An arc extinguishing device for oil-immersed transformers

Abstract

This invention relates to a dedicated arc-extinguishing device for oil-immersed transformers, belonging to the field of arc extinguishing. It includes a transformer body, a high-voltage bushing, and a low-voltage bushing. A tank cover is positioned above the transformer body, and the high-voltage and low-voltage bushings are mounted on the tank cover. Several high-voltage and low-voltage bushings are arranged linearly. A bearing unit is mounted on the high-voltage bushing. An upper arc-inducing angle and a lower arc-inducing angle are set on the high-voltage bushing to form a dedicated arc-extinguishing channel. This design significantly increases the length and fracture area of ​​the arc channel, making it easier for arcs generated by overvoltages such as lightning strikes to form between the arc-inducing angles and gradually lengthen, weaken, and eventually extinguish. This reduces direct flashover and ablation of the high-voltage bushing insulation surface by the arc, effectively reducing the lightning tripping rate and failure probability of outdoor oil-immersed transformers during thunderstorms, extending the overall service life of the transformer, and providing excellent protection for the transformer product.

Description

Technical Field

[0001] This invention belongs to the field of arc extinguishing technology, specifically an arc extinguishing device for oil-immersed transformers. Background Technology

[0002] Power transformers, especially oil-immersed transformers, are mostly installed outdoors and exposed to severe weather conditions such as thunderstorms for a long time. During thunderstorms, transformers are extremely vulnerable to lightning strikes or other atmospheric overvoltages. When lightning overvoltages or switching overvoltages act on the transformer, flashover discharges can easily occur on the surface of the high-voltage bushings, causing the arc to directly burn the bushing insulation surface, resulting in insulation breakdown, or even serious accidents such as bushing explosions and transformer oil combustion. Ultimately, this can lead to transformer tripping, damage, or scrapping, posing a great threat to the safe and stable operation of the power system. Traditional arc-extinguishing devices are often fixed to high-voltage bushings or copper caps using simple threaded connections or clips. During long-term outdoor operation, they are prone to loosening, displacement, or detachment due to wind, vibration, temperature changes, and electromagnetic forces, leading to failure of the arc-extinguishing function and inability to reliably guide and extinguish the arc. Furthermore, the existing arc angle gap design and fixing method are not ideal in increasing the arc channel length and promoting the rapid elongation and extinguishing of the arc. Especially under strong lightning strikes or multiple overvoltage impacts, the protection effect is limited and still cannot fully meet the high reliability requirements of outdoor oil-immersed transformers for lightning protection. In view of this, a special arc-extinguishing device for oil-immersed transformers is proposed. Summary of the Invention

[0003] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0004] Given the following technical problems in existing technologies: Traditional arc-extinguishing angles are mostly fixed to high-voltage bushings or copper covers using simple threaded connections or clips. During long-term outdoor operation, they are prone to loosening, displacement, or detachment due to wind, vibration, temperature changes, and electromagnetic forces, leading to arc-extinguishing failure and inability to reliably guide and extinguish the arc. Furthermore, the existing gap design and fixing methods of arc-extinguishing angles are not ideal in increasing the arc channel length and promoting rapid arc elongation and extinguishing, especially under strong lightning strikes or multiple overvoltage impacts, where the protection effect is limited and still cannot fully meet the high reliability requirements of outdoor oil-immersed transformers for lightning protection.

[0005] To solve the above technical problems, the present invention provides the following technical solution: a special arc extinguishing device for oil-immersed transformers, comprising a transformer body, a high-voltage bushing and a low-voltage bushing, wherein a tank cover is disposed above the transformer body, and the high-voltage bushing and the low-voltage bushing are assembled on the tank cover, wherein a plurality of the high-voltage bushing and the low-voltage bushing are arranged linearly. The high-voltage bushing is equipped with a bearing unit, and a copper pressure cap is fitted on the top of the high-voltage bushing. A stabilizing unit is configured on the copper pressure cap, and an upper arc angle is configured on the copper pressure cap. A bracket is configured around the high-voltage bushing, and a lower arc angle is configured on the bracket. This greatly reduces the generation of electric arc, thereby playing a good protective role for the transformer product. The bearing unit consists of a base, a screw shaft, and a closing sleeve. The screw shaft is located on the top surface of the base, and the closing sleeve is threaded to the outer contour of the screw shaft. The stabilizing unit consists of a base, a variable platform, an insert, and a drive column. The base is fitted onto the spindle and is located on the back of the closed sleeve. The variable platform is embedded in the inner edge of the base.

[0006] As a preferred technical solution for an arc-extinguishing device for oil-immersed transformers, the tank cover is equipped with a hoisting device, a tap changer, and an oil level gauge. When the hoisting device, tap changer, and oil level gauge are misaligned, they are distributed on the top of the tank cover. The oil level gauge is used to monitor the liquid level of transformer oil in the transformer tank, the hoisting device is used for hoisting the entire unit, and the tap changer is used to adjust the output voltage.

[0007] As a preferred technical solution for an arc-extinguishing device for oil-immersed transformers, the insert is movable and docked at the edge of the variable platform, and the drive column is spun-mounted in the variable platform.

[0008] As a preferred technical solution for an arc-extinguishing device for oil-immersed transformers, a circular channel is reserved in the middle of the wire shaft, and the inner bearing is embedded in the circular channel to achieve the effect of internal bearing.

[0009] As a preferred technical solution for an arc-extinguishing device for oil-immersed transformers, the inner edge of the lower part of the closed sleeve is reserved with a continuous bevel, and the outward part of the insert is milled into a wedge shape, and the specifications and contours of the wedge and the bevel are matched.

[0010] As a preferred technical solution for an arc-extinguishing device for oil-immersed transformers, the inner edge of the base is provided with an inner bearing platform, and a straight channel is reserved on the screw shaft. The inner bearing platform moves telescopically in the straight channel. The inner bearing platform is telescopically connected in the straight channel. At this time, the inner bearing platform cannot rotate. The insert is also restricted from rotating. Under the action of the wedge-shaped part and the oblique opening, the closing sleeve cannot move in the B direction, thereby ensuring the reliability of the copper cover after docking and installation.

[0011] As a preferred technical solution for an arc-extinguishing device for oil-immersed transformers, an adjustment channel is reserved on the outer contour of the drive column, and an extension block is arranged on the inner edge of the inner support, with the extension block located in the adjustment channel.

[0012] As a preferred technical solution for an arc-extinguishing device for oil-immersed transformers, the adjustment channel is divided into two sections: a steep section and a gentle section. When the extension block is in the gentle section, the wedge-shaped part corresponds to the inclined opening.

[0013] As a preferred technical solution for an arc-extinguishing device for oil-immersed transformers, a guide shaft is provided at the edge of the mounting platform, and a sloping channel is milled on the moving platform. The guide shaft is located in the sloping channel. When the moving platform moves upward, the guide shaft and the mounting platform move towards the axis of the moving platform through the sloping channel. At this time, the wedge-shaped part separates from the inclined opening, and the closed sleeve is unlocked, thereby facilitating the maintenance and replacement of the copper cover.

[0014] As a preferred technical solution for an arc-extinguishing device for oil-immersed transformers, an elastic element is arranged above the changing platform, the other end of the elastic element is connected to the inner edge of the inner bearing platform, and the elastic element surrounds the outer contour of the drive column.

[0015] The beneficial effects of this invention are: 1. By setting upper and lower arc-extinguishing angles on the high-voltage bushing to form a dedicated arc-extinguishing channel, this design can significantly increase the length and fracture area of ​​the arc channel, making it easier for arcs generated by overvoltages such as lightning strikes to form between the arc-extinguishing angles and gradually lengthen, weaken and extinguish. This reduces the direct flashover and ablation of the high-voltage bushing insulation surface by the arc, effectively reducing the lightning tripping rate and failure probability of outdoor oil-immersed transformers in thunderstorms, extending the overall service life of the transformer and providing excellent protection for the transformer product. 2. Through the innovative combination of the bearing unit and the stabilizing unit, the copper gland and the high-pressure bushing are quickly and reliably connected; by utilizing the wedge fit of the oblique opening and the wedge-shaped part, the anti-rotation limit of the straight channel and the inner bearing platform, the linkage of the slope channel and the guide shaft, and the assistance of the adjustment channel and the elastic element, one-way locking and controllable unlocking are achieved.

[0016] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description and the drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Wherein: Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0018] Figure 2 This is a top view of the present invention.

[0019] Figure 3 This is a schematic diagram of the left side of the present invention.

[0020] Figure 4 This is a schematic diagram of the high-pressure bushing of the present invention.

[0021] Figure 5 This is a schematic diagram of the bracket of the present invention.

[0022] Figure 6 This is a schematic diagram of the supporting unit and the stabilizing unit of the present invention.

[0023] Figure 7 This invention is based on Figure 6 Cross-sectional diagram.

[0024] Figure 8 This is a schematic diagram of the lead spool of the present invention.

[0025] Figure 9 This is a schematic diagram of the closed sleeve of the present invention.

[0026] Figure 10 This is a schematic diagram of the disassembly of the stabilizing unit of the present invention.

[0027] Figure 11 This invention is based on Figure 7 Change diagram Figure 1 .

[0028] Figure 12 This invention is based on Figure 7 Change diagram Figure 2 .

[0029] Figure 13 This invention is based on Figure 7 Partial schematic diagram.

[0030] Figure 14 This invention is based on Figure 11 Partial schematic diagram.

[0031] Figure 15 This invention is based on Figure 12 Partial schematic diagram.

[0032] Figure label: 10. Transformer body; 11. Tank cover; 12. Hoisting device; 13. Tap changer; 14. Oil level gauge; 20. High-voltage bushing; 21. Bracket; 22. Lower bushing arc angle; 23. Copper cover; 24. Upper bushing arc angle; 25. Bearing unit; 26. Stabilizing unit; 30. Base; 31. Lead shaft; 32. Straight channel; 33. Circular channel; 34. Closing sleeve; 35. Slanted opening; 40. Base platform; 41. Inner bearing platform; 42. Extension block; 43. Variable platform; 44. Elastic element; 45. Sloping channel; 46. Embedded platform; 47. Wedge-shaped part; 48. Guide shaft; 49. Drive column; 49-1. Adjustment channel; 49-2. Steep part; 49-3. Softening part; 50. Low-voltage bushing. Detailed Implementation

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0034] This invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of this invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not be construed as limiting the scope of protection of this invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0035] Example, refer to Figures 1 to 6 An arc-extinguishing device for oil-immersed transformers includes a transformer body 10, a high-voltage bushing 20 and a low-voltage bushing 50. A cover 11 is arranged above the transformer body 10. The high-voltage bushing 20 and the low-voltage bushing 50 are assembled on the cover 11. Several high-voltage bushings 20 and low-voltage bushings 50 are arranged in a linear manner. The tank cover 11 is equipped with a hoisting stirrer 12, a tap changer 13 and an oil level gauge 14. When the hoisting stirrer 12, tap changer 13 and oil level gauge 14 are misaligned, they are distributed on the top of the tank cover 11. The oil level gauge 14 is used to monitor the liquid level of transformer oil in the transformer tank. The hoisting stirrer 12 is used for hoisting the whole unit. The tap changer 13 is used to adjust the output voltage. The high-voltage bushing 20 is equipped with a bearing unit 25, and a copper pressure cover 23 is fitted on the top of the high-voltage bushing 20. A stabilizing unit 26 is configured on the copper pressure cover 23, and an upper arc angle 24 is configured on the copper pressure cover 23. A bracket 21 is configured around the high-voltage bushing 20, and a lower arc angle 22 is configured on the bracket 21. This will greatly reduce the generation of electric arc, thus playing a good protective role for the transformer product. Reference Figure 7 , 8 and Figure 10The supporting unit 25 consists of a base 30, a screw 31, and a closing sleeve 34. The screw 31 is located on the top surface of the base 30, and the closing sleeve 34 is threaded to the outer contour of the screw 31. The stabilizing unit 26 consists of a base 40, a movable platform 43, an insert 46, and a drive column 49. The base 40 is fitted onto the screw 31 and is located on the back of the closing sleeve 34. The movable platform 43 is embedded in the inner edge of the base 40. When the insert 46 is movable, it is connected to the edge of the movable platform 43. The drive column 49 is rotatably arranged in the movable platform 43. A circular channel 33 is reserved in the middle of the screw 31, and the inner bearing 41 is embedded in the circular channel 33 to serve as an internal bearing. Reference Figure 10 , 13 14 and Figure 15 The inner edge of the lower part of the closed sleeve 34 is reserved with a continuous bevel 35. One side of the bevel 35 is horizontal and vertical, and the other side is beveled. The outward part of the insert 46 is milled into a wedge-shaped part 47. The specifications and contours of the wedge-shaped part 47 and the bevel 35 are compatible. After the wedge-shaped part 47 and the bevel 35 are engaged, they can limit the movement direction of the closed sleeve 34. After the copper cover 23 is connected, the base 40 is first placed on the screw spool 31, and then the closed sleeve 34 is connected to the screw spool 31. At this time, the position of the copper cover 23 is limited. The stabilizing unit 26 will not cause conflict during the connection of the closed sleeve 34. The closed sleeve 34 moves along the A direction. During this process, the wedge-shaped part 47 will change position due to the wedge-shaped engagement of the bevel 35, so that the closed sleeve 34 can be properly connected and assembled. Reference Figure 7 and 8 The inner edge of the base 40 is provided with an inner bearing 41, and a straight channel 32 is reserved on the screw 31. The inner bearing 41 moves telescopically in the straight channel 32. The inner bearing 41 is telescopically connected in the straight channel 32. At this time, the inner bearing 41 cannot rotate. The insert 46 is also restricted from rotating. Under the action of the wedge 47 and the oblique opening 35, the closing sleeve 34 cannot move in the B direction, thereby ensuring the reliability of the copper cover 23 after docking and installation. Reference Figure 10 and 13An adjustment channel 49-1 is reserved on the outer contour of the drive column 49. An extension block 42 is arranged on the inner edge of the inner support 41. The extension block 42 is located in the adjustment channel 49-1. The adjustment channel 49-1 is divided into two sections: a steep section 49-2 and a gentle section 49-3. When the extension block 42 is in the gentle section 49-3, the wedge-shaped part 47 corresponds to the inclined opening 35. When the whole equipment has been used for a certain period of time, the closing sleeve 34 should be separated from the screw 31 to drive the drive column 49 in a rotating state. When the steep section 49-2 rotates, it is positioned by the extension block 42, so that the drive column 49 will perform a telescopic movement in the state of rotating motion, and finally the gentle section 49-3 will move to the position corresponding to the extension block 42. The drive column 49 moves together with the changing table 43 in this movement step. Reference Figure 10 A guide shaft 48 is provided at the edge of the mounting plate 46. A sloped channel 45 is milled on the moving platform 43. The guide shaft 48 is located in the sloped channel 45. When the moving platform 43 moves to the upward position, the guide shaft 48 and the mounting plate 46 move towards the axis of the moving platform 43 through the sloped channel 45. At this time, the wedge-shaped part 47 separates from the inclined opening 35. At this time, the closed sleeve 34 is unlocked, which facilitates the maintenance and replacement of the copper cover 23. Reference Figure 7 and 10 An elastic element 44 is arranged above the variable platform 43. The other end of the elastic element 44 is connected to the inner edge of the inner support platform 41. The elastic element 44 surrounds the outer contour of the drive column 49. After the copper pressure cap 23 is connected, the closing sleeve 34 is rotated and connected to the screw 31. The wedge-shaped part 47 is subjected to the action of the inclined opening 35 and undergoes lateral extension and retraction. The drive column 49 is allowed to perform vertical extension and retraction by relying on the sloped channel 45. When the wedge-shaped part 47 is subjected to the action of the inclined opening 35 and undergoes lateral extension and retraction, a part of it is still on the outer periphery of the inner support platform 41. During the docking assembly process, the extension block 42 cannot move to the position of the buffer part 49-3. The extension and retraction of the drive column 49 will only unlock the restriction effect between the stabilizing unit 26 and the closing sleeve 34 when it is operated by the operator. The elastic element 44 allows the wedge-shaped part 47 to correspond smoothly in the inclined opening 35, so that the upper arc angle 24 can be used securely and in a fixed position.

[0036] The above can achieve the following: Adding two arc-extinguishing angles to the transformer bushing aims to increase the length and fracture area of ​​the arc channel, thereby gradually weakening the arc and eventually extinguishing it, thus reducing the probability of lightning strikes. The main material for the arc-extinguishing angles is 304 stainless steel. Due to the excellent corrosion resistance, processing performance, high strength and toughness, and high temperature resistance of 304 stainless steel, it is feasible to use 304 stainless steel to make the arc-extinguishing angles.

[0037] After the copper cap 23 is aligned with the screw shaft 31, and the base 40 is embedded into the screw shaft 31, the lower surface of the base 40 touches the upper surface of the copper cap 23. Then, the closing sleeve 34 is rotated and aligned in direction A. The wedge-shaped part 47 will change position due to the wedge fit of the oblique opening 35, so that the closing sleeve 34 can be properly aligned and assembled. The inner support 41 is telescopically connected in the straight channel 32. At this time, the inner support 41 cannot rotate. The mounting plate 46 is also restricted from rotating. Under the action of the wedge-shaped part 47 and the oblique opening 35, the closing sleeve 34 cannot move in direction B, thus ensuring the reliability of the copper cap 23 after alignment and installation. When the wedge-shaped part 47 is subjected to the action of the oblique opening 35 and undergoes lateral telescopic movement, a part of it is still on the outer periphery of the inner support 41. During the alignment and assembly process, the extension block 42 cannot move to the position of the buffer part 49-3, so that the drive column 49 can only be moved by the operator. The extension and retraction movement that occurs will unlock the restrictive effect between the stabilizing unit 26 and the closing sleeve 34. The elastic element 44 allows the wedge-shaped part 47 to smoothly correspond to the inclined opening 35, so that the upper arc angle 24 can be used reliably and in a fixed position. When the whole device has been used for a certain period of time, the closing sleeve 34 should be separated from the screw 31 to drive the drive column 49 in a rotating state. When the steep part 49-2 rotates, it is positioned by the extension block 42, so that the drive column 49 will perform extension and retraction movement in a rotating state, and finally the buffer part 49-3 moves to the position corresponding to the extension block 42. In this movement step, the drive column 49 moves together with the changing table 43. The guide shaft 48 and the insert 46 move toward the axis position of the changing table 43 through the slope channel 45. The wedge-shaped part 47 separates from the inclined opening 35 at this time, and the state of the closing sleeve 34 is unlocked, so as to facilitate the maintenance and replacement of the copper pressure cover 23.

[0038] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A special arc-extinguishing device for oil-immersed transformers, characterized in that: The transformer includes a transformer body (10), a high-voltage bushing (20), and a low-voltage bushing (50). A cover (11) is provided on the upper part of the transformer body (10). The high-voltage bushing (20) and the low-voltage bushing (50) are assembled on the cover (11). Several high-voltage bushings (20) and low-voltage bushings (50) are arranged in a linear manner. The high-voltage bushing (20) is provided with a bearing unit (25), the top of the high-voltage bushing (20) is fitted with a copper pressure cap (23), the copper pressure cap (23) is provided with a stabilizing unit (26), the copper pressure cap (23) is provided with an upper arc angle (24), the high-voltage bushing (20) is provided with a bracket (21) around its perimeter, and the bracket (21) is provided with a lower arc angle (22). The bearing unit (25) consists of a base (30), a screw (31) and a closing sleeve (34). The screw (31) is located on the top surface of the base (30), and the closing sleeve (34) is threaded to the outer contour of the screw (31). The stabilizing unit (26) consists of a base (40), a variable platform (43), an insert (46), and a drive column (49). The base (40) is fitted onto the spindle (31) and is located on the back of the closed sleeve (34). The variable platform (43) is embedded in the inner edge of the base (40).

2. The arc-extinguishing device for oil-immersed transformers according to claim 1, characterized in that: The cover (11) is equipped with a hoisting mixer (12), a tap changer (13) and an oil level gauge (14). When the hoisting mixer (12), tap changer (13) and oil level gauge (14) are misaligned, they are distributed on the top of the cover (11).

3. The arc-extinguishing device for oil-immersed transformers according to claim 1, characterized in that: When the insert (46) is movable, it is docked at the edge of the movable stage (43), and the drive column (49) is spun in the movable stage (43).

4. The arc-extinguishing device for oil-immersed transformers according to claim 1, characterized in that: A circular channel (33) is reserved in the middle of the spindle (31).

5. The arc-extinguishing device for oil-immersed transformers according to claim 1, characterized in that: The inner edge of the lower part of the closed sleeve (34) is reserved with a continuous bevel (35), and the outward part of the insert (46) is milled into a wedge-shaped part (47). The specifications and contours of the wedge-shaped part (47) and the bevel (35) are adapted to each other.

6. The arc-extinguishing device for oil-immersed transformers according to claim 1, characterized in that: The inner edge of the base (40) is provided with an inner support (41), which is embedded in the circular channel (33). A straight channel (32) is reserved on the screw (31), and the inner support (41) moves in the straight channel (32).

7. The arc-extinguishing device for oil-immersed transformers according to claim 6, characterized in that: An adjustment channel (49-1) is reserved on the outer contour of the drive column (49), and an extension block (42) is arranged on the inner edge of the inner support (41), and the extension block (42) is located in the adjustment channel (49-1).

8. The arc-extinguishing device for oil-immersed transformers according to claim 7, characterized in that: The adjustment channel (49-1) is divided into two sections: a steep section (49-2) and a gentle section (49-3).

9. The arc-extinguishing device for oil-immersed transformers according to claim 1, characterized in that: The edge of the mounting platform (46) is provided with a guide shaft (48), and the movable platform (43) is milled with a slope channel (45). The guide shaft (48) is located in the slope channel (45). When the movable platform (43) moves to the upward position...

10. The arc-extinguishing device for oil-immersed transformers according to claim 1, characterized in that: An elastic element (44) is disposed above the variable platform (43), and the other end of the elastic element (44) is connected to the inner edge of the inner support (41). The elastic element (44) surrounds the outer contour of the drive column (49).

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