Vacuum interrupter assembly for power transfer switch, power transfer switch for transformer load tap changer, and transformer load tap changer

Abstract

A vacuum interrupter assembly (10) for a power switching switch comprises: a vacuum interrupter (11); and a drive mechanism (12) coupled to the vacuum interrupter (11) and configured to drive the opening and closing of electrical contacts of the vacuum interrupter (11). The drive mechanism (12) comprises a drive rod (19) and a guide tube (18) surrounding the drive rod (19), so that the drive rod (19) can move axially along the longitudinal axis (L) of the vacuum interrupter assembly (10) inside the guide tube (18). The damping unit (20) is coupled to the drive mechanism (12) and comprises a first chamber (21), a second chamber (22), and a piston (29) arranged therebetween relative to the longitudinal axis (L), wherein the chambers (21, 22) are hydraulically coupled to each other and are limited by a guide tube (18) and the piston (29), and wherein the piston (29) is coupled to a drive rod (19) which is capable of axial movement along the longitudinal axis (L), so that when interacting with a fluid, the damping unit (20) provides hydraulic damping when opening and closing the electrical contacts of the vacuum interrupter (11) due to the movement of the drive rod (19) and the piston (29).

Description

Technical Field

[0001] The present disclosure relates to a vacuum interrupter assembly for a power transfer switch. The present disclosure also relates to a corresponding power transfer switch for a transformer load tap changer and a transformer load tap changer. Background Art

[0002] Vacuum interrupters are widely used in, for example, utility transmission systems, generator sets, and railway distribution systems, where they implement switching of medium voltage circuit breakers, generator circuit breakers, or high voltage circuit breakers using electrical contacts in a vacuum to reliably separate electrical contacts, resulting in rapid extinguishing of metal vapor arcs.

[0003] Document US 9 401 249 B2 discloses an on-load tap changer comprising a plurality of modules arranged in a side-by-side manner in the interior space of a box. Each module has a bypass switch assembly and a vacuum interrupter assembly mounted to a first side of the board. The bypass switch assembly is actuated by the rotation of a bypass cam, and the vacuum interrupter assembly is actuated by the rotation of an interrupter cam.

[0004] Document CN 109 559 933A discloses a damping mechanism in the field of medium and high voltage switchgear. The voltage switchgear comprises a base frame and a switch unit for fixing the base frame. The switch unit comprises an axially connected vacuum bubble, an insulating cylinder, an electromagnetic driver, and a de-jitter device.

[0005] In this regard, it is a challenge to provide a stable and reliable mechanism to transfer motion from the drive cam of the vacuum interrupter to the contact rod while maintaining low wear with respect to the interacting components. Summary of the invention

[0006] Embodiments of the present disclosure relate to a vacuum interrupter assembly for a power conversion switch, which can safely and reliably switch electrical contacts of the vacuum interrupter and help to increase the life of the vacuum interrupter. Further embodiments of the present disclosure relate to a transformer load tap changer including such a vacuum interrupter assembly and a corresponding power conversion switch for the transformer load tap changer.

[0007] According to one embodiment, a vacuum interrupter assembly for a power conversion switch includes a vacuum interrupter and a drive mechanism, the vacuum interrupter being configured to open and close associated electrical contacts in a vacuum, the drive mechanism being coupled to the vacuum interrupter and being configured to drive the opening and closing of the electrical contacts of the vacuum interrupter. The drive mechanism includes a drive rod and a guide tube surrounding the drive rod, so that the drive rod can move axially along the longitudinal axis of the vacuum interrupter assembly arranged in the guide tube. The vacuum interrupter assembly also includes a damping unit, which is coupled to the drive mechanism and includes a first chamber, a second chamber, and a piston arranged between them relative to the longitudinal axis. These chambers are hydraulically coupled to each other and are limited by the guide tube and the piston. The piston is coupled to the drive rod, and the drive rod can move axially along the longitudinal axis, so that when interacting with a fluid, the damping unit provides hydraulic damping due to the movement of the drive rod and the piston in the case of opening the electrical contacts of the vacuum interrupter and in the case of closing the electrical contacts of the vacuum interrupter.

[0008] The vacuum interrupter assembly also includes a first disk and a second disk, which are fixedly arranged to the guide tube on opposite sides of the piston relative to the longitudinal axis to limit the first and second chambers. Therefore, the chambers and their hydraulic volumes are defined by the fixed disk, the wall of the guide tube, and the movable piston. The first disk and the second disk include at least one orifice, each of which defines a corresponding fluid channel for exiting and entering the first chamber and the second chamber. Therefore, due to the movement of the drive rod and the piston thereon toward the first disk, the volume of the first chamber is reduced, and the fluid is pressed out through the orifice of the first disk. Correspondingly, due to the movement of the drive rod and the piston thereon in the opposite direction toward the second disk, the volume of the second chamber is reduced, and the fluid is pressed out through the orifice of the second disk. In this way, the hydraulic damping force can be used to influence the opening and closing speed of the vacuum interrupter, and in particular to reduce the undesirable bounce effect during the closing of the vacuum interrupter. Both the at least one orifice of the first disk and the one orifice of the second disk include a circular shape, or are circularly limited by the corresponding disk, wherein the diameter of the orifice of the first disk can be smaller than the diameter of the orifice of the second disk. The first disk will be configured to provide hydraulic damping when closing the electrical contacts of the vacuum interrupter, and the second disk will be configured to provide hydraulic damping when opening the electrical contacts.

[0009] Due to the described configuration, a vacuum interrupter assembly is feasible which is capable of safely and reliably switching electrical contacts of the vacuum interrupter and helps to reduce wear of interacting components and increase the life of the vacuum interrupter and the corresponding power conversion switch. The damping unit enables a cost-effective design of a damping mechanism for precise vacuum interrupter control.

[0010] The present disclosure recognizes that conventional designs for controls of power conversion switches and vacuum interrupters typically have relatively complex mechanisms with many moving parts and modules. These modules are interdependent and follow a specific sequence, which complicates their design and further complicates their manufacturing and maintenance processes.

[0011] By using the vacuum interrupter assembly of the present disclosure, the above-mentioned adverse effects can be at least offset. Due to the simple, compact design of the damping unit, precise control of the movement of the drive rod in both directions is possible, and the vacuum interrupter assembly helps to reduce bounce by closing the vacuum circuit breaker and its electrical contacts, thereby reducing wear and extending component life.

[0012] According to another embodiment of the vacuum interrupter assembly, the first disk, the second disk, and the piston are all arranged axially relative to the longitudinal axis in a guide tube surrounding the drive rod. The first disk and the second disk are connected to the guide tube, and the piston is connected to the drive rod. Therefore, the disk and the piston are all arranged axially between the guide tube and the drive rod. For example, basically, the guide tube, the drive rod, the disk, and the piston are formed rotationally symmetrically.

[0013] At least one orifice of the first disc and one orifice of the second disc both comprise a circular shape or are circularly bounded by the respective discs. For example, the respective diameter of the orifice of the first disc is 1 mm and the respective diameter of the orifice of the second disc is 2.5 mm. Thus, a higher damping force can be provided in the direction of the first disc comprising the smaller orifice.

[0014] According to a further embodiment of the vacuum interrupter assembly, the guide tube may further include two recesses. Such a recess may be configured to penetrate the wall of the guide tube, thereby defining a first channel and a second channel associated with the first chamber and the second chamber, respectively, so that the fluid channel is defined by the orifice of the first disk, the first channel, the second channel, and the orifice of the second disk. Therefore, in view of the arrangement of the disk in the guide tube, the fluid can flow into the guide tube through the orifice of the first disk, and then flow out of the guide tube again through the first channel. Therefore, the fluid from the outside can flow into the guide tube through the second channel and flow to the outside again through the orifice of the second disk from the inside. In order to advantageously control the fluid flow and the hydraulic damping force, the piston is connected to the drive rod, and the movement of the drive rod causes the piston to close the first channel when closing the electrical contacts of the vacuum interrupter, and causes the piston to close the second channel when opening the electrical contacts of the vacuum interrupter. Therefore, the distance between the first channel and the second channel is configured to be coordinated with the thickness of the piston relative to the longitudinal axis.

[0015] In addition, the size of the piston and / or the size and / or position of the first and second passages in the wall of the guide tube can be configured in a coordinated manner to provide a predetermined hydraulic damping force relative to the operating state of the vacuum interrupter assembly when interacting with a fluid used to clean around the vacuum interrupter assembly and flowing inside and outside the guide tube.

[0016] According to another embodiment of the vacuum interrupter assembly, at least one of the orifice of the first disk, the orifice of the second disk, the first channel, and the second channel comprises a respective size configured in coordination with the viscosity of the fluid for flowing inside and outside the guide tube to provide a predetermined hydraulic damping force relative to an operating state of the vacuum interrupter assembly when interacting with the fluid. The vacuum interrupter assembly is configured to be immersed in a predetermined fluid (e.g., mineral transformer oil) within a tank of a transformer load tap changer, and thus, the size of one or more intentionally implemented fluid openings may also affect the hydraulic damping force depending on the viscosity of the fluid or the temperature of the fluid.

[0017] According to one embodiment, a power transfer switch for a transformer load tap changer includes an insulating plate, a control cam, and an embodiment of the vacuum interrupter assembly, wherein the vacuum interrupter assembly is coupled to both the insulating plate and the control cam. The control cam is configured to drive a drive mechanism of the vacuum interrupter assembly to open or close electrical contacts of the vacuum interrupter.

[0018] According to one embodiment, a transformer on-load tap changer for setting a transmission ratio comprises a tank surrounding a fluid and at least one embodiment of the above-described power transfer switch, the power transfer switch being arranged within the tank immersed in the fluid.

[0019] This configuration of a power switching switch and a transformer load tap changer using an embodiment of the described vacuum interrupter assembly with an improved damper enables safe and reliable switching or separation of the electrical contacts of the vacuum interrupter. Since the power switching switch and the transformer load tap changer include embodiments of the vacuum interrupter, the features and characteristics of the vacuum interrupter relative to the power switching switch and the transformer load tap changer are also disclosed, and vice versa. Therefore, the present disclosure includes several aspects, each feature described with respect to one of the aspects is also disclosed herein with respect to another aspect, even if the corresponding feature is not explicitly mentioned in the context of a particular aspect. With respect to the operating state assembled in the transformer, the described configuration of the vacuum interrupter assembly and its specific hydraulic damper are immersed in the dielectric fluid and allow beneficial control of opening and closing the electrical contacts of the vacuum interrupter. The damping unit enables accurate and reliable operating modes of the vacuum interrupter and the transformer load tap changer, respectively. The described configuration allows a cost-effective assembly with improved damping implemented in the drive mechanism, and further allows one or more of the following advantageous effects:

[0020] Precisely control the movement of the drive rod in two directions;

[0021] Reduce bounce by closing the vacuum interrupter;

[0022] Control the opening and closing speed of the vacuum interrupter;

[0023] Clear and concise design

[0024] Use of the drive rod of the drive mechanism as piston rod and piston for the guide element

[0025] Use the inner diameter of the guide tube as the cylindrical tube that guides the piston. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] An exemplary embodiment is explained below with the aid of schematic diagrams and reference symbols. The figure shows:

[0027] Figure 1 An embodiment of a transformer load tap changer is shown,

[0028] Figure 2 A perspective view showing an embodiment of a vacuum interrupter module for a transformer load tap changer,

[0029] Figure 3 Show according to Figure 2 Side view of the vacuum interrupter module,

[0030] Figure 4 Show according to Figure 2 and Figure 3 a damping unit of a vacuum interrupter assembly of a vacuum interrupter module, and

[0031] Figure 5 Other perspective views showing the damping unit of the vacuum interrupter assembly.

[0032] The accompanying drawings are included to provide further understanding. It should be understood that the embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale. The same reference numerals represent elements or components having the same function. As long as the elements or components correspond to each other in their functions in different figures, their description will not be repeated for the following figures. For clarity, elements may not appear in all figures with corresponding reference symbols. DETAILED DESCRIPTION

[0033] Figure 1A cross-sectional side view of an embodiment of a transformer load tap changer 100 for setting a transmission ratio is shown, the transformer load tap changer comprising a tank 101 surrounding a fluid and three power transfer switches arranged inside the tank 101 and immersed in the fluid. The transformer load tap changer 100 comprises a drive motor drive shaft 102 and an insulating shaft 103 for controlling the power transfer switches and its vacuum circuit breaker module 1. The motion for operating the transformer load tap changer 100 is received by the motor drive shaft 102. The motor drive shaft 102 is connected to a motor drive unit, which is mounted to the tank 101. The motor drive shaft 102 is then connected to a bevel gear structure, which is distributing the motion to the three phases of the corresponding vacuum circuit breaker module 1 through the insulating shaft 103.

[0034] Figure 2 A power conversion switch assembly or vacuum interrupter module 1 of a transformer load tap changer 100 is shown in perspective view. The vacuum interrupter module 1 includes an insulating plate 3 and a current transformer 2 attached to the insulating plate 3. The insulating plate forms a support structure for the vacuum interrupter module 1 and can be composed of a rigid dielectric material (e.g., a fiber reinforced dielectric plastic). A bypass switch assembly and a vacuum interrupter assembly 10 are mounted on the front side of the insulating plate 3. The back side of the insulating plate 3 can be used to carry a copper rod for schematic connection. The input movement from the selector is transmitted to the cam end of the control cam 13 through the insulating shaft 103. The control cam 13 is configured to actuate the bypass contact 4 through the corresponding bypass lever 5. At the same time, the control cam 13 is configured to load and release the spring accumulator inside the drive mechanism 12.

[0035] The vacuum interrupter module 1 includes a vacuum interrupter assembly 10, which includes a vacuum interrupter 11 and a drive mechanism 12, which is coupled to the vacuum interrupter 11 and configured to drive the opening and closing of the electrical contacts of the vacuum interrupter 11. The transformer load tap changer 100 and the corresponding vacuum module 1 may also include a selection switch assembly and a bypass switch module for each phase winding. The selection switch assembly can be configured to connect between taps, and the bypass switch module can be configured to connect the tap to the main power supply. During tap switching, the vacuum interrupter module 1 safely carries current between the tap and the main power circuit. The drive system is configured to move the selection switch, the bypass switch module, and the vacuum interrupter module 1.

[0036] The control cam 13 is coupled to the vacuum interrupter assembly 10 and is configured to drive the drive mechanism 12 to open and close the electrical contacts of the vacuum interrupter 11 (see Figure 3 The drive mechanism 12 includes a drive rod 19 and a guide tube 18 surrounding the drive rod 19 , such that the drive rod 19 can move axially within the guide tube 18 along the longitudinal axis L of the vacuum interrupter assembly 10 .

[0037] The corresponding vacuum interrupter assembly 10 further comprises a damping unit 20, which is coupled to the drive mechanism 12 and comprises a first chamber 21, a second chamber 22, and a piston 29 arranged therebetween with respect to the longitudinal axis L (see Figure 4 and 5 ). The chambers 21, 22 are hydraulically coupled to each other and are bounded by the guide tube 18, the piston 29, and the first and second disks 25, 26, wherein they are all arranged axially inside the guide tube 18 relative to the longitudinal axis. The piston 29 is coupled to the drive rod 19 that can move axially along the longitudinal axis L, so that due to the movement of the drive rod 19 and the piston 29 along the longitudinal axis L, when opening and closing the electrical contacts of the vacuum interrupter 11, the damping unit interacts with the fluid to provide hydraulic damping.

[0038] according to Figure 3 In the cross-sectional view of the illustrated embodiment, the vacuum interrupter module 1 further comprises one or more drive springs 14, a locking mechanism 15, an adjustment system 16, and a locking system 17. The drive spring 14 accumulates the required energy to provide an appropriate switching speed of the vacuum interrupter module 1. The locking mechanism 15 and the locking system 17 are used to define two positions of the vacuum interrupter 11. In addition, the locking system 17 positively clamps the vacuum interrupter 11 toward the insulating plate 3. The adjustment system 16 is configured to adjust the contact gap and is configured to provide a solution for axial differences during assembly of the vacuum interrupter module 1 and the vacuum interrupter assembly 10. The damping unit 20 is configured to provide reliable damping when the drive rod 19 is closing the vacuum interrupter 11 and when the drive rod 19 is opening the vacuum interrupter 11.

[0039] Figure 4 and Figure 5 They are shown respectively Figure 3 An enlarged perspective view of the damping unit 20 of the corresponding vacuum interrupter assembly 10 is encircled by a dotted circle in the middle. The damping unit 20 is configured so as to provide more damping in the case of closing the electrical contacts of the vacuum interrupter 11 than in the case of opening the electrical contacts of the vacuum interrupter 11. This higher hydraulic damping force is achieved by two different chambers 21, 22 and disks 25, 26 including different orifices 27 and 28, respectively.

[0040] The disks 25, 26 and the piston 29 implement washers or bushings including respective central openings through which the drive rod 19 extends. The disks 25 and 26 are fixedly connected to the inner surface of the guide tube 18, while the piston 29 is fixedly connected to the outer surface of the drive rod 19. In addition, the inner surface of the guide tube 18 and / or the outer surface of the drive rod 19 may include edges, protrusions, and / or grooves to achieve precise and stable arrangement of the disks 25, 26 and the piston 29, respectively.

[0041] The first disk 23 includes two orifices 27 and the second disk 24 includes two orifices 28, each of which defines a fluid passageway for exiting and entering the first chamber 21 and the second chamber 22. The orifices 27 and 28 of the first and second disks 25 and 26 are both circularly restricted, and the respective diameter of the orifice 27 of the first disk 25 is smaller than the respective diameter of the orifice 28 of the second disk 26. According to the illustrated embodiment, the first disk 25 is arranged closer to the vacuum interrupter 11 than the second disk 26. The disks 25 and 26 are arranged inside the guide tube 18, on opposite sides of the piston 29 with respect to the longitudinal axis L.

[0042] The vacuum interrupter assembly 10 is configured such that the electrical contacts of the vacuum interrupter are closed when the piston 29 is driven toward the first disk 25. Thus, the vacuum interrupter assembly 10 is configured such that the electrical contacts of the vacuum interrupter are opened when the piston 29 is driven toward the second disk 26.

[0043] Thus, the first disk 25 and its orifices 27 are configured to provide a predetermined hydraulic damping in the event of closing the electrical contacts of the vacuum interrupter 11 .

[0044] Accordingly, the second disk 26 and its orifices 28 are configured to provide a predetermined hydraulic damping in the event of opening of the electrical contacts of the vacuum interrupter 11 .

[0045] In addition, the guide tube 18 includes two recesses penetrating the wall of the guide tube 18, which define a first channel 23 and a second channel 24 from the inside to the outside of the guide tube 18. The first channel 23 is associated with the first chamber 21, and the second channel 24 is associated with the second chamber 22, so that the fluid passage is defined by the orifice 27 of the first disk 25, the first channel 23, the second channel 24, and the orifice 28 of the second disk 26. Due to the movement of the drive rod 19 and the piston 29, the volume of one of the chambers 21, 22 is reduced, while the volume of the other of the chambers 22, 21 is increased. Then, the piston 29 closes the first channel 23 when closing the electrical contacts of the vacuum interrupter 11, and closes the second channel 24 when opening the electrical contacts of the vacuum interrupter 11.

[0046] The size of the piston 29 and the size and position of the first and second passages 23, 24 in the wall of the guide tube 18 are configured in coordination with each other to provide a predetermined hydraulic damping force in the case of interaction with the fluid and the size of the orifices 27 and 28 in the disks 25 and 26. For example, the size of the orifice 27 of the first disk 25, the size of the orifice 28 of the second disk 26, and the size of the first and second passages 23 and 24 are configured to be coordinated with the viscosity of the fluid in the tank 101. For example, the arrangement and size of the disks 25 and 26, the piston 29, and the passages 23 and 24 are such that the piston 29 nearly closes the first and second passages 23 and 24 in the middle position between the disks 25 and 26, and the volumes of the chambers 21 and 22 are substantially the same. This state is as shown in FIG. Figure 4 shown.

[0047] The piston 29 may have a thickness of a few millimeters, for example 8 mm, relative to the longitudinal axis L. The thickness of the piston 29 is advantageously adapted to the stroke of the movable electrical contact of the vacuum interrupter 11, which has a value of, for example, 4 mm. Therefore, the movable distance of the piston 29 in the guide tube 18 should also be adapted to the above-mentioned stroke, so that the piston can be moved reliably.

[0048] For example, when moving the drive rod 19 and the piston 29 in the closing direction, a lower speed is required. The size of the orifice 27 of the first disc 25 and / or the size of the orifice 28 of the second disc 26 are configured to be smaller than the size of the first and / or second channels 23, 24 on the periphery of the guide tube 18 to achieve smoother movement. Regarding the end open position, the second channel 24 is closed by the piston 29, and the first channel 23 is partially opened to a predetermined degree. Therefore, the piston 29 covers only one channel, that is, the area of ​​fluid leakage is larger, and therefore the speed is higher at this point.

[0049] If the piston 29 continues to move to close the electrical contacts, it will close the first channel 23 and the second channel 24 will then be partially opened to a predetermined extent to achieve the desired braking effect, since the oil flow will only pass through the two small orifices 27 of the first disk 25. In the final closed position, the second channel 24 located on the periphery of the guide tube 18 is partially opened, thus preventing any braking effect formed by the vacuum in the second chamber 22 inside the guide tube 18 when moving the piston 29 towards the second disk 28. When moving again in the opening direction, the sequence is the same, but at a higher speed and the orifices 28 of the second disk 26 are larger than those in the first disk 25.

[0050] For example, the respective centers of the first and second channels 23 and 24 may be at a distance of 5 mm from each other, wherein the first and second channels 23 and 24 each comprise a diameter of 4 mm. Thus, relative to the beginning open position equivalent to the end closed position, the second channel 24 may be covered by the piston 29, so that the fluid permeable area is reduced to, for example, 3 mm remaining relative to the 4 mm diameter.

[0051] Thus, relative to a starting closed position equivalent to an ending open position, the first channel 23 may be covered by the piston 29 such that the fluid permeable area is reduced to half, ie, for example, 2 mm remain relative to a 4 mm diameter.

[0052] The damping unit 20 is implemented in the guide tube 18 of the drive mechanism 12 in the power conversion switch. The damping unit 20 comprises only three elements and some adaptations on the guide tube 18 and the drive rod 19 of the vacuum interrupter assembly 10. In particular, the precise position of the holes or channels 23, 24 in the wall of the guide tube 18 enables to provide a precise moment of the damping force, and with the diameters of the orifices 27, 28 being at default values, the desired reactance of the fluid (correspondingly, the damping force) can be achieved. Due to this configuration, the damping unit 20 is able to effectively influence the opening and closing speed of the vacuum interrupter 11 and reduce the unnecessary bouncing effect during the closing of the vacuum interrupter 11.

[0053] The described vacuum interrupter assembly 10 provides a beneficial robustness and contributes to reduced manufacturability and maintenance standards. This is achieved, among other things, due to the specially configured damping unit 20 immersed in the dielectric fluid. The electrical contacts of the vacuum interrupter 11 are opened and closed by the drive mechanism 12, in which the damping unit 20 is implemented. The damping unit 20 according to the illustrated embodiment is configured to provide more damping force when the drive rod 19 closes the vacuum interrupter 11 than when the drive rod 19 opens the vacuum interrupter 11. This can be achieved by two hydraulic chambers 21, 22 and discs 25, 26 with different orifices 27, 28.

[0054] Figures 1 to 5 The embodiments shown and described above represent exemplary embodiments of the improved vacuum interrupter assembly 10, the power conversion switch or vacuum interrupter module 1, and the transformer load tap changer 100, respectively. Therefore, they do not constitute a complete list of all embodiments. The actual arrangement may be different from the embodiments shown in the figures.

[0055] Reference Mark

[0056] 1 Vacuum interrupter module

[0057] 2 Current transformer

[0058] 3 Insulation board

[0059] 4 Bypass contacts

[0060] 5 Bypass joystick

[0061] 10 Vacuum interrupter assembly

[0062] 11 Vacuum interrupter

[0063] 12. Driving mechanism

[0064] 13 Control cam

[0065] 14 Drive spring

[0066] 15 Locking mechanism

[0067] 16. Adjustment system

[0068] 17 Locking system

[0069] 18 Guide tube

[0070] 19 Drive rod

[0071] 20 Damping units

[0072] 21 First Chamber

[0073] 22 Second Chamber

[0074] 23 First Channel

[0075] 24 Second Channel

[0076] 25 First Plate

[0077] 26 Second Set

[0078] 27 First orifice

[0079] 28 Second orifice

[0080] 29 Piston

[0081] 100 Transformer Load Tap Changer

[0082] 101 boxes

[0083] 102 Motor drive shaft

[0084] 103 Insulated shaft

[0085] L Longitudinal axis of the vacuum interrupter assembly

Claims

1. A vacuum interrupter assembly (10) for a power conversion switch, comprising: - a vacuum interrupter (11) configured to open and close associated electrical contacts in a vacuum; a drive mechanism (12) coupled to the vacuum interrupter (11) and configured to drive the opening and closing of the electrical contacts of the vacuum interrupter (11), wherein the drive mechanism (12) comprises a drive rod (19) and a guide tube (18) surrounding the drive rod (19), so that the drive rod (19) can move axially along the longitudinal axis (L) of the vacuum interrupter assembly (10) within the guide tube (18); a damping unit (20) coupled to the drive mechanism (12) and comprising a first chamber (21), a second chamber (22), and a piston (29) arranged therebetween relative to the longitudinal axis (L), wherein the chambers (21, 22) are hydraulically coupled to each other and are bounded by the guide tube (18) and the piston (29), and wherein the piston (29) is coupled to the drive rod (19) which is axially movable along the longitudinal axis (L), so that in interaction with a fluid, the damping unit (20) provides hydraulic damping both when opening the electrical contacts of the vacuum interrupter (11) and when closing the electrical contacts of the vacuum interrupter due to the movement of the drive rod (19) and the piston (29); and - a first disk (25) and a second disk (26), the first disk and the second disk being fixedly arranged to the guide tube (18) on opposite sides of the piston (29) with respect to the longitudinal axis (L) to limit the first and second chambers (21, 22), wherein the first disk (25) comprises at least one orifice (27) and the second disk (26) comprises at least one orifice (28), each orifice defining a fluid passage for entering and exiting the first chamber (21) and the second chamber (22), wherein both the at least one orifice (27) of the first disk (25) and the at least one orifice (28) of the second disk (26) are circularly limited and the diameter of the orifice (27) of the first disk (25) is smaller than the diameter of the orifice (28) of the second disk (26), and wherein the first disk (25) is configured to provide hydraulic damping in the event of closing the electrical contacts of the vacuum interrupter (11).

2. The vacuum interrupter assembly (10) according to claim 1, wherein: The first disk (25), the second disk (26), and the piston (29) are all axially arranged inside the guide tube (18) relative to the longitudinal axis (L) and surround the drive rod (19), so that the first disk (25) and the second disk (26) are connected to the guide tube (18), and the piston (29) is connected to the drive rod (19), and the first disk, the second disk, and the piston are all radially arranged between the guide tube (18) and the drive rod (19).

3. The vacuum interrupter assembly (10) according to claim 1 or 2, wherein: The guide tube (18) comprises two recesses penetrating the wall of the guide tube (18) and defining a first channel (23) and a second channel (24) associated with the first chamber (21) and the second chamber (22), respectively, such that the fluid passage is defined by the orifice (27) of the first disk (25), the first channel (23), the second channel (24), and the orifice (28) of the second disk (26), wherein the piston (29) is connected to the drive rod (19) such that, due to the movement of the drive rod (19), it closes the first channel (23) when closing the electrical contacts of the vacuum interrupter (11), and it closes the second channel (24) when opening the electrical contacts of the vacuum interrupter (11).

4. The vacuum interrupter assembly (10) according to claim 3, wherein: The size of the piston (29) and / or the size and / or position of the first and second channels (23, 24) in the wall of the guide tube (18) are configured in coordination with each other to provide a predetermined hydraulic damping force relative to the operating state of the vacuum interrupter assembly (10) when interacting with a fluid flowing inside and outside the guide tube (18).

5. The vacuum interrupter assembly (10) according to claim 3, wherein: The orifice (27) of the first disk (25), the orifice (28) of the second disk (26), the first passage (23), and / or the second passage (24) include respective sizes configured in coordination with the viscosity of the fluid for flowing inside and outside the guide tube (18) to provide a predetermined hydraulic damping force relative to the operating state of the vacuum interrupter assembly (10) when interacting with the fluid.

6. A power conversion switch for a transformer load tap changer (100), the power conversion switch comprising: Insulation board (3); Control cam (13); as well as The vacuum interrupter assembly (10) according to any one of claims 1 to 5, the vacuum interrupter assembly being coupled to both the insulating plate (3) and the control cam (13), wherein the control cam (13) is configured to drive the drive mechanism (12) of the vacuum interrupter assembly (10) to open and close the electrical contacts of the vacuum interrupter (11).

7. A transformer load tap changer (100) for setting a transmission ratio, comprising: a box (101) enclosing a fluid; as well as At least one power transfer switch according to claim 6, the at least one power transfer switch being arranged inside the tank (101) and immersed in the fluid.

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