Switching device

Abstract

A switchgear (100) is provided with a pair of electrodes (1A, 1B) that are disposed so that electrode surfaces (SA, SB) are opposing in a first direction, and that can be brought close together and father apart to / from one another in the first direction. Accommodation holes (HA, HB) indented from the electrode surfaces (SA, SB) are formed in each of the electrodes (1A, 1B). Magnets (10) are respectively accommodated in the accommodation holes (HA, HB) of the electrodes (1A, 1B) so as to have opposing polarities magnetically attracted to one another between the electrodes (1A, 1B). Ferromagnets (20) for covering magnet surfaces (10S) are respectively disposed on the magnet surfaces (10S) that are part of the magnets (10) accommodated respectively in the electrodes (1A, 1B) and that are opposing between the electrodes (1A, 1B). First substances (21) having a lower relative magnetic permeability than that of the ferromagnets (20) are disposed in proximity to a magnet lateral surface of the magnets (10) that runs along the first direction.

Description

Technical Field

[0001] This application relates to an opening / closing device.

Background Art

[0002] An opening / closing device, which is one of the high-voltage power distribution facilities, is used to interrupt the current in case of a failure or abnormality of the high-voltage power distribution facilities. Generally, a gas-insulated switchgear houses switching devices such as a circuit breaker, a disconnector, and an earthing switch that intermittently conduct current by contacting and separating a pair of electrodes arranged opposite to each other in a container filled with an insulating gas such as SF6 gas (sulfur hexafluoride gas) or dry air. When the pair of electrodes are separated to form an open pole, an arc, which is a discharge phenomenon, occurs between the electrodes. In each switching device, a performance to quickly extinguish the arc generated at the time of opening the pole is required to ensure insulation.

[0003] In the case where the insulating gas inside the gas-insulated switchgear is SF6 gas with high interruption performance, the arc can be extinguished by the subsequent parallel cut-off method. However, in the case of dry air with an interruption performance about 1 / 100 that of SF6 gas, it is known that arc extinction is difficult. The parallel cut-off method is a method of interrupting the current by stretching the path of the arc current generated at the time of opening the pole by a driving device. As technologies for improving the current interruption performance, a quick cut-off method and a magnetic drive method are known. The quick cut-off method is a method that includes a quick-acting mechanism on one side of the electrode and obtains the interruption performance by stretching the arc to a length required for arc extinction within a time when damage to the contact of the electrode does not occur by increasing the separation speed of the electrode. The magnetic drive method is a method of obtaining the interruption performance by magnetically driving the arc by installing a magnet in the opening / closing device. An opening / closing device having the following configuration including such a quick cut-off method and a magnetic drive method has been disclosed.

[0004] In other words, conventional switching devices are provided with a second electrode that is driven to move toward and away from a first electrode, and the electrical conductivity between the electrodes is maintained by the attractive force of magnets placed inside each electrode. The circuit between the first terminal and the second terminal is opened by separating the first electrode and the second electrode, and the first electrode is connected to the first terminal by a spring. This opening of the circuit between the first terminal and the second terminal utilizes the attractive force of the magnets between the second electrode, which is driven in the opening direction while maintaining conductivity, and the first electrode, and the restoring force of the spring that connects the first electrode. The arc generated by the separation of the first electrode and the second electrode is interrupted by rotating in the circumferential direction of the electrode due to the magnetic field created by the magnet, being stretched and cooled (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 7162782 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] In the conventional switchgear described above, the arc generated when the current is interrupted is extinguished by rotating the electrode circumferentially using the magnetic field created by the magnet, and by increasing the separation speed of the electrodes using the restoring force of the spring that holds the first electrode, thereby instantaneously extending its path. However, if the magnetic attraction force of the magnets placed inside the first and second electrodes is weak, the contact between the first and second electrodes may be released before the restoring force of the spring holding the first electrode is accumulated, resulting in insufficient separation speed and, consequently, a decrease in arc interruption performance. Increasing the size of the magnets to ensure sufficient magnetic force increases the price of the magnets, and the weight of the electrodes also increases, leading to higher prices for peripheral equipment that drives the electrodes. Therefore, the problem of increased costs arises. This application discloses technology to solve the above-mentioned problems, and aims to provide a low-cost switchgear while ensuring arc interruption performance. [Means for solving the problem]

[0007] The opening and closing device disclosed in this application is A switching device comprising a pair of electrodes arranged with their respective electrode surfaces facing each other in a first direction and capable of moving toward and away from each other in the first direction, Each of the electrodes has a recessed housing hole formed in the electrode surface. Magnets are housed in the housing holes of each electrode such that the polarities of the electrodes that attract each other by magnetic force are opposite. A ferromagnetic material covering the magnet surface is disposed on each of the magnet surfaces facing each other between the electrodes of the magnet housed in each of the electrodes, and a first material having a relative permeability lower than that of the ferromagnetic material is disposed adjacent to the magnet side surface of each magnet along the first direction. It is. [Effects of the Invention]

[0008] According to the switchgear disclosed herein, a low-cost switchgear can be obtained while ensuring arc interruption performance. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view showing the schematic configuration of the opening / closing device according to Embodiment 1. [Figure 2] This is a conceptual diagram illustrating the magnetic properties of the switchgear according to Embodiment 1. [Figure 3] This is a cross-sectional view showing another configuration of the opening / closing device according to Embodiment 1. [Figure 4] This is a cross-sectional view showing the schematic configuration of the opening / closing device according to Embodiment 2. [Figure 5] This is a cross-sectional view showing the schematic configuration of the opening / closing device according to Embodiment 3. [Figure 6]This is a conceptual diagram showing the current path in the switchgear according to Embodiment 3. [Modes for carrying out the invention]

[0010] Embodiment 1. The switchgear of this embodiment is provided in gas-insulated switchgear used in power distribution equipment, vehicle equipment, etc., and is designed to interrupt the current in the event of an abnormality. Figure 1 is a cross-sectional view showing the schematic configuration of the opening / closing device 100 according to Embodiment 1. As shown in Figure 1, the switching device 100 includes a first electrode 1A and a second electrode 1B, which are a pair of electrodes that can move toward and away from each other. These first electrode 1A and second electrode 1B are cylindrical in shape and are housed inside the hollow cylindrical first terminal 2A and second terminal 2B, respectively. Figure 1 shows the open electrode state where the first electrode 1A and the second electrode 1B are separated.

[0011] In the figure, the axial and radial directions of the cylindrical first electrode 1A and second electrode 1B are shown as X and Y, respectively. In the following explanation, unless otherwise distinguished, the first electrode 1A and the second electrode 1B will simply be referred to as electrode 1.

[0012] The first electrode 1A and the second electrode 1B have recessed housing holes HA and HB formed on their respective electrode surfaces SA and SB, which face each other in the axial direction X, which is the first direction. A cylindrical magnet 10 is housed in these housing holes HA and HB, respectively. The magnet 10 has a side cover 21 attached to its side along the axial direction X, and is fixed to the inner surface of the housing holes HA and HB by this side cover 21. Furthermore, opposing covers 20 are provided on the magnetic surfaces 10S of the first electrode 1A magnet 10 and the second electrode 1B magnet 10, respectively, which face each other in the axial direction X.

[0013] Here, the magnets 10 provided on the first electrode 1A and the second electrode 1B respectively are arranged such that when the first electrode 1A and the second electrode 1B are brought close to each other, the magnetic poles attracting each other due to magnetic force face each other. In this embodiment, the S-pole side is arranged on the electrode surface SA side of the first electrode 1A, and the N-pole side is arranged on the electrode surface SB side of the second electrode 1B.

[0014] The material of the facing cover 20 is a ferromagnetic material such as iron or nickel. Also, the material of the side cover 21 is a first substance having a lower relative permeability than ferromagnetic materials such as iron or nickel. In this embodiment, the first substance constituting the side cover 21 is a non-magnetic material such as aluminum or stainless steel having a relative permeability of 10 or less.

[0015] The first electrode 1A and the second electrode 1B are each supported by guide components (not shown) so as to be movable in the axial direction X inside the hollow cylindrical first terminal 2A and second terminal 2B. Further, the second electrode 1B is connected to a drive device (not shown) that drives the second electrode 1B in the axial direction X so that the second electrode 1B can contact and separate from the first electrode 1A.

[0016] Also, a contact 5A is provided on the outer peripheral surface of the first electrode 1A, and a contact 5B is provided on the outer peripheral surface of the second electrode 1B. The first electrode 1A and the second electrode 1B are electrically connected to the first terminal 2A and the second terminal 2B installed outside in the radial direction Y through these contacts 5A and 5B. When the first electrode 1A is moved by the drive device to the one X1 side in the axial direction, which is the direction of the arrow D shown in FIG. 1, and contacts the second electrode 1B, an energization path through the first terminal 2A and the second terminal 2B is formed, and power is transmitted.

[0017] Also, a movement stopper 7 is attached to the outer peripheral surface of the first electrode 1A. When the first electrode 1A moves in the axial direction X, the outer end face 7OUT on the outer side in the radial direction Y of this movement stopper 7 slidably contacts the inner peripheral surface of the first terminal 2A. Furthermore, a fixed stopper 6 is attached to the inner circumferential surface of the first terminal 2A. When the first electrode 1A moves in the axial direction X, the inner end face 6IN of the fixed stopper 6 in the radial direction Y slides against the outer circumferential surface of the first electrode 1A. Since the fixed stopper 6 is fixed to the first terminal 2A, its axial position X does not change even when the first electrode 1A moves in the axial direction X. A spring 8 is installed between the moving stopper 7 and the fixed stopper 6, and the spring 8 expands and contracts in accordance with the axial movement of the first electrode 1A in the axial direction X.

[0018] The contact and separation operations between the first electrode 1A and the second electrode 1B in the switchgear 100 configured as described above will now be explained. To close the electrode by bringing the first electrode 1A and the second electrode 1B into contact, as described above, the drive device moves the second electrode 1B axially in the direction of arrow D, towards the X1 side, and brings it into contact with the first electrode 1A to create conductivity. At this time, the contact between the first electrode 1A and the second electrode 1B is maintained by the magnetic attraction force between the magnets 10 provided on the first electrode 1A and the second electrode 1B, respectively.

[0019] To separate the first electrode 1A and the second electrode 1B, which are in contact, the drive device moves the second electrode 1B in the opposite direction of arrow D, to the other axial direction X2. At this time, the first electrode 1A maintains contact with the second electrode 1B due to the magnetic attraction force of the magnet 10, and therefore moves together with the second electrode 1B to the other axial direction X2 while maintaining contact with the second electrode 1B. When the first electrode 1A moves to the other axial direction X2, the movement stopper 7 fixed to the first electrode 1A also moves to the other axial direction X2, compressing the spring 8 and accumulating its restoring force.

[0020] When the drive mechanism moves the second electrode 1B further axially to the other X2 side, the magnetic attraction between the first electrode 1A and the second electrode 1B is released when the restoring force of the spring 8 and the magnetic force between the magnets 10 balance each other, and the first electrode 1A moves vigorously axially to the other X1 side in response to the restoring of the spring 8 and opens. By utilizing the restoring force of the energized spring 8 to open the electrode 1 in this way, the separation speed between the first electrode 1A and the second electrode 1B increases, so that the current path can be extended to the length necessary for arc extinguishing within a time that does not cause damage to the electrode 1, and high arc current interruption performance can be obtained.

[0021] Here, the results of the analysis of the magnetic properties of the switchgear 100 of this embodiment will be explained with reference to the figures. Figure 2 is a conceptual diagram illustrating the magnetic characteristics of the electrode 1 in the switchgear 100 according to Embodiment 1 when it is closed. In this embodiment, the switching device 100 has, as described above, a face cover 20 made of a ferromagnetic material provided on each of the magnet surfaces 10S facing each other between the electrodes 1. Furthermore, a side cover 21 made of aluminum, stainless steel, or the like as a first material having a lower relative permeability than the face cover 20 is provided adjacent to the magnetic side surface of the magnet 10.

[0022] The inventors of this invention have repeatedly analyzed the magnetic properties of a switchgear 100 with such a configuration and have discovered that the magnetic attraction force of the magnet 10 between the electrodes 1 increases. This is thought to be because, in the switchgear 100 of this embodiment, a magnetic circuit formed by the magnetic flux M2 passing through the inside of the side cover 21 of the magnet 10, as shown in Figure 2, is not formed, and as a result, the magnetic flux density of the magnetic flux M1 having a component parallel to the axial direction X between the electrodes 1 increases.

[0023] Furthermore, the arc current flowing between the electrodes 1 flows in a manner that expands outward in the radial direction Y. That is, the arc current flows at an angle greater than a certain angle with respect to the magnetic flux M1 having an axial component X. Therefore, when the magnetic flux density of the magnetic flux M1 having an axial component X between the electrodes 1 increases in this way, the radial and circumferential Lorentz forces acting on the arc current also increase. The inventors of this application have discovered that this allows the arc generated between the electrodes 1 to be quickly extinguished by rotating it on the outer circumference of the electrodes 1 outside the radial direction Y. Thus, the switching device 100 of this embodiment has a configuration that can supply a strong magnetic field necessary for arc extinguishing to the arc at the same time that the pair of electrodes 1 separate.

[0024] Furthermore, the inventors discovered that the adhesion of foreign magnetic material generated by the arc to the opposing cover 20 was suppressed. This is thought to be because, as described above, the Lorentz force outward in the radial direction Y increased, causing the arc current to quickly move from the opposing cover 20 to the outer circumference of the electrode 1 outside the radial direction Y. In this way, the adhesion of irregularities caused by foreign material to the surface of the electrode 1 is suppressed, ensuring a secure contact state between the electrodes 1, and preventing demagnetization and damage to the magnet 10 due to the arc.

[0025] Furthermore, as a result of the inventors' diligent efforts, they discovered that the magnetic flux density of the magnetic flux M1 having a component parallel to the X-axis between the electrodes 1 can be increased when the switching device 100 is configured as follows. Figure 3 is a partially enlarged cross-sectional view showing another configuration example of the opening / closing device 100 according to Embodiment 1. As shown in Figure 3, the radial length W1 of the face cover 20, which is perpendicular to the axial direction X, is set to be smaller by a set dimension than the radial length W2 of the magnet 10. In this embodiment, the radial length W1 of the face cover 20 is set to be approximately 5% to 12% smaller than the radial length W2 of the magnet 10. By using this dimensional relationship, the magnetic flux density of the magnetic flux M1 having a component parallel to the X axis between the electrodes 1 can be made larger.

[0026] Furthermore, through diligent efforts by the inventors, they discovered that by making the length W1 in the radial direction Y, which is perpendicular to the axial direction X of the opposing cover 20, larger than the length W3 in the axial direction X of the opposing cover 20, i.e., its thickness, the magnetic flux density of the magnetic flux M1 having a component parallel to the axial direction X between the electrodes 1 can be increased.

[0027] In the above, aluminum, stainless steel, etc., were shown as the first material constituting the side cover 21 placed on the side of the magnet 10, but it is not limited to these. The first material placed on the side of the magnet 10 can be any material with a lower relative permeability than the face cover 20 which is made of a ferromagnetic material, and may be, for example, a gas or an insulator. When the gas is placed on the side of the magnet 10 as the first substance, a gap should be provided between the magnet 10 and the inner circumferential surface of the housing holes HA and HB. In this case, for example, the magnet 10 can be fixed to the bottom surface of the housing holes HA and HB with an adhesive or the like.

[0028] Furthermore, if the relative permeability of the material constituting electrode 1 is lower than the relative permeability of the face cover 20, which is made of a ferromagnetic material, the side cover 21 does not need to be provided. In this case, electrode 1 itself becomes the first material placed on the side of the magnet 10.

[0029] Furthermore, while the above description shows the axial length X of the side cover 21 as being long enough to cover the entire side of the magnet 10, it is not limited to this. Even if the side cover 21 is shorter than the axial length X of the magnet 10, the above-described effect will be achieved as long as it covers at least a portion of the electrode surfaces SA and SB on the side of the magnet 10. Furthermore, the side cover 21 does not need to be attached around the entire circumference of the side of the magnet 10; the same effect can be achieved by attaching it to only a portion of the circumferential surface of the side of the magnet 10.

[0030] The opening and closing device of this embodiment, configured as described above, A switching device comprising a pair of electrodes arranged with their respective electrode surfaces facing each other in a first direction and capable of moving toward and away from each other in the first direction, Each of the electrodes has a recessed housing hole formed in the electrode surface. Magnets are housed in the housing holes of each electrode such that the polarities of the electrodes that attract each other by magnetic force are opposite. A ferromagnetic material covering the magnet surface is disposed on each of the magnet surfaces facing each other between the electrodes of the magnet housed in each of the electrodes, and a first material having a relative permeability lower than that of the ferromagnetic material is disposed adjacent to the magnet side surface of each magnet along the first direction. It is.

[0031] In this configuration, a ferromagnetic material is placed on the magnetic surface of each magnet attached to each electrode, and a first material with a lower relative permeability than the ferromagnetic material is placed on the side surface of the magnet. As a result, the magnetic attraction force is greater than that of a single magnet, allowing for miniaturization, weight reduction, and cost reduction of the magnet. Furthermore, because the magnetic flux density with an axial X component between the electrodes increases, the generated arc can be quickly extinguished. This suppresses the decrease in the magnetic force of the magnet due to the arc, ensuring a stable magnetic attraction force, and also stabilizes the current interruption performance. In addition, it provides the effect of mitigating the electric field and protecting the electrodes from damage caused by the arc.

[0032] Furthermore, in the opening and closing device of this embodiment configured as described above, The length of the ferromagnetic material in the direction perpendicular to the first direction is set to be smaller by a predetermined amount than the length of the magnet in the direction perpendicular to the first direction. Furthermore, in the opening and closing device of this embodiment configured as described above, The length of the ferromagnetic material in the direction perpendicular to the first direction is set to be greater than the length of the ferromagnetic material in the first direction.

[0033] By using this dimensional relationship, the magnetic flux density of the magnetic flux having a component parallel to the X-axis between the electrodes can be increased.

[0034] Embodiment 2. Hereinafter, Embodiment 2 of the present application will be described with reference to the figures, focusing on the differences from Embodiment 1 described above. Parts similar to those in Embodiment 1 are denoted by the same reference numerals and their description is omitted. Figure 4 is a cross-sectional view showing the schematic configuration of the opening / closing device 200 according to Embodiment 2. As shown in Figure 4, each electrode 1 has a recess 20G formed in the opposing cover 20 that is recessed in the axial direction X. By providing such recesses 20G, the contact area between the opposing covers 20 is reduced when the electrodes 1 are closed, thereby increasing the magnetic flux density passing through the opposing covers 20 and increasing the magnetic attraction force of the magnet 10 between the electrodes 1. This makes it possible to miniaturize the magnet.

[0035] Furthermore, if the recess 20G is provided on at least one of the two opposing covers 20, the contact area between the opposing covers 20 can be reduced. Furthermore, the contact area between the opposing covers 20 is adjusted to take magnetic saturation into consideration.

[0036] Furthermore, the inventors of this application, through repeated magnetic analysis, discovered that by configuring the switching device 200 as follows, the magnetic attraction force, which is the force of attraction between each magnet 10 between the electrodes 1, becomes larger. In other words, the depth W4 in the axial direction X of the recess 20G of the face cover 20 is made smaller than the length W1 in the radial direction Y, which is perpendicular to the X-axis of the face cover 20.

[0037] In the opening and closing device of this embodiment configured as described above, At least one of the ferromagnetic materials disposed on each of the electrodes has a recess formed in it that is recessed from each of the opposing surfaces between the electrodes. It is. Furthermore, in the opening and closing device of this embodiment configured as described above, The depth of the recess in the ferromagnetic material in the first direction is configured to be smaller than the length of the ferromagnetic material in the direction perpendicular to the first direction. It is. This allows for an even greater magnetic attraction force, enabling the magnets to be miniaturized, lighter, and less expensive.

[0038] Embodiment 3. Hereinafter, Embodiment 3 of the present application will be described with reference to the figures, focusing on the differences from Embodiment 1 described above. Parts similar to those in Embodiment 1 are denoted by the same reference numerals and their description is omitted. Figure 5 is a cross-sectional view showing the schematic configuration of the opening / closing device 300 according to Embodiment 3. Figure 6 is a conceptual diagram showing the current path in the switchgear 300 according to Embodiment 3.

[0039] In the opening / closing device 300 of this embodiment, an insulating tape 22 is placed between the side surface of the magnet 10 and the inner walls of the housing holes HA and HB, acting as an insulator. When electrode 1 is opened, if the arc is ignited between the side covers 21 rather than between the electrode surfaces SA and SB of electrode 1, current may flow through the path magnet 10 → opposite cover 20 → electrode 1. In this case, the magnet 10 is demagnetized by the current, and its magnetic attraction force decreases. However, by providing an insulating layer of insulating tape 22 around the magnet 10, as shown in Figure 6, current i flows through a path that avoids the magnet 10.

[0040] The insulating tape 22 may be placed between the magnet 10 and the side cover 21, or between the outside of the side cover 21 and the inner walls of the housing holes HA and HB. Even when insulating tape 22 is provided between the outside of the side cover 21 and the inner walls of the housing holes HA and HB, current can be prevented from flowing from the electrode 1 side to the magnet 10 side, thus providing an effect of preventing demagnetization of the magnet.

[0041] In the opening and closing device of this embodiment configured as described above, An insulator is disposed between the magnet and the inner wall of the housing hole. It is. This prevents the magnet from being demagnetized by the electric current, which would reduce its magnetic attraction force, thus ensuring a stable magnetic attraction force between the electrodes.

[0042] Although this application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but can be applied individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are conceivable within the scope of the art disclosed herein. These include, for example, modifying, adding or omitting at least one component, or even extracting at least one component and combining it with components of other embodiments. [Explanation of Symbols]

[0043] 1A First electrode, 1B Second electrode, 10 Magnet, 10S Magnet surface, 20 Opposite cover (ferromagnetic material), 20G Recess, 21 Side cover (first material), 22 Insulating tape (insulator), 100, 200, 300 Switching device, HA, HB Housing holes, SA, SB Electrode surfaces.

Claims

1. A switching device comprising a pair of electrodes arranged with their respective electrode surfaces facing each other in a first direction and capable of moving toward and away from each other in the first direction, Each of the electrodes has a recessed housing hole formed in the electrode surface. Magnets are housed in the housing holes of each electrode such that the polarities of the electrodes that attract each other by magnetic force are opposite. A ferromagnetic material covering the magnet surface is disposed on each of the magnet surfaces facing each other between the electrodes of the magnet housed in each of the electrodes, and a first material having a relative permeability lower than that of the ferromagnetic material is disposed adjacent to the magnet side surface of each magnet along the first direction. Switching device.

2. At least one of the ferromagnetic materials disposed on each of the electrodes has a recess formed in it that is recessed from each of the opposing surfaces between the electrodes. The opening and closing device according to claim 1.

3. An insulator is disposed between the magnet and the inner wall of the housing hole. The opening and closing device according to claim 1.

4. An insulator is disposed between the magnet and the inner wall of the housing hole. The opening and closing device according to claim 2.

5. The length of the ferromagnetic material in the direction perpendicular to the first direction is set to be smaller by a predetermined dimension than the length of the magnet in the direction perpendicular to the first direction. The opening and closing device according to claim 1.

6. The length of the ferromagnetic material in the direction perpendicular to the first direction is set to be smaller by a set dimension than the length of the magnet in the direction perpendicular to the first direction. The opening and closing device according to claim 2.

7. The length of the ferromagnetic material in the direction perpendicular to the first direction is set to be smaller by a specified dimension than the length of the magnet in the direction perpendicular to the first direction. The opening and closing device according to claim 3.

8. The length of the ferromagnetic material in the direction perpendicular to the first direction is set to be greater than the length of the ferromagnetic material in the first direction. The opening and closing device according to any one of claims 1 to 7.

9. The depth of the recess in the ferromagnetic material in the first direction is configured to be smaller than the length of the ferromagnetic material in the direction perpendicular to the first direction. The opening and closing device according to claim 2.

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