Transformer bushing voltage-sharing ball and manufacturing method thereof

Abstract

The invention belongs to the technical field of high-voltage power equipment insulation, and particularly relates to a transformer bushing voltage-sharing ball and a manufacturing method. Comprising a conductive curved surface, the outer layer of the conductive curved surface is covered with an insulating layer, the conductive curved surface is vertically symmetrical along a center line, the upper half section of the conductive curved surface comprises a vertical section, a first arc-shaped section, a horizontal section, a transition section and a main body section which are sequentially connected, and the transition section and the main body section are NURBS curved surfaces. By introducing the NURBS curved surface transition structure, electric field distortion generated at the geometric transition position of a traditional voltage-sharing ball is avoided, and electric field distribution at the oil end of the tail of the sleeve is more uniform. Under high-voltage and extra-high-voltage working conditions, the local electric field intensity can be remarkably reduced, and the risks of partial discharge and breakdown in oil are reduced; and a parametric design method is adopted, so that rapid modeling and optimization under different voltage levels and structure sizes are facilitated, and the design efficiency and precision are improved.

Description

Technical Field

[0001] This invention belongs to the field of high-voltage power equipment insulation technology, specifically relating to a transformer bushing equalizing ball and its manufacturing method. Background Technology

[0002] Transformers are critical equipment in power systems, and their bushings, as important components for conductor lead-out and insulation support, withstand complex electric field distributions under high-voltage and ultra-high-voltage operating conditions. Bushings typically consist of two parts: the air end and the oil end, with the electric field distribution at the tail of the oil end bushing being particularly complex. If the electric field distribution is uneven, localized electric field concentration can easily occur at the oil end, leading to problems such as partial discharge and oil gap breakdown, seriously affecting the safe operation of the transformer.

[0003] To improve the electric field distribution at the bushing tail in oil, equipotential bonding devices are typically installed at the bushing end in engineering projects, with equipotential bonding spheres being a common type. Equipotential bonding spheres reduce local electric field intensity by altering the electric field boundary conditions, making the electric field lines more uniform. However, existing equipotential bonding spheres are mostly single-spherical structures, and their equipotential bonding effect in oil is limited. Existing equipotential bonding sphere structures still have the following shortcomings: First, the equipotential bonding effect is limited. Under ultra-high voltage and extra-high voltage operating conditions, the improvement of electric field distribution by existing spherical structures is not significant enough, and local electric field concentration still exists, increasing the risk of insulation breakdown and partial discharge. Second, the electric field distribution is uneven. Traditional equipotential bonding spheres mostly use single-spherical or near-spherical structures, resulting in varying electric field control capabilities in different orientations, making it difficult to achieve comprehensive optimization of the circumferential and spatial electric field of the bushing. Third, operational reliability is limited. During long-term operation in oil, local electric field distortion can easily accelerate the aging of the oil-paper insulation, reducing the overall service life of the bushing.

[0004] Therefore, existing transformer bushing equalization spheres still suffer from problems such as unsatisfactory voltage equalization, uneven electric field distribution, and easy degradation of insulation performance when operating in oil. There is an urgent need for a novel equalization sphere structure to improve the electric field environment at the tail of the oil-end bushing and enhance the safety and reliability of the transformer under high-voltage operating conditions. Summary of the Invention

[0005] The purpose of this invention is to provide a transformer bushing equalizing ball and its manufacturing method, so as to solve the defects of the existing transformer bushing tail equalizing ball in oil operation, such as unsatisfactory equalizing effect, uneven electric field distribution and insufficient operational reliability. To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, this application discloses a transformer bushing equalizing ball, comprising: a conductive curved surface, the outer layer of which is covered with an insulating layer, the conductive curved surface being symmetrical about the centerline, the upper half of the conductive curved surface comprising a vertical segment, a first arc segment, a horizontal segment, a transition segment and a main segment connected in sequence, the transition segment and the main segment being NURBS curved surfaces.

[0006] Preferably, the junction between the transition segment and the horizontal segment and the main segment satisfies at least one or more of the following: G0 positional continuity, G1 tangential continuity, and G2 curvature continuity.

[0007] Preferably, the NURBS surface is defined by a control point grid and weight parameters, wherein the spatial distribution of the control points and the weight values ​​together determine the surface shape of the transition segment and the main segment.

[0008] Preferably, the NURBS surface is defined by the following formula using a control point grid and weight parameters:

[0009] In the formula, Represents a NURBS surface; Indicates the lateral direction; Indicates the direction of the longitudinal parameter; express Direction indivual B-spline basis functions; express Direction indivual B-spline basis functions; express Number of direction control points – 1; express Number of direction control points -1; express Direction control point index; express Direction control point index; Indicates the weighting parameter; This represents the control point grid.

[0010] Preferably, the vertical segment, the first arc segment, the horizontal segment, the transition segment, and the main body segment are connected by welding.

[0011] Preferably, the equalizing ball is made entirely of a conductive metal material.

[0012] Secondly, this application discloses a method for manufacturing the transformer bushing equalizing ball described in any one of the above claims, comprising: The vertical section, the first arc section, the horizontal section, and the main body section are determined based on the actual working conditions. A geometric model of the NURBS surface is established based on the vertical segment, the first arc segment, the horizontal segment, and the main body segment. The control point mesh is determined based on the geometric model of the NURBS surface. By adjusting the control point grid coordinates and weight parameters, the optimal NURBS surfaces of the transition section and the main body section are obtained, forming a smooth and continuous curve composed of the horizontal section, the transition section, and the main body section. Connecting the vertical segment, the first arc segment, and the smooth continuous curve yields a conductive surface; An insulating layer is uniformly covered on the conductive curved surface to obtain an equalizing sphere.

[0013] Preferably, the step of establishing a geometric model of the NURBS surface based on the vertical segment, the first arc segment, the horizontal segment, and the main body segment, and determining the control point mesh based on the geometric model of the NURBS surface, specifically includes: Taking the free end of the vertical segment as the processing point P0, determine the processing point P1 of the starting point of the horizontal segment based on processing point P0 and the first arc segment, determine the processing point P2 of the starting point of the transition segment based on the horizontal segment, determine the processing point P3 of the starting point of the main segment based on processing point P2 and the radius of the transition segment arc, and determine the processing point P4 of the ending point of the main segment of the upper half of the conductive curved surface based on the radius of the main segment and processing point P1. Based on the principle of axisymmetry, determine the machining points P5, P6 and P7 on the upper half of the conductive surface; Input processing points P1, P2, P3, P4, P5, P6, and P7 into NURBS to generate the geometric model of the NURBS surface; determine the control point mesh based on the geometric model of the NURBS surface.

[0014] Preferably, the optimization objective of adjusting the control point grid coordinates and weight parameters is: The average field strength at each control point on the control point grid varies uniformly, and the margin corresponding to each processing point is the maximum value.

[0015] Preferably, the control point grid coordinates and weight parameters are adjusted using the following formula:

[0016] In the formula, Represents a NURBS surface; Indicates the lateral direction; Indicates the direction of the longitudinal parameter; express Direction indivual B-spline basis functions; express Direction indivual B-spline basis functions; express Number of direction control points -1; express Number of direction control points -1; express Direction control point index; express Direction control point index; Indicates the weighting parameter; This represents the control point grid.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1) By introducing the NURBS curved transition structure, the electric field distortion generated at the geometric transition point of the traditional equalizing ball is avoided, making the electric field distribution at the oil end of the bushing more uniform. 2) Under high voltage and ultra-high voltage conditions, it can significantly reduce the local electric field intensity, thereby reducing the risk of partial discharge and oil breakdown; 3) The use of parametric design methods facilitates rapid modeling and optimization under different voltage levels and structural dimensions, thereby improving design efficiency and accuracy. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram showing the installation positions of the sleeve and the equalizing ball in an embodiment of the present invention; Figure 2 This is a schematic diagram of the equipotential region and the insulating region in an embodiment of the present invention; Figure 3 This is a schematic diagram of the conductive curved surface structure according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the processing points in an embodiment of the present invention; Figure 5 This is a schematic diagram of the control grid according to an embodiment of the present invention.

[0020] Wherein: 1-conductive curved surface; 101-vertical segment; 102-first arc segment; 103-horizontal segment; 104-transition segment; 105-main body segment; 2-insulating layer; 3-equalizing ball; 4-sleeve. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0027] The present invention will now be described in further detail with reference to the accompanying drawings: See Figures 1-3This application discloses a transformer bushing equalizing sphere, comprising: a conductive curved surface 1, the outer layer of which is covered with an insulating layer 2. The conductive curved surface 1 is symmetrical about its centerline. The upper half of the conductive curved surface 1 includes a vertical segment 101, a first arc segment 102, a horizontal segment 103, a transition segment 104, and a main segment 105 connected in sequence. The transition segment 104 and the main segment 105 are NURBS surfaces. By introducing a non-uniform rational B-spline NURBS surface as a transition surface into the arc transition segment domain of a traditional equalizing sphere, the problem of local electric field concentration caused by abrupt curvature changes is effectively improved through smooth curvature changes. This improves the electric field distribution at the oil end and enhances the insulation performance and operational safety of the bushing.

[0028] In some embodiments, the junction of the transition segment 104 with the horizontal segment 103 and the main body segment 105 satisfies at least one or more of the following: G0 positional continuity, G1 tangential continuity, and G2 curvature continuity.

[0029] In some embodiments, the NURBS surface is defined by a control point grid and weight parameters, wherein the spatial distribution of the control points and the weight values ​​together determine the surface shape of the transition segment 104 and the main segment 105.

[0030] In some embodiments, the NURBS surface is defined by the control point mesh and weight parameters and expressed by the following formula:

[0031] In the formula, Represents a NURBS surface; Indicates the lateral direction; Indicates the direction of the longitudinal parameter; express Direction indivual B-spline basis functions; express Direction indivual B-spline basis functions; express Number of direction control points -1; express Number of direction control points -1; express Direction control point index; express Direction control point index; Indicates the weighting parameter; This represents the control point grid.

[0032] In some embodiments, the vertical segment 101, the first arc segment 102, the horizontal segment 103, the transition segment 104, and the main body segment 105 are connected by welding.

[0033] In some embodiments, the equalizing ball is made entirely of a conductive metal material.

[0034] In some embodiments, this invention proposes a novel equalizing sphere structure for the tail end of a transformer bushing. A non-uniform rational B-spline (NURBS) surface is introduced as the transition surface in the arc transition section of the traditional equalizing sphere. This smooth curvature change effectively improves the problem of local electric field concentration caused by abrupt curvature changes. Furthermore, during the design process of the equalizing sphere, NURBS surface modeling facilitates the determination of parameters for each surface segment, enabling computer-aided design and electric field simulation verification. This improves the controllability and reliability of the design process while optimizing the electric field distribution.

[0035] In some embodiments, a non-uniform rational B-spline (NURBS) surface is introduced as a transition surface in the arc transition section of the traditional equalizing sphere. The NURBS surface achieves a smooth transition in the geometry of the equalizing sphere, resulting in a more uniform electric field distribution and effectively reducing local electric field concentration caused by abrupt curvature changes. Simultaneously, the parametric modeling method using NURBS surfaces allows for flexible adjustment of surface parameters according to the bushing operating voltage level and insulation requirements. Furthermore, computer simulation is used to verify and optimize the electric field distribution, thereby ensuring the rationality and effectiveness of the design.

[0036] In some embodiments, the present invention discloses a transformer bushing equalization sphere, comprising a main body section 105 and a transition section 104. The geometry of the transition section 104 and the main body section 105 is determined by a NURBS surface using control points and weighting parameters to ensure continuous curvature and a smooth transition, thereby avoiding local electric field concentration caused by geometric abrupt changes in traditional equalization spheres. Furthermore, the parameters of the NURBS surface can be optimized and adjusted according to the rated voltage level of the transformer bushing, the oil end insulation distance, and the electric field distribution requirements; the size and curvature of the equalization sphere can be verified and optimized through finite element electric field simulation to ensure the uniformity and safety margin of the electric field distribution. Furthermore, the main body of the equalization sphere can be made of a conductive metallic material to maintain equipotential with the bushing conductor; its surface can be smoothed as needed to reduce the possibility of impurity deposition in the oil and electric field distortion.

[0037] Referring to Figures 1-3, the present invention provides a transformer bushing equalizing ball, comprising a vertical section 101, a first arc-shaped section 102, a horizontal section 103, a transition section 104 and a main body section 105 arranged sequentially. The parts are connected into a whole by welding or other fixing methods to form an integral equalizing structure.

[0038] Main body segment 105: It can be constructed using a metal equipotential body with fixed curvature, or it can be optimized based on the electric field intensity distribution on the surface of a uniformly pressure sphere. Specifically, by establishing a geometric model of a non-uniform rational B-spline (NURBS) surface and adjusting the control points and weight parameters, a main body surface configuration that meets the requirements of electric field uniformity is obtained. The design of main body segment 105 should satisfy the curvature continuity conditions of G0, G1, and G2 to ensure a smooth transition of the geometric surface in tangential direction, curvature, and higher-order curvatures, avoiding local electric field concentration.

[0039] Transition section: Located between the main body and the horizontal section, its surface is constructed using NURBS surfaces. By rationally arranging control points and adjusting their weight parameters, G0, G1, and G2 continuity is achieved between the transition section and the main body and horizontal section, resulting in a smooth geometric connection. This design can significantly improve the electric field distortion problem caused by abrupt curvature changes at the transition point in traditional equalizing spheres.

[0040] Horizontal section: The connection between the horizontal section and the transition section also meets the curvature continuity requirement, ensuring that the electric field lines are evenly distributed during the transition from the conductor to the main body of the equalizing sphere.

[0041] Furthermore, in the specific design process, an electric field finite element simulation model can be established based on the transformer bushing voltage level, oil end insulation distance, and operating environment to calculate and verify the electric field strength on the surface of the equalizing sphere. By adjusting the NURBS control points and weight parameters of the main body and transition section, the electric field distribution can be optimized, thereby ensuring the rationality and feasibility of the equalizing sphere structure while meeting electrical performance requirements. Furthermore, the equalizing sphere can be made entirely of conductive metal material to maintain equipotential with the bushing conductor. To improve long-term operational stability, the surface of the equalizing sphere can be polished or smoothed as needed to reduce oil impurity deposition and the resulting local electric field distortion.

[0042] In summary, by introducing the NURBS surface modeling method into the equalizing sphere body and transition section, this invention ensures the smooth continuity of the geometric structure in different regions, effectively improves the electric field distribution at the tail of the oil end bushing, reduces the local electric field intensity, and enhances the insulation performance and operational reliability of the transformer bushing under high-voltage operating conditions.

[0043] This application also discloses a method for manufacturing a transformer bushing equalizing ball, including: The vertical section 101, the first arc section 102, the horizontal section 103, and the main body section 105 are determined based on the actual working conditions. A geometric model of the NURBS surface is established based on the vertical segment 101, the first arc segment 102, the horizontal segment 103, and the main body segment 105. The control point mesh is determined based on the geometric model of the NURBS surface. By adjusting the control point grid coordinates and weight parameters, the optimal NURBS surface of transition segment 104 and main body segment 105 is obtained, which is a smooth and continuous curve composed of horizontal segment 103, transition segment 104 and main body segment 105. Connect the vertical segment 101, the first arc segment 102, and the smooth continuous curve to obtain the conductive surface 1; An insulating layer 2 is uniformly covered on the conductive curved surface 1 to obtain an equalizing sphere.

[0044] In some embodiments, the step of establishing a geometric model of the NURBS surface based on the vertical segment 101, the first arc segment 102, the horizontal segment 103, and the main body segment 105, and determining the control point mesh based on the geometric model of the NURBS surface, specifically includes: Taking the free end of the vertical segment 101 as the processing point P0, the processing point P1 of the starting point of the horizontal segment 103 is determined based on the processing point P0 and the first arc segment 102. The processing point P2 of the starting point of the transition segment 104 is determined based on the horizontal segment 103. The processing point P3 of the starting point of the main body segment 105 is determined based on the processing point P2 and the radius of the arc of the transition segment 104. The processing point P4 of the ending point of the main body segment 105 of the upper half of the conductive curved surface 1 is determined based on the radius of the main body segment 105 and the processing point P1. Based on the principle of axisymmetry, determine the machining points P5, P6 and P7 of the upper half of the conductive surface 1; Input processing points P1, P2, P3, P4, P5, P6, and P7 into NURBS to generate the geometric model of the NURBS surface; determine the control point mesh based on the geometric model of the NURBS surface.

[0045] In some embodiments, the optimization objective of adjusting the control point grid coordinates and weight parameters is: The average field strength at each control point on the control point grid varies uniformly, and the margin corresponding to each processing point is the maximum value.

[0046] In some embodiments, with Figure 4 For example, the processing procedure of this method is explained as follows: First, three processing points P1, P2, and P3 are determined. These three points will... Figure 4 The upper part of the red curve is divided into a horizontal section, a transition section, and the main body. In the figure, the green line segment is divided into a vertical segment and the first arc segment. The horizontal coordinate of the endpoint P0 of the free end of the vertical segment is determined according to the distance between the equalizing ball and the casing, and the vertical coordinate is determined according to the height of the casing. The radius of the first arc segment is an estimated value; The ordinate of P1 is estimated based on the ordinate of P0 and the radius of the first arc segment; the abscissa is estimated based on the abscissa of P0 and the radius of the first arc segment. The length of the horizontal segment of the red curve is a preset value. The horizontal coordinate of P2 is determined based on the horizontal coordinate of P1, the radius of the first arc segment, and the length of the horizontal segment. The vertical coordinate is the same as that of P1. The coordinates of P4 are determined based on the radius of the main body and the coordinates of P1. The radius of the main body is a preset value, which is preset based on experience. The radius of the transition section of the red curve is determined based on the radius of the first arc segment and the main body. The x-coordinate of P3 is determined based on the radius of the transition arc and the x-coordinate of P2; the y-coordinate of P3 is determined based on the radius of the transition arc and the y-coordinate of P2. P5, P6, and P7 are mirror images of P1, P2, and P3, respectively, with corresponding x-coordinates. Their y-coordinates are determined based on the radius of the main body and the corresponding y-coordinates of P1, P2, and P3.

[0047] After identifying 7 processing points, NURBS was used to generate... Figure 5 The control points are shown in yellow. The optimization objective is to ensure that the average field strength at each point on the blue curve changes uniformly, and that the margin corresponding to each processing point is as large as possible. The coordinate information and weights of each control point are adjusted according to the following formula to obtain the following result. Figure 5 The smooth, continuous curve shown in blue:

[0048] In the formula, Represents a NURBS surface; Indicates the lateral direction; Indicates the direction of the longitudinal parameter; express Direction indivual B-spline basis functions; express Direction indivual B-spline basis functions; express Number of direction control points -1; express Number of direction control points -1; express Direction control point index; express Direction control point index; Indicates the weighting parameter; This represents the control point grid.

[0049] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A transformer bushing equalizing ball, characterized in that, include: Conductive surface (1), the outer layer of conductive surface (1) is covered with an insulating layer (2), the conductive surface (1) is symmetrical about the center line, the upper half of conductive surface (1) includes a vertical segment (101), a first arc segment (102), a horizontal segment (103), a transition segment (104) and a main body segment (105) connected in sequence, the transition segment (104) and the main body segment (105) are NURBS surfaces.

2. The transformer bushing equalizing ball according to claim 1, characterized in that, The junction of the transition segment (104) with the horizontal segment (103) and the main segment (105) shall satisfy at least one or more of the following: G0 positional continuity, G1 tangential continuity and G2 curvature continuity.

3. The transformer bushing equalizing ball according to claim 1, characterized in that, The NURBS surface is defined by a control point grid and weight parameters, wherein the spatial distribution of the control points and the weight values ​​together determine the surface shape of the transition segment (104) and the main segment (105).

4. The transformer bushing equalizing ball according to claim 3, characterized in that, The NURBS surface, defined by the control point grid and weight parameters, is expressed by the following formula: In the formula, Represents a NURBS surface; Indicates the lateral direction; Indicates the direction of the longitudinal parameter; express Direction indivual B-spline basis functions; express Direction indivual B-spline basis functions; express Number of direction control points -1; express Number of direction control points -1; express Direction control point index; express Direction control point index; Indicates the weighting parameter; This represents the control point grid.

5. The transformer bushing equalizing ball according to claim 1, characterized in that, The vertical section (101), the first arc-shaped section (102), the horizontal section (103), the transition section (104), and the main body section (105) are connected by welding.

6. The transformer bushing equalizing ball according to claim 1, characterized in that, The equalizing ball is made entirely of conductive metal material.

7. A method for manufacturing the transformer bushing equalizing sphere according to any one of claims 1 to 6, characterized in that, include: The vertical section (101), the first arc section (102), the horizontal section (103), and the main body section (105) are determined according to the actual working conditions. A geometric model of the NURBS surface is established based on the vertical segment (101), the first arc segment (102), the horizontal segment (103), and the main body segment (105). The control point mesh is determined based on the geometric model of the NURBS surface. Adjust the grid coordinates and weight parameters of the control points to obtain the optimal NURBS surface of the transition segment (104) and the main segment (105), and the smooth continuous curve formed by the horizontal segment (103), the transition segment (104) and the main segment (105); Connect the vertical segment (101), the first arc segment (102), and the smooth continuous curve to obtain the conductive surface (1); An insulating layer (2) is uniformly covered on the conductive curved surface (1) to obtain an equal pressure ball.

8. A method for manufacturing a transformer bushing equalizing ball according to claim 7, characterized in that, The geometric model of the NURBS surface is established based on the vertical segment (101), the first arc segment (102), the horizontal segment (103), and the main body segment (105). The control point mesh is determined based on the geometric model of the NURBS surface, specifically including: Taking the free end of the vertical segment (101) as the processing point P0, the processing point P1 of the starting point of the horizontal segment (103) is determined according to the processing point P0 and the first arc segment (102). The processing point P2 of the starting point of the transition segment (104) is determined according to the horizontal segment (103). The processing point P3 of the starting point of the main body segment (105) is determined according to the processing point P2 and the arc radius of the transition segment (104). The processing point P4 of the end point of the main body segment (105) of the upper half of the conductive surface (1) is determined according to the radius of the main body segment (105) and the processing point P1. Based on the principle of axisymmetry, determine the machining points P5, P6 and P7 of the upper half of the conductive surface (1); Input processing points P1, P2, P3, P4, P5, P6, and P7 into NURBS to generate the geometric model of the NURBS surface; determine the control point mesh based on the geometric model of the NURBS surface.

9. A method for manufacturing a transformer bushing equalizing ball according to claim 8, characterized in that, The optimization objective of adjusting the control point grid coordinates and weight parameters is: The average field strength at each control point on the control point grid varies uniformly, and the margin corresponding to each processing point is the maximum value.

10. A method for manufacturing a transformer bushing equalizing ball according to claim 7, characterized in that, Adjust the control point grid coordinates and weight parameters using the following formula: In the formula, Represents a NURBS surface; Indicates the lateral direction; Indicates the direction of the longitudinal parameter; express Direction indivual B-spline basis functions; express Direction indivual B-spline basis functions; express Number of direction control points -1; express Number of direction control points -1; express Direction control point index; express Direction control point index; Indicates the weighting parameter; This represents the control point grid.

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