Oil-immersed composite vacuum on-load tap-changer

Abstract

The invention provides an oil-immersed composite vacuum on-load tap-changer, which comprises an oil chamber and a switching core rotationally sleeved in the oil chamber, and is characterized in that the switching core comprises an insulating main shaft rotationally arranged in the oil chamber and at least one switching mechanism fixed on the insulating main shaft; each switching mechanism comprises an upper mounting plate, a lower mounting plate, a vacuum arc extinguishing system, a moving contact system, a transition resistor and a roller; the upper mounting plate and the lower mounting plate are sequentially fixed on the insulating main shaft from top to bottom; two ends of the vacuum arc extinguishing system are respectively mounted on the upper mounting plate and the lower mounting plate, and the vacuum arc extinguishing system comprises a V1 vacuum arc extinguishing system and a V2 vacuum arc extinguishing system; the moving contact system is installed between the V1 vacuum arc extinguishing system and the V2 vacuum arc extinguishing system. The transition resistor is mounted on the lower mounting plate; the multiple rollers are rotationally installed on the inner side of the oil chamber. The device is compact in structure, small in size, low in height and low in cost, greatly reduces the installation process, saves the assembly time, and improves the assembly efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of on-load tap changers, and in particular to an oil-immersed composite vacuum on-load tap changer. Background Art

[0002] like Figure 1 and Figure 2 This is a structural diagram of an existing oil-immersed composite vacuum on-load tap changer and its switching core, which mainly includes an oil chamber, a switching core installed in the oil chamber, and an energy storage system for driving the switching core to perform switching actions. The switching core is mainly composed of a non-rotatable insulating main shaft, a cam plate with multiple cams installed on the insulating main shaft, three brackets vertically installed on the outside of the main shaft and capable of rotating around the main shaft, and a moving contact system and an arc extinguishing system installed between the brackets. During installation, it is necessary to first install the cam plate and the bracket in sequence, and then install the moving contact system and the arc extinguishing system on the bracket with related connectors. This structure has the following disadvantages: Firstly, the cam disc is arranged between the bracket and the insulating main shaft, and the arc extinguishing system of the bracket needs to cooperate with the cam on the cam disc, so that the bracket needs to be away from the insulating main shaft by a certain distance (outward expansion) to leave enough space for the installation of the cam disc and the space for the coordination of the cam and the arc extinguishing system, thereby resulting in an increase in the overall diameter and volume of the switching core, which in turn increases the volume of the oil chamber, the vacuum on-load tap changer and the transformer, and also increases the material cost and the manufacturing cost.

[0003] Secondly, maintenance is troublesome. When the cam is worn and needs to be repaired, the bracket and its upper moving contact system, vacuum arc extinguishing system and insulating main shaft need to be removed first before the cam disc can be replaced. After replacement, the bracket and its upper moving contact system and vacuum arc extinguishing system need to be reinstalled, and the replacement process is complicated.

[0004] Finally, the moving contact system has a complex structure, is difficult to install and maintain, and also increases material and manufacturing costs.

[0005] In summary, the above defects of the existing oil-immersed composite vacuum on-load tap-changer result in the switch structure being large in size, high in height, and high in manufacturing cost, which also results in an increase in the manufacturing cost of the transformer, especially for transformers below 40.5kV, which have low voltage, small insulation distance, and small transformer body. In order to meet the use requirements of the existing oil-immersed composite vacuum on-load tap-changer, the transformer body must be enlarged and the height increased, which greatly increases the manufacturing cost of the transformer. At the same time, the switch can also replace the same type of oil arc-extinguishing switch on the market. Summary of the invention

[0006] In order to solve the above problems, the object of the present invention is to provide an oil-immersed composite vacuum on-load tap changer with small size, low height and low cost.

[0007] The object of the present invention is achieved by the following technical solutions: An oil-immersed composite type on-load tap-changer with vacuum includes an oil chamber and a switching core rotatably sleeved in the oil chamber. The switching core includes an insulating main shaft rotatably arranged in the oil chamber and at least one switching mechanism fixed on the insulating main shaft. Each switching mechanism includes an upper mounting plate, a lower mounting plate, a vacuum arc extinguishing system, a moving contact system, a transition resistor and rollers. The upper mounting plate and the lower mounting plate are sequentially fixed on the insulating main shaft from top to bottom. The two ends of the vacuum arc extinguishing system are respectively mounted on the upper mounting plate and the lower mounting plate, and it includes a V1 vacuum arc extinguishing system and a V2 vacuum arc extinguishing system. The moving contact system is installed between the V1 vacuum arc extinguishing system and the V2 vacuum arc extinguishing system. The transition resistor is mounted on the lower mounting plate. The number of the rollers is multiple and they are respectively rotatably installed on the inner side of the oil chamber. The vacuum arc extinguishing system can cooperate with the rollers to act as the insulating main shaft rotates, so that the vacuum arc extinguishing system realizes opening and closing actions.

[0008] Further, the moving contact system includes a neutral point leading-out moving contact, a K1 current-carrying conversion contact and a K2 transition conversion contact. The neutral point leading-out moving contact is mounted on the upper mounting plate. The K1 current-carrying conversion contact and the K2 transition conversion contact are both fixed on the lower mounting plate, and the K2 transition conversion contact is located between the V2 vacuum arc extinguishing system and the K1 current-carrying conversion contact. The K1 current-carrying conversion contact, the V1 vacuum arc extinguishing system and the neutral point leading-out moving contact are sequentially connected in series. The K2 transition conversion contact, the transition resistor, the V2 vacuum arc extinguishing system and the neutral point leading-out moving contact are sequentially connected in series.

[0009] Further, at least one static contact system corresponding to the switching mechanism one by one is provided on the oil chamber. Each static contact system includes a leading-out static contact mechanism and an input static contact mechanism. The leading-out static contact mechanism includes a conductive ring fixed on the inner wall of the oil chamber and a leading-out static contact fixed on the outer wall of the oil chamber and electrically connected to the conductive ring. The conductive ring always keeps in contact with the neutral point leading-out moving contact on the corresponding switching mechanism. The input static contact mechanism includes a plurality of input static contact groups dispersedly arranged in a ring shape on the oil chamber. Each input static contact group includes a conductive sheet fixed on the inner wall of the oil chamber and an input static contact fixed on the outer wall of the oil chamber and electrically connected to the conductive sheet. The conductive sheets are respectively in contact with the K1 current-carrying conversion contact and the K2 transition conversion contact, and both the K1 current-carrying conversion contact and the K2 transition conversion contact can move to another position to contact with another conductive sheet as the insulating main shaft rotates.

[0010] Further, the neutral point outgoing moving contact, the K1 current-carrying conversion contact and the K2 transition conversion contact are configured in a consistent manner and are all composed of a support member, a clamping spring and at least one moving contact group. The support member is respectively fixed on the corresponding upper mounting plate and the lower mounting plate. Mounting grooves are respectively arranged on the upper and lower sides of the support member. A vertical through hole is arranged in the support member near the insulating main shaft. Each moving contact group includes two moving contacts respectively located in the upper and lower mounting grooves of the support member. The middle of each moving contact is rotationally mounted in the mounting groove through a positioning pin 1. One end of the moving contact points to the oil chamber, and the other end points to the insulating main shaft and is located above the vertical through hole. The clamping spring is arranged in the vertical through hole, and its two ends respectively extend out of the vertical through hole and are in contact with the two moving contacts respectively, so that the two ends of the two moving contact groups away from the insulating main shaft are close to each other.

[0011] Further, the V1 vacuum arc extinguishing system and the V2 vacuum arc extinguishing system are configured in a consistent manner and are both composed of a vacuum interrupter, a guiding member, a pull rod, a limiting plate, a spring, a supporting member and a lever. The lower end of the vacuum interrupter is mounted on the lower mounting plate. The guiding member is fixed on the top of the upper mounting plate and is located directly above the vacuum interrupter. The lower end of the pull rod is connected to the upper end of the vacuum interrupter and can drive the vacuum interrupter to perform closing and opening actions. The upper end of the pull rod movably passes through a preset mounting hole on the upper mounting plate and is slidably sleeved in a preset guiding hole of the guiding member. The limiting plate is fixed on the pull rod and is located between the vacuum interrupter and the guiding member. The spring is sleeved on the pull rod and is located in the mounting hole of the upper mounting plate. Its upper end is in contact with the bottom of the guiding member, and its lower end is in contact with the top of the limiting plate. The supporting member is fixed on the bottom of the upper mounting plate and is located between the pull rod and the roller. The lever is rotationally mounted on the supporting member. One end of the lever is sleeved on the pull rod and is in contact with the bottom of the limiting plate, and the other end is located below the roller and cooperates with the roller.

[0012] Further, a cam is fixed at one end of the lever that cooperates with the roller. When the cam moves to contact the roller, it is pressed down by the roller to drive the lever to rotate around the shaft rod 2, so that the other end of the lever pries up the limiting plate and the pull rod, compresses the spring and breaks the vacuum interrupter.

[0013] The beneficial effects of the present invention are as follows: The structure of the present invention is compact, with a small volume, low height, low cost, convenient maintenance, greatly reducing the installation process, saving the assembly time and improving the assembly efficiency. The layered switching mechanism design is adopted, and the three switching mechanisms are arranged longitudinally along the insulating main shaft, eliminating the traditional brackets and related supporting mechanisms. At the same time, the structure and driving mode of the arc extinguishing system are optimized, reducing the material cost and making the execution efficiency higher. The integrated layout of the vacuum arc extinguishing system and the contact system reduces the traditional mechanical transmission components and effectively reduces the overall height of the equipment. Through the above settings, on the premise of ensuring the electrical performance, significant reduction in volume, height and cost is achieved, which is particularly suitable for installation scenarios with limited space such as urban power grid transformation and underground substations. Description of the Drawings

[0014] The solution of the present invention will be further described in detail below with reference to the drawings.

[0015] Figure 1 It is a schematic structural diagram of an existing oil-immersed composite vacuum on-load tap-changer.

[0016] Figure 2 It is a schematic structural diagram of a switching core in an existing oil-immersed composite vacuum on-load tap-changer.

[0017] Figure 3 It is a schematic structural diagram of the oil-immersed composite vacuum on-load tap-changer according to the present invention.

[0018] Figure 4 It is a schematic structural diagram of a switching core in the oil-immersed composite vacuum on-load tap-changer according to the present invention.

[0019] Figure 5 It is Figure 3 a cross-sectional view of the K1 current-carrying conversion contact and the neutral point lead-out moving contact in the switching mechanism at the bottom of the switching core in

[0020] Figure 6 It is Figure 3 a cross-sectional view of the V1 vacuum arc-extinguishing system in the switching mechanism at the bottom of the switching core in

[0021] Figure 7 It is Figure 3 a schematic diagram of the state when the lower end of the switching core is assembled into the oil chamber in

[0022] As shown in the figure: 1 - oil chamber, 2 - head cover gear box, 3 - energy storage system, 4 - switching core, 5 - oil extraction pipe, 6 - bearing seat, 7 - insulating main shaft, 8 - upper mounting plate, 9 - moving contact for neutral point lead-out, 10 - connecting wire 1, 11 - transition resistor, 12 - V2 vacuum arc extinguishing system, 13 - connecting wire 2, 14 - lower mounting plate, 15 - counterweight, 16 - K2 transition and conversion contact, 17 - K1 current-carrying conversion contact, 18 - connecting wire 3, 19 - V1 vacuum arc extinguishing system, 20 - connecting wire 4, 21 - fastening bolt, 22 - metal ring, 23 - compression bolt, 24 - clamping spring, 25 - protective shell, 26 - moving contact, 27 - positioning pin 1, 28 - conductive ring, 29 - bolt, 30 - nut, 31 - static contact for lead-out, 32 - positioning pin 2, 33 - support member, 34 - input static contact, 35 - mounting nut, 36 - support ring, 37 - bearing, 38 - mounting bolt, 39 - vacuum bulb, 40 - fastening nut, 41 - pull rod, 42 - spring, 43 - guiding member, 44 - fastening screw, 45 - supporting member, 46 - roller, 47 - shaft rod 1, 48 - lever, 49 - shaft rod 2, 50 - cylinder, 51 - limit plate, 52 - cam, 53 - conductive sheet. Detailed implementation manners

[0023] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The described embodiments are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0024] It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the limiting conditions under which the present invention can be implemented. Therefore, they do not have technical essential significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and the like cited in this specification are only for the convenience of narration and understanding, rather than used to limit the scope under which the present invention can be implemented. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope within which the present invention can be implemented.

[0025] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "connected" and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Embodiment 1

[0026] As Figures 3 to 7 shown, this embodiment provides an oil-immersed composite vacuum on-load tap-changer, which includes an oil chamber 1 and a switching core 4.

[0027] The oil chamber 1 adopts the cylindrical structure used in a conventional oil-immersed composite vacuum on-load tap-changer, providing a sealed container for installing the switching core 4 therein, and at the same time providing an installation position for facilitating the installation of the switch on the transformer body. A cylinder 50 for installing the switching core 4 is provided at the bottom of the oil chamber 1. Similar to a conventional oil-immersed composite vacuum on-load tap-changer, a head cover gear box 2 for transmission and an energy storage system 3 are also installed in the oil chamber 1. Both the head cover gear box 2 and the energy storage system 3 are of the conventional structures of a conventional oil-immersed composite vacuum on-load tap-changer. The head cover gear box 2 (substantially a gear box) is responsible for transmitting the external torque to the energy storage system 3 for energy storage. The energy storage system 3 provides power for the switching of the entire switching core 4 by releasing energy. The energy storage system 3 is connected to the oil chamber 1 and fixed on the top of the oil chamber 1.

[0028] Three static contact systems corresponding to the switching mechanism are provided on the oil chamber 1 from top to bottom; each static contact system includes a lead-out static contact mechanism and an input static contact mechanism.

[0029] The lead-out static contact mechanism includes a conductive ring 28 and a lead-out static contact 31; the conductive ring 28 is fixed on the inner wall of the oil chamber 1, the lead-out static contact 31 is fixed on the outer wall of the oil chamber 1 and is electrically connected to the conductive ring 28. The conductive ring 28 and the lead-out static contact 31 are firmly connected and electrically connected through a bolt 29 and a nut 30; the conductive ring 28 is always in contact with the neutral point lead-out moving contact 9 on the corresponding switching mechanism.

[0030] The input static contact mechanism includes multiple input static contact groups that are dispersedly arranged in a ring shape on the oil chamber 1. Each input static contact group includes a conductive sheet 53 fixed on the inner wall of the oil chamber 1 and an input static contact 34 fixed on the outer wall of the oil chamber 1 and electrically connected to the conductive sheet 53. The conductive sheets 53 are respectively in contact with the K1 current-carrying conversion contact 17 and the K2 transition conversion contact 16. Both the K1 current-carrying conversion contact 17 and the K2 transition conversion contact 16 can move to another position to contact another conductive sheet 53 as the insulating main shaft 7 rotates. The static input contact 34 is fixed on the oil chamber 1 through a mounting nut 35. The input contact 34 is connected to the tap of the transformer coil and is responsible for the input of current.

[0031] The switching core 4 is rotatably sleeved in the oil chamber 1 and is connected to the energy storage system 3. The switching core includes an insulating main shaft 7 rotatably arranged in the oil chamber 1 and three switching mechanisms fixedly arranged on the insulating main shaft in sequence from top to bottom. The three switching mechanisms respectively correspond to the A, B, and C phases one by one.

[0032] The insulating main shaft 7 is the supporting component of the entire switching core 4 and is also responsible for the transmission of the torque of the entire switching core 4. The insulating main shaft 7 is coaxially sleeved outside the oil extraction pipe 5. A bearing seat 6 sleeved outside the oil extraction pipe 5 is installed at the upper end of the insulating main shaft 7. The bearing seat 6 is in transmission connection with the energy storage system 3 to transmit the torque of the energy storage system 3 to the insulating main shaft 7. The lower end of the insulating main shaft 7 is rotatably installed outside the cylinder 50.

[0033] Each switching mechanism includes an upper mounting plate 8, a lower mounting plate 14, a vacuum arc extinguishing system, a moving contact system, a transition resistor 11, and a roller 46.

[0034] The upper mounting plate 8 and the lower mounting plate 14 are fixedly arranged on the insulating main shaft 7 in sequence from top to bottom.

[0035] The upper mounting plate 8 is made of metal and is fixed on the outer wall of the insulating main shaft 7 through fastening bolts 21 and a metal ring 22 (the metal ring 22 is sleeved inside the insulating main shaft 7. Multiple fastening bolts 21 pass through the upper mounting plate 8 and the insulating main shaft 7 in sequence and are screwed into the preset screw holes on the metal ring 22, thereby fixing the upper mounting plate 8 on the outer wall of the insulating main shaft 7).

[0036] The lower mounting plate 14 is made of insulating material and is fixed on the outer wall of the insulating main shaft 7 through other fastening bolts 21 and a support ring 36 (the support ring 36 is sleeved inside the insulating main shaft 7. Multiple fastening bolts 21 pass through the lower mounting plate 14 and the insulating main shaft 7 in sequence and are screwed into the preset screw holes on the support ring 36, thereby fixing the lower mounting plate 14 on the outer wall of the insulating main shaft 7).

[0037] The number of the rollers 46 is multiple, and they are respectively rotatably mounted on the inner side (on the conductive ring 28) of the oil chamber 1 through the first shaft rod 47. The first shaft rod 47 is vertically fixed on the inner wall of the conductive ring 28. The rollers 46 are coaxially mounted on the first shaft rod 47 and can axially rotate on the first shaft rod 47. The diameter of the rollers 46 is smaller than the distance between the upper and lower surfaces of the conductive ring 28, facilitating the smooth passage between the two moving contacts 26 of the moving contact group.

[0038] The transition resistor 11 is mounted on the lower mounting plate 14.

[0039] Both ends of the vacuum arc extinguishing system are respectively mounted on the upper mounting plate 8 and the lower mounting plate 14. The vacuum arc extinguishing system includes the V1 vacuum arc extinguishing system 19 and the V2 vacuum arc extinguishing system 12.

[0040] The V1 vacuum arc extinguishing system 12 and the V2 vacuum arc extinguishing system 19 are identical and each consists of a vacuum bulb 39, a guiding member 43, a pull rod 41, a limiting plate 51, a spring 42, a supporting member 45, and a lever 48.

[0041] The lower end of the vacuum bulb 39 is mounted on the lower mounting plate and is a conventional electrical component. Its lower part is fixed on the lower mounting plate 14 through the mounting bolt 38. The vacuum bulbs 39 are respectively connected in series in the current transition loop system and the current-carrying loop system (the vacuum bulb 39 of the V1 vacuum arc extinguishing system 19 is connected in series in the current-carrying loop system, and the vacuum bulb 39 of the V2 vacuum arc extinguishing system 12 is connected in series in the current transition loop system), playing the role of opening and closing the current and ensuring that the arc extinguishes inside the vacuum bulb when the current is interrupted.

[0042] The guiding member 43 is fixed on the top of the upper mounting plate 8 and is located directly above the vacuum bulb 39. The middle part of the guiding member 43 protrudes upward and is provided with a polygonal guiding hole on the protruding part to provide guidance for the pull rod 41 and prevent the pull rod 41 from rotating during movement.

[0043] The lower end of the pull rod 41 is connected to the upper end (moving contact) of the vacuum bulb 39 and can drive the vacuum bulb 39 to perform closing and opening actions. The upper end of the pull rod 41 movably passes through the preset mounting hole on the upper mounting plate 8 and then is slidably sleeved in the guiding hole of the guiding member 43. The upper end of the pull rod 41 cooperates with the guiding hole of the guiding member 43 and can only move up and down and cannot rotate.

[0044] The limiting plate 51 is fixed on the pull rod 41 and is located between the vacuum bulb 39 and the guiding member 43, and it is located below the upper mounting plate 8.

[0045] The spring 42 is sleeved outside the pull rod 41 and is located within the mounting hole of the upper mounting plate 8. The upper end of the spring 42 extends above the upper mounting plate 8 and contacts the bottom of the guide member 43, while the lower end of the spring 42 extends below the upper mounting plate 8 and contacts the top of the limit plate 51. The spring 42 provides a closing force to the vacuum bubble 39, ensuring reliable contact between the contacts (the moving contact and the stationary contact) inside the vacuum bubble 39.

[0046] The support member 45 is fixed to the bottom of the upper mounting plate 8 by fastening screws 44 and is located between the pull rod 41 and the roller 46.

[0047] The middle part of the lever 48 is rotatably mounted on the support member through the second shaft rod 49 (the second shaft rod 49 is perpendicular to the first shaft rod 47, used to mount the lever 48 on the support member 45 and provide a fulcrum for the rotation of the lever 48). One end of the lever 48 is sleeved on the pull rod 41 and contacts the bottom of the limit plate 51 (this end of the lever 48 is in a U-shaped groove, and the lever 48 is sleeved outside the pull rod 41 through the U-shaped groove), and the other end is located below the roller 56 and cooperates with the roller 46. A cam 52 is fixed to the end of the lever 41 that cooperates with the roller 46. The roller 46 is located on the movement track of the cam 52. The two sides of the top of the cam 52 are inclined planes. When the cam 52 rotates with the lever 48 and moves to contact the roller 46 (the inclined plane of the cam 52 contacts the roller 46 first), its top is pressed down by the roller 46 and moves downward, thereby driving the lever 48 to rotate around the second shaft rod 49, causing the other end of the lever 48 (to tilt upward) to pry the limit plate 51 and the pull rod 41 upward, compressing the spring 42 and disconnecting the vacuum bubble 39. During switching, the switching core 4 rotates, and the cam 52 contacts and cooperates with the roller 46. When the loop breaks the current, the arc extinguishes inside the vacuum bubble 39. Combining the cam 52 for opening and closing the vacuum bubble 39 with the lever 48 into one body, only one cam 52 can meet the usage requirements, reducing the number of cams 52, and lowering the processing difficulty and cycle.

[0048] The moving contact system is installed between the V1 vacuum arc extinguishing system 19 and the V2 vacuum arc extinguishing system 12, and it includes a neutral point leading-out moving contact 9, a K1 current-carrying conversion contact 17, and a K2 transition conversion contact 16.

[0049] The neutral point leading-out moving contact 9 is installed on the upper mounting plate 8 and is responsible for leading out the current of the transformer coil.

[0050] The K1 current-carrying conversion contact 17 is fixed to the lower mounting plate 14 and is located directly below the neutral point leading-out moving contact 9. The K1 current-carrying conversion contact 17 is used to carry the load current of the entire switch.

[0051] The K2 transition and conversion contact 16 is also fixed on the lower mounting plate 14, and the K2 transition and conversion contact 16 is located between the V2 vacuum arc extinguishing system 12 and the K1 current-carrying conversion contact 17. The K2 transition and conversion contact 16 is used to preselect the transformer coil and carry the instantaneous current during switch switching.

[0052] The K1 current-carrying conversion contact 17, the V1 vacuum arc extinguishing system 19, and the neutral point lead-out moving contact 9 are connected in series in turn to form a load current loop system. Among them, the K1 current-carrying conversion contact 17 and the V1 vacuum arc extinguishing system 19 are electrically connected through the third connecting wire 18. Specifically, one end of the third connecting wire 18 is electrically connected to the lower part of the vacuum interrupter 39 in the V1 vacuum arc extinguishing system 19, and the other end is fixed to the moving contact 26 of the K1 current-carrying conversion contact 17 by the compression bolt 23. The V1 vacuum arc extinguishing system 19 and the neutral point lead-out moving contact 9 are electrically connected through the fourth connecting wire 20. Specifically, one end of the fourth connecting wire 20 is pressed against the upper part of the vacuum interrupter 39 (on the pull rod 41) by the fastening nut 40, and the other end of the fourth connecting wire 20 is fixed to the moving contact 26 of the neutral point lead-out moving contact 9 by other compression bolts 23.

[0053] The K2 transition and conversion contact 16, the transition resistor 11, the V2 vacuum arc extinguishing system 12, and the neutral point lead-out moving contact 9 are connected in series in turn to form a current transition loop system. Among them, the lower part of the vacuum interrupter 39 of the V2 vacuum arc extinguishing system 12 is electrically connected to one end of the transition resistor 11 through the second connecting wire 13. The V2 vacuum arc extinguishing system 12 and the neutral point lead-out moving contact 9 are electrically connected through the first connecting wire 10. Specifically, one end of the first connecting wire 10 is pressed against the upper part of the vacuum interrupter 39 of the V2 vacuum arc extinguishing system (on the pull rod 41) by other fastening nuts 40, and the other end of the first connecting wire 10 is fixed to the moving contact 26 of the neutral point lead-out moving contact 9 by other compression bolts 23.

[0054] The structures of the neutral point lead-out moving contact 9, the K1 current-carrying conversion contact 17, and the K2 transition and conversion contact 16 are the same and are all composed of a support member 33, a clamping spring 24, and at least one moving contact group.

[0055] The support members 33 are respectively fixed on the corresponding upper mounting plate 8 and lower mounting plate 14 (the support member 33 of the neutral point lead-out moving contact 9 is fixed on the upper mounting plate 8, and the support members 33 of the K1 current-carrying conversion contact 17 and the K2 transition and conversion contact 16 are fixed on the lower mounting plate 14). Installation grooves are respectively provided on the upper and lower sides of the support member 33, and a vertical through hole is provided in the support member 33 near the insulating main shaft 7.

[0056] Each moving contact set includes two moving contacts 26 respectively located in the upper and lower mounting grooves of the support member 33. The middle of each moving contact 26 is rotatably mounted in the mounting groove through a first positioning pin 27. The moving contact 26 is responsible for switching the electrical connection between the core 4 and the input static contact 34. One end of the moving contact 26 points to the oil chamber 1 and remains in contact with the conductive sheet 53 on the inner wall of the oil chamber 1, and the other end of the moving contact 26 points to the insulating main shaft 7 and is located above the vertical through hole. Among the K1 current-carrying conversion contact 17 and the K2 transition conversion contact 16, the two moving contacts 26 of the moving contact set are respectively located on the upper and lower sides of the conductive sheet 53 and are in contact with the upper and lower sides of the conductive sheet 53 (clamped on the upper and lower sides of the conductive sheet 53 under the action of the clamping spring 24). The moving contact sets of both can move to another position and contact another conductive sheet 53 as the insulating main shaft 7 rotates; in the neutral point lead-out moving contact 9, the two moving contacts 26 of its moving contact set are respectively located on the upper and lower sides of the conductive ring 28 and are in contact with the upper and lower sides of the conductive ring 28 (clamped on the upper and lower sides of the conductive ring 28 under the action of the clamping spring 24). At the same time, in the neutral point lead-out moving contact 9, a gap is formed by the support member 33, the conductive ring 28, and the two moving contacts 26. As the moving contact set rotates, the roller 46 is located on the movement track of this gap and can smoothly pass through it.

[0057] The clamping spring 24 is arranged in the vertical through hole, and its two ends respectively extend out of the vertical through hole and are in contact with the two moving contacts 26 respectively, so that the ends of the moving contact set far from the insulating main shaft 7 approach the conductive sheet 53 to clamp the conductive sheet 53 and provide a clamping force to ensure reliable contact.

[0058] The upper and lower two moving contacts 26 of each moving contact set share one clamping spring 24, so that the pressures of the upper and lower two moving contacts 26 are balanced, the conduction is balanced, the wear of the contacts is balanced, and the service life of the contacts is prolonged.

[0059] In addition, there are two moving contact sets for the neutral point lead-out moving contact 9 and the K1 current-carrying conversion contact 17. The two moving contact sets are arranged side by side and the support members 33 of both are connected as a whole, while there is only one moving contact set for the K2 transition conversion contact 16.

[0060] The switching steps of the core 4 in the oil-immersed composite vacuum on-load tap-changer are as follows: S1. The motor drives the head cover gear box 2 to rotate and drives the energy storage system 3 to store energy. During the switching process of the switch, the energy storage spring 3 releases the stored energy and drives the insulating main shaft 7 to rotate.

[0061] S2. During the rotation of the insulating main shaft 7, one end of the lever 48 of the V2 vacuum arc extinguishing system with the cam 52 first contacts the roller 46 on the inner wall of the conductive ring 28. As the rotation proceeds, the roller 46 moves upward along the inclined surface of the cam 52 to the top of the cam 52, so that the top of the cam 52 is pressed down by the roller 46 and moves downward, thereby driving the lever 48 to rotate around the shaft 49, so that the other end of the lever 48 (tilted upward) pries the limit plate 51 and the pull rod 41 upward, compressing the spring 42 and disconnecting the vacuum bubble 39, disconnecting the current transition circuit system (the load current circuit system remains conductive to ensure that the switching process is not interrupted). When the circuit breaks the current, the arc is extinguished in the vacuum bubble.

[0062] In the S3.V2 vacuum arc extinguishing system, the vacuum bubble 39 is disconnected, and after the arc is extinguished, the K2 transition switching contact 16 is disengaged from the conductive sheet 53 that initially contacts (contacted first) and moves toward the other conductive sheet 53.

[0063] S4. The insulating main shaft 7 continues to rotate. After the K2 transition conversion contact 16 contacts another conductive sheet 53, the end of the lever 48 with the cam 52 in the V2 vacuum arc extinguishing system is out of contact with the roller 46, and the spring 42 releases energy and stretches, pushing the limit plate 51 and the pull rod 41 downward. At the same time, the end of the lever 48 in contact with the limit plate 51 also moves downward under the push of the limit plate 51, causing the lever 48 to rotate, driving the end of the lever 48 with the cam 52 to move downward (to wait for the next roller 46 to cooperate), and the pull rod 41 moves downward to close the vacuum bubble 39. The current transition circuit system and the load current circuit system are both in the connected state. The K2 transition conversion contact 16 and the K1 current-carrying conversion contact 17 are respectively connected across two adjacent conductive sheets 53 to form a short circuit. However, due to the presence of the transition resistor 11 in the current transition circuit system, the current in the circuit remains stable.

[0064] S5. The insulating main shaft 7 rotates continuously again, so that one end of the lever 48 with the cam 52 of the V1 vacuum arc extinguishing system first contacts the roller 46 on the inner wall of the conductive ring 28. As the rotation proceeds, the roller 46 moves upward along the inclined surface of the cam 52 to the top of the cam 52, so that the top of the cam 52 is pressed down by the roller 46 and moves downward, thereby driving the lever 48 to rotate around the shaft 49, so that the other end of the lever 48 (tilted upward) pries the limit plate 51 and the pull rod 41 upward, compressing the spring 42 and disconnecting the vacuum bubble 39, so that the load current circuit system is disconnected (the current transition circuit system remains conductive to ensure that the switching process is not interrupted). When the circuit breaks the current, the arc is extinguished in the vacuum bubble.

[0065] In the S6.V1 vacuum arc extinguishing system, the vacuum bubble 39 is disconnected, and after the arc is extinguished, the K1 current-carrying switching contact 17 is disengaged from the conductive sheet 53 that initially contacts (contacted first) and moves toward the other conductive sheet 53.

[0066] S7. The insulating spindle 7 continues to rotate. After the K1 current-carrying conversion contact 17 contacts another conductive sheet 53, one end of the lever 48 with the cam 52 in the V1 vacuum arc extinguishing system disengages from the roller 46. As the spring 42 releases energy and elongates, it pushes the limit plate 51 and the pull rod 41 downward. At the same time, the end of the lever 48 in contact with the limit plate 51 also moves downward under the push of the limit plate 51, causing the lever 48 to rotate and driving the end of the lever 48 with the cam 52 to move downward (to cooperate with the next roller 46). The downward movement of the pull rod 41 closes the vacuum interrupter 39. Both the current transition loop system and the load current loop system are in the on state, and both the K2 transition conversion contact 16 and the K1 current-carrying conversion contact 17 are connected to the same conductive sheet 53, completing one switching operation. Embodiment 2

[0067] Since the parts of the switching core 4 are all assembled on one side of the insulating spindle 7, the center is offset when the switching core 4 is lifted. In order to balance the center of gravity of the switching core 4 and play a guiding role during the assembly of the switching core 4 to facilitate assembly. The following settings are added based on Embodiment 1 in this embodiment.

[0068] A counterweight block 15 with a guiding function is installed at the bottom of the insulating spindle 7 of the switching core 4. The upper end of the counterweight block 15 is sleeved inside the bottom of the insulating spindle 7 and locked in the insulating spindle 7 by multiple bolts. The lower end of the counterweight block 15 is located outside the insulating spindle 7 and a counterweight ring with an edge protruding outside the insulating spindle 7 is provided on its outer side. The insulating spindle 7 is integrally cylindrical, and the opening inside the lower end is in a flared shape, which is convenient for playing a guiding role during assembly and facilitating assembly. The counterweight block 15 is sleeved outside the cylinder 50 of the oil chamber 1. A bearing 37 is installed inside the counterweight block 15. The lower end of the inner ring of the bearing 37 is combined with the cylinder 50 of the oil chamber 1, responsible for supporting the weight of the entire switching core 4. Embodiment 3

[0069] To provide a housing for the moving contact to prevent the direct wear of the moving contact during movement. The following settings are added based on Embodiment 1 or 2 in this embodiment.

[0070] A protective shell 25 is sleeved on each part of the moving contact 26 located in the installation groove. The protective shell 25 is in direct contact with the clamping spring 24 and bears the pressure of the clamping spring 24. Embodiment 4

[0071] In order to achieve the opening distance between the two moving contacts 26 on the side facing the inner wall of the oil chamber in each moving contact group and avoid the too small opening distance between the two. The following settings are added based on Embodiment 3 in this embodiment.

[0072] A pin hole is vertically provided on the support member 33. A positioning pin two 32 located between the two moving contacts 26 is sleeved in the pin hole, and the positioning pin two 32 adjusts the opening distance of the moving contact 26. Embodiment 5

[0073] Similar to the conventional disconnection switch, an oil extraction pipe 5 is also installed in the oil chamber 1 in this embodiment. The oil extraction pipe 5 is coaxially sleeved in the insulating main shaft 7. The lower end of the oil extraction pipe 5 has a two-stage conical structure. The upper end diameter of the upper-stage cone is larger than its lower end diameter, and the upper end diameter of the lower-stage cone is larger than its lower end diameter. The diameter of the lower end of the upper-stage cone is equal to the upper end diameter of the lower-stage cone. There is a cylindrical transition section between the upper-stage cone and the lower-stage cone. The upper side of the upper-stage cone also has a cylindrical structure that fits with the inner wall of the cylinder 50 and the inner ring of the bearing 37, forming a multi-stage positioning structure. The lower end of the oil extraction pipe 5 rotates through the inner ring of the bearing 37 and is assembled inside the cylinder 50. The oil extraction pipe 5 has a multi-stage positioning function.

[0074] When the switching core 4 is installed, the center of the switching core 4 does not coincide with the center of the oil chamber 1 (as shown in Figure 7 ). It is necessary to first perform primary positioning with the oil extraction pipe 5. Insert the lower end of the oil extraction pipe 5 into the cylinder 50, then close the static and dynamic contacts of phase A of the switching core 4, and finally install the oil extraction pipe 5 in place to simultaneously close the static and dynamic contacts of phases A, B, and C. During positioning, the lower-stage cone at the lower end of the oil extraction pipe 5 first extends into the cylinder 50. Under the guidance of its inclined surface, the cylindrical transition section is sleeved into the cylinder 50. Then, the inclined surface of the lower-stage cone further guides it, so that the upper cylindrical structure is sleeved and assembled into the cylinder 50, realizing the primary positioning of the switching core 4 and the oil chamber 1.

[0075] Other details not elaborated in this invention are all conventional technologies well known to those skilled in the art.

[0076] It should be noted that the term "comprising", "including" or any other variant is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not explicitly listed, or also includes elements inherent to such a process, method, article or device.

[0077] The protection scope of the present invention is not limited to the technical solutions disclosed in the specific embodiments. Any modifications, equivalent replacements, improvements, etc. made to the above embodiments based on the technical essence of the present invention all fall within the protection scope of the present invention.

Claims

1. An oil-immersed composite vacuum on-load tap-changer, comprising an oil chamber and a switching core rotatably sleeved in the oil chamber, characterized in that: The switching core includes an insulating main shaft rotatably arranged in the oil chamber, and at least one switching mechanism fixed on the insulating main shaft; Each switching mechanism includes an upper mounting plate, a lower mounting plate, a vacuum arc-extinguishing system, a moving contact system, a transition resistor and rollers; The upper mounting plate and the lower mounting plate are sequentially fixed on the insulating main shaft from top to bottom; Both ends of the vacuum arc-extinguishing system are respectively mounted on the upper mounting plate and the lower mounting plate, and it includes a V1 vacuum arc-extinguishing system and a V2 vacuum arc-extinguishing system; The moving contact system is installed between the V1 vacuum arc-extinguishing system and the V2 vacuum arc-extinguishing system; The transition resistor is installed on the lower mounting plate; The number of the rollers is multiple and they are respectively rotatably installed on the inner side of the oil chamber. The vacuum arc-extinguishing system can cooperate with the rollers to act as the insulating main shaft rotates, so that the vacuum arc-extinguishing system realizes opening and closing actions.

2. The oil-immersed composite type on-load tap-changer according to claim 1, wherein: The moving contact system includes a neutral point leading-out moving contact, a K1 current-carrying conversion contact and a K2 transition conversion contact; The neutral point leading-out moving contact is installed on the upper mounting plate; both the K1 current-carrying conversion contact and the K2 transition conversion contact are fixed on the lower mounting plate, and the K2 transition conversion contact is located between the V2 vacuum arc-extinguishing system and the K1 current-carrying conversion contact; The K1 current-carrying conversion contact, the V1 vacuum arc-extinguishing system and the neutral point leading-out moving contact are sequentially connected in series; the K2 transition conversion contact, the transition resistor, the V2 vacuum arc-extinguishing system and the neutral point leading-out moving contact are sequentially connected in series.

3. The oil-immersed composite vacuum on-load tap-changer according to claim 2, characterized in that: At least one static contact system corresponding to the switching mechanism one by one is provided on the oil chamber; Each static contact system includes a leading-out static contact mechanism and an input static contact mechanism; The leading-out static contact mechanism includes a conductive ring fixed on the inner wall of the oil chamber and a leading-out static contact fixed on the outer wall of the oil chamber and electrically connected to the conductive ring; the conductive ring always keeps in contact with the neutral point leading-out moving contact on the corresponding switching mechanism; The input static contact mechanism includes a plurality of input static contact groups dispersedly arranged in a ring shape on the oil chamber. Each input static contact group includes a conductive sheet fixed on the inner wall of the oil chamber and an input static contact fixed on the outer wall of the oil chamber and electrically connected to the conductive sheet; the conductive sheets are respectively in contact with the K1 current-carrying conversion contact and the K2 transition conversion contact, and both the K1 current-carrying conversion contact and the K2 transition conversion contact can move to another position to contact with another conductive sheet as the insulating main shaft rotates.

4. The oil-immersed composite type on-load tap-changer according to claim 2, wherein: The neutral point leading moving contact, the K1 current-carrying conversion contact and the K2 transition conversion contact are configured in the same way and are all composed of a support member, a clamping spring and at least one moving contact group. The support member is respectively fixed on the corresponding upper mounting plate and lower mounting plate. Mounting grooves are respectively arranged on the upper and lower sides of the support member. A vertical through hole is arranged in the support member near the insulating main shaft. Each moving contact group includes two moving contacts respectively located in the upper and lower mounting grooves of the support member. The middle of each moving contact is rotationally mounted in the mounting groove through a first positioning pin. One end of the moving contact points to the oil chamber, and the other end points to the insulating main shaft and is located above the vertical through hole. The clamping spring is arranged in the vertical through hole, and its two ends respectively extend out of the vertical through hole and are in contact with the two moving contacts respectively, so that the ends of the two moving contact groups away from the insulating main shaft are close to each other.

5. The oil-immersed composite type on-load tap-changer according to claim 4, wherein: A protective shell is sleeved on the part of each moving contact located in the mounting groove, and the protective shell is directly in contact with the clamping spring.

6. The oil-immersed composite vacuum on-load tap-changer according to claim 4, wherein: The moving contact group of the K2 transition conversion contact is one, while the moving contact groups of the neutral point leading moving contact and the K1 current-carrying conversion contact are both two.

7. The oil-immersed composite type on-load tap-changer according to claim 1, characterized in that: A counterweight is installed at the bottom of the insulating main shaft.

8. The oil-immersed composite type on-load tap-changer according to claim 1, characterized in that: The upper mounting plate is made of metal and is fixed on the outer wall of the insulating main shaft through fastening bolts and a metal ring sleeved in the insulating main shaft. The lower mounting plate is made of insulating material and is fixed on the outer wall of the insulating main shaft through fastening bolts and a support ring sleeved in the insulating main shaft.

9. The oil-immersed composite type on-load tap-changer according to claim 1, characterized in that: The V1 vacuum arc extinguishing system and the V2 vacuum arc extinguishing system are configured in the same way and are both composed of a vacuum interrupter, a guide member, a pull rod, a limit plate, a spring, a support member and a lever. The lower end of the vacuum interrupter is installed on the lower mounting plate. The guide member is fixed on the top of the upper mounting plate and is located directly above the vacuum interrupter. The lower end of the pull rod is connected to the upper end of the vacuum interrupter and can drive the vacuum interrupter to perform closing and opening actions. The upper end of the pull rod movably passes through a preset mounting hole on the upper mounting plate and then is slidably sleeved in a preset guide hole of the guide member. The limit plate is fixed on the pull rod and is located between the vacuum interrupter and the guide member. The spring is sleeved on the pull rod and is located in the mounting hole of the upper mounting plate. Its upper end is in contact with the bottom of the guide member, and its lower end is in contact with the top of the limit plate. The support member is fixed on the bottom of the upper mounting plate and is located between the pull rod and the roller. The lever is rotationally mounted on the support member. One end of the lever is sleeved on the pull rod and is in contact with the bottom of the limit plate, and the other end is located below the roller and cooperates with the roller.

10. The oil-immersed composite type on-load tap-changer according to claim 9, characterized in that: A cam is fixed at the end of the lever that cooperates with the roller. When the cam moves to contact the roller, it is pressed down by the roller to drive the lever to rotate around the second shaft rod, so that the other end of the lever pries up the limit plate and the pull rod, compresses the spring and breaks the vacuum interrupter.

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