Large-current tap selector and polarity change-over switch for converter transformer

Abstract

The invention discloses a large-current tap selector and a polarity change-over switch for a converter transformer, which relate to the field of on-load tap switches and comprise a tap selector and a polarity change-over switch, the tapping selector comprises a first tapping driving shaft, a second tapping driving shaft which is coaxially inserted into the first tapping driving shaft, a plurality of insulating strips which are distributed in a circular array by taking the first tapping driving shaft as a center, and a contact mechanism which is arranged between the insulating strips and the tapping driving shaft; the contact mechanism comprises a moving contact and a static contact. An even number of moving contacts are arranged along the circumferential direction, two moving contacts form a group, the two moving contacts in the group are respectively fixed on the side walls of the first tapping driving shaft and the second tapping driving shaft, the side wall of the first tapping driving shaft is provided with an avoiding groove along the circumferential direction, and the moving contacts penetrate through the avoiding groove and are fixed with the second tapping driving shaft; the static contacts are circularly distributed around the first tapping driving shaft, and the static contacts are arranged in two layers corresponding to the two moving contacts.

Description

Technical Field

[0001] The present application relates to the field of on-load tap changers, and in particular to a high-current tap selector and a polarity changeover switch for a commutation transformer. Background Art

[0002] High-current tap selectors for converter transformers are critical devices used to regulate transformer voltage in power systems. Their performance directly impacts grid stability and operational efficiency. With the continuous expansion of power systems and increasing demands for power quality, the design and manufacturing of tap selectors has rapidly advanced. Significant progress has been made in improving current-carrying capacity, optimizing structural design, and enhancing insulation performance, providing a crucial guarantee for reliable power system operation.

[0003] In existing technology, tap selectors are typically designed using a variety of methods to meet the demands of high-current transmission. For example, the transmission mechanism is optimized to achieve precise progressive motion. Common transmission mechanisms include gear drives and cam drives. The contact system's structure is improved to reduce contact resistance and temperature rise, such as by using multi-point contacts or increasing the conductivity of the contact material. The insulation structure is enhanced to improve the device's voltage resistance, such as by using new insulation materials or improving the geometry of the insulation components. Furthermore, the overall structure is adjusted based on specific application scenarios to accommodate varying installation conditions and usage requirements.

[0004] However, existing tap selectors still have shortcomings when handling higher current levels and more complex operating conditions, particularly in terms of standardization and internal insulation performance. Current technical solutions often struggle to balance compactness with high reliability. Furthermore, problems such as poor contact or insulation failure can occur during long-term operation, limiting their effectiveness in high-voltage and high-current environments. Therefore, further optimizing tap selector design has become a pressing technical challenge. Summary of the Invention

[0005] The present application provides a high-current tap selector and a polarity changeover switch for a commutation transformer.

[0006] The present application provides a high-current tap selector for a commutation transformer, which adopts the following technical solution: A high-current tap selector and polarity changeover switch for a commutation transformer, comprising a tap selector and a polarity changeover switch, the tap selector comprising a first tap drive shaft, a second tap drive shaft coaxially inserted in the first tap drive shaft, a plurality of insulating strips distributed in a circular array with the first tap drive shaft as the center, and a contact mechanism installed between the insulating strips and the tap drive shaft; the contact mechanism comprising a moving contact and a static contact; an even number of moving contacts are arranged along the circumference, and the moving contacts are arranged in a group of two, and a group of two moving contacts are respectively fixed on the side walls of the first tap drive shaft and the second tap drive shaft, an avoidance groove is opened on the side wall of the first tap drive shaft along the circumference, and the moving contact passes through the avoidance groove and is fixed to the second tap drive shaft; a plurality of static contacts are provided and are respectively installed on each insulating strip, the static contacts are distributed in a circular pattern around the first tap drive shaft, and the static contacts are provided in two layers corresponding to the two moving contacts.

[0007] By adopting the above technical solution, the tap selector adopts an up-and-down arrangement of single- and double-speed contacts. By providing a circumferential avoidance groove on the side wall of the first tap drive shaft, the upper and lower moving contacts can rotate independently in steps. After one moving contact switches to a new gear joint with the corresponding tap drive shaft, the other moving contact is controlled to rotate and switch to the new gear joint, thereby achieving stable gear shifting. The up-and-down arrangement of the single- and double-speed contacts and the coaxial sleeve arrangement of the first and second tap drive shafts optimize the contact layout in the tap selector, and the distribution of contacts and metal structural parts is more even, thereby avoiding the concentrated distribution of components inside the tap selector and helping to improve the internal insulation of the tap selector.

[0008] Optionally, the moving contact includes a contact bracket, an upper contact bridge, a lower contact bridge and an elastic pressing piece; the contact bracket is fixed on the driving shaft corresponding to the moving contact; the upper contact bridge and the lower contact bridge are respectively located on both sides of the static contact; a waist-shaped mounting hole is vertically penetrated through the middle parts of the upper contact bridge and the lower contact bridge, and two fixing pins are provided on the contact bracket, respectively passing through the waist-shaped mounting holes to fix the upper contact bridge and the lower contact bridge, and the upper contact bridge and the lower contact bridge are arranged in multiple rows side by side in the transverse direction; the elastic pressing pieces are respectively arranged on the side of the upper contact bridge and the lower contact bridge away from each other, and the elastic pressing piece is abutted between the contact bracket and the contact bridge; The contact mechanism also includes a conductive ring, and the ends of the upper and lower contact bridges away from the static contact are clamped on the conductive ring and slideably cooperate with the conductive ring. The conductive ring is coaxially arranged with the transmission shaft corresponding to the moving contact; a partition plate is provided between adjacent contact bridges to separate them.

[0009] By adopting the above technical solution, the movable contact of the contact mechanism is improved to a clip-type contact structure. The upper and lower contact bridges achieve a compound movement of up and down displacement and hinge rotation through the cooperation of their own waist-shaped mounting holes and fixed pins. Combined with the pressure applied by the elastic clamping member, the ends of the upper and lower contact bridges are reliably clamped on the conductive ring and the gear contact. The sliding contact of the contacts is relatively reliable. Even when the movable contact slides repeatedly relative to the conductive ring, it can also ensure close contact between the movable contact and the conductive ring. The five contact bridges are clamped and energized simultaneously, and the contact bridges are separated by a partition plate to form a certain gap. Each contact bridge is independently energized. This arrangement can reduce the temperature rise of the movable contact and enhance its short-circuit resistance.

[0010] Optionally, four elastic pressing members are provided corresponding to one upper contact bridge or one lower contact bridge, and the four elastic pressing members are symmetrically arranged on both sides of the fixing pin.

[0011] By adopting the above technical solution, the pressing force on both sides of the contact bridge is balanced, which helps to ensure that the upper and lower contact bridges can reliably clamp the gear contacts and the conductive ring; and the clamping of the upper and lower contact bridges is not easy to loosen.

[0012] Optionally, the elastic pressing member is a spring; and a through hole for pressure relief is provided on the side wall of the contact bracket corresponding to the elastic pressing member.

[0013] By adopting the above technical solution and setting up a through-hole for pressure relief, the smooth movement of the contact bridge is facilitated, the smooth progress of the gear shifting action is ensured, and the structural damage caused by the pressure change in the contact can be reduced to a certain extent, thereby ensuring safe use.

[0014] Optionally, the static contact includes a gear contact and an external contact; the gear contact includes a contact body and a shielding cover, the contact body is fixed on the insulating strip, the shielding cover is fixed on one end of the contact body close to the moving contact, the shielding cover has a C-shaped cross-section and covers the ends of the upper contact bridge and the lower contact bridge that are in contact with the static contact; the gear contacts are arranged in plurality around the corresponding moving contacts, and the gear contacts have the same axial position as the corresponding moving contacts; one end of the external contact is fixed on the conductive ring, and the other end of the external contact passes through the insulating strip and out.

[0015] By adopting the above technical solution, the structure and distribution of the static contacts are optimized, and a shielding cover is provided on the contact body of the gear contact. The shielding cover can provide a certain degree of protection for the contact body, thereby ensuring the smooth shifting of the tap changer to a certain extent. The shielding cover can also block the arc and reduce the impact of the arc.

[0016] Optionally, a fixing sleeve is fixed on the first tap drive shaft, and a mounting groove for slidingly cooperating with the conductive ring is formed on a side of the fixing sleeve close to the first tap drive shaft.

[0017] By adopting the above technical solution, a fixing sleeve is provided to fix the axial position of the conductive ring. The conductive ring is initially fixed by the external contact and the insulating strip. However, the moving contact in the tap selector switches relatively frequently, and the mechanical fixation strength simply by the external contact is insufficient. The fixing sleeve can reliably fix the axial position of the conductive ring without affecting the relative rotation of the first tap drive shaft and the conductive ring, thereby effectively sharing the force on the external contact.

[0018] Optionally, the polarity conversion switch includes the above-mentioned insulating strip, the polarity switching drive shaft and the above-mentioned contact mechanism, and the contact mechanism also includes a gear contact, an external contact, a moving contact and a conductive ring; the conductive ring is coaxially arranged with the polarity switching drive shaft, one end of the moving contact is fixed to the polarity switching drive shaft and the power terminal at the corresponding end is slidably mounted on the conductive ring; two gear contacts are provided for each moving contact, and the two gear contacts are respectively mounted on two insulating strips; one external contact is provided for each conductive ring; One movable contact of the polarity changeover switch corresponds to a group of movable contacts in the tap selector; the height of the movable contact of the polarity changeover switch is the same as the axial position of the movable contact fixed on the second tap drive shaft in the tap selector, and the conductive ring of the polarity changeover switch is fixedly electrically connected to the gear contact at the corresponding axial position on the tap selector and close to the conductive ring.

[0019] By adopting the above technical solution, the polarity changeover switch cooperates with the tap selector to increase the voltage regulation range of the tap selector.

[0020] Optionally, the polarity conversion switch also includes a position sensor and a trigger rod, the trigger rod is fixed on the moving contact, two position sensors are provided corresponding to the two gear contacts, and the two position sensors are respectively fixed on the insulating strips where the two gear contacts are located; after the moving contact overlaps with the gear contact, the trigger rod will toggle and trigger the position sensor.

[0021] By adopting the above technical solution, a sensor is set to monitor the switching position of the transfer switch, thereby ensuring the normal operation of the on-load tap changer as a whole and timely detecting any faults.

[0022] Optionally, it also includes an upper base, a lower base, a tap contact frame and a polarity contact frame, wherein the tap contact frame is an annular frame corresponding to the annular distribution profile of the insulating strip in the tap selector, and the polarity contact frame is an arc-shaped frame corresponding to the arc-shaped distribution profile of the insulating strip in the polarity conversion switch. The tap contact frame and the polarity contact frame are provided in two groups, and the two groups of the tap contact frames and the polarity contacts are respectively fixed on the upper base and the lower base, and the two ends of the insulating strip are respectively fixed on the corresponding tap contact frame or the polarity contact frame; the first tap drive shaft, the second tap drive shaft and the two ends of the polarity switching drive shaft are respectively rotatably mounted on the upper base and the lower base.

[0023] By adopting the above technical solution, the structure of the tap selector and polarity change-over switch is optimized, the level of product standardization is improved, the cage diameter is increased according to design requirements, and the internal insulation of the tap selector is improved. At the same time, the upper and lower base structures remain unchanged, and the dimensions of the tap contact frame and the polarity contact frame can be adjusted. This contributes to the efficient design and production of on-load tap changers.

[0024] Optionally, it also includes a transmission mechanism for linkage control of the tap selector and the polarity change-over switch, and the transmission mechanism is mounted on the upper base; the transmission mechanism includes an upper shift lever, a lower shift lever, an upper groove wheel disc, a lower groove wheel disc and a crank connecting rod; the upper shift lever and the lower shift lever are coaxially mounted on the upper base, and the upper shift lever and the lower shift lever are 180 degrees apart; the upper groove wheel disc and the lower groove wheel disc are coaxially mounted on the upper base, and the upper groove wheel disc and the lower groove wheel disc rotate independently of each other, and the upper groove wheel disc and the lower groove wheel disc are respectively provided with an upper shift lever and a lower shift lever There are multiple shift grooves along the circumference of the groove wheel disc, and the shift grooves on the upper groove wheel disc and the lower groove wheel disc are mirror-set; the upper groove wheel disc is coaxially fixed with the second tap drive shaft, and the lower groove wheel disc is coaxially fixed with the first tap drive shaft; a linkage shift rod is provided on the side of the lower groove wheel disc away from the upper groove wheel disc, and a linkage groove wheel is rotatably mounted on the upper base, and a shift groove adapted to the linkage shift rod is provided on the linkage groove wheel, and the linkage groove wheel is hingedly connected to one end of a crank connecting rod, and the end of the crank connecting rod away from the linkage groove wheel is fixed to the polarity switching drive shaft.

[0025] By adopting the above technical solution, the upper and lower levers are 180 degrees apart, which can drive the upper and lower sheaves to rotate a certain angle in steps, thereby distributing the rotation of the first and second tap drive shafts, achieving step-by-step movement of the two moving contacts in a group. The linkage lever, linkage sheave, and crank-connecting rod mechanism are then used to link the operation between the tap selector and the polarity changeover switch. When the lower sheave rotates one circle, the linkage lever on the lower sheave moves the linkage sheave, which in turn drives the crank-connecting rod, which in turn drives the polarity changeover drive shaft to rotate, completing the polarity changeover action.

[0026] In summary, this application includes at least one of the following beneficial technical effects: By adopting an up-and-down arrangement of single- and double-speed contacts in the tap selector and circumferentially provided avoidance grooves on the sidewalls of the first tap drive shaft, the upper and lower moving contacts can rotate independently in steps. After one moving contact switches to a new gear position with the corresponding tap drive shaft, the other moving contact is controlled to rotate and switch to the new gear position, achieving stable shifting. The up-and-down arrangement of the single- and double-speed contacts and the coaxial sleeve arrangement of the first and second tap drive shafts optimize the contact layout within the tap selector, making the distribution of contacts and metal structural parts more uniform, avoiding the concentrated distribution of internal components of the tap selector and helping to improve the internal insulation of the tap selector. By adopting the clip-type moving contact and the conductive ring, it has the characteristics of high reliability, low temperature rise and strong short-circuit resistance; The tap selector cooperates with the polarity change-over switch to increase the voltage regulation range and expand the application range of the switch; The tap selector and the polarity change-over switch are linked via a transmission mechanism, which simplifies the control method and uses a mechanical structure to achieve linked switching, thus reducing the probability of failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present application; Figure 2 yes Figure 1 Schematic diagram of the structure of the middle and lower base; Figure 3 yes Figure 1 Schematic diagram of the structure of the middle and upper base; Figure 4 It is a schematic diagram of the overall structure of the transmission mechanism; Figure 5 It is a schematic diagram of the cross-sectional structure of the transmission mechanism; Figure 6 yes Figure 1 Schematic diagram of the middle contact mechanism; Figure 7 yes Figure 1 Schematic diagram of the structure of area A; Figure 8 It is a schematic diagram of the structure of the moving contact and the conductive ring; Figure 9 yes Figure 8 BB cross-sectional view; Figure 10 yes Figure 8 CC cross-sectional view; Figure 11 Schematic diagram ad of the switching principle of this embodiment; Figure 12 FIG. 1 is a schematic diagram ef of the switching principle of this embodiment.

[0028] Figure 1: 1. tap selector; 11. first tap drive shaft; 111. avoidance groove; 12. second tap drive shaft; 2. polarity changeover switch; 21. polarity switching drive shaft; 31. lower base; 32. upper base; 33. insulating strip; 34. annular frame; 35. arc frame; 4. transmission mechanism; 41. mounting shaft; 42. upper shift lever; 43. lower shift lever; 44. first driven shaft; 45. upper groove wheel; 46. lower groove wheel; 47. crank connecting rod; 48. second Driven shaft; 5. Contact mechanism; 6. Static contact; 61. Gear contact; 62. Contact body; 63. Shielding cover; 64. External contact; 7. Moving contact; 71. Contact bracket; 711. Lower bracket; 712. Upper bracket; 713. Through hole; 72. Upper contact bridge; 73. Lower contact bridge; 74. Elastic pressing member; 75. Trigger rod; 76. Fixing pin; 77. Partition plate; 8. Conductive ring; 81. Connection pole; 82. Fixing sleeve; 83. Friction ring; 9. Position sensor. DETAILED DESCRIPTION

[0029] The following is combined with Figure 1-12 This application is described in further detail.

[0030] The embodiment of the present application discloses a high current tap selector and polarity changeover switch for commutation transformer, referring to Figure 1 The tap selector 1 and the polarity changer are both cage-shaped structures surrounded by a plurality of vertically arranged insulating strips 33 . The polarity changer 2 is used to expand the voltage regulation range of the tap selector 1 .

[0031] refer to Figure 1 and Figure 2 Annular ring frames 34 are installed at the upper and lower ends of the tap selector 1. The two ends of the insulating strip 33 are screwed to the edges of the ring frame 34, forming a cylindrical cage. Arc-shaped brackets 35 are installed at the upper and lower ends of the polarity selector. The two ends of the insulating strip 33 are screwed to the outer edges of the bracket 35, forming a circular cage. The tap selector 1 and the polarity converter are connected and fixed via a lower base 31 and an upper base 32. The ring frame 34 and the arc frame 35 are screwed to the upper base 32 or lower base 31 on the corresponding side. A cavity is provided at the top of the upper base 32, away from the end faces of the tap selector 1 and the polarity selector. The transmission mechanism 4 that links the tap selector 1 and the polarity selector is installed within the cavity of the upper base 32.

[0032] refer to Figure 3 and Figure 4The transmission mechanism 4 is a sheave drive mechanism. The transmission mechanism 4 includes a mounting shaft 41, an upper shift rod 42, a lower shift rod 43, a first driven shaft 44, an upper groove pulley 45, a lower groove pulley 46, a crank connecting rod 47 and a second driven shaft 48. The mounting relationship is shown in the figure. The mounting shaft 41 is fixed to the upper base 32, the upper shift rod 42 and the lower shift rod 43 are rotatably mounted on the mounting shaft 41, the first driven shaft 44 is rotatably mounted on the upper base 32, the upper groove pulley 45 is coaxially fixed with the first driven shaft 44, the lower groove pulley 46 is coaxially rotatably mounted on the first driven shaft 44, the lower groove pulley 46 and the second driven shaft 48 are linked by a crank connecting rod 47, and the second driven shaft 48 is rotatably mounted on the upper base 32. The installation shaft 41 rotates to drive the upper shift rod 42 and the lower shift rod 43 to rotate synchronously. The upper shift rod 42 and the lower shift rod 43 have different circumferential positions. The upper shift rod 42 shifts the upper groove pulley 45 to rotate, and the lower shift rod 43 shifts the lower groove pulley 46 to rotate. When the lower groove pulley 46 rotates to a certain position, it will drive the crank connecting rod 47 and then drive the second driven shaft 48 to rotate.

[0033] refer to Figure 5 The tap selector 1 further includes a first tap drive shaft 11 and a second tap drive shaft 12. The first tap drive shaft 11 is fixedly connected to the lower grooved disc 46 and rotates synchronously with the lower grooved disc 46. The second tap drive shaft 12 is fixedly connected to the end of the first driven shaft 44 and rotates synchronously with the upper grooved disc 45. The polarity changeover switch 2 further includes a polarity switching drive shaft 21, which is fixedly connected to the second driven shaft 48 and rotates synchronously.

[0034] refer to Figure 1 The tap selector 1 and the polarity change-over switch 2 are both provided with a contact mechanism 5 , which adopts a top-bottom arrangement of single- and double-speed contacts, with a total of 4 layers of contacts.

[0035] Take the contact mechanism 5 near one end of the upper base 32 as an example for explanation. Figure 6, which are two layers of single and double-stage contacts arranged up and down. In order to facilitate the display of the contact structure, the insulating strip 33 and the static contact 6 on the front side of the figure are hidden. The contact mechanism 5 includes a static contact 6, a moving contact 7 and a conductive ring 8; the conductive ring 8 is a circular conductive metal ring, which is coaxially installed with the corresponding drive shaft; one end of the moving contact 7 is fixed on the corresponding drive shaft and slidably overlapped on the conductive ring 8 to form an electrical connection, and the other end of the moving contact 7 overlaps with different static contacts 6 as the drive shaft rotates; the static contact 6 includes a gear contact 61 and an external contact 64; the gear contact 61 includes a contact body 62 and a shielding cover 63 sleeved on the contact body 62, the contact body 62 is fixed to the insulating strip 33 with screws and passes through the insulating strip 33, the shielding cover 63 is located on the side of the static contact 6 close to the moving contact 7, and the shielding cover 63 has a C-shaped cross-section so that the moving contact 7 can rotate through; the external contact 64 is a long straight plate, one end of the external contact 64 is fixed to the conductive ring 8 and electrically connected, and the other end of the external contact 64 passes through the insulating strip 33.

[0036] The polarity conversion switch 2 is provided with a conductive ring 8, a moving contact 7, two gear contacts 61 and an external contact 64; the conductive ring 8 is coaxially sleeved on the polarity switching drive shaft 21, one end of the external contact 64 is fixed to the conductive ring 8 and electrically connected, and the other end of the external contact 64 passes through an insulating strip 33 and is electrically connected, and the external contact cluster head is plugged and fixed to the insulating strip 33; the two gear contacts 61 are distributed along the arc direction, and the two gear contacts 61 are respectively fixed to the two insulating strips 33; the moving contact 7 is fixed to the polarity switching drive shaft 21, and the end of the moving contact 7 close to the polarity switching drive shaft 21 slides and overlaps on the conductive ring 8 and is electrically connected. The end of the moving contact 7 away from the polarity switching drive shaft 21 switches and overlaps (electrically connects) between the two gear contacts 61 through the rotation of the polarity switching drive shaft 21. Figure 6 and Figure 7 The polarity conversion switch 2 is also provided with a position sensor 9 for detecting the position of the moving contact 7. Two position sensors 9 are provided. The two position sensors 9 are respectively located above the gear contact 61 and are screwed to the corresponding insulating strip 33. A trigger rod 75 for triggering the position sensor 9 is screwed to the moving contact 7. Figure 7 A hinged trigger plate is provided on the position sensor 9. The trigger plate is kept in an extended state by two springs. During the overlap process of the moving contact 7 and the static contact 6, the trigger rod 75 presses the trigger plate, causing the trigger plate to be pressed down. The trigger plate then contacts the electronic components in the position sensor 9 to generate a signal, indicating that the moving contact 7 of the polarity change-over switch 2 is switched into place.

[0037] refer to Figure 6The tap selector 1 is provided with two conductive rings 8, two moving contacts 7, two layers of position contacts 61, and two external contacts 64. The two conductive rings 8 are arranged vertically, with the height of the lower conductive ring 8 corresponding to that of the conductive ring 8 in the polarity reversing switch 2. A fixing sleeve 82 is fixed to the side wall of the first tap drive shaft 11 with screws, and the conductive ring 8 is coaxially arranged with the first tap drive shaft 11 via the fixing sleeve 82. Multiple position contacts 61 are evenly arranged around the first tap drive shaft 11, and each position contact 61 is fixed to an insulating strip 33. The position contacts 61 are arranged in two corresponding layers, one above the other. The two moving contacts 7 are arranged corresponding to the two layers of position contacts 61, respectively. The upper moving contact 7 is fixed to the first tap drive shaft 11 with screws, and the lower moving contact 7 is fixed with screws. On the second tap drive shaft 12, an avoidance groove 111 is provided on the side wall of the first tap drive shaft 11, corresponding to the movement range of the lower movable contact 7. The gear contact 61, located near the side of the polarity reversing switch 2 and at the same height as the conductive ring 8 in the polarity reversing switch 2, is fixed to the conductive ring 8 in the polarity reversing switch 2 with screws to achieve electrical connection. The conductive ring 8 of the tap selector 1, located away from the polarity reversing switch 2, is electrically connected to the external contact 64, which is inserted through the insulating strip 33 on the corresponding side.

[0038] refer to Figure 8 and Figure 9 A friction ring 83 is sleeved within the conductive ring 8, separating the rotating drive shaft from the conductive ring 8 to prevent wear on the conductive ring 8. A fixed sleeve 82 is a circular ring secured to the first tap drive shaft 11 with screws. A mounting groove for sliding engagement with the conductive ring 8 is defined on the side of the fixed sleeve 82 adjacent to the conductive ring 8, allowing the conductive ring 8 and fixed sleeve 82 to rotate relative to each other about the first tap drive shaft 11. A power connection rod 81 is integrally mounted on one side of the conductive ring 8. The power connection rod 81 is located in the gap between the fixed sleeve 82 and the first tap drive shaft 11. The external contacts 64 within the tap selector 1 are secured to the power connection rod 81.

[0039] The moving contact 7 includes a contact bracket 71, an upper contact bridge 72 and a lower contact bridge 73 as power terminals, an elastic pressing member 74 that provides clamping force for the contact bridge, and a fixing pin 76. Five upper contact bridges 72 and five lower contact bridges 73 are arranged side by side and one by one opposite each other. The contacts include a lower bracket 711 and an upper bracket 712. The upper contact bridge 72 and the lower contact bridge 73 are supported between the upper bracket 712 and the lower bracket 711. Two fixing pins 76 are used to penetrate the upper bracket 712, the lower bracket 711, the upper contact bridge 72 and the lower contact bridge 73 respectively. Waist-shaped holes are opened on the upper contact bridge 72 and the lower contact bridge 73 corresponding to the fixing pins 76, and the waist-shaped holes are arranged vertically.

[0040] refer to Figure 9 and Figure 10, the elastic pressing members 74 are springs, and the elastic pressing members 74 are respectively arranged between the upper contact bridge 72 and the upper bracket 712, and between the lower contact bridge 73 and the lower bracket 711. Four groups of elastic pressing members 74 are provided along the length direction of the contact bridge, and the four groups of elastic pressing members 74 are respectively located on both sides of the fixing pin 76 and are symmetrically distributed; each group of elastic pressing members 74 is provided along the width direction of the contact bridge, corresponding to the upper contact bridge 72 and the lower contact bridge 73, and the five elastic pressing members 74 correspond to the contact bridges one by one; a partition plate 77 is provided between adjacent lower contact bridges 73 and adjacent upper contact bridges 72, and the partition plate 77 has a C-shaped cross section, which separates The plate 77 is inserted into the north side of the lower contact bridge 73 and the upper contact bridge 72, and the partition plates 77 of adjacent contact bridges abut each other, and the partition plates 77 separate the adjacent contact bridges by a certain distance; a partition plate 77 is also provided on the end of the spring compression member abutting the contact bridge, and the partition plates 77 on the spring compression member abut against the partition plates 77 on the contact bridge, and the abutting partition plates 77 form a pair in pairs, and multiple pairs of partition plates 77 are provided corresponding to the spring compression members; the side walls of the upper bracket 712 and the lower bracket 711 are provided with mounting holes for inserting the spring ends corresponding to the elastic abutting members, and the bottom of the mounting holes is provided with a pressure relief through hole 713.

[0041] The polarity conversion switch 2 is used to expand the voltage regulation range. In this embodiment, the tap selector 1 has 27 tap positions, with a maximum of 35 positions. Figure 11 and Figure 12 The current circuit when the tap changer is in the middle position is shown in Figure (a), gears 14 and 13 are connected, and the transfer switch is on both sides; when the tap changer electric mechanism moves to the 12th turn, the odd-layer moving contact 7 of the tap selector 1 leaves 13, as shown in Figure (b); at the 14th turn, the moving contact 7 of the polarity changer 2 leaves 21, as shown in Figure (c); at the 19th turn, the moving contact 7 of the polarity changer 2 is connected to 22, as shown in Figure (d); at the 21st turn, the moving contact 7 of the tap selector 1 is connected to 1, as shown in Figure (e); at the 28th turn, the transfer switch is turned on, and the odd side is connected, as shown in Figure (f).

[0042] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A high current tap selector and polarity changeover switch for a commutation transformer, comprising a tap selector (1) and a polarity changeover switch (2), characterized in that: The tap selector (1) comprises a first tap drive shaft (11), a second tap drive shaft (12) coaxially inserted in the first tap drive shaft (11), a plurality of insulating strips (33) distributed in a circular array with the first tap drive shaft (11) as the center, and a contact mechanism (5) installed between the insulating strips (33) and the tap drive shaft; the contact mechanism (5) comprises a moving contact (7) and a stationary contact (6); an even number of the moving contacts (7) are arranged along the circumference, two moving contacts (7) are arranged in a group, and a group of two moving contacts (7) is provided. The contacts (7) are respectively fixed on the side walls of the first tap drive shaft (11) and the second tap drive shaft (12); a circumferential avoidance groove (111) is provided on the side wall of the first tap drive shaft (11); the moving contact (7) passes through the circumferential avoidance groove (111) and is fixed to the second tap drive shaft (12); a plurality of static contacts (6) are provided and respectively installed on each insulating strip (33); the static contacts (6) are distributed in a circular pattern around the first tap drive shaft (11); and two layers of static contacts (6) are provided corresponding to the two moving contacts (7).

2. A high current tap selector and polarity changeover switch for a commutation transformer according to claim 1, characterized in that: The moving contact (7) comprises a contact support (71), an upper contact bridge (72), a lower contact bridge (73) and an elastic pressing member (74); the contact support (71) is fixed on a driving shaft corresponding to the moving contact (7); the upper contact bridge (72) and the lower contact bridge (73) are respectively located on both sides of the static contact (6); waist-shaped mounting holes are vertically penetrated in the middle of the upper contact bridge (72) and the lower contact bridge (73); two fixing pins (76) are provided on the contact support (71) and respectively pass through the waist-shaped mounting holes to fix the upper contact bridge (72) and the lower contact bridge (73); a plurality of the upper contact bridges (72) and the lower contact bridge (73) are arranged side by side in the transverse direction; the elastic pressing member (74) is respectively arranged on the side of the upper contact bridge (72) and the lower contact bridge (73) away from each other, and the elastic pressing member (74) is arranged in contact with the contact support (71) and the contact bridge; The contact mechanism (5) further comprises a conductive ring (8), wherein one end of the upper and lower contact bridges (73) away from the static contact (6) is clamped on the conductive ring (8) and slideably engaged with the conductive ring (8), and the conductive ring (8) is coaxially arranged with a transmission shaft corresponding to the moving contact (7); and a partition plate (77) is provided between adjacent contact bridges to separate them.

3. The high current tap selector and polarity changeover switch for commutation transformer according to claim 2, characterized in that: Four elastic pressing members (74) are provided corresponding to one upper contact bridge (72) or one lower contact bridge (73), and the four elastic pressing members (74) are symmetrically arranged on both sides of the fixing pin (76).

4. A high current tap selector and polarity changeover switch for a commutation transformer according to claim 3, characterized in that: The elastic pressing member (74) is a spring; a pressure relief through hole (713) is provided on the side wall of the contact support (71) corresponding to the elastic pressing member (74).

5. The high current tap selector and polarity change-over switch for commutation transformer according to claim 2, characterized in that: The static contact (6) includes a gear contact (61) and an external contact (64); the gear contact (61) includes a contact body (62) and a shielding cover (63); the contact body (62) is fixed on the insulating strip (33); the shielding cover (63) is fixed on one end of the contact body (62) close to the moving contact (7); the shielding cover (63) has a C-shaped cross section and covers the ends of the upper contact bridge (72) and the lower contact bridge (73) in contact with the static contact (6); a plurality of gear contacts (61) are arranged around the corresponding moving contact (7), and the axial position of the gear contacts (61) and the corresponding moving contact (7) is the same; one end of the external contact (64) is fixed on the conductive ring (8), and the other end of the external contact (64) passes through the insulating strip (33) and out.

6. A high current tap selector and polarity change-over switch for a commutation transformer according to claim 5, characterized in that: A fixing sleeve (82) is fixed on the first tap drive shaft (11), and a mounting groove for slidingly cooperating with the conductive ring (8) is provided on a side of the fixing sleeve (82) close to the first tap drive shaft (11).

7. A high-current tap selector and polarity change-over switch for a commutation transformer according to any one of claims 2 to 5, characterized in that: The polarity conversion switch (2) comprises the above-mentioned insulating strip (33), the polarity switching drive shaft (21) and the above-mentioned contact mechanism (5), and the contact mechanism (5) also comprises a gear contact (61), an external contact (64), a moving contact (7) and a conductive ring (8); the conductive ring (8) is coaxially arranged with the polarity switching drive shaft (21), one end of the moving contact (7) is fixed to the polarity switching drive shaft (21) and the power terminal at the corresponding end is slidably mounted on the conductive ring (8); two gear contacts (61) are provided for each moving contact (7), and the two gear contacts (61) are respectively mounted on two insulating strips (33); one external contact (64) is provided for each conductive ring (8); A movable contact (7) of the polarity changeover switch (2) corresponds to a group of movable contacts (7) in the tap selector (1); the height of the movable contact (7) of the polarity changeover switch (2) is the same as the axial position of the movable contact (7) fixed on the second tap drive shaft (12) in the tap selector (1); and the conductive ring (8) of the polarity changeover switch (2) is fixedly electrically connected to a gear contact (61) at a corresponding axial position on the tap selector (1) and close to the conductive ring (8).

8. The high-current tap selector and polarity change-over switch for commutation transformer according to claim 7, characterized in that: The polarity conversion switch (2) further comprises a position sensor (9) and a trigger rod (75), wherein the trigger rod (75) is fixed on the movable contact (7), two position sensors (9) are provided corresponding to the two gear contacts (61), and the two position sensors (9) are respectively fixed on the insulating strip (33) where the two gear contacts (61) are located; after the movable contact (7) is overlapped with the gear contact (61), the trigger rod (75) will toggle and trigger the position sensor (9).

9. The high-current tap selector and polarity change-over switch for commutation transformer according to claim 7, characterized in that: The utility model also comprises an upper base (32), a lower base (31), a tap contact frame and a polarity contact frame, wherein the tap contact frame is an annular frame (34) corresponding to the annular distribution profile of the insulating strip (33) in the tap selector (1), and the polarity contact frame is an arc-shaped frame (35) corresponding to the arc-shaped distribution profile of the insulating strip (33) in the polarity changeover switch (2). The tap contact frame and the polarity contact frame are provided in two groups, and the two groups of the tap contact frames and the polarity contacts are fixed on the upper base (32) and the lower base (31) respectively, and the two ends of the insulating strip (33) are fixed on the corresponding tap contact frame or the polarity contact frame respectively; and the two ends of the first tap drive shaft (11), the second tap drive shaft (12) and the polarity switching drive shaft (21) are rotatably mounted on the upper base (32) and the lower base (31) respectively.

10. A high current tap selector and polarity change-over switch for commutation transformer according to claim 9, characterized in that: The invention also includes a transmission mechanism (4) for controlling the tap selector (1) and the polarity changeover switch (2) in a linkage manner, wherein the transmission mechanism (4) is mounted on the upper base (32); the transmission mechanism (4) includes an upper shifting rod (42), a lower shifting rod (43), an upper groove wheel disc (45), a lower groove wheel disc (46) and a crank connecting rod (47); the upper shifting rod (42) and the lower shifting rod (43) are coaxially rotatably mounted on the upper base (32), and the upper shifting rod (42) and the lower shifting rod (43) form an angle of 180 degrees with each other; the upper groove wheel disc (45) and the lower groove wheel disc (46) are coaxially rotatably mounted on the upper base (32), and the upper groove wheel disc (45) and the lower groove wheel disc (46) rotate independently of each other, and the upper groove wheel disc (45) and the lower groove wheel disc (46) rotate independently of each other. A shifting groove is provided corresponding to the upper shifting rod (42) and the lower shifting rod (43), and a plurality of shifting grooves are provided along the circumference of the groove wheel disc. The shifting grooves on the upper groove wheel disc (45) and the lower groove wheel disc (46) are mirror-imaged. The upper groove wheel disc (45) is coaxially fixed with the second tapping drive shaft (12), and the lower groove wheel disc (46) is coaxially fixed with the first tapping drive shaft (11). A linkage shifting rod is provided on the side of the lower groove wheel disc (46) away from the upper groove wheel disc (45). A linkage groove wheel is rotatably mounted on the upper base (32). The linkage groove wheel is provided with a shifting groove adapted to the linkage shifting rod. The linkage groove wheel is hingedly connected to one end of a crank connecting rod (47), and the end of the crank connecting rod (47) away from the linkage groove wheel is fixed to the polarity switching drive shaft (21).

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