Simulation calculation method and device for identifying stress concentration point of transformer oil tank

Abstract

The invention discloses a simulation calculation method and device for identifying a stress concentration point of a transformer oil tank, and the method comprises the steps: firstly building a three-dimensional finite element model of the transformer oil tank, building a fault source in the three-dimensional finite element model, and then obtaining the stress distribution of the oil tank after a fault through a fluid-structure interaction simulation calculation method, concentration points where stress is always larger than a surrounding area under the conditions of different fault energy and different fault positions are found out, and the concentration points are stress concentration points of the oil tank and weak points where the oil tank is prone to cracking. Different fault energies avoid the influence of the fault energies on the oil tank stress distribution concentration point, different fault positions avoid the influence of the fault positions on the oil tank stress distribution concentration point, and the simulation calculation method can obtain the stress concentration points of different oil-immersed type oil tanks through simulation.

Description

[Technical field]

[0001] The invention belongs to the technical field of transformers, and in particular relates to explosion-proof technology for transformer oil tanks. [Background technology]

[0002] As an important component of the power system, the safe and reliable operation of the transformer plays a decisive role in the reliable transportation and safe use of electric energy. Transformer oil tanks are often deformed, ruptured or even exploded due to the sudden increase in internal pressure, and the fires caused by them seriously threaten the safety of operators and surrounding equipment.

[0003] Finding the stress concentration points of the transformer oil tank is of great significance to improving the overall explosion-proof capability of the transformer oil tank, but there is currently a lack of simulation calculation methods for identifying the stress concentration points of the transformer oil tank. [Summary of the invention]

[0004] The technical problem to be solved by the present invention is to provide a simulation calculation method and device for identifying stress concentration points of a transformer oil tank, so as to solve the problem of how to determine the stress concentration points of the transformer oil tank, so as to take technical measures for the stress concentration points of the transformer oil tank, thereby improving the overall explosion-proof capability of the transformer oil tank and ensuring the safe use of the transformer oil tank.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A simulation calculation method for identifying stress concentration points of a transformer oil tank comprises the following steps:

[0007] S1: Establish a three-dimensional finite element model of the transformer oil tank according to the actual transformer oil tank size;

[0008] S2: A pressure source is set inside the transformer oil tank to change the pressure field distribution inside the oil tank through the pressure source;

[0009] S3: Using the calculation method of fluid-structure coupling, the stress distribution cloud diagram of the oil tank after different faults occur is calculated;

[0010] S4: Analyze the stress distribution cloud map obtained in step S3, and compare the concentration point where the stress is always greater than the surrounding area under different fault energies and different fault locations. The concentration point is the stress concentration point of the oil tank.

[0011] Preferably, the pressure source is a heating wall surface without thickness, and the heating wall surface serves as a heating source for decomposing the liquid inside the oil tank to generate gas, thereby changing the pressure field distribution inside the oil tank.

[0012] Preferably, the power input of the heating source is controlled according to a fault energy curve obtained from an actual transformer fault.

[0013] Preferably, the calculation method of fluid-solid coupling is to change the pressure field distribution in the flow field based on the evaporation-condensation phase change model, and then act on the solid oil tank wall to obtain a stress distribution cloud map of the oil tank wall.

[0014] Preferably, the fluid-solid coupling is realized by using the coupling effect of two analysis systems, fluid flow and transient structure, in Ansys simulation software.

[0015] On the other hand, a simulation calculation device for identifying stress concentration points of a transformer oil tank is provided, comprising a three-dimensional finite element model module of the transformer oil tank, a pressure source module, a tank stress distribution cloud map module and a stress concentration point analysis module, wherein the three-dimensional finite element model module of the transformer oil tank establishes a three-dimensional finite element model of the transformer oil tank according to the actual transformer oil tank size; the pressure source module sets a pressure source inside the transformer oil tank, and changes the pressure field distribution inside the oil tank through the pressure source; the tank stress distribution cloud map module uses a fluid-solid coupling calculation method to calculate the stress distribution cloud map of the oil tank after different faults occur; the stress concentration point analysis module analyzes the stress distribution cloud map, compares the concentration point where the stress is always greater than the surrounding area under different fault energies and different fault locations, and determines that the concentration point is the stress concentration point of the oil tank.

[0016] The simulation calculation method of the present invention first establishes a three-dimensional finite element model of the transformer oil tank, establishes a fault source inside, and then uses a fluid-solid coupling simulation calculation method to obtain the stress distribution of the oil tank after the fault occurs, and finds out the concentration points where the stress is always greater than the surrounding area under different fault energies and different fault positions. These concentration points are the stress concentration points of the oil tank and are also the weak points where the oil tank is prone to rupture. Different fault energies avoid the influence of fault energy on the concentration points of the stress distribution of the oil tank, and different fault positions avoid the influence of the fault position on the concentration points of the stress distribution of the oil tank.

[0017] Therefore, the simulation calculation method of the present invention can simulate the stress concentration points of different oil-immersed oil tanks, so that technical measures can be taken for the stress concentration points of the transformer oil tank, thereby improving the overall explosion-proof capability of the transformer oil tank and ensuring the safe use of the transformer oil tank.

[0018] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings.

Brief Description of the Drawings

[0019] The invention will be further described below in conjunction with the accompanying drawings:

[0020] Figure 1 A flow chart of a simulation calculation method for identifying stress concentration points of a transformer oil tank according to the present invention;

[0021] Figure 2 This is a schematic diagram of the fault energy curve obtained by performing two example simulations in the present invention. [Specific implementation method]

[0022] The technical solutions of the embodiments of the present invention are explained and described below in conjunction with the drawings of the embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the protection scope of the present invention.

[0023] Embodiment 1

[0024] A simulation calculation device for identifying stress concentration points of a transformer oil tank comprises a three-dimensional finite element model module of the transformer oil tank, a pressure source module, a stress distribution cloud map module of the oil tank and a stress concentration point analysis module, wherein the three-dimensional finite element model module of the transformer oil tank establishes a three-dimensional finite element model of the transformer oil tank according to the actual transformer oil tank size; the pressure source module sets a pressure source inside the transformer oil tank to change the pressure field distribution inside the oil tank through the pressure source; the oil tank stress distribution cloud map module uses a fluid-solid coupling calculation method to calculate the stress distribution cloud map of the oil tank after different faults occur; the stress concentration point analysis module analyzes the stress distribution cloud map, compares the concentration point where the stress is always greater than the surrounding area under different fault energies and different fault positions, and determines that the concentration point is the stress concentration point of the oil tank.

[0025] Embodiment 2

[0026] like Figure 1 As shown, a simulation calculation method for identifying stress concentration points of a transformer oil tank specifically includes the following steps:

[0027] S1: Establish a three-dimensional finite element model of the transformer oil tank according to the actual transformer oil tank size;

[0028] S2: A pressure source is set inside the transformer oil tank to change the pressure field distribution inside the oil tank through the pressure source;

[0029] S3: Using the calculation method of fluid-structure coupling, the stress distribution cloud diagram of the oil tank after different faults occur is calculated;

[0030] S4: Analyze the stress distribution cloud map obtained in step S3, and compare the concentration point where the stress is always greater than the surrounding area under different fault energies and different fault locations. The concentration point is the stress concentration point of the oil tank.

[0031] The pressure source is a heating wall without thickness, which is used as a heating source to decompose the liquid inside the oil tank to generate gas and change the pressure field distribution inside the oil tank. The power input of the heating source is a fault energy curve obtained from an actual fault.

[0032] Specifically, the calculation method of fluid-solid coupling is to change the pressure field distribution in the flow field based on the evaporation-condensation phase change model, and then act on the solid oil tank wall to obtain the stress distribution cloud map of the oil tank wall. The fluid-solid coupling is realized by using the coupling effect of the two analysis systems of fluid flow and transient structure in the Ansys simulation calculation software. Fluent is used to calculate the distribution change of the pressure field in the fluid domain after the fault occurs, and transient structure is used to calculate the coupling effect on the transformer tank after the pressure field in the fluid domain changes.

[0033] By finding out the concentration points where the stress is always greater than the surrounding areas under different fault energies and different fault locations, these concentration points are the stress concentration points of the oil tank, and are also the weak points where the oil tank is prone to rupture. Therefore, the simulation calculation method of the present invention can simulate the stress concentration points of oil tanks of different oil-immersed types, so that technical measures can be taken for the stress concentration points of the transformer oil tank, thereby improving the overall explosion-proof capability of the transformer oil tank and ensuring the safe use of the transformer oil tank.

[0034] The above method was used to perform two simulations to simulate the stress distribution of the transformer tank under different fault locations and fault energies. The fault energy curves are shown in Figure 2. Figure 2 shown.

[0035] In Example I, the fault point is set at the top of the oil tank, the fault energy is 0.1 MJ, and the stress distribution cloud diagram after the oil tank fails is obtained.

[0036] In case II, the fault point is set in the middle of the oil tank, the fault energy is 0.9 MJ, and the stress distribution cloud diagram after the oil tank fails is obtained.

[0037] Comparing the stress distribution cloud diagrams of the transformer oil tank of the two simulation calculation results, it can be seen that the stress of channel-type structures such as the transformer oil tank bushing is greater than that of the surrounding area after changing the fault energy and fault location. Therefore, the transformer oil tank bushing is the stress concentration point of the oil tank in this model.

[0038] It can be understood that the simulation calculation method for identifying stress concentration points of a transformer oil tank disclosed in the present invention can be applied to various types of transformer oil tanks.

[0039] In addition, the present invention implements the simulation calculation method for identifying stress concentration points of a transformer oil tank through a computer device, and the computer device includes at least one processor and a memory; the memory stores computer execution instructions; the at least one processor executes the computer execution instructions stored in the memory, so that the at least one processor executes the simulation calculation method for identifying stress concentration points of a transformer oil tank.

[0040] The above is only a specific embodiment of the invention, but the protection scope of the invention is not limited thereto. Those skilled in the art should understand that the invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the invention will be included in the scope of the claims.

Claims

1. A simulation calculation method for identifying stress concentration points of a transformer oil tank, characterized in that: The steps include: S1: Establish a three-dimensional finite element model of the transformer oil tank according to the actual transformer oil tank size; S2: A pressure source is set inside the transformer oil tank to change the pressure field distribution inside the oil tank through the pressure source; S3: Using the calculation method of fluid-structure coupling, the stress distribution cloud diagram of the oil tank after different faults occur is calculated; S4: Analyze the stress distribution cloud map obtained in step S3, and compare the concentration point where the stress is always greater than the surrounding area under different fault energies and different fault locations. The concentration point is the stress concentration point of the oil tank.

2. A simulation calculation method for identifying stress concentration points of a transformer oil tank according to claim 1, characterized in that: The pressure source is a heating wall surface without thickness. The heating wall surface is used as a heating source to decompose the liquid inside the oil tank to generate gas and change the pressure field distribution inside the oil tank.

3. A simulation calculation method for identifying stress concentration points of a transformer oil tank according to claim 2, characterized in that: The power input of the heating source is controlled according to the fault energy curve obtained from the actual transformer fault.

4. A simulation calculation method for identifying stress concentration points of a transformer oil tank according to claim 2, characterized in that: The calculation method of fluid-solid coupling is to change the pressure field distribution in the flow field based on the evaporation-condensation phase change model, and then act on the solid oil tank wall to obtain the stress distribution cloud map of the oil tank wall.

5. The simulation calculation method for identifying stress concentration points of a transformer oil tank according to claim 1 is characterized in that: Fluid-solid coupling is achieved by using the coupling of two analysis systems, fluid flow and transient structure, in Ansys simulation software.

6. A simulation calculation device for identifying stress concentration points in a transformer oil tank, characterized in that: The invention comprises a three-dimensional finite element model module of a transformer oil tank, a pressure source module, a tank stress distribution cloud map module and a stress concentration point analysis module. The three-dimensional finite element model module of the transformer oil tank establishes a three-dimensional finite element model of the transformer oil tank according to the actual transformer oil tank size; the pressure source module sets a pressure source inside the transformer oil tank, and changes the pressure field distribution inside the oil tank through the pressure source; the tank stress distribution cloud map module uses a fluid-solid coupling calculation method to calculate the stress distribution cloud map of the oil tank after different faults occur; the stress concentration point analysis module analyzes the stress distribution cloud map, compares the concentration point where the stress is always greater than the surrounding area under different fault energies and different fault positions, and determines that the concentration point is the stress concentration point of the oil tank.

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