Mobile on-load tap changer

Abstract

A mobile on-load tap changer, comprising a driving mechanism and a switch control mechanism, characterized in that the switch control mechanism comprises a common terminal and a plurality of tap terminals, a switch unit is arranged inside the switch control mechanism, a guide mechanism is arranged on the back of the switch unit, the guide mechanism is composed of a guide rail fixed in the switch control mechanism, two sliders mounted on the guide rail and a mounting plate fixed on the sliders, the switch unit is fixed on the mounting plate, when the switch unit moves along the guide mechanism, the switch unit can control the on-off of each tap terminal and the common terminal, and the switching of gears is realized; the driving mechanism can drive the switch unit to move along the guide mechanism. The present application is a mobile tap changer, through controlling the movement of the switch unit, the switching of gears can be realized without power interruption, the switch unit does not need to rely on the timing of the cam, each switch unit can be independently disassembled and connected without wires, and has the advantages of simple structure, low cost and easy installation.

Description

Technical Field

[0001] This invention relates to an on-load tap changer for a transformer, specifically a movable on-load tap changer that can switch taps without power supply by controlling the movement of the switching unit. Background Technology

[0002] Currently, most on-load tap changers for transformers are rotary. Rotary tap changers rely on the rotation of an insulated main shaft to drive the moving contact along a circumference to switch taps. They are divided into off-load and on-load types: off-load rotary tap changers must be operated without power and cannot be opened or closed under load; rotary vacuum on-load tap changers rely on a cam mechanism to control the timing of dual vacuum arc extinguishers, and work with a transition resistor to achieve on-load voltage regulation. The vacuum arc extinguishers are responsible for extinguishing the arc generated during switching, achieving uninterrupted transfer of load current. The disadvantage of this structure is that the switching relies on cam timing, requiring high precision in machining. If jammed, timing errors can easily occur, leading to switching failure and arc reignition.

[0003] A horizontal on-load tap changer with patent number 202111294289.9, published by the Chinese Patent Office on March 29, 2024, includes a housing and a drive assembly, a vacuum arc-extinguishing assembly, an interleaved movable assembly, a low-voltage contact assembly, a high-voltage wiring assembly, and a connecting assembly fixed within the housing. The high-voltage wiring assembly includes a first high-voltage wiring group and a second high-voltage wiring group that connect to different taps on the high-voltage side of the transformer. The low-voltage wiring assembly includes a first low-voltage wiring component and a second low-voltage wiring component that connect to different taps on the low-voltage side of the transformer. The vacuum arc-extinguishing assembly includes a first vacuum tube and a second vacuum tube. The drive assembly includes a drive component and a drive rod. In this tap changer, the vacuum arc-extinguishing assembly is fixed; switching between two positions is achieved only by moving the drive component, making it unsuitable for multi-position switching. Summary of the Invention

[0004] The purpose of this invention is to address the deficiencies and shortcomings of the prior art by providing a mobile on-load tap changer that allows for uninterrupted switching of tap positions by controlling the movement of the switching unit.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The mobile on-load tap changer includes a drive mechanism and a switch control mechanism. The switch control mechanism includes a common terminal and multiple tap terminals. A switch unit is disposed inside the switch control mechanism, and a guide mechanism is disposed on the back of the switch unit. The guide mechanism consists of a guide rail fixed inside the switch control mechanism, two sliders mounted on the guide rail, and a mounting plate fixed on the sliders. The switch unit is fixed on the mounting plate. When the switch unit moves along the guide mechanism, it can control the connection / disconnection between each tap terminal and the common terminal, thereby achieving gear switching. The drive mechanism can drive the switch unit to move along the guide mechanism.

[0006] The drive mechanism includes a base, a gearbox mounted on the base, a gear transmission mechanism installed inside the gearbox, and a motor mounted above the gearbox. The gear transmission mechanism includes a drive shaft, a transmission shaft, and an output shaft. The drive shaft is connected to the drive end of the motor and has a drive gear mounted on it. The transmission shaft has a transmission gear meshing with the drive gear, and a push pin is eccentrically positioned on the end face of the transmission gear. The output shaft has a transmission disc with n U-shaped grooves evenly distributed on it. When the transmission gear rotates, the push pin can enter the U-shaped grooves and drive the transmission disc to rotate 1 / n revolutions before leaving the U-shaped grooves. The bottom end of the output shaft extends out of the base and is linked to the guide mechanism through the output gear.

[0007] The output shaft is equipped with a signal output gear, and a signal indicator shaft is also provided in the gearbox. The signal indicator shaft is equipped with a signal indicator gear, and the signal indicator gear meshes with the signal output gear.

[0008] The switch unit includes a first vacuum interrupter and a second vacuum interrupter, which are installed side-by-side laterally on a base. The stationary ends of the first and second vacuum interrupters are normally connected to a common end on the back of the base. A contact head frame is installed on the front of the base, and a first contact clamp connected to the moving end of the first vacuum interrupter and a second contact clamp connected to the moving end of the second vacuum interrupter are provided on the contact head frame. Multiple tap terminals are provided on the front side of the base. When the switch unit moves, the first and second contact clamps can communicate with the tap terminals. A lever is provided on the moving end pull rod of the first and second vacuum interrupters. The upper end of the lever is the trigger end. When the trigger end of the lever encounters resistance, it will rotate the lever, causing the first or second vacuum interrupter to open.

[0009] The lever has multiple protruding teeth on its front side. When the trigger end of the lever encounters the protruding teeth, the lever will rotate, causing the first vacuum arc extinguisher or the second vacuum arc extinguisher to trip.

[0010] A common conductive plate is provided on the back of the base. The stationary ends of the first vacuum arc extinguisher and the second vacuum arc extinguisher are fixed on the common conductive plate. A rearward flange is provided at the bottom of the common conductive plate. A common contact connected to the common terminal is fixedly installed on the flange. When the switching unit moves, the common contact is always connected to the common terminal.

[0011] The base has resistor frames installed at the front and back, and multiple transition resistors are installed in parallel between the two resistor frames. These transition resistors are connected in series with the second vacuum arc extinguisher.

[0012] The switching unit has five states when switching from the N position to the N+1 position; In the first state, the first contact clamp is connected to the N-position tap, the lever of the first vacuum interrupter is not in contact with the protruding tooth and is in the closed state, and the lever trigger end of the second vacuum interrupter abuts against the protruding tooth and is in the open state; at this time, the common terminal is connected to the N-position tap through the first vacuum interrupter. In the second state, the second contact clamp is connected to the N+1 tap, the first contact clamp is still connected to the N tap, and the levers of the first and second vacuum interrupters are not in contact with the protruding teeth and are in the closed state. At this time, one common terminal is connected to the N tap through the first vacuum interrupter, and the other is connected to the N+1 tap through the second vacuum interrupter and the transition resistor. In the third state, the first contact clamp leaves the N-position tap, the second contact clamp connects to the N+1-position tap, the lever of the first vacuum interrupter contacts the convex tooth, opening the circuit to extinguish the arc, and the lever trigger end of the second vacuum interrupter does not abut against the convex tooth, and is in the closed state; at this time, the common terminal is connected to the N+1-position tap through the second vacuum interrupter and the transition resistor. In the fourth state, both the first and second contact clamps are connected to the N+1 tap position, and the levers of the first and second vacuum interrupters are not in contact with the protruding teeth, indicating that the circuit is closed. At this time, one common terminal is connected to the N+1 tap position through the first vacuum interrupter, and the other terminal is connected to the N+1 tap position through the second vacuum interrupter and the transition resistor. In the fifth state, the first contact clamp is connected to the N+1 tap position, the lever of the first vacuum interrupter is not in contact with the protruding tooth and is in the closed state, and the lever trigger end of the second vacuum interrupter is in contact with the protruding tooth and is in the open state; at this time, the common terminal is connected to the N+1 tap position through the first vacuum interrupter.

[0013] When the switching unit switches from N+1 to N, the order of the five states is changed.

[0014] This invention relates to a movable tap changer, in which the output gear of the drive mechanism is asynchronous with the transmission shaft, only moving the switch unit during gear shifting. This design offers advantages such as precise driving distance and high driving force. Within the tap changer, the switch unit can achieve gear shifting without power interruption simply by moving the entire switch unit left and right, and automatically control the opening and closing of the two vacuum arc interrupters to prevent arcing when the contact clamps leave the tap end. This type of switch unit does not rely on cam timing; each switch unit can be independently assembled and disassembled without wire connections, offering advantages such as simple structure, low cost, and convenient installation. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention.

[0016] Figure 2 This is a schematic diagram of the internal structure of the switch control mechanism of the present invention.

[0017] Figure 3 This is an exploded view of the guide mechanism of the switch control mechanism of the present invention.

[0018] Figure 4 This is an exploded view of the drive mechanism structure of the present invention.

[0019] Figure 5 This is a schematic diagram of the internal gear transmission mechanism of the drive mechanism of the present invention.

[0020] Figure 6 This is a schematic diagram of the drive shaft and output shaft of the drive mechanism of the present invention.

[0021] Figure 7 This is a cross-sectional view of the drive shaft and output shaft of the drive mechanism of the present invention.

[0022] Figure 8 This is a front view of the switching unit of the present invention.

[0023] Figure 9 This is a cross-sectional view of the switching unit of the present invention.

[0024] Figure 10 This is a schematic diagram of the back structure of the switching unit of the present invention.

[0025] Figure 11 This is an exploded view of the switching unit, protrusion, and tap terminal of the present invention.

[0026] Figure 12 This is a schematic diagram of the planar structure of the switching unit, the protruding tooth, and the tap end of the present invention.

[0027] Figure 13 This is a schematic diagram of the first state of the switching unit of the present invention.

[0028] Figure 14This is a schematic diagram of the second state of the switching unit of the present invention.

[0029] Figure 15 This is a schematic diagram of the third state of the switching unit of the present invention.

[0030] Figure 16 This is a schematic diagram of the fourth state of the switching unit of the present invention.

[0031] Figure 17 This is a schematic diagram of the fifth state of the switching unit of the present invention. Detailed Implementation

[0032] like Figure 1 As shown, the present invention is a mobile on-load tap changer, which includes a drive mechanism 100 and a switch control mechanism 200. The switch control mechanism 200 includes a front side plate 203 and a rear side plate 202. Multiple fastening plates 204 are fastened to the top and bottom of the front side plate 203 and the rear side plate 202. The front side plate 203, the rear side plate 202, and the fastening plates 204 together form the outer shell 201 of the switch control mechanism 200. The drive mechanism 100 is mounted on top of the outer shell 201.

[0033] like Figure 2 , Figure 3 As shown, the switch control mechanism 200 has three switch units 300 inside. The three switch units 300 are fixedly mounted on the same mounting plate 402. A guide rail 400 is provided on the back of the mounting plate 402. The guide rail 400 is fixed on the rear side plate 202. Two sliders 401 are mounted on the guide rail 400. The mounting plate 402 is fixed on the sliders 401. The guide rail 400, sliders 401, and mounting plate 402 form the guiding mechanism of the switch control mechanism 200, enabling the three switch units 300 to move synchronously.

[0034] A common terminal 205 is provided on the rear side of each switch unit 300, and the common terminal 205 is also fixed on the rear side plate 202. Multiple tap terminals 206 are provided on the front side of the switch unit 300. The movement of the switch unit 300 can control the connection and disconnection between any tap terminal 206 and the common terminal 205, thereby realizing the switching of gears.

[0035] A rack 403 is provided on the front side of the mounting plate 402. The rack 403 is fixed together with the mounting plate 402 and the switch unit 300. The rack 403 can be driven by the drive mechanism 100 to drive the three switch units 300 to move synchronously.

[0036] like Figure 4As shown, the drive mechanism 100 includes a base 110, which can be directly mounted on top of the front side plate 203 and the rear side plate 202 by screws. A gearbox 111 is mounted on the base 110, and a gear transmission mechanism is installed inside the gearbox 111. A cover plate 112 is provided above the gearbox 111, and a motor 130 is mounted on the cover plate 112. An outer cover 101 is provided above the base 110, and a junction box 102 is provided on the side of the outer cover 101.

[0037] like Figure 5 As shown, the gear transmission mechanism includes a drive shaft 131, a transmission shaft 125, and an output shaft 121. The drive shaft 131 is connected to the drive end 313 of the motor 130. A drive gear 132 is mounted on the drive shaft 131. A transmission gear 124 meshes with the drive gear 132 on the transmission shaft 125. A push pin 128 is eccentrically mounted on the end face of the transmission gear 124. A transmission disk 122 is mounted on the output shaft 121. When the push pin 128 rotates eccentrically, it can drive the transmission disk 122 to rotate. The bottom end of the output shaft 121 extends out of the base 110, and an output gear 120 is mounted on the bottom end. A spline is provided at the bottom of the output shaft 121, and the output gear 120 is linked to the output shaft 121 through the spline. The output gear 120 meshes with the rack 403 in the switch control mechanism 200, which can drive the three switch units 300 to move.

[0038] The output shaft 121 is equipped with a signal output gear 123, and a signal indicator shaft 126 is also provided inside the gearbox 111. A signal indicator gear 127 is provided on the signal indicator shaft 126, and the signal indicator gear 127 meshes with the signal output gear 123. The signal indicator gear 127 outputs a gear position signal through a sensor, thereby allowing the equipment and the user to know the current gear position.

[0039] like Figure 6 , Figure 7 As shown, n U-shaped grooves 1221 are evenly distributed on the transmission disk 122. When the transmission gear 124 rotates, the push pin 128 can enter the U-shaped groove 1221 and drive the transmission disk 122 to rotate 1 / n revolutions before leaving the U-shaped groove 1221. In this embodiment, the transmission disk 122 has 6 U-shaped grooves 1221 evenly distributed, that is, when the transmission gear 124 rotates one revolution, the transmission disk 122 rotates 1 / 6 revolutions. The transmission shaft 125 is provided with an inner concave surface 1251 opposite to the push pin 128, and an inner concave arc 1222 is provided between two adjacent U-shaped grooves 1221 of the transmission disk 122. The inner concave surface 1251 and the inner concave arc 1222 can prevent the transmission shaft 125 and the transmission disk 122 from interfering with each other when rotating.

[0040] like Figure 8 , Figure 9As shown, the switching unit 300 includes a first vacuum interrupter 311 and a second vacuum interrupter 312, which are mounted side-by-side laterally on a base 310. A fixing screw 301 is installed on the base 310 and is connected to a mounting plate 402, allowing the switching unit 300 to be fixed on the mounting plate 402. A contact head frame 320 is installed on the front of the base 310, and a first contact clamp 321 connected to the moving end 313 of the first vacuum interrupter 311 and a second contact clamp 322 connected to the moving end 313 of the second vacuum interrupter 312 are provided on the contact head frame 320. A lever seat 341 is also provided on the front of the base 310, and two levers 340 are installed in the lever seat 341. The levers 340 are hinged to the lever seat 341 by pins. The lower end of lever 340 is provided with lugs 344 extending downward on both sides. The lugs 344 are fitted onto the outside of the moving end pull rod 314 of the first vacuum interrupter 311 and the second vacuum interrupter 312, so that lever 340 is linked with the moving end pull rod 314. The upper end of lever 340 is the trigger end 343. When the trigger end 343 of lever 340 encounters resistance, it will cause lever 340 to rotate, thereby causing the first vacuum interrupter 311 or the second vacuum interrupter 312 to trip.

[0041] A transition resistor 330 is installed at the bottom of the base 310, and the transition resistor 330 is connected in series with the second vacuum interrupter 312. Resistor frames 331 are installed at the front and rear of the bottom of the base 310, and multiple transition resistors 330 are installed in parallel between the two resistor frames 331. The multiple transition resistors 330 are connected in series through end mounting connecting pieces 332.

[0042] like Figure 10 As shown, a common conductive plate 350 is provided on the back of the base 310, and the stationary ends 315 of the first vacuum interrupter 311 and the second vacuum interrupter 312 are fixed on the common conductive plate 350. The bottom of the common conductive plate 350 is provided with a rearward flange 351, and a common contact 352 connected to the common end 205 is fixedly installed on the flange 351. The common end 205 is elongated, and the common contact 352 is always connected to the common end 205 when the switching unit 300 moves.

[0043] like Figure 11As shown, the lever 340 has multiple protruding teeth 207 on its front side, all of which are fixed to the front plate 203. When the trigger end 343 of the lever 340 encounters the protruding teeth 207, the lever 340 rotates, causing the first vacuum interrupter 311 or the second vacuum interrupter 312 to open. The trigger end 343 of the lever 340 is fitted with a bearing 342, which reduces the friction between the trigger end 343 and the protruding teeth 207. After the trigger end 343 of the lever 340 leaves the protruding teeth 207, the lever 340 automatically resets, and the moving end pull rod 314 of the first vacuum interrupter 311 or the second vacuum interrupter 312 automatically retracts under its own restoring force, putting the first vacuum interrupter 311 or the second vacuum interrupter 312 into the closed state.

[0044] Multiple taps 206 are located on the front side of the base 310. When the switching unit 300 moves, the first contact clamp 321 and the second contact clamp 322 can communicate with the taps 206. The tap contact frame 320 is provided with an upper clamping groove and a lower clamping groove. The first contact clamp 321 and the second contact clamp 322 include an upper clamping plate embedded in the upper clamping groove and a lower clamping plate embedded in the lower clamping groove. A bolt 323 and a nut 325 are installed between the upper clamping plate and the lower clamping plate, and a spring 324 is fitted on the bolt 323. When the first contact clamp 321 and the second contact clamp 322 move to the tap 206, the upper clamping plate and the lower clamping plate can wrap around the tap 206. Through the restoring force of the spring 324, the upper clamping plate and the lower clamping plate clamp the tap 206 tightly.

[0045] like Figure 12 As shown, the front end of the tap head bracket 320 is provided with multiple tap terminals 206. When the switch unit 300 moves, the first contact clamp 321 and the second contact clamp 322 can communicate with the tap terminals 206. The width of the tap terminal 206 must be sufficient to allow the first contact clamp 321 and the second contact clamp 322 to clamp simultaneously. The spacing between the tap terminals 206 must be sufficient so that when the first contact clamp 321 has not left the N-position tap terminal 2061, the second contact clamp 322 is already clamped with the N+1-position tap terminal 2062.

[0046] When the switch unit 300 moves from the N position to the N+1 position, it has five states.

[0047] like Figure 13 As shown, in the first state, the first contact clamp 321 is connected to the N-position tap 2061, the lever 340 of the first vacuum interrupter 311 is not in contact with the tooth 207, and is in the closed state. The trigger end 343 of the lever 340 of the second vacuum interrupter 312 abuts against the tooth 207, and is in the open state. At this time, the common terminal 205 is connected to the N-position tap 2061 through the first vacuum interrupter 311, and the current tap changer is in the N position.

[0048] like Figure 14As shown, in the second state, the second contact clamp 322 is connected to the N+1 tap 2062, while the first contact clamp 321 remains connected to the N tap 2061. Neither the lever 340 of the first vacuum interrupter 311 nor the second vacuum interrupter 312 is in contact with the tooth 207, indicating they are in the closed state. At this time, the common terminal 205 is connected to the N tap 2061 via the first vacuum interrupter 311, and to the N+1 tap 2062 via the second vacuum interrupter 312 and the transition resistor 330. The transition resistor 330 limits the circulating current between the N tap 2061 and the N+1 tap 2062, preventing a direct short circuit between the two taps 206 and ensuring continuous power supply to the load.

[0049] like Figure 15 As shown, in the third state, the first contact clamp 321 is disengaged from the N-position tap 2061, the second contact clamp 322 is connected to the N+1-position tap 2062, the lever 340 of the first vacuum interrupter 311 contacts the tooth 207, opening the circuit and extinguishing the arc, and the trigger end 343 of the lever 340 of the second vacuum interrupter 312 is not in contact with the tooth 207, remaining in the closed state. At this time, the common terminal 205 is connected to the N+1-position tap 2062 through the second vacuum interrupter 312 and the transition resistor 330. When switching from the second state to the third state, the trigger end 343 of the lever 340 on the first vacuum interrupter 311 first abuts against the tooth 207, causing the first vacuum interrupter 311 to open first, and then the first contact clamp 321 is disengaged from the N-position tap 2061, thereby preventing arcing when the first contact clamp 321 is disengaged from the N-position tap 2061.

[0050] like Figure 16 As shown, in the fourth state, both the first contact clamp 321 and the second contact clamp 322 are connected to the N+1 tap position 2062, and the levers 340 of the first vacuum interrupter 311 and the second vacuum interrupter 312 are not in contact with the protrusion 207, indicating that the circuit is closed. At this time, the common terminal 205 is connected to the N+1 tap position 2062 through the first vacuum interrupter 311, and through the second vacuum interrupter 312 and the transition resistor 330.

[0051] like Figure 17As shown, in the fifth state, the first contact clamp 321 is connected to the N+1 tap position 2062, the lever 340 of the first vacuum interrupter 311 is not in contact with the protrusion 207 and is in the closed state, and the trigger end 343 of the lever 340 of the second vacuum interrupter 312 abuts against the protrusion 207 and is in the open state. At this time, the common terminal 205 is connected to the N+1 tap position 2062 through the first vacuum interrupter 311. When switching from the fourth state to the fifth state, the trigger end 343 of the lever 340 on the second vacuum interrupter 312 first abuts against the protrusion 207, causing the second vacuum interrupter 312 to open first, and then the second contact clamp 322 leaves the N+1 tap position 2062. This avoids arcing when the second contact clamp 322 leaves the N+1 tap position 2062.

[0052] This completes the switch from gear N to gear N+1.

[0053] When the switch unit 300 moves from the N+1 position to the N position, the order of the five states is reversed, that is, it moves from the fifth state to the first state in reverse order.

[0054] When switching from the fourth state to the third state, the trigger end 343 of the lever 340 on the first vacuum interrupter 311 first abuts against the protrusion 207, causing the first vacuum interrupter 311 to open first. Then, the first contact clamp 321 moves away from the N+1 tap position 2062, preventing arcing when the first contact clamp 321 moves away from the N+1 tap position 2062. When switching from the second state to the first state, the trigger end 343 of the lever 340 on the second vacuum interrupter 312 first abuts against the protrusion 207, causing the second vacuum interrupter 312 to open first. Then, the second contact clamp 322 moves away from the N+1 tap position 2062, preventing arcing when the second contact clamp 322 moves away from the N+1 tap position 2062.

[0055] This invention relates to a movable tap changer. The output gear 120 of its drive mechanism 100 is asynchronous with the transmission shaft 125, only moving the switch unit 300 during gear shifting. This design offers advantages such as precise driving distance and high driving force. Within the tap changer, the switch unit 300 can achieve gear shifting without power interruption simply by moving the entire switch unit 300 left and right. It also automatically controls the opening and closing of the two vacuum arc interrupters, preventing arcing when the contact clamps leave the tap end 206. This type of switch unit 300 does not rely on cam timing; each switch unit 300 can be independently assembled and disassembled without wire connections, offering advantages such as simple structure, low cost, and convenient installation.

Claims

1. A mobile on-load tap changer, comprising a drive mechanism and a switch control mechanism, characterized in that... The switch control mechanism includes a common terminal and multiple tap terminals. A switch unit is arranged inside the switch control mechanism, and a guide mechanism is arranged on the back of the switch unit. The guide mechanism consists of a guide rail fixed inside the switch control mechanism, two sliders mounted on the guide rail, and a mounting plate fixed on the sliders. The switch unit is fixed on the mounting plate. When the switch unit moves along the guide mechanism, it can control the on / off state of each tap terminal and the common terminal, realizing the switching of gears. The drive mechanism can drive the switch unit to move along the guide mechanism.

2. The mobile on-load tap changer according to claim 1, characterized in that... The drive mechanism includes a base, a gearbox mounted on the base, a gear transmission mechanism installed inside the gearbox, and a motor mounted above the gearbox. The gear transmission mechanism includes a drive shaft, a transmission shaft, and an output shaft. The drive shaft is connected to the drive end of the motor and has a drive gear mounted on it. The transmission shaft has a transmission gear meshing with the drive gear, and a push pin is eccentrically positioned on the end face of the transmission gear. The output shaft has a transmission disc with n U-shaped grooves evenly distributed on it. When the transmission gear rotates, the push pin can enter the U-shaped grooves and drive the transmission disc to rotate 1 / n revolutions before leaving the U-shaped grooves. The bottom end of the output shaft extends out of the base and is linked to the guide mechanism through the output gear.

3. The mobile on-load tap changer according to claim 2, characterized in that... The output shaft is equipped with a signal output gear, and a signal indicator shaft is also provided in the gearbox. The signal indicator shaft is equipped with a signal indicator gear, and the signal indicator gear meshes with the signal output gear.

4. The mobile on-load tap changer according to claim 1, characterized in that... The switch unit includes a first vacuum interrupter and a second vacuum interrupter, which are installed side-by-side laterally on a base. The stationary ends of the first and second vacuum interrupters are normally connected to a common end on the back of the base. A contact head frame is installed on the front of the base, and a first contact clamp connected to the moving end of the first vacuum interrupter and a second contact clamp connected to the moving end of the second vacuum interrupter are provided on the contact head frame. Multiple tap terminals are provided on the front side of the base. When the switch unit moves, the first and second contact clamps can communicate with the tap terminals. A lever is provided on the moving end pull rod of the first and second vacuum interrupters. The upper end of the lever is the trigger end. When the trigger end of the lever encounters resistance, it will rotate the lever, causing the first or second vacuum interrupter to open.

5. The mobile on-load tap changer according to claim 4, characterized in that... The lever has multiple protruding teeth on its front side. When the trigger end of the lever encounters the protruding teeth, the lever will rotate, causing the first vacuum arc extinguisher or the second vacuum arc extinguisher to trip.

6. The mobile on-load tap changer according to claim 4, characterized in that... A common conductive plate is provided on the back of the base. The stationary ends of the first vacuum arc extinguisher and the second vacuum arc extinguisher are fixed on the common conductive plate. A rearward flange is provided at the bottom of the common conductive plate. A common contact connected to the common terminal is fixedly installed on the flange. When the switching unit moves, the common contact is always connected to the common terminal.

7. The mobile on-load tap changer according to claim 4, characterized in that... The base has resistor frames installed at the front and back, and multiple transition resistors are installed in parallel between the two resistor frames. These transition resistors are connected in series with the second vacuum arc extinguisher.

8. The mobile on-load tap changer according to claim 1, characterized in that... The switching unit has five states when switching from the N position to the N+1 position; In the first state, the first contact clamp is connected to the N-position tap, the lever of the first vacuum interrupter is not in contact with the protruding tooth and is in the closed state, and the lever trigger end of the second vacuum interrupter abuts against the protruding tooth and is in the open state; at this time, the common terminal is connected to the N-position tap through the first vacuum interrupter. In the second state, the second contact clamp is connected to the N+1 tap, the first contact clamp is still connected to the N tap, and the levers of the first and second vacuum interrupters are not in contact with the protruding teeth and are in the closed state. At this time, one common terminal is connected to the N tap through the first vacuum interrupter, and the other is connected to the N+1 tap through the second vacuum interrupter and the transition resistor. In the third state, the first contact clamp leaves the N-position tap, the second contact clamp connects to the N+1-position tap, the lever of the first vacuum interrupter contacts the convex tooth, opening the circuit to extinguish the arc, and the lever trigger end of the second vacuum interrupter does not abut against the convex tooth, and is in the closed state; at this time, the common terminal is connected to the N+1-position tap through the second vacuum interrupter and the transition resistor. In the fourth state, both the first and second contact clamps are connected to the N+1 tap position, and the levers of the first and second vacuum interrupters are not in contact with the protruding teeth, indicating that the circuit is closed. At this time, one common terminal is connected to the N+1 tap position through the first vacuum interrupter, and the other terminal is connected to the N+1 tap position through the second vacuum interrupter and the transition resistor. In the fifth state, the first contact clamp is connected to the N+1 tap position, the lever of the first vacuum interrupter is not in contact with the protruding tooth and is in the closed state, and the lever trigger end of the second vacuum interrupter is in contact with the protruding tooth and is in the open state; at this time, the common terminal is connected to the N+1 tap position through the first vacuum interrupter.

9. The mobile on-load tap changer according to claim 8, characterized in that... When the switching unit switches from N+1 to N, the order of the five states is changed.

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