for simulation; Deformation analysis is achieved by cyclically updating the physical simulation model and the first operating parameters.

2. The power transformer winding deformation analysis method taking into account the electromagnetic field model update as claimed in claim 1, characterized in that: The parameter information of the first object includes physical quantities for 3D modeling of the first object.

3. The power transformer winding deformation analysis method taking into account the electromagnetic field model update as claimed in claim 2, characterized in that: The physical simulation model includes 3D modeling of the first object and recording excitations in actual engineering applications of the first object for testing.

4. The power transformer winding deformation analysis method taking into account the electromagnetic field model update as claimed in claim 3, characterized in that: The first operating parameter includes a physical quantity that affects the deformation of the first object during operation.

5. The power transformer winding deformation analysis method taking into account the electromagnetic field model update as claimed in claim 4, characterized in that: Acquiring the first operating parameter of the first object for simulation includes applying the first operating parameter to the first object using simulation software to simulate deformation.

6. The power transformer winding deformation analysis method taking into account the electromagnetic field model update as claimed in claim 5, characterized in that: The cyclic updating includes, through bidirectional coupling, feeding back the deformation amount to the first operating parameter while applying the first operating parameter to the first object, thereby updating the first operating parameter; After completing the update of the first operating parameter, the 3D modeling of the first object is re-acted, and the bidirectional coupling process is continuously repeated to complete the cyclic update.

7. The power transformer winding deformation analysis method taking into account the electromagnetic field model update as claimed in claim 6, characterized in that: The 3D modeling includes, but is not limited to, before updating, the winding of the power transformer is equivalent to a cylinder, and 3D modeling of three-phase three-winding is performed; After the update, replace the undeformed winding with the deformed winding, and check to confirm that there is no rigid overlap between the deformed winding and the core; Set material parameters for the deformed winding, add interfaces and currents, and analyze and calculate the distribution and magnitude of the electromagnetic force again.

8. A power transformer winding deformation analysis system taking into account the electromagnetic field model update using the method as claimed in any one of claims 1 to 7, characterized in that: A model building unit, which obtains parameter information of a first object and builds a physical simulation model of the first object; A simulation unit, which obtains a first operating parameter of the first object for simulation; The analysis unit implements deformation analysis by cyclically updating the physical simulation model and the first operating parameter.

9. A computer device comprising: A memory and a processor; the memory stores a computer program, wherein the processor implements the steps of any method as claimed in claim 1 when executing the computer program.

10. 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 according to any one of claims 1 to 7 are implemented.

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