A method for optimizing the air-gap structure of a shunt reactor core

Abstract

The present invention relates to the technical field of the vibration of reactors, and provides a method for optimizing the air-gap structure of the core of a shunt reactor, including obtaining the mechanical structure parameters and electrical parameters of the shunt reactor; setting the range of the number of air gaps, and establishing a three-dimensional model for each number of air gaps; calculating the vibration of the core of the shunt reactor by using finite element and fluid-structure coupling equations to obtain the optimal number of air gaps; uniformly arranging the air gaps with the total number being the optimal number of air gaps on the core, and setting and selecting the arrangement mode of the air-gap positions. This method can optimize the number of air gaps and the air-gap positions of the core according to the mechanical structure and electrical parameters of the preliminary design of the high-voltage shunt reactor, and calculate the vibration condition of the high-voltage shunt reactor through finite element calculation and fluid-structure coupling equations, which can provide reasonable suggestions for the optimal design of the high-voltage shunt reactor, is beneficial to improving the vibration characteristics of the high-voltage shunt reactor and reducing the noise on the premise of not significantly increasing the production cost.

Description

Technical Field

[0001] The present invention relates to the technical field of the vibration of reactors, and particularly to a method for optimizing the air-gap structure of the iron core of a shunt reactor. Background Art

[0002] The high-voltage power grid is the core of the existing power grid in our country. Reactive power balance is one of the key technologies in the design of high-voltage power grids. High-voltage shunt reactors are key devices to achieve this technology. Excessive vibration is an important problem that has long troubled the safe and stable operation of high-voltage shunt reactors. Studying the influencing factors of the vibration of high-voltage shunt reactors helps to design targeted vibration reduction schemes, which is of crucial significance for improving the operation reliability of high-voltage power grids.

[0003] Before studying the influencing factors of the vibration of the iron core of UHV shunt reactors, it is necessary to clarify its vibration mechanism first. The iron core cakes and yokes of UHV shunt reactors are both stacked by silicon steel sheets. Magnetostriction is one of the main reasons for causing their vibration. At the same time, the iron core columns of UHV shunt reactors also contain multiple air gaps. When magnetic flux passes through the boundary between the high-permeability iron core cakes and the low-permeability air gaps, Maxwell force will be generated, which is another main reason for the vibration of the iron core of UHV shunt reactors. At present, a series of studies on the influencing factors of reactor vibration have been carried out at home and abroad. Setting additional damping, changing the materials of each component of the iron core, and adjusting the iron core structure are feasible directions for vibration reduction of UHV shunt reactors. However, setting additional damping will inevitably add other components inside the reactor, which makes the insulation design inside the reactor more complex. At the same time, problems such as the aging and heat dissipation of the newly added components need to be considered, so there are difficulties in popularization. Changing the materials of each component of the iron core can effectively reduce the vibration of the reactor iron core in theory, but it will also greatly increase the production cost of the reactor, which is also difficult to promote. Adjusting the characteristics of the air gap is an effective method to improve the vibration characteristics of high-voltage shunt reactors, but existing research generally focuses on the air-gap materials, lacking research on the influence of the air-gap structure on the vibration of the reactor iron core. The force on the high-voltage shunt reactor is not only related to the iron core material but also affected by the iron core structure (especially the air-gap structure). On the premise of not affecting other performances of the reactor, optimizing the design of the air-gap structure of the iron core can also improve the vibration performance of the iron core. Therefore, it is very important to carry out research on the influence of the air-gap structure on the vibration of the reactor iron core. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a method for optimizing the air-gap structure of the iron core of a shunt reactor, which can analyze the air-gap structure, mainly the influence of the number of air gaps and the air-gap position on the vibration of the iron core of a high-voltage shunt reactor, and select the optimal number of air gaps n P and the optimal air-gap position arrangement method and apply them to the production of shunt reactors. The specific technical solutions are as follows:

[0005] A method for optimizing the air-gap structure of a shunt reactor core, comprising the following steps:

[0006] S1: Obtain the mechanical structure parameters and electrical parameters of the shunt reactor; the structure parameters include the total length δ of the core air-gap and the number of air-gaps n N ;

[0007] S2: Set the range of the number of air-gaps n, and establish a three-dimensional model for each number of air-gaps n;

[0008] S3: Calculate the vibration of the shunt reactor core by using the finite element method and the fluid-structure coupling equation to obtain the optimal number of air-gaps n P ;

[0009] S4: Uniformly arrange the air-gaps with the total number being the optimal number of air-gaps n P and the length of a single air-gap being m on the core, and set the arrangement mode of the air-gap positions;

[0010] S5: Repeat steps S3 - S4 to select the optimal arrangement mode of the air-gap positions.

[0011] Preferably, the structure parameters in step S1 further include: the size of the core window, the size of the winding, the size of the clamping parts and the oil tank, and the cross-sectional area of the core.

[0012] Preferably, the size of the core window includes the length, width and height of the core window;

[0013] The size of the winding includes the height, inner diameter and outer diameter of the winding;

[0014] The size of the clamping parts includes the length, width, height and thickness of the clamping parts;

[0015] The size of the oil tank includes the length, width, height and thickness of the oil tank.

[0016] Preferably, the electrical parameter includes the rated current of the reactor.

[0017] Preferably, step S2 is specifically: set the range of the number of air-gaps n, n is [n N - 5, n N + 5], the length m of each air-gap = δ / n, each group of air-gaps is evenly distributed on the core column, the distance between adjacent air-gaps is the same, establish a three-dimensional model for each number of air-gaps n, the cross-section is the same as the core column, and the length is δ / n.

[0018] Preferably, the optimal number of air-gaps n obtained in step S3 P is specifically as follows:

[0019] S31: Calculate the Maxwell force F of the shunt reactor core by using the finite element method maxand magnetostrictive force F mag The external force F causing the core to vibrate is F = F max + F mag ;

[0020] S32: Calculate the average value σ of the surface stress of the core ave = F / S;

[0021] S33: Use the fluid-structure coupling equation to calculate the root mean square d of the vibration displacement of the shunt reactor core;

[0022] S34: Respectively plot the relationship curve between the root mean square d of the vibration displacement of the shunt reactor core and the number n of air gaps, and the relationship curve between the average value σ of the surface stress of the core ave and the relationship curve of the number n of air gaps, conduct trend analysis, and select the optimal number n of air gaps P .

[0023] Preferably, the arrangement method of the air gap positions in step S4 includes: single air gap, double air gaps, triple air gaps, quadruple air gaps, quintuple air gaps, and the remainder is set at the 1 / 2 position of the core.

[0024] Preferably, the arrangement method of the air gap positions corresponding to the minimum root mean square d of the vibration displacement of the shunt reactor core selected in step S5 is the optimal air gap position arrangement method.

[0025] The beneficial effects of the present invention are as follows: The present invention provides a method for optimizing the air gap structure of a shunt reactor core, including step S1: Obtain the mechanical structure parameters and electrical parameters of the shunt reactor; the structure parameters include the total length of the core air gap and the number of air gaps; S2: Set the range of the number of air gaps, and establish a three-dimensional model for each number of air gaps; S3: Use the finite element method and the fluid-structure coupling equation to calculate the vibration of the shunt reactor core to obtain the optimal number of air gaps; S4: Evenly set the air gaps with the total number of the optimal number of air gaps and the length of a single air gap of m on the core, and set the air gap position arrangement method; S5: Repeat steps S3 - S4 to select the optimal air gap position arrangement method. This method can optimize the air gap structure - the number of air gaps and the air gap positions of the core according to the mechanical structure and electrical parameters of the preliminary design of the high-voltage shunt reactor, and calculate the vibration conditions of the high-voltage shunt reactor through finite element calculation and the fluid-structure coupling equation, which can provide reasonable suggestions for the optimal design of the high-voltage shunt reactor, is conducive to improving the vibration characteristics of the high-voltage shunt reactor and reducing noise without significantly increasing the production cost. Description of the Drawings

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0027] Figure 1 It is a schematic flow chart of the present invention. Specific embodiments

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] It should be understood that when used in this specification and the appended claims, the terms "comprises" and "comprising" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0030] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0031] It should be further understood that the term " / and / " used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0032] As Figure 1 shown, the specific embodiments of the present invention provide a method for optimizing the air-gap structure of the core of a shunt reactor, including the following steps:

[0033] S1: Obtain the mechanical structure parameters and electrical parameters of the shunt reactor; the structure parameters include the total length δ of the air gap of the core, and the number of air gaps is n N; The structural parameters also include: the dimensions of the iron core window, the dimensions of the winding, the dimensions of the clamping parts and the oil tank, and the cross-sectional area S of the iron core. The dimensions of the iron core window include the length, width, and height of the iron core window; the dimensions of the winding include the height, inner diameter, and outer diameter of the winding; the dimensions of the clamping parts include the length, width, height, and thickness of the clamping parts; the dimensions of the oil tank include the length, width, height, and thickness of the oil tank. The electrical parameters include the rated current of the reactor.

[0034] S2: Set the range of the number of air gaps n, where n is in the range of [n N -5, n N +5], and the length m of each air gap = δ / n. Each group of air gaps is evenly distributed on the iron core column, and the distance between adjacent air gaps is the same. A three-dimensional model is established for each number of air gaps n, with the cross-section being the same as that of the iron core column and the length being δ / n.

[0035] S3: Use the finite element and fluid-structure coupling equations to calculate the vibration of the parallel reactor iron core to obtain the optimal number of air gaps n P ; Specifically as follows:

[0036] S31: Use the finite element method to calculate the Maxwell force F max and magnetostrictive force F mag of the parallel reactor iron core. The external force F for the iron core vibration is F = F max + F mag ;

[0037]

[0038]

[0039] where ν x ′, ν y ′ respectively represent the changes of the magnetic resistivity relative to the stress in the horizontal rolling direction (x direction) and the vertical rolling direction (y direction). N is the unit vector along the normal direction of the unit surface, ν0 is the air magnetic resistivity, B is the magnetic induction intensity, α is the Poisson's ratio, E is the Young's modulus, σ is the conductivity of the medium, are the magnetic induction intensities in the horizontal rolling direction (x direction) and the vertical rolling direction (y direction) respectively.

[0040] S32: Calculate the average value σ ave of the stress on the iron core surface = F / S;

[0041] S33: Use the fluid-structure coupling equation to calculate the root mean square d of the vibration displacement of the parallel reactor iron core;

[0042]

[0043] where M cis the mass matrix of the iron core, which can be calculated from the cross-sectional area, height, density, filling coefficient, etc. of the iron core; d is the displacement matrix of the iron core; K c is the stiffness matrix of the iron core, and the stiffness value of the iron core is 6×10 6 ; t is time.

[0044] S34: Respectively plot the relationship curve d-n curve of the root mean square d of the vibration displacement of the shunt reactor iron core and the number of air gaps n, and the relationship curve σ ave of the average value σ of the surface stress of the iron core and the number of air gaps n ave -n curve, conduct trend analysis, and select the optimal number of air gaps n P .

[0045] S4: Evenly set the air gaps with the total number of the optimal number of air gaps n P and the length of a single air gap of m on the iron core, and set the arrangement method of the air gap positions; the arrangement method of the positions is selected as single air gap, double air gaps, triple air gaps, quadruple air gaps, quintuple air gaps, and the remainder is set at the 1 / 2 position of the iron core. When n P = 25, double air gaps are adopted, and the air gap quantity distribution from the top to the bottom of the air gap structure is 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, where the number of air gaps at the 1 / 2 position of the iron core is 1.

[0046] S5: Repeat steps S3 - S4, respectively plot the relationship curve d-n curve of the root mean square d of the vibration displacement of the shunt reactor iron core and the number of air gaps n, and the relationship curve σ ave of the average value σ of the surface stress of the iron core and the number of air gaps n ave -n curve, conduct trend analysis, and select the optimal arrangement method of the air gap positions. Select the arrangement method of the air gap positions corresponding to the minimum root mean square d of the vibration displacement of the shunt reactor iron core as the optimal arrangement method of the air gap positions. If in the relationship curve d-n curve of the root mean square d of the vibration displacement of the shunt reactor iron core and the number of air gaps n, the root mean square d of the vibration displacement of the shunt reactor iron core decreases as the number of air gaps decreases, it indicates that the fewer the number of air gaps, the weaker the vibration intensity of the UHV shunt reactor iron core. At this time, the minimum value of n should be selected according to the process allowable range. Similarly, the air gap position corresponding to the minimum root mean square d of the vibration displacement of the shunt reactor iron core should be selected. By selecting the optimized number of air gaps n and air gap positions, it is beneficial to weaken the vibration of the UHV shunt reactor iron core.

[0047] According to the mechanical structure and electrical parameters of the preliminary design of the high-voltage shunt reactor, this method can optimize the air-gap structure (the number and position of air gaps) of the iron core, and calculate the vibration condition of the high-voltage shunt reactor through finite element calculation and fluid-structure coupling equation, which can provide reasonable suggestions for the optimized design of the high-voltage shunt reactor, is conducive to improving the vibration characteristics of the high-voltage shunt reactor and reducing the noise on the premise of not significantly increasing the production cost.

[0048] It can be understood that if the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a corresponding computer-readable storage medium. Based on such an understanding, to implement all or part of the processes in the corresponding method embodiments of the present invention, it can also be completed by instructing relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-mentioned method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0049] Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the above-described systems, devices, and units can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0050] In several embodiments provided in the present application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of the units is only a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces, and the indirect couplings or communication connections of devices or units can be in electrical, mechanical, or other forms.

[0051] The unit described as a separation component may or may not be physically separated. The component displayed as a unit may or may not be a physical unit, that is, it may be located in one place or may be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0052] In addition, each functional unit in various embodiments of the present invention may be integrated in a processing unit, may exist separately as individual physical units, or two or more units may be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0053] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0054] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of various embodiments of the present invention.

Claims

1. A method for optimizing the air gap structure of a shunt reactor core, characterized in that: It includes the following steps: S1: Obtain the mechanical structure parameters and electrical parameters of the shunt reactor; The structural parameters include the total length of the iron core air gap δ, and the number of air gaps is n N ; The structure parameters also include: the dimensions of the iron core window, the dimensions of the winding, the dimensions of the clamping parts and the oil tank, and the cross-sectional area of the iron core; the dimensions of the iron core window include the length, width and height of the iron core window; the dimensions of the winding include the height, inner diameter and outer diameter of the winding; the dimensions of the clamping parts include the length, width, height and thickness of the clamping parts; the dimensions of the oil tank include the length, width, height and thickness of the oil tank; S2: Set the range of the number of air gaps n, and establish a three-dimensional model for each number of air gaps n; S3: Calculate the vibration of the shunt reactor core using finite element and fluid-structure interaction equations to obtain the optimal number of air gaps n P ; S4: Uniformly arrange the air gaps with the total number being the optimal number \(n\) of air gaps and the length of a single air gap being \(m\) on the iron core, and set the arrangement mode of the air gap positions; the arrangement mode of the air gap positions includes: single air gap, double air gaps, triple air gaps, quadruple air gaps, quintuple air gaps, and the remainder is set at the 1 / 2 position of the iron core; P P S5: Repeat steps S3 - S4 to select the optimal air gap position arrangement method.

2. The method for optimizing the air gap structure of a shunt reactor core according to claim 1, characterized in that: The electrical parameters include the rated current of the reactor.

3. The method for optimizing the air gap structure of a shunt reactor core according to claim 1, characterized in that: The specific steps of step S2 are as follows: Set the range of the number of air gaps n, where n is in the range of [n N -5, n N +5]. The length m of each air gap is m = δ / n. Each group of air gaps is evenly distributed on the iron core column, and the distance between adjacent air gaps is the same. A three-dimensional model is established for each number of air gaps n, with a cross-section consistent with the iron core column and a length of δ / n.

4. The method for optimizing the air gap structure of a shunt reactor core according to claim 1, characterized in that: The optimal number of air gaps n is obtained in the step S3 P Specifically as follows: S31: Calculate the Maxwell force F of the shunt reactor core using the finite element method max and the magnetostrictive force F mag , and the external force F of the core vibration is F = F max + F mag ; S32: Calculate the average value σ of the stress on the iron core surface ave = F / S; S33: Calculate the root mean square d of the vibration displacement of the shunt reactor iron core by using the fluid-structure coupling equation; S34: Respectively plot the relationship curve between the root mean square d of the vibration displacement of the shunt reactor core and the number n of air gaps, and the relationship curve between the average value σ of the surface stress of the core and the number n of air gaps, conduct trend analysis, and select the optimal number n of air gaps ave to select the optimal number of air gaps n P .

5. The method for optimizing the air gap structure of a shunt reactor core according to claim 1, characterized in that: In step S5, the air gap position arrangement method corresponding to the minimum root mean square d of the vibration displacement of the shunt reactor iron core is the optimal air gap position arrangement method.

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