Switchgear

Abstract

An opening / closing device (100) comprises a hermetic container (1), a fixed electrode (5) installed inside the hermetic container (1), and a movable electrode (3) installed movably inside the hermetic container (1). The movable electrode (3) comprises a tubular cylinder (32), a piston (33) installed inside the cylinder (32), a movable-side contactor (31) in a tubular shape smaller in diameter than the cylinder (32) and fixed to the piston (33), a support stand (35) installed inside the movable-side contactor (31), a permanent magnet (36) fixed to the support stand (35), and a rod-shaped member (39) made from a magnetic substance and installed adjacent to the support stand (35) on the side on which the fixed electrode (5) is disposed. The movable-side contactor (31) includes a vent hole formed to pass through in a radial direction. A puffer chamber (41) that is a space formed between the cylinder (32) and the movable-side contactor (31) communicates with a space inside the movable-side contactor (31) through the vent hole.

Description

[Technical Field]

[0001] The present disclosure relates to a switchgear that interrupts current in a sealed container filled with insulating gas. [Background technology]

[0002] A known device for interrupting high voltage current is a switchgear that interrupts current within a sealed container filled with insulating gas. The switchgear includes a fixed electrode fixed within the sealed container and a movable electrode that is movably installed within the sealed container. In a closed state where the movable electrode and the fixed electrode are in contact, the switchgear passes current, and in an open state where the movable electrode is separated from the fixed electrode, the switchgear interrupts current.

[0003] During the opening operation, which transitions from a closed state to an open state, an arc occurs between the movable electrode and the fixed electrode. If an arc exists between the movable electrode and the fixed electrode, current will flow even if the movable electrode and the fixed electrode are not in contact. For this reason, it is necessary to quickly extinguish the arc that occurs between the movable electrode and the fixed electrode during the opening operation.

[0004] Patent Document 1 discloses a technique for cooling and extinguishing an arc by magnetically driving the arc to rotate using magnetic field lines generated by a permanent magnet. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-187829 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the technology disclosed in Patent Document 1, the current interruption performance depends solely on the magnetic driving of the arc, and the structure is based on the premise of a low-speed contact opening operation in order to apply a magnetic driving force to the arc strong enough to cause the arc to rotate. Therefore, when interrupting a high-voltage current that requires a high-speed contact opening operation, the rotation speed of the arc due to the magnetic driving decreases, and the arc cooling performance deteriorates.

[0007] In recent years, in consideration of environmental issues, the insulating gas in sealed containers has been replaced from SF6 gas with dry air. However, since dry air has lower arc-extinguishing performance than SF6 gas, when dry air is used, it is more important to improve the arc cooling performance.

[0008] The present disclosure has been made in view of the above, and has an object to provide a switching device with improved arc cooling performance. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems and achieve the object, a switchgear according to the present disclosure includes a sealed container filled with insulating gas, a fixed electrode installed inside the sealed container, and a movable electrode installed movably inside the sealed container, and the switchgear closes when the movable electrode comes into contact with the fixed electrode and opens when the movable electrode moves away from the fixed electrode. The movable electrode includes a cylindrical cylinder, a piston installed inside the cylinder, a movable contactor that is cylindrical and has a smaller diameter than the cylinder and is fixed to the piston, a support base installed inside the movable contactor, a permanent magnet fixed to the support base, and a magnetic rod-shaped member installed adjacent to the side of the support base where the fixed electrode is located. The movable contactor has a vent hole formed therethrough in the radial direction, and a puffer chamber, which is a space formed between the cylinder and the movable contactor, is connected to the space inside the movable contactor through the vent hole. [Effects of the Invention]

[0010] According to the present disclosure, an effect is achieved in that a switching device with improved arc cooling performance can be obtained. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view of a switching device according to a first embodiment; [Figure 2] 1 is a cross-sectional view of a switching device according to a first embodiment; [Figure 3] FIG. 1 is an enlarged view of a movable portion of a movable electrode of a switching device according to the first embodiment; [Figure 4] FIG. 1 is a perspective view of a support base of an opening and closing device according to a first embodiment; [Figure 5] FIG. 10 is a diagram showing magnetic field lines generated by a permanent magnet of a movable electrode of the switching device according to the first embodiment. [Figure 6] FIG. 10 is a diagram showing an arc-extinguishing operation during a contact-opening operation of the switchgear according to the first embodiment. [Figure 7] FIG. 10 is a diagram showing an arc-extinguishing operation during a contact-opening operation of the switchgear according to the first embodiment. [Figure 8] 10 is a plan view of a support base of a switching device according to a second embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an opening / closing device according to an embodiment will be described in detail with reference to the drawings.

[0013] Embodiment 1 1 and 2 are cross-sectional views of a switchgear according to embodiment 1. The switchgear 100 includes an airtight container 1 filled with insulating gas, a fixed electrode 5 installed inside the airtight container 1, and a movable electrode 3 installed movably inside the airtight container 1. Note that Fig. 1 shows a closed state in which the movable electrode 3 and the fixed electrode 5, which will be described later, are in contact with each other, and Fig. 2 shows an open state in which the movable electrode 3 and the fixed electrode 5 are separated from each other.

[0014] The fixed electrode 5 has a cylindrical fixed contactor 51, and the movable electrode 3 has a cylindrical movable contactor 31 that is thinner than the fixed contactor 51. The outer diameter of the movable contactor 31 is slightly larger than the inner diameter of the fixed contactor 51, and in a closed state, the movable contactor 31 and the fixed contactor 51 are in close contact with each other due to the elastic forces of each of them. In addition, in the arrangement direction of the movable contactor 31 and the fixed contactor 51, the direction from the fixed contactor 51 toward the movable contactor 31 is referred to as the "moving side," and the direction from the movable contactor 31 toward the fixed contactor 51 is referred to as the "fixed side." Furthermore, a state in which the movable contactor 31 and the fixed contactor 51 are in contact with each other is referred to as a "closed state," and a state in which the movable contactor 31 is separated from the fixed contactor 51 is referred to as an "open state." Here, an example is given in which the fixed contactor 51 is cylindrical and has a larger diameter than the movable contactor 31, but the fixed contactor 51 may also be tulip-shaped and inserted into the movable contactor 31.

[0015] In this way, the switching device 100 is closed when the movable electrode 3 comes into contact with the fixed electrode 5, and is opened when the movable electrode 3 moves away from the fixed electrode 5.

[0016] The movable electrode 3 includes, in addition to the movable contactor 31, a cylindrical cylinder 32 having a larger diameter than the movable contactor 31, a piston 33 installed inside the cylinder 32, and a rod 34 to which the piston 33 is fixed. The rod 34 is connected to an operating rod of an operating device (not shown), and moves the piston 33 by a driving force transmitted from the operating device (not shown). As the piston 33 moves, the movable contactor 31 moves inside the cylinder 32.

[0017] 3 is an enlarged view of a movable portion of a movable electrode of a switchgear according to the first embodiment. The movable contactor 31 includes a first portion 311 that comes into contact with and separates from the fixed contactor 51, and a second portion 312 that supports the first portion 311. As shown in FIGS. 1 and 2, the second portion 312 is fixed to the piston 33. A support base 35, a first cylinder 371, and a second cylinder 372 are installed within the movable contactor 31. The support base 35 is made of a non-magnetic material such as a non-magnetic metal or an insulator. The first cylinder 371 is made of a magnetic material, and the second cylinder 372 is made of a non-magnetic material. A permanent magnet 36 is embedded in the support base 35.

[0018] 4 is a perspective view of a support base of the switchgear according to embodiment 1. Support base 35 includes a cylindrical magnet holding portion 351 into which permanent magnet 36 is fitted, and support legs 352 extending radially outward from the outer circumferential surface of magnet holding portion 351.

[0019] The opening on the fixed side of the magnet holder 351 is smaller than the permanent magnet 36, and the opening on the movable side is larger than the permanent magnet 36, and the permanent magnet 36 is fitted into the opening on the movable side. The opening on the movable side of the magnet holder 351 is closed by a cover 38 made of a magnetic material, so that the permanent magnet 36 will not fall off the magnet holder 351.

[0020] 3, the support base 35 is fixed inside the movable contactor 31 by sandwiching the support leg 352 between a first tube 371 and a second tube 372. By forming slits in the first tube 371 and the second tube 372 and fitting the support leg 352 into the slits, it is possible to prevent the support base 35 from rotating around the axis of the movable contactor 31.

[0021] A rod-shaped member 39 is installed adjacent to the permanent magnet 36 on the fixed side. The rod-shaped member 39 is made of a magnetic material, and its movable end is inserted into the magnet holder 351 and is in contact with the permanent magnet 36. An insulating layer 40 is provided on the surface of the rod-shaped member 39 except for the portion that contacts the permanent magnet 36. The insulating layer 40 is formed by wrapping insulating tape around a magnetic core material or molding an insulating material. A cap 42 made of an insulating material is attached to the fixed end of the rod-shaped member 39. Note that if the insulating layer 40 is formed by molding a magnetic material around the rod-shaped member 39, the fixed end of the rod-shaped member 39 can also be covered with the insulating layer 40, eliminating the need for the cap 42. The gap between the rod-shaped member 39 and the movable contact 31 serves as a nozzle portion 60 through which insulating gas passes. The rod-shaped member 39 is installed so that the fixed end of the movable contactor 31 protrudes further toward the fixed contactor 51 than the fixed end of the rod-shaped member 39, or so that the fixed end of the movable contactor 31 and the fixed end of the rod-shaped member 39 are flush with each other.

[0022] A vent hole 312a is formed in the second portion 312 of the movable contact 31 so as to penetrate radially. A puffer chamber 41 is formed between the cylinder 32 and the movable contact 31. The volume of the puffer chamber 41 changes with the movement of the piston 33. In a closing operation in which the open contact state is changed to a closed contact state, the volume of the puffer chamber 41 decreases, and in an opening operation in which the closed contact state is changed to an open contact state, the volume of the puffer chamber 41 increases.

[0023] When the volume of the puffer chamber 41 increases, gas in the sealed container 1 is sucked in through the opening at the fixed end of the movable contactor 31, and a gas flow is generated in the nozzle portion 60 in the gap between the movable contactor 31 and the rod-shaped member 39.

[0024] FIG. 5 is a diagram showing magnetic field lines generated by the permanent magnet of the movable electrode of the switchgear according to the first embodiment. Because the rod-shaped member 39 and the lid 38 are made of a magnetic material, while the support base 35 is made of a non-magnetic material, the magnetic field lines generated by the permanent magnet 36, indicated by arrows in FIG. 5, easily pass through the rod-shaped member 39 and the lid 38 but have difficulty passing through the support leg 352. Furthermore, because the first tube 371 is made of a magnetic material, while the second tube 372 is made of a non-magnetic material, and the rod-shaped member 39 is longer than the lid 38, the magnetic field generated on the fixed side of the permanent magnet 36 is stronger than the magnetic field generated on the movable side of the permanent magnet 36. Note that, although magnetic field lines pass more easily through the rod-shaped member 39 when the rod-shaped member 39 is in close contact with the permanent magnet 36, even if a magnetic gap exists between the rod-shaped member 39 and the permanent magnet 36, the magnetic field generated on the fixed side of the permanent magnet 36 can be stronger than the magnetic field generated on the movable side of the permanent magnet 36. Furthermore, the first cylinder 371 may be made of a non-magnetic material. Even if the first cylinder 371 is made of a non-magnetic material, the magnetic field generated on the fixed side of the permanent magnet 36 can be made stronger than the magnetic field generated on the movable side of the permanent magnet 36 because the rod-shaped member 39 is installed adjacent to the fixed side of the permanent magnet 36.

[0025] 6 and 7 are diagrams illustrating the arc-extinguishing operation during the opening operation of the switchgear according to the first embodiment. FIG. 6 illustrates the arc-extinguishing operation during the opening operation in a cross section of the movable electrode 3, and FIG. 7 illustrates the arc-extinguishing operation during the opening operation in a side view of the movable electrode 3 viewed from the fixed side. In FIG. 6, the gas flow generated by the increase in the volume of the puffer chamber 41 is indicated by dashed arrows, and the magnetic field lines generated by the permanent magnet 36 are indicated by dashed arrows. During the opening operation, when the movable contact 31 separates from the fixed contact 51, an arc 70 is generated between the movable contact 31 and the fixed contact 51. In FIGS. 6 and 7, the arc 70 is generated at position A. Note that in FIG. 7, the direction of the current in the arc 70 is from the front to the back of the page. The arc 70 generated between the movable contact 31 and the fixed contact 51 is sucked into the movable contact 31 by the gas flow generated in the nozzle portion 60 as the volume of the puffer chamber 41 increases. 6 and 7, the arc 70 moves from position A to position B due to the gas flow generated in the nozzle portion 60. As the arc 70 approaches the rod-shaped member 39, it is captured by the magnetic field of the permanent magnet 36. The magnetic field lines emanating from the permanent magnet 36 and passing through the rod-shaped member 39 include components that intersect with the arc 70 generated between the moving contact 31 and the fixed contact 51, so the arc 70 rotates within the magnetic field generated by the permanent magnet 36. In FIGS. 6 and 7, the arc 70 captured by the magnetic field generated by the permanent magnet 36 is drawn in while rotating, moving from position B to position C, and then from position C to position D. During the opening operation, the arc 70 generated between the moving contact 31 and the fixed contact 51 is drawn into the moving contact 31 while rotating, and is thereby elongated, cooled, and extinguished.

[0026] Because an insulating layer 40 is formed on the surface of the rod-shaped member 39, when the arc 70 comes into contact with the insulating layer 40 on the surface of the rod-shaped member 39, the heat of the arc 70 evaporates the insulator that forms the insulating layer 40, generating insulating gas. The insulating gas generated from the insulating layer 40 on the surface of the rod-shaped member 39 mixes with the arc 70, further cooling the arc 70 and making it easier to extinguish. If the insulating layer 40 is worn away by the arc 70, the rod-shaped member 39 can be removed from the support base 35 and rewrapped with insulating tape or replaced with another rod-shaped member 39, thereby restoring it to its original state.

[0027] The switchgear 100 according to the first embodiment forcibly generates a gas flow at the opening on the fixed side of the movable contactor 31, and applies a rotational driving force to the arc 70 by the rod-shaped member 39 made of a magnetic material and the permanent magnet 36, thereby improving the cooling performance of the arc 70. Therefore, the switchgear 100 according to the first embodiment can obtain interrupting performance that satisfies the required switching duty even if dry air is used as the insulating gas sealed in the sealed container 1.

[0028] Embodiment 2 The switching device 100 according to the second embodiment is similar to the switching device 100 according to the first embodiment except for the support base 35. Fig. 8 is a plan view of the support base of the switching device according to the second embodiment. The support base 35 of the switching device 100 according to the second embodiment has support legs 352 that extend obliquely with respect to the axial direction of the magnet holding portion 351. The switching device 100 according to the second embodiment is used for interrupting direct current.

[0029] In the switchgear 100 according to the second embodiment, the support legs 352 of the support base 35 installed in the movable contactor 31 extend in a direction oblique to the axial direction of the magnet holder 351, and therefore a spiral gas flow is generated in the movable contactor 31 during the contact opening operation. By aligning the rotation direction of the gas flow generated in the movable contactor 31 with the direction of rotational drive of the arc 70 by the rod-shaped member 39 and the permanent magnet 36, the rotational drive of the arc 70 during the contact opening operation is promoted, and the cooling performance of the arc 70 can be further improved.

[0030] The configurations shown in the above embodiments are merely examples of the content, and may be combined with other known technologies, or parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0031] 1 sealed container, 3 movable electrode, 5 fixed electrode, 31 movable contactor, 32 cylinder, 33 piston, 34 rod, 35 support base, 36 permanent magnet, 38 lid, 39 rod-shaped member, 40 insulating layer, 41 puffer chamber, 42 cap, 51 fixed contactor, 60 nozzle portion, 70 arc, 100 switchgear, 311 first portion, 312 second portion, 312a ventilation hole, 351 magnet holder, 352 support leg, 371 first cylinder, 372 second cylinder.

Claims

1. A switching device comprising: a sealed container filled with insulating gas; a fixed electrode installed inside the sealed container; and a movable electrode installed movably inside the sealed container, wherein the movable electrode is brought into contact with the fixed electrode to close the switch; and the movable electrode is separated from the fixed electrode to open the switch; The movable electrode is A cylindrical cylinder; a piston disposed within the cylinder; a movable contactor having a cylindrical shape with a smaller diameter than the cylinder and fixed to the piston; a support base installed within the movable contact; a permanent magnet fixed to the support base; a magnetic rod-shaped member disposed adjacent to the support base on a side where the fixed electrode is disposed, The movable contactor has a vent hole formed therethrough in the radial direction, A switching device characterized in that a puffer chamber, which is a space formed between the cylinder and the movable contact, is connected to a space within the movable contact through the ventilation hole.

2. The opening and closing device according to claim 1 , wherein the rod-shaped member is in close contact with the permanent magnet.

3. 2. The opening and closing device according to claim 1, wherein the support base is made of a non-magnetic material.

4. 2. The switching device according to claim 1, wherein the rod-shaped member is installed so that the fixed end of the movable contactor protrudes further toward the fixed electrode than the fixed end of the rod-shaped member, or so that the fixed end of the movable contactor and the fixed end of the rod-shaped member are flush with each other.

5. 2. The switchgear according to claim 1, wherein an insulating layer is provided on a surface of the rod-shaped member.

6. the support base includes a cylindrical magnet holding portion into which the permanent magnet is fitted, and support legs extending radially outward from an outer circumferential surface of the magnet holding portion, 6. The opening and closing device according to claim 1, wherein the support legs extend in a direction oblique to an axial direction of the magnet holding portion.

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