Diverter switch of on-load tap changer and the on-load tap changer

Abstract

To provide a diverter switch of an on-load tap changer and the on-load tap changer, which can suppress a cost.SOLUTION: A diverter switch of an on-load tap changer of an embodiment, comprises: a vacuum valve; a switch mechanism; and an energization member. The switch mechanism opens and closes en electrode of the vacuum valve. The energization member energizes the vacuum valve to an electrode opening.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present invention relate to a changer switch for an on-load tap changer and to an on-load tap changer. [Background technology]

[0002] An on-load tap changer changes the tap while the transformer is in operation. An on-load tap changer changer switch switches the circuit to the selected tap. On-load tap changer changer switches and on-load tap changers are required to keep costs down. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-200962 A [Patent Document 2] JP 2019-212821 A Summary of the Invention [Problem to be solved by the invention]

[0004] The problem to be solved by the present invention is to provide a changer switch for an on-load tap changer and an on-load tap changer that can reduce costs. [Means for solving the problem]

[0005] The changeover switch of the on-load tap changer of the first embodiment has a vacuum valve, a switching mechanism, and a biasing member. The switching mechanism opens and closes the vacuum valve. The biasing member biases the vacuum valve in the opening direction.

[0006] In a second aspect of the embodiment, in the changeover switch of the on-load tap changer of the first aspect, the vacuum valve has a fixed electrode, a movable electrode, a case, and an electrode shaft. The case accommodates the fixed electrode and the movable electrode, and the inside is held in a vacuum. The electrode shaft extends from the movable electrode to the outside of the case. The opening and closing mechanism has a conductor supporting a conductor connection part connected to the electrode shaft. The biasing member is disposed between the case and the conductor.

[0007] In an aspect 3 of the embodiment, in the changeover switch of the on-load tap changer of the aspect 1 or 2, the biasing member is a coil spring. In a fourth aspect of the embodiment, in the changeover switch of the on-load tap changer of the second aspect, the conductor connection portion is formed in a cylindrical shape. The biasing member is a coil spring that is fitted onto the electrode shaft and the conductor connection portion.

[0008] An on-load tap changer according to a fifth aspect of the embodiment includes a diverter switch of the on-load tap changer according to any one of the first to fourth aspects, and a tank body. The tank body can accommodate the diverter switch and can be filled with insulating gas. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a cross-sectional view of an on-load tap changer according to an embodiment. [Diagram 2] FIG. [Diagram 3] A portion of a side cross-sectional view of a change-over switch. [Figure 4] FIG. [Diagram 5] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a changeover switch of an on-load tap changer and an on-load tap changer according to an embodiment will be described with reference to the drawings. FIG 1 is a cross-sectional view of an on-load tap changer 1 according to an embodiment. The on-load tap changer 1 changes a tap while the transformer is in operation. The on-load tap changer 1 includes a tap selector 2, a diverter switch 10, and a tank body 8. The diverter switch 10 includes a vacuum valve 21 (see FIG 4) which will be described later.

[0011] In the present application, the Z direction and R direction of the cylindrical coordinate system are defined as follows. The Z direction is the central axial direction of the tank body 8 and the vacuum valve 21. For example, the Z direction is the vertical direction, the +Z direction is the vertically upward direction, and the -Z direction is the vertically downward direction. The R direction is the radial direction of the vacuum valve 21. The +R direction is the direction away from the central axis, and the -R direction is the direction toward the central axis.

[0012] In the on-load tap changer 1, the tap selector 2 is arranged in the -Z direction, and the diverter switch 10 is arranged in the +Z direction. The tap selector 2 selects a tap of the transformer. The diverter switch 10 switches the circuit to the selected tap.

[0013] The tank body 8 is formed in a cylindrical shape. The tank body 8 houses a change-over switch 10 inside. The change-over switch 10 is fixed to a bottom plate of the tank body 8. The tank body 8 can be filled with insulating gas inside. The insulating gas has electrical insulation properties and temperature rise suppression properties. For example, the insulating gas is SF6 gas.

[0014] The on-load tap changer 1 has a gear mechanism 4, a drive shaft 5, and a power introduction section 6. The gear mechanism 4 reduces the speed of the power generated by an electric operation mechanism (not shown) and transmits it to the drive shaft 5. The drive shaft 5 is disposed outside the tank body 8 and extends downward from the gear mechanism 4. The lower end of the drive shaft 5 is connected to a power introduction unit 6. The power introduction unit 6 is disposed between the tank body 8 and the tap selector 2. The power introduction unit 6 introduces the power transmitted from the drive shaft 5 to the tap selector 2 and the changeover switch 10. The tap selector 2 and the changeover switch 10 operate by the power transmitted from the drive shaft 5.

[0015] The change-over switch 10 will now be described in detail. 2 is a side view of the changeover switch 10 of the embodiment. The changeover switch 10 switches the connection to a pair of taps for each phase of a three-phase AC. The changeover switch 10 has a current-limiting resistor 18, a vacuum valve unit 20, a switch unit 16, a cam unit 14, and an energy storage mechanism 11.

[0016] The current limiting resistor 18 limits the inrush current when the tap is connected. The vacuum valve unit 20 suppresses arcing when the tap is disconnected. The switch unit 16 connects and disconnects the current limiting resistor 18 and other components to and from the tap.

[0017] FIG. 3 is a partial cross-sectional side view of the diverter switch 10. As shown in FIG. The cam unit 14 operates the vacuum valve unit 20 and the switch unit 16. The shaft 13 is disposed at the center of the cam unit 14. The cam unit 14 rotates together with the shaft 13.

[0018] The energy storage mechanism 11 is disposed in the -Z direction of the changeover switch 10 as shown in FIG. 2. The energy storage mechanism 11 has an energy storage spring 12. The energy storage spring 12 is expanded or compressed (energized) by power introduced from the power introduction section 6 (see FIG. 1). The energy storage mechanism 11 releases the stored energy storage spring 12 after the selection operation of the tap selector 2 is completed. The energy storage mechanism 11 rotates the shaft 13 and the cam unit 14 by a predetermined angle by the restoring force of the energy storage spring 12 (release of the stored force). As a result, the energy storage mechanism 11 instantaneously performs the switching operation of the changeover switch 10.

[0019] The vacuum valve unit 20 will now be described in detail. Fig. 4 is an exploded perspective view of the vacuum valve unit 20. Fig. 5 is a side view of the vacuum valve unit 20. As shown in Fig. 4, the vacuum valve unit 20 has a vacuum valve 21 and an opening / closing mechanism 30.

[0020] The vacuum valve 21 has a case 22 , a fixed electrode 23 , and a movable electrode 25 . The case 22 is made of an electrically insulating material and has a cylindrical shape. The inside of the case 22 is maintained in a vacuum.

[0021] The fixed electrode 23 and the movable electrode 25 are housed inside the case 22. The fixed electrode 23 is fixed to the end of the case 22 in the +Z direction. The fixed electrode 23 is conductive to a fixed terminal 24 arranged outside the case 22. The fixed terminal 24 is connected to the circuit of the change-over switch 10.

[0022] The movable electrode 25 is disposed in the -Z direction of the fixed electrode 23. The movable electrode 25 is movable in the Z direction along the central axis of the case 22. An electrode shaft 26 extends in the -Z direction from the movable electrode 25. The tip of the electrode shaft 26 extends to the outside of the case 22. A male screw is formed on the tip of the electrode shaft 26.

[0023] The opening and closing mechanism 30 opens and closes the vacuum valve 21. The opening and closing mechanism 30 is disposed in the -Z direction of the vacuum valve 21. The opening and closing mechanism 30 has a lever 31, a conductor 35, and a cam follower .

[0024] The lever 31 is formed in an L-shape. The lever 31 is rotatable around a rotation shaft 32 disposed in the center of the lever 31. The rotation shaft 32 extends in a direction perpendicular to the R direction and the Z direction. The lever 31 extends from the rotation shaft 32 in the -R direction and the +Z direction.

[0025] The conductor 35 is disposed at a first end of the lever 31. The first end of the lever 31 is a tip portion of the lever 31 extending in the -R direction from the rotation shaft 32. The conductor 35 is rotatable around a conductor shaft 37 disposed at the first end of the lever 31. The conductor shaft 37 is parallel to the rotation shaft 32.

[0026] The conductor connection part 36 is fixed in the +Z direction of the conductor 35. The conductor connection part 36 is formed in a cylindrical (disk) shape. A female thread is formed along the central axis of the conductor connection part 36. The male thread of the electrode shaft 26 is connected to the female thread of the conductor connection part 36.

[0027] A movable terminal 38 is provided on the conductor 35. The movable terminal 38 is electrically connected to the movable electrode 25 via the conductor connection portion 36 of the conductor 35 and the electrode shaft 26. The movable terminal 38 is connected to the circuit of the change-over switch 10.

[0028] The cam follower 34 is disposed at a second end of the lever 31. The second end of the lever 31 is a tip of the lever 31 extending in the +Z direction from the rotation shaft 32. The cam follower 34 is rotatable around a rotation axis along the Z direction. As shown in FIG. 3, the cam follower 34 is capable of abutting against a cam surface on the outer periphery of the cam unit 14.

[0029] Rotation of shaft 13 causes cam unit 14 to push cam follower 34 in the direction of the central axis of vacuum valve 21. Lever 31 rotates, and conductor 35 moves in the -Z direction. Together with conductor connection portion 36 of conductor 35 and electrode shaft 26 shown in Figure 4, movable electrode 25 moves in the -Z direction and moves away from fixed electrode 23. This causes vacuum valve 21 to open.

[0030] Conversely, when the cam unit 14 moves away from the cam follower 34, the conductor 35 moves in the +Z direction as shown in Fig. 5. The movable electrode 25 moves in the +Z direction and comes into contact with the fixed electrode 23. This causes the vacuum valve 21 to close.

[0031] As described above, insulating gas is sealed inside tank body 8 (see FIG. 1). Meanwhile, the inside of case 22 of vacuum valve 21 shown in FIG. 4 is a vacuum. The pressure of the insulating gas acts on movable electrode 25 via conductor 35, conductor connection portion 36, and electrode shaft 26. The insulating gas biases vacuum valve 21 in the direction of closing. This prevents opening due to malfunction of vacuum valve 21.

[0032] In order to improve the electrical insulation performance and temperature rise suppression performance of the insulating gas, it is necessary to increase the pressure of the insulating gas. As the pressure of the insulating gas increases, the biasing force in the direction in which the vacuum valve 21 closes increases. In this case, a large force is required to open the vacuum valve 21.

[0033] In contrast, the vacuum valve unit 20 has a biasing member. For example, the biasing member is a coil spring 40. The coil spring 40 is disposed between the case 22 and the conductor 35. The coil spring 40 is extrapolated to the electrode shaft 26 and the conductor connection portion 36. In other words, the coil spring 40 is disposed coaxially with the electrode shaft 26 and the conductor connection portion 36 and outside the outer periphery of the electrode shaft 26 and the conductor connection portion 36.

[0034] The coil spring 40 is disposed in a compressed state between the case 22 and the conductor 35. Due to the restoring force of the coil spring 40, the conductor 35 receives a force in a direction away from the case 22 (-Z direction). The coil spring 40 biases the vacuum valve 21 in a direction to open the contacts. The biasing force of the coil spring 40 is set to a magnitude equivalent to the increase in the biasing force that accompanies an increase in the pressure of the insulating gas. The biasing force of the coil spring 40 is set to be smaller than the total biasing force due to the pressure of the insulating gas.

[0035] The insulating gas biases the conductor 35 in the +Z direction. When opening the vacuum valve 21, the cam unit 14 (see FIG. 3) moves the conductor 35 in the -Z direction against the biasing force of the insulating gas. The coil spring 40 biases the conductor 35 in the -Z direction. Therefore, even if the pressure of the insulating gas is increased, the cam unit 14 can open the vacuum valve 21 with a small force.

[0036] As described above in detail, the changeover switch 10 of the on-load tap changer 1 of the embodiment has the vacuum valve 21, the switching mechanism 30, and the biasing member. The switching mechanism 30 opens and closes the vacuum valve 21. The biasing member biases the vacuum valve 21 in the opening direction.

[0037] According to this configuration, even when the changeover switch 10 is placed in insulating gas, the vacuum valve 21 can be opened with a small force. Since the electrical insulation performance and temperature rise suppression performance of the insulating gas are increased, even when the pressure of the insulating gas is increased, the vacuum valve 21 can be opened with a small force. Therefore, it is not necessary to increase the spring constant of the energy storage spring 12 of the energy storage mechanism 11. In addition, it is not necessary to increase the rigidity and size of the energy storage mechanism 11. Therefore, the cost of the changeover switch 10 of the on-load tap changer 1 can be reduced. In addition, the pressure of the insulating gas can be freely set according to the required electrical insulation performance and temperature rise suppression performance of the insulating gas.

[0038] The vacuum valve 21 has a fixed electrode 23, a movable electrode 25, a case 22, and an electrode shaft 26. The case 22 houses the fixed electrode 23 and the movable electrode 25, and the inside is maintained in a vacuum. The electrode shaft 26 extends from the movable electrode 25 to the outside of the case 22. The opening / closing mechanism 30 has a conductor 35 that supports a conductor connection part 36 that is connected to the electrode shaft 26. The biasing member is disposed between the case 22 and the conductor 35. According to this configuration, the biasing member is disposed in the empty space of the vacuum valve unit 20. Therefore, an increase in size of the changeover switch 10 of the on-load tap changer 1 is suppressed.

[0039] The biasing member is a coil spring 40 . The coil spring 40 is inexpensive, which reduces the cost of the diverter switch 10 of the on-load tap changer 1.

[0040] The conductor connection portion 36 is formed in a cylindrical shape. The biasing member is a coil spring 40 that is fitted onto the electrode shaft 26 and the conductor connection portion 36. According to this configuration, the coil spring 40 can be easily and stably supported.

[0041] The on-load tap changer 1 of the embodiment includes the diverter switch 10 of the on-load tap changer 1 described above, and a tank body 8. The tank body 8 accommodates the diverter switch 10 and can be filled with insulating gas therein. According to this configuration, the vacuum valve 21 of the change-over switch 10 placed in an insulating gas can be opened with a small force.

[0042] In the embodiment described above, the fixed electrode 23 of the vacuum valve 21 is fixed to the end of the case 22 in the +Z direction. The movable electrode 25 is arranged in the -Z direction of the fixed electrode 23, and the opening and closing mechanism 30 is arranged in the -Z direction of the vacuum valve 21. In contrast, the vacuum valve unit 20 may be inverted in the Z direction. In this case, the fixed electrode 23 of the vacuum valve 21 is fixed to the end of the case 22 in the -Z direction. The movable electrode 25 is arranged in the +Z direction of the fixed electrode 23, and the opening and closing mechanism 30 is arranged in the +Z direction of the vacuum valve 21.

[0043] In the embodiment described above, as an example, the urging member is the coil spring 40. However, the urging member may be something other than the coil spring 40. For example, the urging member may be a torsion spring disposed on the rotation shaft 32 of the opening / closing mechanism 30.

[0044] According to at least one of the embodiments described above, the vacuum valve 21 has a biasing member that biases it in the opening direction. This makes it possible to reduce the cost of the changeover switch 10 of the on-load tap changer 1.

[0045] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0046] 1...on-load tap changer, 8...tank body, 10...changer switch, 21...vacuum valve, 22...case, 23...fixed electrode, 25...movable electrode, 26...electrode shaft, 30...opening / closing mechanism, 35...conductor, 36...conductor connection part, 40...coil spring (biasing member).

Claims

1. A vacuum valve, an opening and closing mechanism for opening and closing the vacuum valve; and a biasing member for biasing the vacuum valve in a direction to open the contacts. Changeover switch for on-load tap changer.

2. The vacuum valve is A fixed electrode and a movable electrode; a case that houses the fixed electrode and the movable electrode and has an interior that is maintained in a vacuum; an electrode shaft extending from the movable electrode to the outside of the case; having the opening and closing mechanism has a conductor supporting a conductor connection part connected to the electrode shaft, The biasing member is disposed between the case and the conductor.

2. A changeover switch for an on-load tap changer according to claim 1.

3. The biasing member is a coil spring.

3. A changeover switch for an on-load tap changer according to claim 1 or 2.

4. The conductor connection portion is formed in a cylindrical shape, the biasing member is a coil spring that is fitted around the electrode shaft and the conductor connection portion; 3. A changeover switch for an on-load tap changer according to claim 2.

5. A changeover switch for an on-load tap changer according to claim 1 or 2; A tank body that houses the change-over switch and can be filled with insulating gas. On-load tap changer.

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