Dry-type bushing for transformer

Abstract

The invention relates to the technical field of transformer bushings, and discloses a dry-type bushing for a transformer, the dry-type bushing comprises a transformer box body and a bushing body mounted on the transformer box body, the bushing body comprises a conducting rod and an insulating bushing fixed on the periphery of the conducting rod, and the insulating bushing is provided with an umbrella skirt section and an anti-vibration section. The umbrella skirt section is provided with a plurality of umbrella skirts, the anti-vibration section is provided with a flange base used for being connected with a transformer box body, the anti-vibration section is located between the umbrella skirt section and the flange base, the diameter of the anti-vibration section is larger than that of the umbrella skirt section, and the anti-vibration section is further provided with a binding belt wrapping the outer wall of the insulating sleeve; the diameter difference of the umbrella skirt section and the anti-vibration section forms a stepped structure, vibration transmission paths can be dispersed, the diameter of the anti-vibration section is increased, the structural rigidity is enhanced, the binding belt restrains radial deformation of the sleeve body, bending stress caused by vibration can be directly restrained, axial and radial deformation of the sleeve in high-bending-moment areas such as the root of a flange due to vibration is reduced, and the service life of the sleeve is prolonged. The fatigue damage risk is reduced.

Description

Technical Field

[0001] This application relates to the technical field of transformer bushings, and in particular to a dry bushing for transformers. Background Technology

[0002] In power systems, transformers are key equipment for power transmission and distribution. Their stable operation is crucial for ensuring the reliability and quality of power supply. In practical applications, transformers are equipped with several insulating bushings. These bushings are the main insulation devices outside the transformer box. Inside each bushing is a conductive copper rod. One end of the conductive copper rod is located inside the transformer and connected to the lead wire of the transformer winding, while the other end is located outside the transformer and connected to a wire.

[0003] However, various conditions during the operation of a transformer, such as vibration and heat generation, will have a significant impact on its own lifespan and performance as well as that of related components. Due to the severe vibration of the power supply or receiving transformer, and the inconsistency of the natural vibration frequencies at both ends of the bushing, the vibration frequency that the bushing experiences is its composite frequency. Therefore, fatigue damage to the bushing material occurs in the middle of the long section of the bushing (where the composite amplitude is the largest) and near the flange base root (where the bending moment stress is the largest). The radial and axial concentrated stress of this composite vibration causes damage to the bushing insulation and changes the electric field distribution, which in turn generates discharge along the surface (or layer interface). Summary of the Invention

[0004] To reduce fatigue damage to bushings caused by transformer vibration, a dry bushing for transformers is provided.

[0005] The above-mentioned objective of this application is achieved through the following technical solution: A dry bushing for a transformer includes a transformer housing and a bushing body mounted on the transformer housing. The bushing body includes a conductive rod and an insulating bushing fixed to the outer periphery of the conductive rod. The insulating bushing is provided with a skirt section and a vibration damping section. The skirt section has a plurality of skirts. The vibration damping section has a flange base for connecting to the transformer housing. The vibration damping section is located between the skirt section and the flange base. The diameter of the vibration damping section is larger than the diameter of the skirt section. The vibration damping section is also provided with a binding strap covering the outer wall of the insulating bushing.

[0006] By adopting the above technical solution, the difference in diameter between the umbrella skirt section and the vibration isolation section forms a stepped structure, which can disperse the vibration transmission path. The increased diameter of the vibration isolation section enhances the structural rigidity, and the binding band constrains the radial deformation of the bushing body, which can directly suppress the bending stress caused by vibration, reduce the axial and radial deformation of the bushing in the high bending moment area at the flange root due to vibration, reduce the risk of fatigue damage, avoid bushing insulation damage and electric field distribution changes caused by vibration, and prevent surface or delamination interface discharge.

[0007] Preferably, a vibration damping cylinder is fixedly provided on the outer wall of the vibration damping section, a vibration damping body is provided inside the vibration damping cylinder, a first gap is left between the vibration damping body and the vibration damping section, and an elastic buffer is provided between the vibration damping body and the inner wall of the vibration damping cylinder to connect the two.

[0008] By adopting the above technical solution, when the transformer vibrates during operation, the vibration damping cylinder, vibration damping body and elastic buffer on the vibration isolation section work together to make the vibration damping body swing freely within the swing gap by utilizing the swing gap and the elastic effect of the elastic buffer. This buffers and absorbs vibration energy by inertia, reduces the impact of vibration on the bushing body, reduces the possibility of bushing insulation damage and electric field distribution changes, and thus reduces the discharge phenomenon along the surface or layer interface.

[0009] Preferably, one end of the vibration damping cylinder is fixed to the vibration isolation section, and a second gap is left between the other end of the vibration damping cylinder and the vibration isolation section.

[0010] By adopting the above technical solution, when the transformer vibrates during operation, the oscillation action of the damping body within the oscillation gap is used to further absorb and buffer the vibration energy. At the same time, the setting of the oscillation gap allows one end of the damping cylinder to generate a micro-displacement within the gap, avoiding the transmission of vibration through the rigid structure, reducing the transmission of vibration to the transformer tank, and protecting the internal windings.

[0011] Preferably, the elastic buffers on both sides of the vibration damper are symmetrically arranged upward along the vertical insulating sleeve axis, and the elastic buffers on the same side are arranged circumferentially along the insulating sleeve.

[0012] By adopting the above technical solution, the symmetrical arrangement ensures that the vibration energy is evenly transmitted to both sides of the damper, avoiding excessive force on one side leading to local fatigue or buffer failure, improving the stability of the damper, and preventing the damper from shifting or loosening due to long-term vibration.

[0013] Preferably, one end of the elastic buffer is fixed to the inner wall of the vibration damping cylinder, and the other end of the elastic buffer is close to the axis of the insulating sleeve and is inclined.

[0014] By adopting the above technical solution, the stiffness of the elastic buffer changes nonlinearly when it is stretched and compressed, which allows the vibration frequency of the elastic buffer to vary within a certain range. At the same time, the elastic buffer can provide radial and axial damping forces simultaneously when the damping body swings, rather than just buffering in one direction. The tilt angle allows the buffer to stretch or compress, absorb more energy, and avoid rigid collisions. Compared with vertically arranged buffers, the tilt design can more flexibly adapt to different vibration amplitudes and improve vibration damping adaptability.

[0015] Preferably, the outer wall of the vibration damping section is fixedly provided with a vibration damping member made of elastic material, and the vibration damping member is located within the first gap and the second gap.

[0016] By adopting the above technical solution, when the transformer tank causes the bushing body to vibrate, the vibration generated by the vibration damper pulled by the elastic buffer can offset the vibration generated by the bushing body. This allows the vibration damper to cooperate with the first vibration damper. The first vibration damper, made of elastic material, can effectively attenuate the vibration of the body by increasing its deformation, converting kinetic energy into internal energy and dissipating it. At the same time, it significantly reduces the wear of the bushing body caused by the vibration damper and the noise generated by the vibration damper to buffer the vibration of the bushing body.

[0017] Preferably, the transformer housing is fixed with a plurality of pressing members for pressing against the flange base along the circumference of the flange base, and also includes a binding member made of rigid material, one end of the binding member being connected to the bottom of the vibration damping cylinder, and the other end of the binding member being connected to the upper surface of the pressing member.

[0018] By adopting the above technical solution, when the vibration damper vibrates, the vibration energy is transmitted to the pressure-retaining component through the rigid material binding component, so that the pressure-retaining component applies a greater pressure to the flange base. The vibration energy is converted into a continuous clamping force on the flange base. The vibration of the vibration damper, through the linkage between the binding component and the pressure-retaining component, forms a dynamic reinforcement of the flange root, further suppressing the vibration deformation of this high-stress area and reducing the risk of fatigue damage.

[0019] Preferably, the bottom of the vibration damping cylinder is fixed with several limiting members, and the limiting members have limiting grooves for the end of the restraining member to be engaged and limited.

[0020] By adopting the above technical solution, the limiting component ensures that the restraint component always maintains the correct locking position and transmission direction during vibration, while also making it easier for operators to install the restraint component and improving the efficiency of assembly and disassembly.

[0021] Preferably, the restraint member is fixed with stiffening ribs that abut against the outer wall of the vibration damping cylinder.

[0022] By adopting the above technical solution, the stiffening rib increases the contact area and makes the contact between the restraint and the outer wall of the vibration damper more compact. The structure of the stiffening rib also enhances the bending stiffness of the restraint itself, making it more stable and reliable in transmitting vibration energy, and further improving the dynamic clamping effect on the flange base.

[0023] In summary, this application includes at least one of the following beneficial technical effects: 1. The difference in diameter between the umbrella skirt section and the vibration isolation section forms a stepped structure. At the same time, the binding strap restrains the radial deformation of the sleeve body, which can directly suppress the bending stress caused by vibration and reduce the axial and radial deformation of the sleeve caused by vibration in the bending moment area at the flange root. 2. When the transformer vibrates during operation, the vibration damping cylinder, vibration damping body and elastic buffer on the vibration isolation section work together to make the vibration damping body swing freely within the swinging gap by utilizing the swing gap and the elastic effect of the elastic buffer, so as to buffer and absorb the vibration energy by inertia and reduce the impact of vibration on the bushing body. 3. The vibration of the damping cylinder, through the linkage of the restraint and the pressing parts, forms a dynamic reinforcement of the flange root. The vibration energy is converted into a continuous pressing force on the flange base, further suppressing the vibration deformation of this high-stress area and reducing the risk of fatigue damage. Attached Figure Description Figure 1 This is a schematic diagram of the sleeve body installation in Example 1; Figure 2 This is a sectional view of the figure; Figure 3 This is a cross-sectional view of the sleeve body installation in Example 2; Figure 4 This is a cross-sectional view of the vibration damper. Figure 5 This is a schematic diagram of the installation structure of the sleeve body in Example 2.

[0024] Reference numerals in the attached drawings: 1. Transformer housing; 2. Bushing body; 21. Conductive rod; 211. Lead end; 212. Terminal; 22. Insulating bushing; 221. Umbrella skirt section; 222. Vibration damping section; 223. Umbrella skirt; 224. Restraining strap; 23. Flange base; 3. Rubber seal; 4. Vibration damping cylinder; 41. Vibration damping body; 42. Elastic buffer; 43. Vibration damping component; 44. First gap; 45. Second gap; 5. Fixing component; 6. Pressing component; 7. Restraining component; 71. Stiffening rib; 8. Limiting component; 81. Limiting groove. Detailed Implementation The following section provides a more detailed description, in conjunction with the accompanying diagrams: Example 1: As attached Figure 1 and attached Figure 2As shown, a dry bushing for a transformer includes a transformer housing 1 and a bushing body 2. The transformer housing 1 has holes for mounting the bushing body 2. A conductive rod 21 is provided inside the bushing body 2. The two ends of the conductive rod 21 are a lead end 211 and a terminal 212, respectively. The lead end 211 is located inside the transformer housing 1 and is connected to the lead wire of the winding inside the transformer housing 1. The terminal 212 is located outside the transformer housing 1 and is used for wiring, so as to realize the electrical connection between the winding inside the transformer housing 1 and the external circuit.

[0025] The bushing body 2 also includes an insulating bushing 22 and a flange base 23. The insulating bushing 22 is integrally formed and fixed to the outer periphery of the conductive rod 21. The insulating bushing 22 is the main insulation device outside the transformer box 1. The bushing body 2 is fixed to the transformer box 1 by bolts on the flange base 23. A rubber seal 3 is also provided between the flange base 23 and the transformer box 1 to reduce the rigid connection between the flange base 23 and the transformer box 1 and provide a buffering effect.

[0026] The insulating sleeve 22 is provided with an integrally formed umbrella skirt section 221 and a vibration damping section 222. The umbrella skirt section 221 is provided with several umbrella skirts 223. The umbrella skirts 223 are usually umbrella-shaped and made of insulating material. The areas of two adjacent umbrella skirts 223 are different in the radial direction. Compared with the prior art, the addition of a vibration damping section 222 to the insulating sleeve 22 reduces the number of umbrella skirts 223 on the insulating sleeve 22, thereby reducing the intervention time and labor intensity of personnel during the manufacturing process, and can also greatly reduce the manufacturing cost of the insulating sleeve 22.

[0027] The vibration damping section 222 is located between the umbrella skirt section 221 and the transformer housing 1. The vibration damping section 222 is located in the middle of the bushing body 2, and the diameter of the insulating bushing 22 is larger than the diameter of the umbrella skirt section 221. This difference in diameter between the umbrella skirt section 221 and the vibration damping section 222 forms a stepped structure, which can disperse the vibration transmission path. Furthermore, the increased diameter of the vibration damping section 222 enhances the structural rigidity and improves the bending resistance of the middle part of the bushing body 2.

[0028] The vibration isolation section 222 is also provided with a binding band 224 covering the outer wall of the bushing body 2. The binding band 224 is a limiting structure such as steel strip fixed to the outside of the vibration isolation section 222. The steel strip has high strength and can more firmly fix the bushing body 2. The binding band 224 restricts the radial deformation of the bushing body 2, which can directly suppress the bending stress caused by vibration, reduce the axial and radial deformation of the bushing in the high bending moment area at the root of the flange base 23 caused by vibration, reduce the risk of fatigue damage, avoid bushing insulation damage and electric field distribution changes caused by vibration, and prevent surface or delamination.

[0029] The implementation effect of this first embodiment: The stepped structure formed by the umbrella skirt section 221 and the vibration damping section 222 fundamentally changes the transmission path of vibration energy. At the same time, the increased diameter of the vibration damping section 222 significantly enhances the structural rigidity of the middle part of the sleeve, improving its inherent resistance to bending and deformation. On this basis, the binding band 224 effectively suppresses radial deformation during vibration, directly reducing the risk of fatigue fracture of the insulation material due to periodic deformation.

[0030] Example 2: As attached Figure 3 and attached Figure 4 As shown, this second embodiment is an improvement on the vibration damping section 222 based on the first embodiment. The rest of the structure is the same as that of the first embodiment, and will not be described in detail here.

[0031] A vibration damping cylinder 4 is fixedly installed on the outer wall of the vibration damping section 222. The vibration damping cylinder 4 is generally a cylindrical structure made of metal. The metal vibration damping cylinder 4 has high strength and rigidity. One end of the vibration damping cylinder 4 is fixed to the vibration damping section 222. The fixing method can be welding or bolt connection to ensure the firmness of the connection. A second gap 45 is left between the other end of the vibration damping cylinder 4 and the vibration damping section 222. The setting of the second gap 45 allows one end of the vibration damping cylinder 4 to generate a micro displacement within the second gap 45, avoiding the transmission of vibration through the rigid structure and reducing the transmission of vibration to the transformer box 1.

[0032] The vibration damping cylinder 4 is provided with a vibration damping body 41. The vibration damping body 41 can be cylindrical in shape and made of metal. The metal vibration damping body 41 has a large mass and can better absorb vibration energy. A first gap 44 is left between the vibration damping body 41 and the vibration isolation section 222, and an elastic buffer 42 connecting the vibration damping body 41 and the inner wall of the vibration damping cylinder 4 is provided.

[0033] The elastic buffer 42 can be made of elastic material, such as a rope or rod. The elastic buffer 42 is located on both sides of the vibration damper 43 along the axial direction of the insulating sleeve 22. There are four elastic buffers 42 in a single operation. The elastic buffers 42 on both sides are symmetrically arranged along the axial direction of the sleeve body 2. The elastic buffers 42 on the same side are arranged along the circumference of the sleeve body 2. This ensures that the vibration energy is evenly transmitted to both sides of the vibration damper 41, avoids excessive force on one side leading to local fatigue or buffer failure, improves the stability of the vibration damper 41, and prevents the vibration damper 41 from shifting or loosening due to long-term vibration.

[0034] One end of the elastic buffer 42 is fixed to the inner wall of the damping cylinder 4, and the other end is close to the axis of the sleeve body 2 and is inclined. The stiffness of the elastic buffer 42 is nonlinear when it is stretched and compressed, so that the vibration frequency of the elastic buffer 42 itself can vary within a certain range. At the same time, the elastic buffer 42 can provide radial and axial damping forces when the damping body 41 swings, rather than just buffering in a single direction. The tilt angle allows the buffer to be stretched or compressed, avoiding rigid collisions.

[0035] The outer wall of the vibration damping section 222 is fixedly provided with a vibration damping component 43 of elastic material, and the vibration damping component 43 is located in the first gap 44 and extends downward. The vibration damping component 43 has an annular sealed hollow structure. The material can be rubber or silicone or other materials with elasticity and sealing properties. When the transformer box 1 drives the bushing body 2 to vibrate, the vibration generated by the vibration damping body 41 pulled by the elastic buffer 42 can offset the vibration generated by the bushing body 2, so that the vibration damping body 41 can cooperate with the vibration damping component 43. The vibration damping component 43 of elastic material can attenuate the vibration of the vibrating body 41 and convert kinetic energy into internal energy and dissipate it.

[0036] As attached Figure 3 and attached Figure 5 As shown, the transformer housing 1 is also fixed with several fasteners 5. The fasteners 5 are made of metal or other materials and are block-shaped. The fasteners 5 are arranged upward around the flange base 23. There are four fasteners 5 here. The upper end of each of the four fasteners 5 is rotatably provided with a pressing member 6. The pressing member 6 is plate-shaped. One end of the pressing member 6 is rotatably installed on the upper end of the fastener 5, and the other end of the pressing member 6 presses against the top of the flange base 23.

[0037] A restraining member 7 is also fixedly connected to the upper surface of the pressing member 6. The restraining member 7 and the pressing member 6 can be integrally formed or connected by bolts or other means. The restraining member 7 is made of a hard material such as metal. The restraining member 7 has a sheet structure, and the end of the restraining member 7 away from the pressing member 6 is bent and extended toward the vibration damping cylinder 4. When the vibration damping cylinder 4 vibrates, the vibration energy is transmitted to the pressing member 6 through the hard material restraining member 7, so that the pressing member 6 applies a greater pressing force to the flange base 23.

[0038] As attached Figure 4 and attached Figure 5 As shown, the bottom of the vibration damper 4 is fixedly connected with four limiting members 8 that correspond one-to-one with the restraint member 7, and the limiting members 8 have limiting grooves 81 for the end of the restraint member 7 to be engaged, which facilitates the installation of the restraint member 7 by the operator and improves the efficiency of disassembly and assembly.

[0039] The upper surface of the restraint member 7 is fixed with stiffening ribs 71 that abut against the outer wall of the vibration damping cylinder 4, which enhances the bending stiffness of the restraint member 7 itself, making it more stable and reliable when transmitting vibration energy, and further improving the dynamic clamping effect on the flange base 23.

[0040] The implementation effect of this second embodiment: The multi-stage energy dissipation system, consisting of vibration damping cylinder 4, vibration damping body 41, elastic buffer 42 and vibration damping component 43, efficiently absorbs and dissipates broadband vibration energy, converting mechanical kinetic energy into internal energy, and greatly reducing the vibration intensity transmitted to the sleeve body 2. At the same time, the vibration of the vibration damping cylinder 4 is converted into dynamic clamping force on the pressing component 6 through the restraint component 7, so that the flange base 23 connection obtains a continuously enhanced clamping effect in the vibration environment, effectively resisting bolt loosening and interface micro-movement, and greatly improving the stability and sealing of the connection.

[0041] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of protection claimed in this application.

Claims

1. A dry bushing for a transformer, comprising a transformer housing (1) and a bushing body (2) mounted on the transformer housing (1), characterized in that, The bushing body (2) includes a conductive rod (21) and an insulating bushing (22) fixed to the outer periphery of the conductive rod (21). The insulating bushing (22) is provided with a skirt section (221) and a vibration damping section (222). The skirt section (221) is provided with a plurality of skirts (223). The vibration damping section (222) is provided with a flange base (23) for connecting the transformer box (1). The vibration damping section (222) is located between the skirt section (221) and the flange base (23). The diameter of the vibration damping section (222) is larger than the diameter of the skirt section (221). The vibration damping section (222) is also provided with a binding strap (224) covering the outer wall of the insulating bushing (22).

2. A dry bushing for a transformer according to claim 1, characterized in that, A damping cylinder (4) is fixedly provided on the outer wall of the vibration damping section (222). A damping body (41) is provided inside the damping cylinder (4). A first gap (44) is left between the damping body (41) and the vibration damping section (222). An elastic buffer (42) is provided between the damping body (41) and the inner wall of the damping cylinder (4).

3. A dry bushing for a transformer according to claim 2, characterized in that, One end of the damping cylinder (4) is fixed to the anti-vibration section (222), and a second gap (45) is left between the other end of the damping cylinder (4) and the anti-vibration section (222).

4. A dry bushing for a transformer according to claim 2, characterized in that, The elastic buffers (42) on both sides of the damper (41) are symmetrically arranged along the vertical insulating sleeve (22) axis, and the elastic buffers (42) on the same side are arranged along the circumference of the insulating sleeve (22).

5. A dry bushing for a transformer according to claim 2, characterized in that, One end of the elastic buffer (42) is fixed to the inner wall of the damping cylinder (4), and the other end of the elastic buffer (42) is close to the axis of the insulating sleeve (22) and is inclined.

6. A dry bushing for a transformer according to claim 3, characterized in that, The outer wall of the vibration damping section (222) is fixedly provided with a vibration damping member (43) of elastic material, and the vibration damping member (43) is located in the first gap (44).

7. A dry bushing for a transformer according to claim 2, characterized in that, The transformer housing (1) has several pressing parts (6) fixed around the flange base (23) for pressing against the flange base (23), and also includes a binding part (7) made of rigid material. One end of the binding part (7) is connected to the bottom of the vibration damping cylinder (4), and the other end of the binding part (7) is connected to the upper surface of the pressing part (6).

8. A dry bushing for a transformer according to claim 7, characterized in that, The bottom of the damping cylinder (4) is fixed with several limiting members (8), and the limiting members (8) have limiting grooves (81) for the end of the restraining member (7) to be engaged and limited.

9. A dry bushing for a transformer according to claim 7, characterized in that, The restraint member (7) is fixed with a stiffening rib (71) that abuts against the outer wall of the damping cylinder (4).

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