Method and device for modal analysis of distribution transformer tank structure

Abstract

The present invention provides a method and device for modal analysis of a distribution transformer tank structure. Among them, the method includes the following steps: performing modal analysis on the modal analysis model of the transformer tank with a complete radiator according to the first boundary condition of the modal analysis model of the transformer tank with a complete radiator to obtain the modal analysis result of the modal analysis model of the transformer tank with a complete radiator; performing modal analysis on the modal analysis model of the transformer tank with a simplified radiator according to the second boundary condition of the modal analysis model of the transformer tank with a simplified radiator to obtain the modal analysis result of the modal analysis model of the transformer tank with a simplified radiator; taking the modal analysis result of the modal analysis model of the transformer tank with a simplified radiator as a reference, and determining the true vibration mode and natural frequency of the transformer from the modal analysis result of the modal analysis model of the transformer tank with a complete radiator. In this way, it is possible to obtain the true natural frequency and corresponding vibration mode of the transformer, and the calculation is more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of noise control, and in particular, to a method and device for modal analysis of the oil tank structure of a distribution transformer. Background Art

[0002] With the rapid development of the power grid and the continuous increase of the power consumption load, the number of distribution transformers is increasing. The noise generated by the operation of the transformers will have an adverse impact on people's lives and work. Noise pollution is a very important environmental problem, and transformer noise has attracted extensive public attention, and disputes and complaints often occur. The research and development of low-noise and environmentally friendly transformer equipment has become a research hotspot in the field of power grid noise control.

[0003] Most of the research on low-noise transformers starts from the calculation and analysis of internal windings and iron cores. There is less research on the simulation calculation and structural transformation of the external oil tank structure, especially almost no simulation modeling of the oil tank of distribution transformers. Due to the complex internal structure of the transformer, the noise finally propagates outward through the vibration of the oil tank surface. If the optimization design starts from the surface structure of the oil tank, it will neither affect the main electromagnetic performance of the transformer nor require complicated technological requirements. The structural mode is an important parameter for structural optimization. Therefore, it is very important to study the modal analysis method of distribution transformers for the development of the structure of low-noise transformers. Summary of the Invention

[0004] In view of this, the present invention proposes a method and device for modal analysis of the oil tank structure of a distribution transformer, aiming to solve the problem that the calculation of the vibration mode and natural frequency of the transformer is inaccurate due to a large number of radiators arranged on the oil tank surface.

[0005] On the one hand, the present invention proposes a method for modal analysis of the oil tank structure of a distribution transformer. The method includes the following steps: performing modal analysis on the modal analysis model of the transformer oil tank with complete radiators according to the first boundary condition of the modal analysis model of the transformer oil tank with complete radiators to obtain the modal analysis result of the modal analysis model of the transformer oil tank with complete radiators; performing modal analysis on the modal analysis model of the transformer oil tank with simplified radiators according to the second boundary condition of the modal analysis model of the transformer oil tank with simplified radiators to obtain the modal analysis result of the modal analysis model of the transformer oil tank with simplified radiators; using the modal analysis result of the modal analysis model of the transformer oil tank with simplified radiators as a reference to determine the true vibration mode and natural frequency of the transformer from the modal analysis result of the modal analysis model of the transformer oil tank with complete radiators.

[0006] Further, in the above method for modal analysis of the distribution transformer tank structure, establishing the modal analysis model of the transformer tank with a complete radiator includes: establishing a finite element model of the transformer according to the size parameters of the transformer tank and the radiator, where both the transformer tank and the radiator are simulated using shell quadrilateral elements; converting the finite element model into an acoustic mesh analysis model, and using the acoustic mesh analysis model as the modal analysis model of the transformer tank with a complete radiator.

[0007] Further, in the above method for modal analysis of the distribution transformer tank structure, according to the first boundary condition of the modal analysis model of the transformer tank with a complete radiator, performing modal analysis on the modal analysis model of the transformer tank with a complete radiator, and obtaining the modal analysis results of the modal analysis model of the transformer tank with a complete radiator includes: treating the outer surface of the bottom of the transformer tank as the first boundary condition, where the first boundary condition is a fixed support boundary condition, performing modal analysis on the modal analysis model of the transformer tank with a complete radiator, obtaining the natural frequencies of each order and the corresponding modal vibration modes, and taking the natural frequencies of each order and the corresponding modal vibration modes as the modal analysis results of the modal analysis model of the transformer tank with a complete radiator.

[0008] Further, in the above method for modal analysis of the distribution transformer tank structure, establishing the modal analysis model of the transformer tank with a simplified radiator includes: simulating the radiator using one-dimensional beam elements so that the inertia matrix of the equivalent element is exactly the same as that of the original element; simplifying the radiator into an inertia matrix by specifying the parameters of the cross-section and applying it to the tank wall structure; representing the bending deformation of the simplified radiator using the deformation of a space curve to obtain the true vibration mode of the tank wall.

[0009] Further, in the above method for modal analysis of the distribution transformer tank structure, according to the second boundary condition of the modal analysis model of the transformer tank with a simplified radiator, performing modal analysis on the modal analysis model of the transformer tank with a simplified radiator, and obtaining the modal analysis results of the modal analysis model of the transformer tank with a simplified radiator includes: treating the outer surface of the bottom of the transformer tank as the second boundary condition, where the second boundary condition is a fixed support boundary condition, performing modal analysis on the modal analysis model of the transformer tank with a simplified radiator, obtaining the natural frequencies of each order and the corresponding modal vibration modes, and taking the natural frequencies of each order and the corresponding modal vibration modes as the modal analysis results of the modal analysis model of the transformer tank with a simplified radiator.

[0010] Further, in the above method for modal analysis of the distribution transformer tank structure, determining the true vibration modes and natural frequencies of the transformer includes: selecting the natural frequencies and corresponding vibration modes obtained by performing modal analysis on the modal analysis model of the transformer tank with a complete radiator that are close to the natural frequencies and corresponding vibration modes obtained by performing modal analysis on the modal analysis model of the transformer tank with a simplified radiator, and taking the selected natural frequencies and corresponding vibration modes as the true natural frequencies and vibration modes of each order of the transformer.

[0011] In the present invention, by simplifying the modeling of the radiator, the influence of the radiator on the true vibration modes and natural frequencies of the transformer is reduced; using the modal analysis results of the modal analysis model of the transformer tank with a simplified radiator as a reference basis to screen the modal analysis results of the modal analysis model of the transformer tank with a complete radiator, the true natural frequencies and corresponding vibration modes of the transformer are obtained, the calculation is more accurate, and the modal analysis model of the transformer tank with a simplified radiator can be used for structural optimization design calculations.

[0012] On the other hand, the present invention also proposes a device for modal analysis of the distribution transformer tank structure. The device includes: a first analysis module for performing modal analysis on the modal analysis model of the transformer tank with a complete radiator according to the first boundary conditions of the modal analysis model of the transformer tank with a complete radiator to obtain the modal analysis results of the modal analysis model of the transformer tank with a complete radiator; a second analysis module for performing modal analysis on the modal analysis model of the transformer tank with a simplified radiator according to the second boundary conditions of the modal analysis model of the transformer tank with a simplified radiator to obtain the modal analysis results of the modal analysis model of the transformer tank with a simplified radiator; a determination module for using the modal analysis results of the modal analysis model of the transformer tank with a simplified radiator as a reference to determine the true vibration modes and natural frequencies of the transformer from the modal analysis results of the modal analysis model of the transformer tank with a complete radiator.

[0013] Further, in the above device for modal analysis of the distribution transformer tank structure, the first analysis module includes: a first establishment sub-module for establishing a finite element model of the transformer according to the size parameters of the transformer tank and the radiator, where both the transformer tank and the radiator are simulated using shell quadrilateral elements; converting the finite element model into an acoustic grid analysis model and using the acoustic grid analysis model as the modal analysis model of the transformer tank with a complete radiator; a first modal analysis sub-module for processing the outer surface of the bottom of the transformer tank into the first boundary conditions, where the first boundary conditions are fixed support boundary conditions, and performing modal analysis on the modal analysis model of the transformer tank with a complete radiator to obtain the natural frequencies of each order and the corresponding vibration modes, and taking the natural frequencies of each order and the corresponding vibration modes as the modal analysis results of the modal analysis model of the transformer tank with a complete radiator

[0014] Further, in the above-mentioned device for modal analysis of the distribution transformer tank structure, the second analysis module includes: a second establishment sub-module, which is used to simulate the radiator using one-dimensional beam elements, so that the inertia matrix of the equivalent element is exactly the same as that of the original element. By specifying the parameters of the cross-section, the radiator is simplified into an inertia matrix and applied to the tank wall structure, reducing the number of variables, so as to reduce the dense vibration modes of the transformer surface structure caused by the local vibration of the radiator, and obtain the true vibration modes of the tank wall; a second modal analysis sub-module, which is used to process the outer surface of the bottom of the transformer tank into a second boundary condition, and the second boundary condition is a fixed support boundary condition. Perform modal analysis on the modal analysis model of the transformer tank with the simplified radiator to obtain the natural frequencies and corresponding modal vibration modes of each order, and use the natural frequencies and corresponding modal vibration modes of each order as the modal analysis results of the modal analysis model of the transformer tank with the simplified radiator.

[0015] Further, in the above-mentioned device for modal analysis of the distribution transformer tank structure, the determination module includes: a selection sub-module, which is used to select the natural frequencies and corresponding vibration modes that are similar to the natural frequencies and corresponding vibration modes obtained by performing modal analysis on the modal analysis model of the transformer tank with a complete radiator and the natural frequencies and corresponding vibration modes obtained by performing modal analysis on the modal analysis model of the transformer tank with a simplified radiator; a determination sub-module, which is used to use the selected natural frequencies and corresponding vibration modes as the true natural frequencies and vibration modes of each order of the transformer.

[0016] In the present invention, the second analysis module simplifies the modeling of the transformer radiator, reducing the influence of the radiator on the true vibration modes and natural frequencies of the transformer; the determination module uses the modal analysis results of the modal analysis model of the transformer tank with the simplified radiator as a reference basis to screen the modal analysis results of the modal analysis model of the transformer tank with a complete radiator, obtaining the true natural frequencies and corresponding vibration modes of the transformer, with more accurate calculation, and the modal analysis model of the transformer tank with the simplified radiator can be used for structural optimization design calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0018] Figure 1 It is a flowchart of the method for modal analysis of the distribution transformer tank structure provided by the embodiment of the present invention;

[0019] Figure 2In the method for modal analysis of the distribution transformer tank structure provided by the embodiment of the present invention, a two-dimensional shell finite element analysis model of the transformer radiator and the tank;

[0020] Figure 3 In the method for modal analysis of the distribution transformer tank structure provided by the embodiment of the present invention, the modal vibration mode corresponding to the second-order natural frequency before modeling of the transformer two-dimensional shell model; Figure 3 The numbers in it are the fixed vibration frequencies, where (a) is the first-order modal vibration mode and (b) is the second-order modal vibration mode;

[0021] Figure 4 In the method for modal analysis of the distribution transformer tank structure provided by the embodiment of the present invention, the modal vibration mode corresponding to the second-order natural frequency before modeling of the simplified transformer radiator model; Figure 4 The numbers in it are the fixed vibration frequencies, where (a) is the first-order modal vibration mode and (b) is the second-order modal vibration mode;

[0022] Figure 5 In the method for modal analysis of the distribution transformer tank structure provided by the embodiment of the present invention, the modal vibration mode corresponding to the true first two natural frequencies of the transformer two-dimensional shell model; Figure 5 The numbers in it are the fixed vibration frequencies, where (a) is the first-order modal vibration mode and (b) is the second-order modal vibration mode;

[0023] Figure 6 The structural block diagram of the device for modal analysis of the distribution transformer tank structure provided by the embodiment of the present invention. Specific embodiments

[0024] Hereinafter, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. Hereinafter, the present invention will be described in detail with reference to the drawings and in combination with the embodiments.

[0025] Method embodiments:

[0026] See Figure 1 , Figure 1 shows the method for modal analysis of the distribution transformer tank structure provided by this embodiment. The method includes the following steps:

[0027] Step S110: According to the first boundary condition of the transformer tank modal analysis model of the complete radiator, perform modal analysis on the transformer tank modal analysis model of the complete radiator to obtain the modal analysis results of the transformer tank modal analysis model of the complete radiator.

[0028] Specifically, establish a finite element model of the transformer based on the size parameters of the transformer tank and the radiator. Both the transformer tank and the radiator are simulated using shell quadrilateral elements. Convert the finite element model into an acoustic mesh analysis model, and use the acoustic mesh analysis model as the transformer tank modal analysis model of the complete radiator. Considering that the transformer tank is generally placed on the ground and the lower surface of the transformer tank contributes little to sound radiation, the lower surface of the transformer tank in the transformer tank modal analysis model of the complete radiator is processed into a fixed support boundary condition, which is the first boundary condition. Then perform modal analysis on the transformer tank modal analysis model of the complete radiator to obtain the natural frequencies of each order and the corresponding modal vibration modes.

[0029] Step S120: According to the second boundary condition of the transformer tank modal analysis model of the simplified radiator, perform modal analysis on the transformer tank modal analysis model of the simplified radiator to obtain the modal analysis results of the transformer tank modal analysis model of the simplified radiator.

[0030] Specifically, perform simplified modeling of the radiator. Use lumped mass elements to replace distributed mass elements, that is, simulate the radiator with one-dimensional beam elements. To ensure the equivalence of the equivalent lumped mass elements in terms of statics and dynamics, it is necessary to ensure that the inertia matrix of the equivalent elements is exactly the same as that of the original elements, that is, the equivalence principle between the equivalent elements is that their inertia matrices are the same. A beam element is a one-dimensional geometrically and two- or three-dimensional spatially element. Then simplify the radiator into an inertia matrix acting on the tank wall structure by specifying the cross-section parameters of the radiator. The bending deformation of the simplified radiator can be represented by the deformation of a space curve, which can reduce the number of variables and reduce the dense vibration modes of the transformer surface structure caused by local vibration of the radiator, thereby obtaining a more realistic vibration mode of the tank wall.

[0031] Similarly, set the lower surface of the transformer tank in the transformer tank modal analysis model of the simplified radiator as the fixed support boundary condition, which is the second boundary condition. Perform modal analysis on the transformer tank modal analysis model of the simplified radiator to obtain the natural frequencies of each order and the corresponding modal vibration modes.

[0032] Step S130: Use the modal analysis results of the transformer tank modal analysis model of the simplified radiator as a reference to determine the true vibration mode and natural frequency of the transformer from the modal analysis results of the transformer tank modal analysis model of the complete radiator.

[0033] Specifically, compare the modal natural frequencies and corresponding modal vibration modes calculated in step S110 with the natural frequencies and corresponding modal vibration modes calculated in step S120, and select the natural frequencies and corresponding modal vibration modes similar to the calculation results of step S120 from the calculation results of step S110, which are the true natural frequencies and corresponding modal vibration modes of each order of the transformer.

[0034] The following will illustrate the specific implementation steps of the method provided in this embodiment with examples:

[0035] Select a transformer with a voltage of 10 kV and a capacity of 200 MVA. The structural parameters are shown in Table 1. There are 7 heat sinks on each of the left and right sides of the transformer, and 15 heat sinks on each of the front and back sides.

[0036] Table 1 Transformer tank dimensions

[0037]

[0038] In step S110, the size parameters of the transformer tank and heat sinks are shown in Table 1. Based on these parameters, establish a two-dimensional shell model of the heat sinks and the transformer tank, simulate it using shell quadrilateral elements, and convert the finite element model into an acoustic mesh analysis model. The acoustic mesh includes 13,052 quadrilateral elements and 13,482 nodes, as Figure 2 shown. After setting the first boundary condition, perform modal analysis calculation to obtain the modal vibration modes and natural frequencies of the modal analysis model of the transformer tank with complete heat sinks, as Figure 3 shown (only the first-order and second-order results are listed for illustration). In the subsequent multi-order modes, very dense and close phenomena occur. In such dense natural frequencies, the vibration modes are all cases where the amplitude localization of the heat sinks is severe.

[0039] In step S120, equivalent the heat sinks using the inertia matrix parameters, perform simulation calculations using the LMS Virtual.Lab software. In the finite element, simulate the heat sinks with simple one-dimensional beam elements, specify the size parameters of the heat sink cross-section as shown in Table 1, and simplify the heat sinks into an inertia matrix acting on the tank wall structure. After setting the same boundary conditions as in step S110, perform modal analysis to obtain the modal vibration modes and natural frequencies of the modal analysis model of the transformer tank with simplified heat sinks, as Figure 4 shown (only the first-order and second-order results are listed for illustration).

[0040] In step S130, compare the calculation results of step S110 and step S120 to obtain the true natural frequencies and corresponding modal vibration modes of the transformer, as Figure 5 shown.

[0041] In summary, in this embodiment, the heat sink is simplified in modeling, reducing the influence of the heat sink on the true vibration modes and natural frequencies of the transformer; the modal analysis results of the transformer tank modal analysis model with the simplified heat sink are used as a reference basis to screen the modal analysis results of the transformer tank modal analysis model with the complete heat sink, obtaining the true natural frequencies and corresponding vibration modes of the transformer, with more accurate calculations, and the transformer tank modal analysis model with the simplified heat sink can be used for structural optimization design calculations.

[0042] Device embodiment:

[0043] See Figure 6 , Figure 6 shows a structural block diagram of a distribution transformer tank structure modal analysis device provided in this embodiment. As shown in FIG. 6, the device includes: a first analysis module 100, a second analysis module 200, and a determination module 300. The first analysis module 100 is configured to perform modal analysis on the transformer tank modal analysis model with the complete heat sink according to the first boundary condition of the transformer tank modal analysis model with the complete heat sink, and obtain the modal analysis results of the transformer tank modal analysis model with the complete heat sink. Specifically, the first analysis module 100 includes a first establishment sub-module and a first modal analysis sub-module. The first establishment sub-module is configured to establish a finite element model of the transformer according to the size parameters of the transformer tank and the heat sink, where both the transformer tank and the heat sink are simulated using shell quadrilateral elements; convert the finite element model into an acoustic mesh analysis model, and use the acoustic mesh analysis model as the transformer tank modal analysis model with the complete heat sink; the first modal analysis sub-module is configured to process the outer surface of the bottom of the transformer tank into a first boundary condition, where the first boundary condition is a fixed support boundary condition, perform modal analysis on the transformer tank modal analysis model with the complete heat sink, obtain the natural frequencies of each order and the corresponding modal vibration modes, and use the natural frequencies of each order and the corresponding modal vibration modes as the modal analysis results of the transformer tank modal analysis model with the complete heat sink.

[0044] The second analysis module 200 is configured to perform modal analysis on the modal analysis model of the transformer oil tank with a simplified radiator according to the second boundary condition of the modal analysis model of the transformer oil tank with a simplified radiator, so as to obtain the modal analysis result of the modal analysis model of the transformer oil tank with a simplified radiator. Specifically, the second analysis module includes a second establishment sub-module and a second modal analysis sub-module. The second establishment sub-module is configured to simulate the radiator by using one-dimensional beam elements, so that the inertia matrix of the equivalent element is exactly the same as the inertia matrix of the original element. By specifying the parameters of the cross-section, the radiator is simplified into an inertia matrix and applied to the oil tank wall structure, reducing the number of variables, so as to reduce the dense vibration modes of the transformer surface structure caused by the local vibration of the radiator, and obtain the true vibration mode of the oil tank wall. The second modal analysis sub-module is configured to process the outer surface of the bottom of the transformer oil tank into a second boundary condition, where the second boundary condition is a fixed support boundary condition, perform modal analysis on the modal analysis model of the transformer oil tank with a simplified radiator, obtain the natural frequencies of each order and the corresponding modal vibration modes, and use the natural frequencies of each order and the corresponding modal vibration modes as the modal analysis result of the modal analysis model of the transformer oil tank with a simplified radiator.

[0045] The determination module 300 is configured to use the modal analysis result of the modal analysis model of the transformer oil tank with a simplified radiator as a reference to determine the true vibration mode and natural frequency of the transformer from the modal analysis result of the modal analysis model of the transformer oil tank with a complete radiator. Specifically, the determination module includes a selection sub-module and a determination sub-module. The selection sub-module is configured to select the natural frequencies and the corresponding vibration modes whose natural frequencies and corresponding vibration modes obtained by performing modal analysis on the modal analysis model of the transformer oil tank with a complete radiator are similar to those obtained by performing modal analysis on the modal analysis model of the transformer oil tank with a simplified radiator. The determination sub-module is configured to use the selected natural frequencies and the corresponding vibration modes as the true natural frequencies and vibration modes of each order of the transformer.

[0046] It should be noted that the principle of the distribution transformer oil tank structure modal analysis device provided in this embodiment is the same as that of the distribution transformer oil tank structure modal analysis method, and the similarities can be referred to each other.

[0047] In summary, the second analysis module simplifies the modeling of the transformer radiator, reducing the influence of the radiator on the true vibration mode and natural frequency of the transformer. The determination module uses the modal analysis result of the modal analysis model of the transformer oil tank with a simplified radiator as a reference basis to screen the modal analysis result of the modal analysis model of the transformer oil tank with a complete radiator, obtaining the true natural frequency and the corresponding vibration mode of the transformer, with more accurate calculation, and the modal analysis model of the transformer oil tank with a simplified radiator can be used for structural optimization design calculation.

[0048] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) that contain computer-usable program code.

[0049] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0050] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing devices to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device that implements the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0051] These computer program instructions can also be loaded onto a computer or other programmable data processing devices, such that a series of operation steps are executed on the computer or other programmable devices to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable devices provide steps for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: still can modify the specific embodiments of the present invention or make equivalent replacements, and any modification or equivalent replacement without departing from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A method for modal analysis of the oil tank structure of a distribution transformer, characterized in that, it includes the following steps: S110. According to the first boundary condition of the modal analysis model of the transformer oil tank with complete radiators, perform modal analysis on the modal analysis model of the transformer oil tank with complete radiators to obtain the modal analysis results of the modal analysis model of the transformer oil tank with complete radiators; S120. According to the second boundary condition of the modal analysis model of the transformer oil tank with simplified radiators, perform modal analysis on the modal analysis model of the transformer oil tank with simplified radiators to obtain the modal analysis results of the modal analysis model of the transformer oil tank with simplified radiators; S130. Using the modal analysis results of the modal analysis model of the transformer oil tank with simplified radiators as a reference, determine the true vibration modes and natural frequencies of the transformer from the modal analysis results of the modal analysis model of the transformer oil tank with complete radiators; Establishing the modal analysis model of the transformer oil tank with complete radiators includes: According to the size parameters of the transformer oil tank and the radiators, establish a finite element model of the transformer, where both the transformer oil tank and the radiators are simulated using shell quadrilateral elements; Convert the finite element model into an acoustic grid analysis model, and use the acoustic grid analysis model as the modal analysis model of the transformer oil tank with complete radiators; The step of performing modal analysis on the modal analysis model of the transformer oil tank with complete radiators according to the first boundary condition of the modal analysis model of the transformer oil tank with complete radiators to obtain the modal analysis results of the modal analysis model of the transformer oil tank with complete radiators includes: Treat the outer surface of the bottom of the transformer oil tank as the first boundary condition, where the first boundary condition is a fixed support boundary condition, perform modal analysis on the modal analysis model of the transformer oil tank with complete radiators to obtain the natural frequencies of each order and the corresponding modal vibration modes, and use the natural frequencies of each order and the corresponding modal vibration modes as the modal analysis results of the modal analysis model of the transformer oil tank with complete radiators; Establishing the modal analysis model of the transformer oil tank with simplified radiators includes: Simulate the radiators using one-dimensional beam elements so that the inertia matrix of the equivalent element is exactly the same as the inertia matrix of the original element; Simplify the radiators into an inertia matrix by specifying the parameters of the cross-section and apply it to the oil tank wall structure; The bending deformation of the simplified radiators is represented by the deformation of a space curve to obtain the true vibration mode of the oil tank wall; The step of performing modal analysis on the modal analysis model of the transformer oil tank with simplified radiators according to the second boundary condition of the modal analysis model of the transformer oil tank with simplified radiators to obtain the modal analysis results of the modal analysis model of the transformer oil tank with simplified radiators includes: Treat the outer surface of the bottom of the transformer oil tank as the second boundary condition, where the second boundary condition is a fixed support boundary condition. Perform modal analysis on the modal analysis model of the transformer oil tank with the simplified radiator fins to obtain the natural frequencies of each order and the corresponding modal vibration modes, and take the natural frequencies of each order and the corresponding modal vibration modes as the modal analysis results of the modal analysis model of the transformer oil tank with the simplified radiator fins. Compare the modal natural frequencies and the corresponding modal vibration modes calculated in step S110 with the natural frequencies and the corresponding modal vibration modes calculated in step S120, and select the natural frequencies and the corresponding modal vibration modes similar to the calculation results in step S120 from the calculation results in step S110, which are the true natural frequencies of each order of the transformer and the corresponding modal vibration modes.

2. The method for modal analysis of the structure of a distribution transformer oil tank according to claim 1, characterized in that, the determination of the true vibration mode and natural frequency of the transformer includes: Select the natural frequencies and the corresponding vibration modes with similar natural frequencies and the corresponding vibration modes obtained by performing modal analysis on the modal analysis model of the transformer oil tank with the complete radiator fins and the modal analysis model of the transformer oil tank with the simplified radiator fins, and take the selected natural frequencies and the corresponding vibration modes as the true natural frequencies and vibration modes of each order of the transformer.

3. A device for modal analysis of the structure of a distribution transformer oil tank, characterized in that, it includes: A first analysis module for performing modal analysis on the modal analysis model of the transformer oil tank with the complete radiator fins according to the first boundary condition of the modal analysis model of the transformer oil tank with the complete radiator fins to obtain the modal analysis results of the modal analysis model of the transformer oil tank with the complete radiator fins; A second analysis module for performing modal analysis on the modal analysis model of the transformer oil tank with the simplified radiator fins according to the second boundary condition of the modal analysis model of the transformer oil tank with the simplified radiator fins to obtain the modal analysis results of the modal analysis model of the transformer oil tank with the simplified radiator fins; A determination module for using the modal analysis results of the modal analysis model of the transformer oil tank with the simplified radiator fins as a reference to determine the true vibration mode and natural frequency of the transformer from the modal analysis results of the modal analysis model of the transformer oil tank with the complete radiator fins; The first analysis module includes: A first establishment sub-module for establishing a finite element model of the transformer according to the size parameters of the transformer oil tank and the radiator fins, where both the transformer oil tank and the radiator fins are simulated using shell quadrilateral elements; convert the finite element model into an acoustic grid analysis model, and use the acoustic grid analysis model as the modal analysis model of the transformer oil tank with the complete radiator fins. The first modal analysis sub-module is used to process the outer surface of the bottom of the transformer tank into the first boundary condition, where the first boundary condition is a fixed support boundary condition, perform modal analysis on the modal analysis model of the transformer tank with the complete radiator fins, obtain the natural frequencies and corresponding modal vibration modes of each order, and use the natural frequencies and corresponding modal vibration modes of each order as the modal analysis results of the modal analysis model of the transformer tank with the complete radiator fins; The second analysis module includes: The second establishment sub-module is used to simulate the radiator fins using one-dimensional beam elements, make the inertia matrix of the equivalent element exactly the same as the inertia matrix of the original element, simplify the radiator fins into an inertia matrix and act on the tank wall structure by specifying the parameters of the cross-section, reduce the number of variables, so as to reduce the dense vibration modes of the transformer surface structure caused by the local vibration of the radiator fins, and obtain the true vibration mode of the tank wall; The second modal analysis sub-module is used to process the outer surface of the bottom of the transformer tank into the second boundary condition, where the second boundary condition is a fixed support boundary condition, perform modal analysis on the modal analysis model of the transformer tank with the simplified radiator fins, obtain the natural frequencies and corresponding modal vibration modes of each order, and use the natural frequencies and corresponding modal vibration modes of each order as the modal analysis results of the modal analysis model of the transformer tank with the simplified radiator fins; Compare the modal natural frequencies and corresponding modal vibration modes calculated by the first analysis module with the natural frequencies and corresponding modal vibration modes calculated by the second analysis module, and select the natural frequencies and corresponding modal vibration modes similar to the calculation results of the second analysis module from the calculation results of the first analysis module, which are the true natural frequencies and corresponding modal vibration modes of each order of the transformer.

4. The device for modal analysis of the distribution transformer tank structure according to claim 3, wherein, the determination module includes: A selection sub-module is used to select the natural frequencies and corresponding vibration modes whose modal natural frequencies and corresponding vibration modes obtained by performing modal analysis on the modal analysis model of the transformer tank with the complete radiator fins are similar to the modal natural frequencies and corresponding vibration modes obtained by performing modal analysis on the modal analysis model of the transformer tank with the simplified radiator fins; A determination sub-module is used to use the selected natural frequencies and corresponding modal vibration modes as the true natural frequencies and vibration modes of each order of the transformer.

Images