Method and device for evaluating the displacement of a dry-type air-core reactor under the action of wind loads

Abstract

The application discloses a kind of displacement evaluation method and device of dry-type hollow electric reactor under the action of wind load, and belongs to the technical field of high-voltage electrical equipment wind resistance design.The method first obtains the structural parameters of electric reactor and site wind parameters, then based on the mechanical model considering the axial deformation and bending deformation of support insulator, the overall bending stiffness of support system is calculated.On this basis, combined with the wind vibration coefficient considering the natural vibration characteristics of structure, the total overturning moment generated by wind load is calculated.Finally, the top corner is obtained by the relationship between total moment and overall stiffness, and then the maximum lateral displacement of the top of electric reactor is calculated.The application significantly improves the accuracy of wind-induced displacement evaluation of extra-high voltage electric reactor through analytical calculation model, overcomes the shortcomings of large deviation of traditional simplified model and low efficiency of finite element method, and provides an efficient and reliable theoretical tool for wind resistance design and fatigue life evaluation of electric reactor support system.

Description

Technical Field

[0001] This invention relates to the field of reactor technology, and in particular to a method and apparatus for evaluating the offset of a dry-type air-core reactor under wind load. Background Technology

[0002] Dry-type air-core reactors are key equipment in ultra-high voltage power systems. They are typically installed outdoors and frequently encounter harsh weather conditions such as wind and sandstorms. Regarding wind resistance, the State Grid's procurement standard Q / GDW 13064.3-2018, "Procurement Standard for 10kV-35kV Dry-type Air-core Current-limiting Reactors," generally requires the equipment to withstand a maximum wind speed of 35m / s and assesses the mechanical strength safety factor of the insulators to be greater than 1.67. However, regarding the stiffness of the support system, there is no clear limit requirement for the maximum deflection of dry-type air-core reactors under wind loads, nor are there any relevant standards that constrain this.

[0003] Currently, ultra-high voltage direct current (UHVDC) transmission projects are underway in China, and dry-type air-core reactors, as crucial primary reactive power equipment in the power transmission and transformation equipment of converter stations, are vital for the safe and stable operation of the power grid. Considering that some converter stations on UHV transmission lines are located in areas with high wind speeds and frequent occurrences, during the design and development phase of the reactors, in addition to ensuring that the mechanical stress meets the minimum safety factor requirements, it is also necessary to further assess the stiffness of the support system to prevent fatigue damage to supporting components such as post insulators under repeated wind loads. According to the fatigue damage evolution mechanism, fatigue life is closely related to the magnitude of structural offset. Therefore, it is crucial to quickly and accurately assess the maximum offset of the main coil of the dry-type air-core reactor under wind loads and propose improvement measures accordingly.

[0004] With the rapid development of computer technology, CAE (Computer-Aided Calculation) has been widely used for structural strength and stiffness verification of power equipment. However, its disadvantages include the need for detailed modeling, which leads to long processing times, and the huge amount of finite element calculations, which makes it impossible for microcomputers to solve the problems. This makes it difficult to support efficient design and development work in the scheme stage.

[0005] According to relevant mechanics knowledge, the offset of a dry-type air-core reactor under wind load is closely related to the lateral stiffness of the supporting structure. Although some experts and scholars have proposed corresponding evaluation methods for calculating the lateral stiffness of the support insulators of dry-type air-core reactors, in the case of UHV reactors, especially bridge arm reactors and smoothing reactors at voltage levels of ±800kV and above, the results calculated using the current lateral stiffness evaluation methods deviate significantly from the actual test / simulation calculation results. The main reason is that the existing evaluation methods simplify the multi-column insulators distributed along the main coil ring array into a cantilever beam-mass point model, only considering the synchronous lateral bending of the multi-column insulators, and ignoring the contribution of the support insulator installation section diameter distribution and the axial deformation of the support insulators to the overall stiffness. Summary of the Invention

[0006] Therefore, the purpose of this invention is to provide a method and apparatus for evaluating the offset of a dry-type air-core reactor under wind load, taking into account both the bending deformation and axial deformation of the post insulator, in order to evaluate the lateral stiffness of the reactor equipment and improve the development efficiency and accuracy of new reactor products.

[0007] To achieve the above objectives, the present invention provides a method for evaluating the offset of a dry-type air-core reactor under wind load, comprising the following steps: S1. Obtain the structural parameters and installation environment parameters of the reactor; the structural parameters of the reactor include the main structural parameters of the reactor and the parameters of the support insulator. S2. Calculate the overall bending stiffness of the reactor support system based on the structural parameters of the reactor. S3. Calculate the wind vibration coefficient based on the overall bending stiffness and the total mass of the equipment; S4. Calculate the lateral forces of each component of the reactor using the wind vibration coefficient; S5. Calculate the equivalent total bending moment caused by wind load based on the lateral force, and calculate the maximum lateral offset of the reactor based on the obtained total bending moment.

[0008] More preferably, the main structural parameters of the reactor include: The windward area A1 and height above ground H1 of the rain cap, the windward area A2 and height above ground H2 of the soundproof cover, the windward area A3 and height above ground H3 of the encapsulated winding, and the mass M of the main coil. The parameters of the post insulator include: the installation radius of the array along the circumferential direction of the main coil. R Number of post insulators n ,high L Rod diameter D, elastic modulus E， ground height H in and the windward area A of each post insulator in ; The installation environment parameters include: basic wind pressure q0, ground roughness category f. i .

[0009] More preferably, in S2, the step of calculating the overall bending stiffness of the reactor support system based on the structural parameters of the reactor includes: calculating the overall bending stiffness K according to the following formula based on the axial deformation contribution and the bending deformation contribution; More preferably, in S3, calculating the wind vibration coefficient based on the overall bending stiffness and the total mass of the equipment includes: Calculate the first-order natural period based on the overall bending stiffness K and the total mass M of the reactor. , Based on the first-order natural period Based on the wind load parameters of the installation site, the wind vibration coefficient βz,i is determined; in, This is the pulsation amplification factor. The pulsation effect coefficient is... The mode shape coefficient, This is the wind pressure height variation coefficient.

[0010] A further preferred method is to calculate the lateral forces of each component of the reactor using the following formula based on the wind vibration coefficient: Lateral forces of various components of the reactor ;in, These are the standard values ​​for wind load pressure of each component; This refers to the windward area of ​​each component.

[0011] Further preferably, the standard value of wind load pressure for each component The following formula is used for calculation: in, The wind vibration coefficient at height z; The shape factor is the wind load factor. This is the coefficient for wind pressure height variation; This is the basic wind pressure.

[0012] More preferably, in S5, the equivalent total bending moment caused by the wind load is calculated based on the lateral force as follows: in, This refers to the ground elevation of each component.

[0013] In a further preferred embodiment, when calculating the maximum lateral offset of the reactor based on the obtained total bending moment, the rotation angle generated under the action of the total bending moment is first calculated: The maximum lateral displacement under wind load is: In the formula, This represents the total height of the reactor.

[0014] The present invention also provides a device for calculating the offset of a dry-type air-core reactor under wind load, comprising: The parameter information input module is used to obtain the structural parameters and installation environment parameters of the reactor; the structural parameters of the reactor include the main structural parameters of the reactor and the parameters of the support insulator. The total bending stiffness calculation module calculates the axial stiffness contribution and bending stiffness contribution respectively based on the structural parameters of the reactor, and finally calculates the total bending stiffness. The lateral force calculation module calculates the wind vibration coefficient based on the overall bending stiffness and the total mass of the equipment, and uses the wind vibration coefficient to calculate the lateral force of each component of the reactor; The lateral displacement calculation module calculates the equivalent total bending moment caused by wind load based on the lateral force, and calculates the maximum lateral offset of the reactor based on the obtained total bending moment.

[0015] The method and apparatus for evaluating the offset of a dry-type air-core reactor under wind load disclosed in this application have the following advantages compared with the prior art: This application significantly improves the accuracy of the evaluation and the reliability of the model. Existing technologies simplify multi-post insulator systems to a cantilever beam-mass model that only considers synchronous bending, neglecting the contribution of axial deformation of the post insulators to the overall stiffness. This application, for the first time, simultaneously and quantitatively considers both bending and axial deformation of the post insulators in the evaluation model, making the mechanical model closer to the actual stress mechanism of the structure. This fundamentally solves the problem of excessive deviation in the stiffness evaluation of ±800kV and above UHV reactors using existing methods, providing a more accurate theoretical basis for wind-resistant design and fatigue life assessment.

[0016] This application only requires input of basic structural and site parameters to sequentially complete stiffness calculation, wind load (including dynamic wind vibration effect) calculation, and displacement calculation. This method avoids the complex finite element modeling and solution process, and can be completed instantaneously on a regular computer, greatly improving the development efficiency of new products during the conceptual design and feasibility study stages. It effectively overcomes the two major bottlenecks of large model deviations and cumbersome calculations in the background technology, and has significant technical and economic value for ensuring the safe and stable operation of UHV dry-type hollow reactors in strong wind areas and improving the wind-resistant design level of my country's UHV equipment. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the method for evaluating the offset of a dry-type air-core reactor under wind load according to the present invention.

[0018] Figure 2 This is a structural diagram of the offset evaluation system for the dry-type air-core reactor under wind load according to the present invention. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] like Figure 1 As shown, an embodiment of the present invention provides a method for evaluating the offset of a dry-type air-core reactor under wind load, comprising the following steps: S1. Obtain the structural parameters and installation environment parameters of the reactor; the structural parameters of the reactor include the main structural parameters of the reactor and the parameters of the support insulator; wherein, the main structural parameters of the reactor include: The windward area A1 and height above ground H1 of the rain cap, the windward area A2 and height above ground H2 of the soundproof cover, the windward area A3 and height above ground H3 of the encapsulated winding, and the mass M of the main coil. The parameters of the post insulator include: the installation radius of the array along the circumferential direction of the main coil. R Number of post insulators n ,high L Rod diameter D, elastic modulus E， ground height H in and the windward area A of each post insulator in ; The installation environment parameters include: basic wind pressure q0, ground roughness category f. i .

[0021] S2. Calculate the overall bending stiffness of the reactor support system based on the structural parameters of the reactor. Since the support structure of the dry-type air-core reactor exhibits an "axisymmetric" characteristic, the lateral stiffness in any horizontal direction can be considered. Here, it is assumed that the dry-type air-core reactor is bent around the y-axis (the coordinate system is located on the central axis of the main coil) with a curvature of k. The contributions of bending deformation and axial deformation to the overall stiffness are also considered.

[0022] Axial stiffness contribution: When the overall curvature of the reactor around the y-axis is k, the axial deformation of the post insulator at a horizontal distance x from the neutral axis (y-axis) originates from the tilt of the main coil. The axial force of a single post insulator is: In the formula, E is the elastic modulus of the post insulator, A is the cross-sectional area, and k is the bending curvature. The x-coordinate value of a single-column insulator arranged in a circular array.

[0023] The contribution of the axial force to the bending of the y-axis is: and The signs are opposite, and the product is positive.

[0024] Summing the overall bending moments, we get: Bending stiffness contribution: The post insulator is fixed at both ends, and when the top end rotates... At that time, the bending moment at the end of the post insulator is: Where I is the moment of inertia of the section of a single support column, and since the bottom is fixed, =0, resulting in: Because the post insulator has a circular cross-section and isotropic properties, when the overall structure bends around the y-axis, the top rotation angle of the i-th post is... Therefore, the bending moment contributed by each support is The component about the y-axis, therefore, the total bending contribution. Calculate the equivalent moment of inertia The total bending moment is Considering You can get therefore, Because the arrangement of the post insulators exhibits circumferential symmetry, the coordinates satisfy... n supports are arranged in a circle, with the origin defined by the central axis. The horizontal x-axis is the angle between the insulator of the i-th support and the center of the circle. 。 Considering the characteristics of symmetrical distribution, ,therefore: Based on the moment-curvature relationship of the beam: so, Substitution , The simplified equivalent moment of inertia is obtained as follows: Therefore, if the bending stiffness is defined as Then there is That is, overall bending stiffness .

[0025] S3. Calculate the wind vibration coefficient based on the overall bending stiffness and the total mass of the equipment; In S3, the calculation of the wind vibration coefficient based on the overall bending stiffness and the total mass of the equipment includes: Calculate the first-order natural period based on the overall bending stiffness K and the total mass M of the reactor. , Based on the first-order natural period Based on the wind load parameters of the installation site, the wind vibration coefficient βz,i is determined;

[0026] in, This is the pulsation amplification factor. The pulsation effect coefficient is... The mode shape coefficient, This is the wind pressure height variation coefficient.

[0027] The values ​​corresponding to each coefficient are shown in Tables 1 to 4. For intermediate values ​​not listed in the tables, interpolation fitting can be used to calculate them.

[0028] Table 1. Pulsation Increase Coefficient Note: In the table The first-order vibration frequency is calculated using the following formula: M is the mass of the main coil plus one-third of the mass of the post insulator.

[0029] Table 2 Pulsation Influence Coefficient Table 3 Mode Shape Coefficients Where H max The maximum height of the reactor above ground Table 4 Wind pressure height variation coefficient S4. Calculate the lateral forces of each component of the reactor using the wind vibration coefficient; Standard values ​​of wind load pressure for each component The following formula is used for calculation: in, The wind vibration coefficient at height z; The shape factor is the wind load factor. This is the coefficient for wind pressure height variation; This is the basic wind pressure; Based on the above calculations, the standard value of wind load pressure is obtained. Then, multiply by the windward area A of each component. i The lateral forces F of each component of the reactor were calculated. i .

[0030] S5. Calculate the equivalent total bending moment caused by wind load based on the lateral force, and calculate the maximum lateral offset of the reactor based on the obtained total bending moment.

[0031] The equivalent total bending moment caused by wind load, calculated based on lateral force, is: in, This refers to the ground elevation of each component.

[0032] To calculate the maximum lateral offset of the reactor based on the obtained total bending moment, firstly, calculate the rotation angle generated under the action of the total bending moment: The maximum lateral displacement under wind load is: In the formula, This represents the total height of the reactor.

[0033] like Figure 2 As shown, the present invention also provides a device for calculating the offset of a dry-type air-core reactor under wind load, which is used to implement the above method, including: A parameter information input module is used to acquire the structural parameters and installation environment parameters of the reactor; the structural parameters of the reactor include the main structural parameters of the reactor and the parameters of the support insulator. Total bending stiffness calculation module: Based on the structural parameters of the reactor, the axial stiffness contribution and bending stiffness contribution are calculated separately, and finally the total bending stiffness is calculated. Lateral force calculation module; calculates the wind vibration coefficient based on the overall bending stiffness and total mass of the equipment, and uses the wind vibration coefficient to calculate the lateral force of each component of the reactor; Lateral displacement calculation module: Calculates the equivalent total bending moment caused by wind load based on lateral force, and calculates the maximum lateral offset of reactor based on the obtained total bending moment.

[0034] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for evaluating the offset of a dry-type air-core reactor under wind load, characterized in that, Includes the following steps: S1. Obtain the structural parameters and installation environment parameters of the reactor; the structural parameters of the reactor include the main structural parameters of the reactor and the parameters of the support insulator. S2. Calculate the overall bending stiffness of the reactor support system based on the structural parameters of the reactor. The calculation of the overall bending stiffness of the reactor support system based on the structural parameters of the reactor includes: calculating the overall bending stiffness K according to the following formula based on the axial deformation contribution and the bending deformation contribution; in, E It is the elastic modulus; L This refers to the height of the post insulator; R D is the installation radius of the post insulator array along the circumferential direction of the main coil; n is the rod diameter; n is the number of post insulators. S3. Calculate the wind vibration coefficient based on the overall bending stiffness and the total mass of the equipment; S4. Calculate the lateral forces of each component of the reactor using the wind vibration coefficient; The lateral forces of each component of the reactor are calculated using the following formula based on the wind vibration coefficient: Lateral forces of various components of the reactor ;in, These are the standard values ​​for wind load pressure of each component; The frontal area of ​​each component; Standard values ​​of wind load pressure for each component The following formula is used for calculation: in, The wind vibration coefficient at height z; The shape factor is the wind load factor. This is the wind pressure height variation coefficient; This is the basic wind pressure; S5. Calculate the equivalent total bending moment caused by wind load based on the lateral force, and calculate the maximum lateral offset of the reactor based on the obtained equivalent total bending moment.

2. The method for evaluating the offset of a dry-type air-core reactor under wind load according to claim 1, characterized in that, The main structural parameters of the reactor include: The windward area A1 and height above ground H1 of the rain cap, the windward area A2 and height above ground H2 of the soundproof cover, the windward area A3 and height above ground H3 of the encapsulated winding, and the mass M of the main coil. The parameters of the post insulator include: height above ground H. in and the windward area A of each post insulator in ; The installation environment parameters include: basic wind pressure q0, ground roughness category f. i .

3. The method for evaluating the offset of a dry-type air-core reactor under wind load according to claim 1, characterized in that, In S3, the calculation of the wind vibration coefficient based on the overall bending stiffness and the total mass of the equipment includes: Calculate the first-order natural period T1 based on the overall bending stiffness K and the total mass M of the reactor. Based on the first-order natural vibration period T1 and the wind load parameters of the installation site, the wind vibration coefficient βz,i is determined. in, This is the pulsation amplification factor. The pulsation effect coefficient, The mode shape factor, This is the wind pressure height variation coefficient.

4. The method for evaluating the offset of a dry-type air-core reactor under wind load according to claim 3, characterized in that, In S5, the equivalent total bending moment caused by wind load, calculated based on lateral force, is: in, This refers to the ground elevation of each component.

5. The method for evaluating the offset of a dry-type air-core reactor under wind load according to claim 4, characterized in that, When calculating the maximum lateral offset of the reactor based on the obtained equivalent total bending moment, the first step is to calculate the rotation angle generated under the action of the total bending moment: The maximum lateral displacement under wind load is: In the formula, This represents the total height of the reactor.

6. A device for calculating the offset of a dry-type air-core reactor under wind load, based on the method for evaluating the offset of a dry-type air-core reactor under wind load as described in any one of claims 1-5, characterized in that... include: Parameter information input module; Used to obtain the structural parameters and installation environment parameters of the reactor; the structural parameters of the reactor include the main structural parameters of the reactor and the parameters of the support insulator; Total bending stiffness calculation module: Based on the structural parameters of the reactor, the axial stiffness contribution and bending stiffness contribution are calculated separately, and finally the total bending stiffness is calculated. Lateral force calculation module; calculates the wind vibration coefficient based on the overall bending stiffness and total mass of the equipment, and uses the wind vibration coefficient to calculate the lateral force of each component of the reactor; Lateral displacement calculation module: Calculates the equivalent total bending moment caused by wind load based on lateral force, and calculates the maximum lateral offset of reactor based on the obtained equivalent total bending moment.

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