A switch assembly and on-load tap changer

Abstract

The application provides a switch assembly and a load regulating tap changer, and belongs to the technical field of voltage regulating devices. The switch assembly comprises a second fixed plate, a vacuum tube assembly and two groups of switch structures arranged on the two sides of the second fixed plate respectively, and the two groups of switch structures are symmetrically arranged on one side of the second fixed plate along the horizontal direction. Each group of switch structures comprises a first flange plate, a single-peak cam, a connecting rod mechanism and a first lead post. The single-peak cam is fixed on the second fixed plate through the first flange plate. A driving rod passes through the first flange plate and the single-peak cam in sequence. The connecting rod mechanism and the first lead post are arranged below the single-peak cam. When the peak section of the single-peak cam is in contact with one end of the connecting rod mechanism, the other end of the connecting rod mechanism is in communication with the first lead post. The first lead post is connected with a signal input end of the vacuum tube assembly. The peak section and the base circle section of the single-peak cam of the two groups of switch structures are staggered. The switch assembly is opened and closed by adopting the double connecting rod mechanism, so that the time sequence drift caused by gear wear is avoided, and the action time sequence precision is greatly improved.

Description

Technical Field

[0001] This invention belongs to the technical field of voltage regulating devices, specifically relating to a switching assembly and an on-load tap changer. Background Technology

[0002] In power systems, transformers use electromagnetic induction to raise and lower voltage, enabling efficient transmission and distribution of electrical energy and ensuring the interconnection of power grids at different voltage levels and the safe operation of electrical equipment. Traditional transformers mostly use non-excitation voltage regulation, requiring the power supply to be cut off first, followed by manual adjustment of the voltage regulating switch, and then power restoration after adjustment. Because transformers require power outages for voltage regulation, this not only leads to low voltage qualification rates and poor stability in actual power grids, but also increases losses for both the transformer itself and the electrical equipment.

[0003] With the rapid development of the power industry and the ever-growing national economy, the demands for power reliability and quality are increasing, posing greater challenges to the power grid. Improving power quality and ensuring the safe and reliable operation of equipment are therefore essential. Consequently, on-load tap-changing transformers are increasingly widely used at critical nodes in the power system to achieve uninterrupted voltage regulation, ensuring voltage quality for the system and users while preventing increased losses. The on-load tap changer is a key component of the on-load tap-changing transformer, being its only moving part. Connected to the high-voltage side coil of the transformer, the on-load tap changer allows for on-load voltage regulation in the distribution network by changing the switching between the tap changer contacts and the taps in the transformer windings. Therefore, the proper functioning of the on-load tap changer is crucial to the safety of the transformer and the entire power system, placing more stringent requirements on its voltage regulation process.

[0004] Existing on-load tap changers generally include a tap selector, a polarity selector, a switching switch, and a drive mechanism. The tap selector is used to select the coarse adjustment range, the polarity selector is used to change the winding polarity to achieve positive and negative voltage regulation, the switching switch is used to switch current under load, and the drive mechanism is used to provide power and control. The switching switch in existing on-load tap changers uses a crank-rocker mechanism with a pair of meshing gears. The rotation of the driving gear on the main shaft drives the driven gear to rotate, which in turn drives the rocker arm fixed to the driven gear to swing. The swing of the rocker arm causes a straight rod connected to the other end to reciprocate within a fixed groove, thereby opening and closing the switch.

[0005] Such a structure has certain drawbacks. First, it is complex, involving multiple kinematic pairs, and the insulation distance is difficult to guarantee. There is backlash in the meshing of gears, which will cause lag in motion transmission and timing drift as the number of operations increases, thus creating safety hazards. At the same time, the crank-rocker mechanism itself has a dead point position, and the mechanical transmission efficiency is uneven during the switching stroke, which can easily lead to switching jamming or incomplete action. When the rocker moves to the limit position, it needs to be mechanically limited to stop its movement. This strong impact may cause the contacts to bounce mechanically. Summary of the Invention

[0006] To address the aforementioned technical problems, the present invention provides a switching assembly and an on-load tap changer.

[0007] To achieve the above objectives, the present invention provides the following technical solution: On one hand, the present invention provides a switching assembly, including a second fixing plate, vacuum tube assemblies respectively disposed on both sides of the second fixing plate, and two sets of switching structures, the two sets of switching structures being symmetrically arranged on one side of the second fixing plate in the horizontal direction; Each of the switch structures includes a first flange, a single-peak cam, a linkage mechanism, and a first lead post. The single-peak cam is fixed to a second fixed plate via the first flange. The drive rod passes through the first flange and the single-peak cam in sequence. The linkage mechanism and the first lead post are located below the single-peak cam. When the convex section of the single-peak cam contacts one end of the linkage mechanism, the other end of the linkage mechanism is connected to the first lead post. The first lead post is connected to the signal input terminal of the vacuum tube assembly. The convex peak segment and base circle segment of the single-peak cam in the two sets of switch structures are arranged alternately.

[0008] Preferably, the linkage mechanism includes a swing arm and a switch lever; the switch lever is disposed below the single-peak cam and rotatably connected to the second fixed plate, and a roller disposed at one end of the switch lever abuts against the outer side of the single-peak cam; the lower end of the swing arm is rotatably connected to the second fixed plate through a first rotating shaft, and a limiting post is disposed on the lower end sidewall of the swing arm that abuts against the other end of the switch lever; When the convex section of the single-peak cam contacts the roller, the single-peak cam drives the switch lever to rotate, and the other end of the switch lever drives the swing arm to rotate through the limit post, so that the upper end of the swing arm abuts against the first lead post.

[0009] Preferably, it also includes a limiting rod, with a limiting groove provided at the lower end of the swing arm, one end of the limiting rod being connected to the second fixed plate, and the other end being disposed in the limiting groove, and a spring being provided on the limiting rod.

[0010] Preferably, the included angles of the single-peak cams in the two sets of the switch structures are ° and °, respectively.

[0011] Preferably, the vacuum tube assembly includes a bimodal cam, a vacuum tube, and a transition resistor; the bimodal cam is mounted on the other side of the second fixed plate via a first flange, the vacuum tube is mounted on the other side of the second fixed plate via a vacuum tube fixing block, a vacuum tube lever is hinged to one side of the vacuum tube fixing block, a roller at one end of the vacuum tube lever abuts against the outer side of the bimodal cam, and the other end is connected to the movable end of the vacuum tube; one end of the transition resistor is connected to the terminal block of the fixed end of the vacuum tube. A slot terminal is connected to the first rotating shaft, and the movable end terminal of the vacuum tube is connected to the slot terminal.

[0012] Preferably, the included angles of the two cams of the bimodal cam are ° and °, respectively.

[0013] Preferably, it also includes a switch mounting plate, which is disposed on one side wall of the first fixing plate, and the linkage mechanism of the two sets of switch structures and the first lead post are arranged symmetrically on the left and right sides of the switch mounting plate.

[0014] Preferably, the first lead post of both sets of the switch structures is connected to a common terminal connection post.

[0015] On the other hand, the present invention also provides an on-load tap changer, including a drive mechanism, a drive rod (4), multiple sets of tap changer mechanisms, and a switch assembly (5) as described above. Each voltage regulating mechanism includes a left / right selector assembly (9) and a polarity selector assembly (11); the drive mechanism drives the drive rod (4) to rotate, and the switch assembly (5) and multiple voltage regulating mechanisms are connected by the drive rod (4).

[0016] The switching assembly provided by this invention has the following beneficial effects: This invention uses a first fixed plate as a base, with a rack slidably mounted in a slide rail at the bottom of the fixed plate. The rack has contacts that engage with two polarity lead posts above it. The intermittently moving assembly driven by the drive rod consists of a gear, a second drive wheel, and a second grooved wheel. The second drive wheel achieves intermittent rotation through a locking arc engagement between a pin and the second grooved wheel, synchronously driving the gear to rotate. The meshing of the gear and rack converts the rotational motion into the horizontal reciprocating movement of the rack, thereby achieving precise alternating contact between the contacts and the two polarity lead posts. This structure abandons the elastic contact of the traditional clip-on moving contact bridge, replacing the spring contacts with the rigid meshing transmission of the gear and rack, eliminating the potential for poor contact caused by spring fatigue at its source. The rack moves horizontally and linearly along the slide rail, replacing the swinging contact of the traditional rocker arm, ensuring uniform contact pressure and precise alignment between the contacts and lead posts, avoiding the contact misalignment problem of the rocker arm structure, and preventing increased contact resistance and overheating / burning. Meanwhile, the intermittent transmission between the Geneva wheel and the drive wheel is precisely coordinated, and the transmission gap is controllable. This solves the problem of component wear and jamming in traditional incomplete Geneva wheel direct-drive structures. Furthermore, all components are integrated into the first fixed plate, resulting in a simple transmission chain and high assembly precision. This reduces the probability of wear and misalignment of multiple components and avoids polarity switching failures under high-intensity use. The coordinated operation of all components ensures smooth and precise contact between the contacts and the polarity lead post, significantly improving the stability and positional accuracy of polarity switching. This effectively reduces contact resistance and component wear, significantly extending the service life and operational reliability of the polarity selector, ensuring the accuracy of polarity switching in on-load tap changers, and meeting the high requirements of refined voltage regulation in power systems. Attached Figure Description

[0017] To more clearly illustrate the embodiments and design schemes of the present invention, the accompanying drawings required for this embodiment will be briefly described below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a three-dimensional structural schematic diagram of the voltage regulating tap changer according to Embodiment 1 of the present invention; Figure 2 A three-dimensional structural diagram of the left and right selector components; Figure 3 A three-dimensional structural diagram of the left and right selector assemblies after the selector groove wheel has been removed; Figure 4 This is an exploded view of the selector's grooved wheel. Figure 5 This is a schematic diagram of the exploded structure of the polarity selector component; Figure 6 This is a three-dimensional structural diagram of one side of the switch structure of the switch assembly; Figure 7A three-dimensional structural diagram of the switch assembly having the vacuum tube assembly side; Figure 8 This is a three-dimensional structural diagram of the switch structure; Figure 9 This is a three-dimensional structural diagram of a vacuum tube assembly; Figure 10 This is a three-dimensional structural diagram of the drive mechanism.

[0019] Explanation of reference numerals in the attached figures: Drive motor 1, base 2, fixing rod 3, drive rod 4, driving bevel gear 44, driven bevel gear 45; Switch assembly 5: Second fixing plate 6, vacuum tube assembly 7, common end connecting post 27, single peak cam 28, switch mounting plate 29, double peak cam 30, first flange 31, transition resistor 32, vacuum tube 33, vacuum tube fixing block 34, swing arm 35, switch lever 36, roller 37, first lead post 38, first rotating shaft 39, limit rod 40, vacuum tube lever 41, movable end 42, fixed end terminal block 43, limit post 49, movable end terminal block 50, slot terminal block 51; Left and right selector assembly 9: third fixing plate 8, first drive wheel 12, second flange 13, first grooved wheel 14, positioning plate 15, first lead post 16, second rotating shaft 17, connector 18; Polarity selector assembly 11: first fixed plate 10, gear 19, third flange 20, second drive wheel 21, second grooved wheel 22, rack 23, slide rail 24, polarity lead post 25, third rotating shaft 26, contact 46, groove 47, polarity common terminal 48. Detailed Implementation

[0020] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the technical solution of this 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. Therefore, they should not be construed as limitations on this invention.

[0022] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "connected" or "linked" 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. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. In the description of this invention, unless otherwise stated, "a plurality of" means two or more, which will not be elaborated further here.

[0023] Existing small on-load tap changers have few voltage regulation ranges. Increasing the number of voltage regulation ranges would increase the complexity of the tap changer, resulting in a slow switching response and further increasing production costs. This invention adds a polarity selector component to the existing small on-load tap changer, increasing the number of voltage regulation ranges of the small on-load tap changer without significantly increasing the complexity of the switch components, enabling more precise voltage regulation within the voltage regulation range. Existing small on-load tap changers use a single-pole double-throw switch for their main on / off contacts. The switching sequence is fixed and cannot be adjusted, and the arc energy and switching stress are relatively large, thus creating safety hazards. In contrast, the main on / off contacts of the strip-type on-load tap changer of this invention use two single-pole single-throw switches. The arc energy during the switching process is smaller, the switching process is smoother, the electrical stress is lower, and the operating sequence can be precisely designed and controlled. Furthermore, only a single current-carrying branch operates during the switching process, making the switching process safer and more reliable.

[0024] Example 1 Existing on-load tap changers, when employing two main on-off contacts, mostly use two current-carrying branches, resulting in complex switch structures, higher costs, and relatively larger sizes, making it difficult to meet the requirements of miniaturization of tap changers and refined voltage regulation of transformers. Therefore, this invention proposes a switch assembly 5.

[0025] like Figures 6 to 9 As shown, in this embodiment, the switch assembly 5 includes a second fixed plate 6, vacuum tube assemblies 7 respectively disposed on both sides of the second fixed plate 6, and two sets of switch structures. Both sets of switch structures are single-pole single-throw switches, and the two sets of switch structures are symmetrically arranged on one side of the second fixed plate 6 in the horizontal direction.

[0026] Each set of switch structures includes a first flange 31, a single-peak cam 28, a linkage mechanism, and a first lead post 38. The single-peak cam 28 is fixed to the second fixed plate 6 through the first flange 31. The drive rod 4 passes through the first flange 31 and the single-peak cam 28 in sequence and is connected to the single-peak cam 28 in a transmission connection. The linkage mechanism and the first lead post 38 are located below the single-peak cam 28. When the convex peak of the single-peak cam 28 contacts one end of the linkage mechanism, the other end of the linkage mechanism is connected to the first lead post 38. The first lead post 38 is connected to the signal input terminal of the vacuum tube assembly 7. The convex peak and base circle segments of the single-peak cam 28 of the two sets of switch structures are staggered.

[0027] As a preferred option, such as Figure 8 As shown, in this embodiment, the linkage mechanism includes a swing arm 35, a switch lever 36, and a limiting rod 40. The switch lever 36 is located below the single-peak cam 28 and is rotatably connected to the second fixed plate 6. A roller 37 at one end of the switch lever 36 abuts against the outer side of the single-peak cam 28. The lower end of the swing arm 35 is rotatably connected to the second fixed plate 6 via a first rotating shaft 39. A limiting post 49 is provided on the lower side wall of the swing arm 35, abutting against the other end of the switch lever 36. A limiting groove is provided at the lower end of the swing arm 35, and a slot is provided at the movable end (upper end) of the swing arm 35. During the rotation of the swing arm 35, the slot will contact the corresponding first lead post 38. One end of the limiting rod 40 is connected to the second fixed plate 6, and the other end is located in the limiting groove. A spring is provided on the limiting rod 40, and the spring is sleeved on the limiting rod 40 with both ends abutting against the inner wall of the limiting groove of the swing arm 35. When the convex section of the single-peak cam 28 contacts the roller 37, the single-peak cam 28 drives the switch lever 36 to rotate. The other end of the switch lever 36 drives the swing arm 35 to rotate through the limiting post 49, so that the upper end of the swing arm 35 abuts against the first lead post 38. The first lead posts 38 of both sets of switch structures are connected to the common terminal of the transformer through the common terminal connecting post 27. When the swing arm 35 is driven to rotate by the switch lever 36, the spring is compressed or stretched. When the base circle section of the cam contacts the roller 37, the spring's rebound force drives the swing arm 35 to reset, and the limiting rod 40 acts as a guide.

[0028] Preferably, the two sets of single-peak cams 28 of the switching structure can be set as a whole. The single-peak cam 28 is composed of two layers of cams with different included angles and different protrusion directions, and is assembled on the outside of the first flange 31 with the switching structure through bearings. The included angles of the two protruding parts of the double-peak cam 30 are also different. Specifically, in this embodiment, the included angles of the cams (protruding parts) of the two sets of single-peak cams 28 of the switching structure are 145° and 165°, respectively, and the included angles of the two cams (protruding parts) of the double-peak cam 30 are 95° and 110°, respectively.

[0029] For ease of installation, the switch assembly 5 also includes a switch mounting plate 29. The linkage mechanism of the two sets of switch structures and the first lead post 38 are arranged symmetrically on the left and right sides of the switch mounting plate 29, so that the switch levers 36 in the two sets of switch structures are staggered and abut against the single-peak cams 28 of each switch structure respectively. The switch mounting plate 29 is fixed to one side of the second fixing plate 6 by bolts.

[0030] Furthermore, such as Figure 9 As shown, the vacuum tube assembly 7 includes a double-peaked cam 30, a vacuum tube 33, and a transition resistor 32. The double-peaked cam 30 is mounted on the other side of the second fixed plate 6 via a first flange 31. The vacuum tube 33 is mounted on the other side of the second fixed plate 6 via a vacuum tube fixing block 34. A vacuum tube lever 41 is hinged to one side of the vacuum tube fixing block 34. A roller at one end of the vacuum tube lever 41 abuts against the outer side of the double-peaked cam 30, and the other end is connected to the movable end 42 of the vacuum tube 33. One end of the transition resistor 32 is connected to the fixed end terminal 43 of the vacuum tube 33, and the other end is connected to the transformer winding. It can form a current-limiting branch through the transition resistor 32 at the moment the vacuum tube 33 opens and closes, thus preventing excessive arc energy. A slot terminal 51 is connected to the first rotating shaft 39, and the movable end terminal 50 of the vacuum tube 33 is connected to the slot terminal 51. The switching assembly 5 undertakes load switching. Through the current limiting of the transition resistor 32, the current transfer is completed quickly without interrupting the power supply or generating short-circuit circulating current.

[0031] When the on-load tap changer is working, the drive rod 4 synchronously drives the single-peak cam 28 and double-peak cam 30 on both sides to rotate. The single-peak cam 28 of the two sets of single-pole single-throw switches, through the staggered cooperation of the convex peak section and the base circle section, sequentially pushes the roller 37 to drive the switch lever 36 and the swing arm 35 to move, realizing the alternating opening and closing of the two sets of switches, ensuring that only a single current-carrying branch works throughout the process; at the same time, the double-peak cam 30 is linked to the vacuum tube lever 41 to control the opening and closing sequence of the vacuum tube 33. At the moment of switch switching, the transition resistor 32 is connected to the circuit to form a current-limiting branch, suppressing arc energy and reducing electrical stress, realizing the uninterrupted safe transfer of load current, and completing the core action of on-load switching. The switch assembly 5 of this invention adopts a symmetrical arrangement of two single-pole single-throw switches, and with the staggered single-peak cam, it realizes continuous operation of a single current-carrying branch, which greatly reduces the arc energy and switching stress during the switching process and structurally avoids the safety hazards of traditional single-pole double-throw switch switching. With the vacuum tube and transition resistor precisely controlled by the double-peak cam, arc suppression and current limiting are achieved at the moment of switching, which further improves the safety and reliability of on-load switching, and the action sequence can be precisely designed and controlled. The spring reset design of the limit rod in the linkage mechanism ensures the accuracy of the switch on-off action. All components are integrated into the second fixed plate, which is simple in structure and stable in transmission. It takes into account the production cost control and the convenience of assembly and maintenance, and at the same time meets the dual requirements of transformer voltage regulation and switch miniaturization.

[0032] In summary, this invention employs a double-link mechanism to realize the opening and closing of the switch in the switching assembly. Since gear transmission inevitably involves tooth backlash, this invention does not use gear transmission but directly uses a double-link mechanism, avoiding timing drift caused by gear wear and significantly improving the timing accuracy of the action. At the same time, the double-link mechanism has a low coefficient of friction, high transmission efficiency, and is less affected by oil viscosity. Furthermore, the double-link mechanism can optimize the motion trajectory by adjusting the ratio of the link lengths, achieving a soft landing of the contacts, greatly reducing contact bounce and extending contact life.

[0033] Example 2 Based on the switching assembly 5 provided in Embodiment 1, the present invention also provides an on-load tap changer, specifically a strip-shaped on-load tap changer with a polarity selector, such as... Figure 1 As shown, the switch includes a drive mechanism, a fixed rod 3, a drive rod 4, and multiple voltage regulating mechanisms. Each voltage regulating mechanism includes a switch assembly 5, a left / right selector assembly 9, and a polarity selector assembly 11 arranged sequentially. The drive mechanism and multiple voltage regulating mechanisms are all mounted on the fixed rod 3, and the multiple voltage regulating mechanisms are connected by the drive rod 4. The drive mechanism drives the drive rod 4 to rotate, and the drive rod 4 in turn drives the drive wheels and cams of each component to rotate. The three voltage regulating components are coordinated in sequence according to the left / right selector pre-selection tap, the polarity selector switching polarity increment, and the switch assembly on / off current limiting under load, to achieve precise voltage regulation of the transformer without power interruption, and only a single current-carrying branch works throughout the process, ensuring switching safety. The specific structure of the switch assembly 5 is as described in Embodiment 1, and will not be repeated here.

[0034] Specifically, such as Figures 2 to 4As shown, in this embodiment, a spring is provided on the connector 18 of the left and right selector assembly 9. To achieve elastic contact with the first lead post 16, the spring is built into or embedded inside the grooved contact end of the connector 18. One end of the spring is fixedly connected to the inner wall of the groove in the connector 18, and the other end directly abuts against the contact portion between the connector 18 and the first lead post 16 (or the movable contact piece connecting the connector 18). The entire spring is integrated with the connector 18 at the radial position of the first grooved wheel 14. In addition, the left and right selector assembly 9 also includes a third fixing plate 8 and two sets of selector switches respectively disposed on both sides of the third fixing plate 8. Each set of selector switches includes a second flange 13, a first drive wheel 12, a first grooved wheel 14, and multiple first lead posts 16. Because existing small on-load tap changers have a limited number of voltage regulation ranges and a wide regulation range, while on-load tap changers with more ranges are structurally too complex, it is difficult to achieve a simpler tap changer structure while providing more voltage regulation ranges and enabling a more precise voltage regulation process. Therefore, in this embodiment, each group of two selector switches is equipped with multiple first lead posts 16. These multiple first lead posts 16 are horizontally and equally spaced around the third fixed plate 8. A second rotating shaft 17 is located at the center of the third fixed plate 8. A first grooved wheel 14 is rotatably connected to the second rotating shaft 17 via a bearing and a positioning plate 15. A connector 18 is radially disposed on the first grooved wheel 14, with one end of the connector 18 having a groove that makes movable contact with the first lead post 16. The connector 18, radially disposed on the first grooved wheel 14, rotates with the wheel and makes movable contact with the different first lead posts 16 arranged circumferentially, thus enabling the tap switching of the left and right selectors. The second flange 13 is positioned above the first grooved wheel 14 and is fixedly connected to the third fixing plate 8 by bolts. The first drive wheel 12 is mounted on the outside of the second flange 13 via bearings. Simultaneously, the arc side of the first drive wheel 12 engages with the locking arc on the first grooved wheel 14, allowing the first drive wheel 12 to rotate using a pin. The first lead posts 16 on both sides of the left and right selector assembly 9 correspond to the odd-numbered and even-numbered taps of the voltage regulating winding, respectively. The operating timing of the left and right selector 9 is coordinated with the on / off timing of the switch assembly 5. When the left and right selector switches taps, the switch assembly 5 maintains a single current-carrying branch conduction.

[0035] When the on-load tap changer is working, the drive rod 4 drives the first drive wheel 12 to rotate continuously. The first drive wheel 12, through the cooperation of the pin and the locking arc, drives the first slotted wheel 14 to rotate precisely intermittently around the second rotating axis 17. The connector 18 on the first slotted wheel 14 rotates synchronously with the slotted wheel and makes stable contact with the first lead post 16 of the corresponding transformer tap changer on the third fixed plate 8 in sequence, thus completing the no-load pre-selection switching of the transformer tap changer. The load current is not interrupted throughout the process, and only the circuit pre-selection of the next tap is completed.

[0036] The left and right selector assembly 9 of this invention adopts an intermittent transmission structure of a drive wheel and a grooved wheel, coupled with a connector with elastic compensation. It has the core advantage of uninterrupted power supply without no-load pre-selection, and can complete tap pre-selection while the main switch is on, meeting the core requirement of uninterrupted switching of on-load tap changers. At the same time, the grooved wheel mechanism achieves precise indexing at a fixed angle, ensuring that the connector and lead post have no misalignment or slippage, and has high positioning accuracy. The pure mechanical transmission design is simple in structure, with low wear and strong operational stability, and is suitable for the long-term operation requirements of transformers. The elastic compensation design of the connector ensures tight contact, effectively avoiding faults such as poor contact, overheating and arcing, and significantly reducing the equipment failure rate. In addition, all components are integrated into a single fixed plate, with high modular integration, making subsequent assembly, maintenance and replacement operations very convenient. It meets the compact design requirements of the overall switch and is a key module for achieving safe and stable coarse adjustment of the tap changer on load.

[0037] Specifically, such as Figure 5 As shown, the polarity selector assembly 11 includes a first fixed plate 10, a rack 23, and an intermittent moving assembly. A slide rail 24 is provided near the bottom of one side of the first fixed plate 10, and the slide rail 24 is fixed to the first fixed plate 10 by bolts. Two polarity lead posts 25 are provided near the slide rail 24 on one side of the first fixed plate 10. The rack 23 is slidably disposed within the slide rail 24. A contact 46 that engages with the two polarity lead posts 25 is provided on the side of the rack 23 near the first fixed plate 10. In this embodiment, the contact 46 is located in the center of the rack 23. The two polarity lead posts 25 are connected to a transformer via copper wires. The driving mechanism drives the intermittent moving assembly to rotate via a driving rod 4. The intermittent moving assembly drives the rack 23 to move horizontally back and forth within the groove, achieving alternating contact between the contact and the two polarity lead posts 25. Further, in this embodiment, a polarity common terminal 48 is also provided on the first fixed plate 10. One end of the polarity common terminal 48 is connected to the contact 46 via a copper wire, and the other end is connected to the common terminal of the transformer via a copper wire.

[0038] Furthermore, in this embodiment, the intermittent movement component includes a gear 19, a third flange 20, a second drive wheel 21, and a second grooved wheel 22.

[0039] The drive rod 4 passes sequentially through the third flange 20 and the second drive wheel 21, and is connected to the second drive wheel 21 in a transmission manner. A third rotating shaft 26 is provided on one side of the first fixed plate 10. The gear 19 and the second grooved wheel 22 are sequentially mounted on the third rotating shaft 26 through bearings and maintain synchronous rotation. In this embodiment, the third rotating shaft 26 is arranged in the center of the first fixed plate 10. In this embodiment, the second grooved wheel 22 is mounted on the third rotating shaft 26 through bearings and is located outside the gear 19. It is fixed to the rear gear 19 by bolts and maintains synchronous rotation. At the same time, the rack 23 meshes with the gear 19. Specifically, the third flange 20 is located above the second grooved wheel 22 and is fixed to one side of the first fixed plate 10 by bolts. The second drive wheel 21 is mounted on the outside of the third flange 20 via bearings. The arc side of the second drive wheel 21 engages with the locking arc on the second grooved wheel 22, allowing the second drive wheel 21 to rotate using a pin. The second grooved wheel 22 then drives the synchronous gear 19 to rotate, thereby causing the rack 23 to reciprocate horizontally within the slide rail 24, enabling the contact 46 to move between the two polarity lead posts 25. The polarity (positive / reverse) of the voltage regulating winding connection to the main circuit is switched via the polarity selector assembly 11.

[0040] In order to reduce the volume of the first fixing plate 10, in this embodiment, a groove 47 is provided on one side of the first fixing plate 10 near the slide rail 24, and the two polarity lead posts 25 are both arranged in the groove 47.

[0041] When the on-load tap changer is working, the drive rod 4 drives the second drive wheel 21 to rotate synchronously. With the help of the pin and the locking arc, the second drive wheel 21 drives the second slotted wheel 22 to rotate intermittently around the third rotating shaft 26 at a fixed angle. The gear 19, which is fixed coaxially with the second slotted wheel 22, rotates together. Through the meshing transmission of the gear and rack, the rotational motion is converted into the horizontal linear reciprocating movement of the rack 23 along the slide rail 24. Finally, the contact 46 on the rack is driven to precisely switch and alternately contact between the two polarity lead posts 25, realizing the positive and negative switching of the polarity of the transformer voltage regulating winding and the main circuit, and completing the refined expansion of the voltage regulating range. This component innovatively adopts a design combining gear and rack meshing with intermittent transmission of Geneva wheel. The Geneva wheel mechanism enables precise intermittent movement of the contacts at a fixed angle, ensuring positional accuracy and operational stability during polarity switching. Simultaneously, the gear and rack transmission characteristics convert rotational motion into linear motion, resulting in high transmission efficiency, smooth operation, and no jamming. This effectively solves the problems of poor contact and transmission jamming in traditional polarity selectors. The overall structure is streamlined, with fewer parts and convenient assembly. It achieves a doubling of voltage adjustment ranges without significantly increasing the overall complexity of the switch, meeting the needs for refined voltage regulation. Furthermore, the contacts move horizontally along the slide rail with the rack, ensuring a fixed contact stroke and controllable clearance, greatly reducing component wear and extending equipment lifespan. All components are integrated into the first fixed plate, and the modular design adapts to the compact layout of the overall switch, balancing practicality with ease of assembly and maintenance.

[0042] like Figure 1 , Figures 5-6 and Figure 10 As shown, in this embodiment, the drive mechanism includes a drive motor 1, which is vertically mounted on a fixed rod 3 via a base 2. The output end of the drive motor 1 is connected to a meshing active bevel gear 44 and a driven bevel gear 45. The drive rod 4 horizontally passes through the driven bevel gear 45 and is fixedly connected to it, thus transmitting power. Simultaneously, the drive rod 4 horizontally passes through each fixed plate and is connected to the single-peak cam 28, double-peak cam 30, and second drive wheel 21 on each fixed plate. When the on-load tap changer is operating, under the action of the drive motor 1, the active bevel gear 44 rotates, driving the driven bevel gear 45 to rotate, causing the drive rod 4 to rotate horizontally synchronously, thereby driving the drive wheels and cams of each component to rotate, transmitting power to each tap changer component.

[0043] In this embodiment, the second fixing plate 6, the third fixing plate 8 and the first fixing plate 10 are all vertically connected to one side of the fixing rod 3.

[0044] The working principle of the strip-type on-load tap changer with polarity selector provided in this embodiment is as follows: Power transmission: After the core drive motor 1 starts, it drives the driven bevel gear 45 to rotate through the active bevel gear 44. The driven bevel gear 45 drives the drive rod 4 to rotate, and the drive rod 4 transmits power to the drive wheels and cams of each component, providing power for the operation of the entire switch.

[0045] Transformer winding tap switching: Drive rod 4 drives the first drive wheel 12 to rotate. The first drive wheel 12 uses the locking arc of the pin and the first slotted wheel 14 to drive the first slotted wheel 14 to rotate. The connector 18 on the first slotted wheel 14 rotates accordingly and contacts the different first lead posts 16 on both sides of the third fixed plate 8, realizing the switching of transformer winding taps and completing the initial voltage regulation tap selection.

[0046] Adding a voltage adjustment range: The second drive wheel 21 drives the second grooved wheel 22 to rotate, and the second grooved wheel 22 rotates synchronously with the gear 19. The gear 19 meshes with the rack 23, driving the rack 23 to move horizontally within the slide rail 24. The contact in the center of the rack 23 switches between two polarity lead posts 25, changing the current polarity. In this way, without increasing the complexity of the components, a voltage adjustment range is added, achieving precise voltage regulation.

[0047] By controlling the rotation of the single-peak cam 28, the switch levers 36 of the two single-pole single-throw switches are pushed respectively. The switch lever 36 drives the swing arm 35 to move, and the groove on the swing arm 35 contacts or separates from the first lead post 38 to realize the circuit switching. The first lead post 38 is connected to a common terminal connection post 27, which is the common terminal of the two sets of switch structures. The spring on the limit rod 40 assists the swing arm 35 to reset, ensuring accurate action. At the same time, the double-peak cam 30 drives the vacuum tube lever 41 to move, controlling the opening and closing of the vacuum tube 33. The transition resistor 32 on the right side of the second fixed plate 6 suppresses the electric arc generated during the switching process and reduces electrical stress. The entire switching process only operates on a single current-carrying branch, improving the safety and reliability of switch operation.

[0048] The strip-shaped on-load tap changer provided by this invention uses a polarity selector equivalent to a single-pole double-throw switch, and two single-pole single-throw switches as the switching assembly. During switching, only one current-carrying branch operates, making switching more convenient and safer. This avoids the increased wear and safety issues caused by frequent switching when using multiple single-pole double-throw switches. Specifically, by adding a polarity selector assembly, this invention increases the number of voltage adjustment levels of the on-load tap changer while using the same number of parts, making the voltage adjustment more precise and its application range wider. The polarity selector assembly of this invention adopts a design combining gear and rack meshing with a grooved wheel, reducing the number of parts and complexity, making the production and assembly of the on-load tap changer more flexible and convenient. Furthermore, this invention is highly practical and worthy of promotion.

[0049] It should be noted that the specific embodiments described above enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way. Therefore, although the present invention has been described in detail in this specification and embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention; and all technical solutions and improvements that do not depart from the spirit and scope of the present invention are covered within the protection scope of the present invention patent. No reference numerals in the claims should be construed as limiting the scope of the claims. Any simple variations or equivalent substitutions of technical solutions that can be readily obtained by those skilled in the art within the scope of the technology disclosed in the present invention are within the protection scope of the present invention.

Claims

1. A switching assembly, characterized in that, It includes a second fixing plate (6) and vacuum tube assemblies (7) respectively disposed on both sides of the second fixing plate (6) and two sets of switch structures. The two sets of switch structures are symmetrically arranged on one side of the second fixing plate (6) in the horizontal direction. Each of the switch structures includes a first flange (31), a single-peak cam (28), a linkage mechanism, and a first lead post (38). The single-peak cam (28) is fixed on the second fixed plate (6) through the first flange (31). The drive rod (4) passes through the first flange (31) and the single-peak cam (28) in sequence. The linkage mechanism and the first lead post (38) are located below the single-peak cam (28). When the convex peak of the single-peak cam (28) contacts one end of the linkage mechanism, the other end of the linkage mechanism is connected to the first lead post (38). The first lead post (38) is connected to the signal input end of the vacuum tube assembly (7). The convex peaks and base circles of the single-peak cams (28) of the two sets of switch structures are staggered.

2. The switching assembly according to claim 1, characterized in that, The linkage mechanism includes a swing arm (35) and a switch lever (36); the switch lever (36) is located below the single-peak cam (28) and is rotatably connected to the second fixed plate (6); a roller (37) is provided at one end of the switch lever (36) and abuts against the outer side of the single-peak cam (28); the lower end of the swing arm (35) is rotatably connected to the second fixed plate (6) through a first rotating shaft (39); a limiting post (49) is provided on the lower side wall of the swing arm (35) and abuts against the other end of the switch lever (36). When the convex section of the single-peak cam (28) contacts the roller (37), the single-peak cam (28) drives the switch lever (36) to rotate, and the other end of the switch lever (36) drives the swing arm (35) to rotate through the limit post (49), so that the upper end of the swing arm (35) abuts against the first lead post (38).

3. The switching assembly according to claim 2, characterized in that, It also includes a limiting rod (40), the lower end of the swing arm (35) is provided with a limiting through groove, one end of the limiting rod (40) is connected to the second fixing plate (6), and the other end is set in the limiting through groove. A spring is provided on the limiting rod (40).

4. The switching assembly according to claim 2, characterized in that, The cam included angles of the two sets of single-peak cams (28) of the switch structure are 145° and 165°, respectively.

5. The switching assembly according to claim 2, characterized in that, The vacuum tube assembly (7) includes a bimodal cam (30), a vacuum tube (33), and a transition resistor (32); the bimodal cam (30) is mounted on the other side of the second fixed plate (6) via a first flange (31), and the vacuum tube (33) is mounted on the other side of the second fixed plate (6) via a vacuum tube fixing block (34). A vacuum tube lever (41) is hinged to one side of the vacuum tube fixing block (34), and a roller at one end of the vacuum tube lever (41) abuts against the outer side of the bimodal cam (30), while the other end is connected to the movable end (42) of the vacuum tube (33); one end of the transition resistor (32) is connected to the terminal block (43) of the fixed end of the vacuum tube (33). The first rotating shaft (39) is connected to a slot terminal (51), and the movable end terminal (50) of the vacuum tube (33) is connected to the slot terminal (51).

6. The switching assembly according to claim 5, characterized in that, The included angles of the two cams of the bimodal cam (30) are 95° and 110°, respectively.

7. The switching assembly according to claim 1, characterized in that, It also includes a switch mounting plate (29), which is set on one side wall of the first fixing plate (6), and the linkage mechanism of the two sets of switch structures and the first lead post (38) are arranged symmetrically on the left and right sides of the switch mounting plate (29).

8. The switching assembly according to claim 1, characterized in that, The first lead post (38) of both sets of switch structures is connected to the common terminal connection post (27).

9. An on-load tap changer, characterized in that, It includes a drive mechanism, a drive rod (4), multiple sets of voltage regulating mechanisms, and a switch assembly (5) as described in any one of claims 1-8. Each voltage regulating mechanism includes a left / right selector assembly (9) and a polarity selector assembly (11); the drive mechanism drives the drive rod (4) to rotate, and the switch assembly (5) and multiple voltage regulating mechanisms are connected by the drive rod (4).

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