Dry-type hollow light bridge arm reactor lifting device and design method thereof

Abstract

The invention discloses a dry-type hollow light bridge arm reactor lifting device and a design method thereof. Belongs to the technical field of dry-type air-core reactor design and manufacturing. A three-dimensional model of a reactor lifting device is built according to the side length and thickness of a top square plate and the diameter and thickness of a bottom circular plate; and taking the hot-spot temperature rise as an objective function, performing multi-objective optimization on the parameters of the middle structure by combining a genetic algorithm and finite element simulation, and outputting an optimization result as a final design parameter. According to the method, the problem of long time consumption of design and development caused by purely relying on multiple tests or simulation iteration is solved. Meanwhile, based on the technical difficulties of poor fatigue resistance and high temperature rise of the current dry-type hollow bridge arm reactor lifting device for offshore flexible direct current power transmission, the invention provides a lifting device structure which is high in reliability, low in temperature rise and good in mechanical shock resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of design and manufacturing of dry-type hollow reactors, and in particular to a dry-type hollow lightweight bridge arm reactor raising device and a design method thereof, aimed at solving the strength, fatigue and eddy current loss and heating problems of a dry-type hollow lightweight bridge arm reactor raising device for offshore wind power flexible direct current transmission. Background Art

[0002] my country is gradually building a new power system with new energy as the main body. Wind power is a key link and plays an increasingly important role. In the growing wind energy market and limited available space on land, the total power generation and installation capacity of offshore wind farms are increasing year by year. From the perspective of economic benefits, offshore AC transmission systems are mostly suitable for transmission distances of 80 kilometers offshore. For long distances, DC must be used for transmission. The deep sea has become a key area for offshore wind power layout in various countries.

[0003] As an indispensable and important equipment to ensure the normal operation of the offshore wind power flexible DC system, the bridge arm reactor mainly plays the role of suppressing the circulating current between the bridge arms and suppressing the fault current between the bridge arms that rises too fast during short circuit. This equipment is generally fixed inside the offshore platform. Since the offshore platform reaches 10,000 tons, in order to reduce the difficulty of installation and transportation of the entire platform, the development of lightweight and compact bridge arm reactors is of far-reaching significance.

[0004] As a key component of the dry-type hollow light bridge arm reactor equipment, the lifting device mainly plays the role of transition connection and reducing the temperature rise of the flange at the end of the pillar insulator. The temperature rise, strength and fatigue problems of the lifting device body need to be considered during the design process. The difference from conventional smoothing or parallel reactors is that the current component of the bridge arm reactor is a composite of AC and DC, and the reactor lifting device will produce a large temperature rise under the action of the leakage magnetic field. In addition, since the dry-type hollow light bridge arm reactor is installed inside the offshore platform, the platform and the internal power equipment will vibrate under the impact of waves. In addition to meeting the strength requirements of the equipment, the lifting device must also reduce the stress concentration area as much as possible to avoid fatigue damage.

[0005] In summary, the existing disclosed design method and structure of the dry-type hollow bridge arm reactor lifting device cannot quickly meet the design and development requirements of dry-type hollow lightweight bridge arm reactors for large-capacity offshore flexible DC converter stations. Summary of the invention

[0006] Therefore, the purpose of the present invention is to provide a dry-type hollow lightweight bridge arm inductor lifting device and a design method thereof, to improve the previous development method of the lifting device that relies solely on design experience, to propose a forward design calculation method, and to reduce the problem of time-consuming design and development caused by relying solely on multiple tests or simulation iterations.

[0007] In order to achieve the above object, the present invention provides a design method for a dry-type hollow light bridge arm reactor elevation device, comprising the following steps: S1. Generate structural composition information and material parameter information of the reactor lifting device, wherein the structural composition information of the lifting device includes a top square plate, a middle structure and a bottom circular plate; the middle structure includes a hollow cylinder and stiffening plates arranged around the hollow cylinder; S2. Determine the side length and thickness of the top square plate, and the diameter and thickness of the bottom circular plate according to the structural information of the star frame arm fixing plate and the flange on the support insulator of the dry-type air-core reactor; S3. Use genetic algorithm to perform multi-objective optimization on the parameters of the middle structure, including: The outer diameter and wall thickness of the hollow cylinder, and the height and thickness of the stiffening plate are taken as the design variables X; The objective function is established with the strain energy unchanged and the hot spot temperature rise as minimum: min T (X) = K In the formula, X is the design variable; K is the hot spot temperature rise; C is the structural strain energy; —Lower limit of design variables; —Upper limit of design variables; J—strain energy constraint value calculated based on target stiffness constraint conditions; Finite element simulation is performed using the structural composition information and material parameter information generated by S1 and the parameters determined in S2 to calculate the strain energy and hot spot temperature rise of the structure. The genetic algorithm is used to change the values ​​of each design variable to determine whether the objective function has achieved the minimum value. When the minimum value is achieved and the population data converges, the optimization result is output as the final design parameter.

[0008] Further preferably, in S2, the determining of the side length and thickness of the top square plate, and the diameter and thickness of the bottom circular plate according to the installation requirements and material properties includes: Set the side length of the top square plate W Not greater than the side length of the bottom plate of the fixed star rack arm mounting plate structure in the reactor support system; The diameter of the bottom circular plate is not greater than the diameter of the flange on the post insulator; The thickness of the top square plate and the bottom circular plate is calculated as follows: in, f is the tensile design value of the structural material; is the bending moment in the plate.

[0009] Further, preferably, the bending moment in the plate is calculated using the following formula: in, is the bending moment coefficient and q is the equivalent uniformly distributed load on the plate; lx is the size of the stress-bearing area of ​​the flange plate.

[0010] Further, preferably, the equivalent uniformly distributed load on the plate is calculated using the following formula: In the formula, lx、ly are the characteristic dimensions of the stress-bearing area of ​​the flange plate; is the maximum tension of the flange bolts.

[0011] Further preferably, the maximum tension of the flange bolt The calculation is done using the following formula: In the formula, M is the bending moment of the flange, N·mm; N is the axial force acting on the flange, the pressure is taken as a negative value, N; is the number of bolts on the corresponding plate; is the distance from the bolt center to the rotation axis, is the distance from the center of the bolt with maximum force to the rotation axis, mm.

[0012] Further preferably, the stiffening plate profile is divided into a straight line segment and a curved line segment along the height direction, wherein the curvature of the curved line segment arc is calculated according to the following formula: in, H To increase the overall height of the middle structure of the device, is the height of the straight section of the stiffener, is the height of the stiffening plate step; is the curvature control parameter; x is the horizontal length coordinate value of the curve segment from the outermost side of the bottom of the stiffening plate, is the length of the top side of the stiffening plate; is the bottom side length of the stiffener.

[0013] The present invention also provides a dry-type hollow light bridge arm reactor raising device, which is designed based on the steps of the design method of the above-mentioned dry-type hollow light bridge arm reactor raising device, and comprises a top square plate, a middle structure and a bottom circular plate; the middle structure comprises a hollow cylinder and a stiffening plate arranged around the hollow cylinder; Further preferably, there are four stiffening plates evenly distributed around the hollow cylinder.

[0014] Further preferably, the side of the hollow cylinder is provided with a groove, and the groove width is 5 mm.

[0015] Further preferably, a step is provided at the end of the stiffening plate, and when the thickness of the stiffening plate is less than 6 mm, the step height is 10 mm; when the thickness of the stiffening plate is 6 mm-12 mm, the step height is 15 mm; when the thickness of the stiffening plate is greater than 12 mm, the step height is 20 mm.

[0016] The dry hollow lightweight bridge arm reactor lifting device and its design method disclosed in the present application reduce the problem of time-consuming design and development due to simple reliance on multiple tests or simulation iterations. At the same time, it solves the technical difficulties of poor fatigue resistance and high temperature rise of the current dry hollow bridge arm reactor lifting device for offshore flexible direct current transmission; by optimizing the structure of the annular hollow cylinder, reducing eddy current loss and heat generation, and by improving the profile of the stiffening plate, improving stress distribution, and enhancing seismic mechanical properties, it is ensured that the lifting device can meet the reliability application of AC / DC composite action and long-period sea wave excitation conditions, and improve the safety and reliability of the bridge arm reactor support system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the lifting device designed for the present invention in the reactor support system.

[0018] Figure 2 A schematic diagram of the structure of the lifting device designed for the present invention.

[0019] Figure 3 It is the stress-bearing area of ​​the flange plate connected to the lifting device in the present invention.

[0020] Figure 4 It is a schematic diagram of the force on the flange bolts in the present invention.

[0021] Figure 5 The present invention discloses a flow chart of a design method for a dry-type hollow light-duty bridge arm reactor elevation device.

[0022] Figure 6 It is a schematic diagram of the structure of the annular hollow cylinder in the lifting device.

[0023] Figure 7 This is a schematic diagram of the stiffening plate structure in the lifting device. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below through the accompanying drawings and specific embodiments.

[0025] like Figure 1As shown, in order to realize the connection between the upper part of the lifting device A and the star frame arm mounting plate B, and the lower part of the lifting device and the upper flange of the support insulator C, the top structure of the lifting device is generally designed as a square plate, and the bottom structure is designed as a circular plate. In order to further reduce the eddy current loss and heat generation of the lifting device, the side length of the top square plate is not greater than the side length of the bottom plate of the fixed star frame arm mounting plate structure in the reactor support system, and the diameter of the bottom circular plate is not greater than the diameter of the upper flange of the support insulator.

[0026] like Figure 2 As shown, the dry-type hollow light bridge arm reactor raising device provided by an embodiment of the present invention is designed based on the steps of the design method of the dry-type hollow light bridge arm reactor raising device, and includes a top square plate 1, a middle structure and a bottom circular plate 4; the middle structure includes a hollow cylinder 3 and a stiffening plate 2 arranged around the hollow cylinder. The structural material is stainless steel.

[0027] In order to reduce eddy current loss and heat generation, the annular hollow cylinder structure is slotted with a slot width of 5 mm. Four stiffening plates are arranged along the circumference of the annular hollow cylinder.

[0028] Considering that sharp angles are prone to stress concentration, which can easily cause cracking under cyclic load conditions and that sharp angle welding is difficult to achieve, a step design is made at the end of the stiffener plate. The step height ( h2b ) must be greater than the weld height in the design. The selection principles can be referred to as follows: When the thickness of the stiffening plate is less than 6mm, the step height is 10mm; When the thickness of the stiffening plate is 6mm-12mm, the step height is 15mm; When the thickness of the stiffening plate is greater than 12mm, the step height is 20mm.

[0029] In order to avoid the biaxial tensile stress condition that may be caused by the intersection of the main weld and the rib plate weld, improve the plasticity of the joint, and avoid the occurrence of brittle cracks, the inner side angle of the stiffener, such as Figure 7 At point P1 shown, the inner angle of the top of the rib is cut off to improve the stress state.

[0030] like Figure 5 As shown, according to the start - parameterized model of the middle structure of the lifting device - prepare material parameters for mechanical simulation and thermal simulation - determine the calculation conditions - the upper and lower bottom lengths of the stiffening plate - pre-processing - simulation calculation - post-processing - goal: minimum constraint condition for hot spot temperature rise: strain energy remains unchanged - whether the iteration converges - end / no change of design variables - return to the pre-processing step.

[0031] Specifically, the present invention provides a design method for a dry-type hollow light bridge arm reactor elevation device, comprising the following steps: S1. Generate structural composition information and material parameter information of the reactor lifting device, wherein the structural composition information of the lifting device includes a top square plate, a middle structure and a bottom circular plate; the middle structure includes a hollow cylinder and stiffening plates arranged around the hollow cylinder; S2. Determine the side length and thickness of the top square plate, and the diameter and thickness of the bottom circular plate according to the structural information of the star frame arm fixing plate and the flange on the support insulator of the dry-type air-core reactor; Further preferably, in S2, the side length and thickness of the top square plate, and the diameter and thickness of the bottom circular plate according to the structural information of the star frame arm fixing plate and the flange on the support insulator of the dry-type air-core reactor are determined, including: Set the side length of the top square plate W Not greater than the side length of the bottom plate of the fixed star rack arm mounting plate structure in the reactor support system; The diameter of the bottom circular plate is not greater than the diameter of the flange on the post insulator; The thickness of the top square plate and the bottom circular plate is calculated as follows: in, f is the tensile design value of the structural material; is the bending moment in the plate.

[0032] Further, preferably, the bending moment in the plate in, is the bending moment coefficient and q is the equivalent uniformly distributed load on the plate; lx is the size of the flange plate stress area. Bending moment coefficient It can be obtained according to the following Table 1.

[0033] Table 1 Bending moment coefficient like Figure 3 As shown, the equivalent uniformly distributed load on the plate is calculated using the following formula: In the formula, lx、ly are the characteristic dimensions of the stress-bearing area of ​​the flange plate; is the maximum tension of the flange bolts.

[0034] Further, if Figure 4 As shown, the maximum tension of the flange bolts The calculation is done using the following formula: In the formula, M is the bending moment of the flange, N·mm; Nis the axial force acting on the flange, the pressure is taken as a negative value, N; is the number of bolts on the corresponding plate; is the distance from the bolt center to the rotation axis, is the distance from the center of the bolt with maximum force to the rotation axis, mm.

[0035] S3. Use genetic algorithm to perform multi-objective optimization on the parameters of the middle structure, including: S301, based on the structural information of S1, the outer diameter and wall thickness of the hollow cylinder, the width and thickness of the stiffening plate are used as design variables X; the design variables of the annular hollow cylinder mainly include the outer diameter With wall thickness The design variables of the stiffener plate mainly include the stiffener plate width , Thickness of stiffener .like Figure 6 shown.

[0036] S302: Determine constraints Comprehensively consider the design requirements and actual needs, combine the analysis of the influence of dimensional parameters on strength and temperature rise, and adjust the design variables X The value of is restricted, and its lower limit is set to , upper limit The size-optimized model should ensure that its overall stiffness does not decrease, thus constraining the structural strain energy. C。

[0037] S303, establish the objective function with constant strain energy and minimum hot spot temperature rise: min T (X) = K In the formula, X is the design variable; K is the hot spot temperature rise; C is the structural strain energy; —Lower limit of design variables; —Upper limit of design variables; J—Strain energy constraint value calculated based on target stiffness constraint condition Finite element simulation is performed using the structural composition information and material parameter information generated by S1 and the parameters determined in S2 to calculate the strain energy and hot spot temperature rise of the structure. The genetic algorithm is used to change the values ​​of each design variable to determine whether the objective function has achieved the minimum value. When the minimum value is achieved and the population data converges, the optimization result is output as the final design parameter.

[0038] Through genetic algorithms, the values ​​of each design variable are changed to determine whether the constraints are met and whether the design goal is achieved. If the optimization is not completed, the above process is repeated; if the optimization is completed, the optimization result is output. Whether the population data generated during the iteration converges is used as the criterion for the completion of the optimization.

[0039] Further preferably, Figure 7As shown, the method further includes dividing the stiffening plate profile into straight segments and curved segments along the height direction, wherein the curvature of the curved segment arc is calculated according to the following formula: in, H To increase the overall height of the middle structure of the device, is the height of the straight section of the stiffener, is the height of the stiffening plate step; is the curvature control parameter; x The horizontal length coordinate value of the curve segment from the outermost side of the bottom of the stiffener ， is the length of the top side of the stiffening plate; is the bottom side length of the stiffener.

[0040] By optimizing the structure of the annular hollow cylinder, reducing eddy current loss and heat generation, and improving the profile of the stiffening plate, improving the stress distribution and enhancing the seismic mechanical properties, it is ensured that the lifting device can meet the reliability application of AC / DC combined effects and long-period wave excitation conditions, thereby improving the safety and reliability of the bridge arm reactor support system.

[0041] Obviously, the above embodiments are only examples for clear explanation, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. A design method for a dry-type hollow light bridge arm reactor elevation device, characterized in that: The following steps are involved: S1. Generate structural composition information and material parameter information of the reactor lifting device, wherein the structural composition information of the lifting device includes a top square plate, a middle structure and a bottom circular plate; the middle structure includes a hollow cylinder and stiffening plates arranged around the hollow cylinder; S2. Determine the side length and thickness of the top square plate, and the diameter and thickness of the bottom circular plate according to the structural information of the star frame arm fixing plate and the flange on the support insulator of the dry-type air-core reactor; S3. Use genetic algorithm to perform multi-objective optimization on the parameters of the middle structure, including: The outer diameter and wall thickness of the hollow cylinder, and the width and thickness of the stiffening plate are taken as the design variables X; The objective function is established with the strain energy unchanged and the hot spot temperature rise as minimum: min T (X) = K In the formula, X is the design variable; K is the hot spot temperature rise; C is the structural strain energy; —Lower limit of design variables; —Upper limit of design variables; J—strain energy constraint value calculated based on target stiffness constraint conditions; Finite element simulation is performed using the structural composition information and material parameter information generated by S1 and the dimensional parameters determined in S2 to calculate the strain energy and hot spot temperature rise of the structure. The genetic algorithm is used to change the values ​​of each design variable to determine whether the objective function has achieved the minimum value. When the minimum value is achieved and the population data converges, the optimization result is output as the final design parameter.

2. The design method of the dry-type hollow light bridge arm reactor elevation device according to claim 1 is characterized in that: In S2, the step of determining the side length and thickness of the top square plate and the diameter and thickness of the bottom circular plate according to the structural information of the star frame arm fixing plate and the upper flange of the post insulator of the dry-type air-core reactor includes: Set the side length of the top square plate W Not greater than the side length of the bottom plate of the fixed star rack arm mounting plate structure in the reactor support system; The diameter of the bottom circular plate is not greater than the diameter of the flange on the post insulator; The thickness of the top square plate and the bottom circular plate is calculated as follows: in, f is the tensile design value of the structural material; is the bending moment in the plate.

3. The design method of the dry-type hollow light bridge arm reactor elevation device according to claim 2 is characterized in that: The bending moment in the plate is calculated using the following formula: in, is the bending moment coefficient, q is the equivalent uniformly distributed load on the plate; lx is the size of the stress-bearing area of ​​the flange plate.

4. The design method of the dry-type hollow light bridge arm reactor elevation device according to claim 3 is characterized in that: The equivalent uniformly distributed load on the plate is calculated using the following formula: In the formula, lx、ly are the characteristic dimensions of the stress-bearing area of ​​the flange plate; is the maximum tension of the flange bolts.

5. The design method of the dry-type hollow light bridge arm reactor elevation device according to claim 4 is characterized in that: The maximum tension of the flange bolts The calculation is done using the following formula: In the formula, M is the bending moment of the flange, N·mm; N is the axial force acting on the flange, the pressure is taken as a negative value, N; is the number of bolts on the corresponding plate; is the distance from the bolt center to the rotation axis, is the distance from the center of the bolt with maximum force to the rotation axis, mm.

6. The design method of the dry-type hollow light bridge arm reactor elevation device according to claim 1 is characterized in that , and also includes dividing the stiffening plate profile into straight segments and curved segments along the height direction, wherein the curvature of the curved segment arc is calculated according to the following formula: in, H To increase the overall height of the middle structure of the device, is the height of the straight section of the stiffener, is the height of the stiffening plate step; is the curvature control parameter; x is the horizontal length coordinate value of the curve segment from the outermost side of the bottom of the stiffening plate; is the length of the top side of the stiffening plate; is the bottom side length of the stiffener.

7. A dry-type hollow light bridge arm reactor lifting device, characterized in that: The dry-type hollow lightweight bridge arm reactor lifting device is manufactured based on the steps of the design method of any one of claims 1-6, and includes a top square plate, a middle structure and a bottom circular plate; the middle structure includes a hollow cylinder and stiffening plates arranged around the hollow cylinder.

8. The dry-type hollow light bridge arm reactor raising device according to claim 7, characterized in that: There are four stiffening plates evenly distributed around the hollow cylinder.

9. The dry-type hollow light bridge arm reactor raising device according to claim 7, characterized in that: The side of the hollow cylinder is provided with a slot, and the slot width is 5mm.

10. The dry-type hollow light bridge arm reactor raising device according to claim 7, characterized in that: The end of the stiffening plate is provided with a step, When the thickness of the stiffening plate is less than 6mm, the step height is 10mm; When the thickness of the stiffening plate is 6mm-12mm, the step height is 15mm; When the thickness of the stiffening plate is greater than 12mm, the step height is 20mm.

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