Gas-insulated switchgear

Abstract

To attain downsizing of a housing and reduction in usage of an insulating gas.SOLUTION: A switchgear (1) comprises: a housing (10) which is filled with an insulating gas; an opening / closing shaft (20) which is provided while penetrating the housing; a holding section (30) which holds the opening / closing shaft at a penetration position of the housing while keeping airtightness of the housing; and a plurality of electrodes (40) of which the electrical connections with the opening / closing shaft are switched by driving the opening / closing shaft. The opening / closing shaft includes: a linking section (21) which is connected to an operation mechanism (3) outside of the housing; a movable contact (23) which electrifies the plurality of electrodes (40) in contact therewith; and an insulation section (22) which is provided between the linking section and the movable contact. The electrode to be electrically connected with the movable contact is changed, thereby switching an electrified state, a disconnected state and a grounded state. The insulation section is disposed inside of the housing as a whole in the electrified state and the disconnected state, and the insulation section is partially disposed from the holding section to the outside of the housing in the grounded state.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a gas-insulated switchgear, and more particularly to a gas-insulated switchgear used for power receiving and distribution equipment.

Background Art

[0002] In the gas-insulated switchgear disclosed in Patent Document 1, an insulating gas such as SF6 gas is enclosed in a housing, and it is configured to include fixed electrodes, movable electrodes, insulating operating rods, etc. Further, Patent Document 1 also discloses a gas-insulated switchgear having a grounding disconnection function. Such a gas-insulated switchgear drives a movable electrode via an insulating operating rod by a three-position electromagnetic operator, and can be switched to any one of an on state, a disconnection state, and a grounding state by changing the fixed electrode to which the movable electrode is electrically connected.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the gas-insulated switchgear having the above-described grounding disconnection function, in all of the on state, the disconnection state, and the grounding state, the insulating operating rod is arranged in the housing in which the SF6 gas is enclosed. For this reason, there is a problem that the housing becomes large in the axial direction of the insulating operating rod, and the amount of SF6 gas used in the housing also increases.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide a gas-insulated switchgear capable of reducing the size of the housing and reducing the amount of insulating gas used.

Means for Solving the Problems

[0006] A gas-insulated switchgear according to one embodiment of the present invention comprises a housing filled with insulating gas, an opening / closing shaft provided through the housing, an operating mechanism provided on the outside of the housing for driving the opening / closing shaft, a holding portion for holding the opening / closing shaft at the position where it passes through the housing while maintaining airtightness inside the housing, and a plurality of electrodes provided on the inside of the housing on the same axis as the opening / closing shaft, the electrical connection with the opening / closing shaft being switched by driving the opening / closing shaft, wherein the opening / closing shaft comprises a connecting portion connected to the operating mechanism on the outside of the housing, a movable contact that contacts the plurality of electrodes and conducts current, and an insulating portion provided between the connecting portion and the movable contact, wherein the electrode electrically connected to the movable contact among the plurality of electrodes changes when the opening / closing shaft is driven, thereby switching between a powered state, a disconnected state and a grounded state, the entire insulating portion being located inside the housing in the powered state and the disconnected state, and a part of the insulating portion being located outside the housing from the holding portion in the grounded state. [Effects of the Invention]

[0007] According to the present invention, the opening / closing shaft penetrates the housing, and a portion of the insulating part of the opening / closing shaft is positioned to protrude to the outside of the housing when grounded. This allows for a smaller housing compared to a configuration in which all of the insulating part is contained inside the housing when grounded, and consequently, a reduction in the amount of insulating gas used to seal the housing. [Brief explanation of the drawing]

[0008] [Figure 1] Figures 1A to 1C are schematic cross-sectional views of a gas-insulated switchgear according to an embodiment. [Figure 2] This is a schematic cross-sectional view of the holding portion and its surrounding area. [Figure 3] Figure 3A is a schematic cross-sectional view of the opening / closing shaft, and Figure 3B is an enlarged view of section A in Figure 3A. [Modes for carrying out the invention]

[0009] Hereinafter, a gas-insulated switchgear according to an embodiment of the present invention (hereinafter simply referred to as "switchgear") will be described in detail with reference to the attached drawings. It should be noted that the present invention is not limited to the embodiments described below, and can be implemented with appropriate modifications without altering its essence. In the following figures, some components may be omitted for the sake of clarity.

[0010] The present invention is applicable, for example, to cubicle-type gas-insulated switchgear (C-GIS; hereinafter simply referred to as "switchgear"). However, the switchgear to which the present invention is applied is not limited to this and can be modified as appropriate. For example, it can also be applied to other gas-insulated switchgears that are not of the cubicle type.

[0011] Figures 1A to 1C are schematic cross-sectional views of a gas-insulated switchgear according to an embodiment. As shown in Figure 1A, the switchgear 1 comprises a metal housing 10 that forms a sealed internal space and is filled with an insulating gas (arc-extinguishing gas) such as SF6 gas. Hereinafter, in this specification and the claims, "up," "down," "left," and "right" are used with reference to Figures 1 to 3.

[0012] Figure 1A shows a partition wall 11 that is provided vertically as part of the housing 10. The right side of the partition wall 11 in Figure 1A is formed as an inner space filled with insulating gas, and the left side in the same figure is the outer space where air is present.

[0013] The opening / closing device 1 further comprises an operating mechanism 3 provided on the outside of the housing 10, and an opening / closing shaft 20 connected to the operating mechanism 3, extending in the left-right direction and penetrating the partition wall 11 of the housing 10. The operating mechanism 3, although a detailed illustration is omitted, transmits driving force from an appropriate rotating mechanism or cylinder or other drive source to the opening / closing shaft 20 via a lever or link mechanism, and drives the opening / closing shaft 20 between the three positions shown in Figures 1A to 1C.

[0014] The opening / closing device 1 further comprises a holding part 30 that is attached to the partition wall 11 of the housing 10 and holds the opening / closing shaft 20, and a plurality of electrodes 40 arranged in a left-right direction inside the housing 10. The plurality of electrodes 40 include an input electrode 41 located on the right side in Figure 1A, two cut-off electrodes 42 located to the left of the input electrode 41, and a ground electrode 43 located to the left of the cut-off electrodes 42.

[0015] The input electrode 41, the cut-off electrode 42, and the ground electrode 43 are each formed in a ring shape that can pass through while contacting the movable contact 23 of the opening / closing shaft 20 (described later), and are arranged side by side on the same axis as the opening / closing shaft 20.

[0016] The input electrode 41 is connected to the first conductor 46 while being held via a holder 45. The two cutting electrodes 42 are held side by side via a cylindrical holder 47 and connected to the second conductor (not shown) via the cylindrical holder 47. An opening / closing shaft 20 that contacts the cutting electrodes 42 can be inserted into the inside of the cylindrical holder 47. Either the first conductor 46 or the second conductor is connected to a power source (not shown), and the other is connected to a load (not shown).

[0017] The grounding electrode 43 is held via a holder 48 and connected to a grounding conductor 49. The grounding conductor 49 is supported via a base member 12 attached to the inner surface of the partition wall 11 of the housing 10. The grounding conductor 49 comprises a plate-shaped portion 49a interposed between the base member 12 and the holder 48, and an axial portion 49b connected to the plate-shaped portion 49a and penetrating the base member 12 in the left-right direction. The penetrating portion of the axial portion 49b in the base member 12 is inserted into a base hole 13 formed in the partition wall 11, allowing the axial portion 49b of the grounding conductor 49 to be connected to the ground potential on the outside of the housing 10.

[0018] Figure 2 is a schematic cross-sectional view of the holding portion and its surrounding area. As shown in Figure 2, the holding portion 30 holds the opening / closing shaft 20 at a position where it penetrates the housing 10. The holding portion 30 comprises a flange portion 31 arranged along the outer surface (left side) of the partition wall 11 and a sleeve portion 32 that is inserted into the opening / closing shaft hole 14 formed in the partition wall 11.

[0019] An O-ring 34 is provided between the flange portion 31 and the partition wall 11 to prevent leakage of the insulating gas from the inside to the outside of the housing 10 through the opening and closing shaft hole 14.

[0020] The sleeve portion 32 is provided with a dust seal 35, two bearings 36, two X-rings 37, and lubricating grease 38.

[0021] The dust seal 35 is provided on the flange portion 31 side to prevent foreign matter from entering from the outside to the inside of the housing 10. The bearings 36 are provided on the right end side of the sleeve portion 32 and in the vicinity of the right side of the dust seal 35. The bearings 36 suppress friction with the opening and closing shaft 20 and support the opening and closing shaft 20 so as to be smoothly movable in the left-right direction (axial direction). The X-ring 37 is a ring-shaped sealing material having an X-shaped cross section and maintains the airtightness inside the housing 10. The X-ring 37 has four tip portions each having a lip function and is provided so as to be able to hold the grease 38 between the lips.

[0022] Returning to FIG. 1A, the opening and closing shaft 20 extends substantially parallel in the left-right direction. The opening and closing shaft 20 includes a connecting portion 21, an insulating portion 22, and a movable contact 23 that are connected side by side from left to right. The connecting portion 21, the insulating portion 22, and the movable contact 23 are each formed in a substantially round shaft shape and provided on the same central axis. The connecting portion 21 and the insulating portion 22 are formed to have substantially the same diameter. The movable contact 23 is formed to have a diameter dimension larger than a predetermined amount than the connecting portion 21 and the insulating portion 22. Thereby, the movable contact 23 can contact a plurality of electrodes 40, and the connecting portion 21 and the insulating portion 22 are maintained in non-contact with the plurality of electrodes 40.

[0023] The connecting portion 21 is not limited in material as long as it has a predetermined strength. For example, it is constituted by a metal rod. One end portion (left end portion) of the connecting portion 21 is connected to the operating mechanism 3 outside the housing 10. The other end portion (right end portion) of the connecting portion 21 is connected to one end portion (left end portion) of the insulating portion 22 by screw connection. The connecting portion 21 is held so as to penetrate through the sleeve portion 32 in the holding portion 30 in the state shown in FIG. 1A.

[0024] The insulating portion 22 is provided between the connecting portion 21 and the movable contact 23. The insulating portion 22 is formed of an appropriate insulating material such as a resin material, and has a function of blocking and insulating the electrical conduction between the connecting portion 21 and the movable contact 23.

[0025] FIG. 3A is a schematic cross-sectional view of the opening / closing shaft. As shown in FIG. 3A, the insulating portion 22 includes a shaft-shaped core material 22a and a surface layer 22b provided so as to cover the outer peripheral surface of the core material 22a. The core material 22a is made of a material having excellent dimensional stability in which shape change over time hardly occurs, and can be constituted by, for example, polyamide or the like. The surface layer 22b is made of a material having a small friction coefficient, good fluidity, and high strength, and can be constituted by, for example, polytetrafluoroethylene (PTFE) or the like.

[0026] FIG. 3B is an enlarged view of part A in FIG. 3A. As shown in FIG. 3B, a male screw portion 22c is formed at one end portion (the end portion on the connecting portion 21 side) of the insulating portion 22. A female screw portion 21a that screws into the male screw portion 22c is formed at the other end portion (the end portion on the insulating portion 22 side) of the connecting portion 21. The screwed state of the male screw portion 22c and the female screw portion 21a maintains the connection state of the connecting portion 21 and the insulating portion 22.

[0027] A recessed portion 21b is formed on the outer periphery of the end portion of the connecting portion 21 where the female screw portion 21a is formed so as to surround the female screw portion 21a around the axis. The recessed portion 21b is formed such that the diameter dimension is smaller than other regions in a partial region in the left-right direction from the end portion of the connecting portion 21 and shorter than the female screw portion 21a.

[0028] A surface layer 22b is also formed inside the recessed portion 21b, and the surface layer 22b is formed spanning the connecting portion 21 and the insulating portion 22. In other words, the recessed portion 21b is formed at the location where the surface layer 22b is formed in the connecting portion 21. In the opening / closing shaft 20, the diameter dimensions of the location where the surface layer 22b is formed in the connecting portion 21 and the location where the surface layer 22b is formed in the insulating portion 22 are approximately the same. Furthermore, in the connecting portion 21, the diameter dimensions of the location where the recessed portion 21b and the surface layer 22b are formed and the location to the left of the formation location where the recessed portion 21b and the surface layer 22b are not formed are approximately the same. Therefore, by forming the recessed portion 21b and the surface layer 22b in the connecting portion 21, the connecting portion 21 and the insulating portion 22 have uniformly the same diameter dimension in the axial direction and are formed to have the same cross-sectional shape.

[0029] The movable contact 23 is made of a conductor such as metal and is provided to be electrically conductive with the electrode 40 that is in contact with it (see Figure 1). As shown in Figure 3A, a male threaded portion 22d is formed at the other end of the insulating portion 22 (the end on the movable contact 23 side). A female threaded portion 23a is formed at one end of the movable contact 23 (the end on the insulating portion 22 side) that screws into the male threaded portion 22d. The connection between the insulating portion 22 and the movable contact 23 is maintained by the screwing of the male threaded portion 22d and the female threaded portion 23a.

[0030] Next, the relative positional relationship between the opening / closing shaft 20 and the multiple electrodes 40, as well as the switching of the electrical connection between the opening / closing shaft 20 and the multiple electrodes 40, and the change in the position of the opening / closing shaft 20 relative to the housing 10 will be explained with reference to Figures 1A to 1C.

[0031] Figure 1A shows the state in which the movable contact 23 is positioned as far to the right as possible by the operating mechanism 3 within the movable range of the opening / closing shaft 20. As shown in Figure 1A, the lateral separation distance between the input electrode 41 and the right-side cutting electrode 42 is set to be shorter than the length of the movable contact 23. As a result, the movable contact 23 makes contact with the input electrode 41 and the right-side cutting electrode 42 simultaneously, and the input electrode 41 and the right-side cutting electrode 42 are electrically connected via the movable contact 23. This connection results in an energized state where the power supply and the load are connected through the input electrode 41, the movable contact 23, and the cutting electrode 42.

[0032] In the energized state shown in Figure 1A, the entire insulating section 22 is located inside the housing 10, and the connecting section 21 of the opening / closing shaft 20 is located and held inside the holding section 30.

[0033] From the energized state shown in Figure 1A, the opening / closing shaft 20 is driven by the operating mechanism 3, and the movable contact 23 can be positioned in the state shown in Figure 1B. As shown in Figure 1B, the distance between the two disconnecting electrodes 42 in the left-right direction is set to be shorter than the length of the movable contact 23. As a result, the movable contact 23 is in contact with the two disconnecting electrodes 42 simultaneously, while the input electrode 41 and the ground electrode 43 are separated from the movable contact 23 and are not electrically connected. Therefore, in the state shown in Figure 1B, the two disconnecting electrodes 42 are in a disconnected state, with both the power supply and the ground potential disconnected for the load to which they are connected.

[0034] Even in the disconnected state shown in Figure 1B, the entire insulating section 22 is located inside the housing 10, and the opening / closing shaft 20 is held in place with the connecting section 21 located inside the holding section 30.

[0035] Figure 1C shows the state in which the opening / closing shaft 20 is driven by the operating mechanism 3 from the disconnected state in Figure 1B, and the movable contact 23 is positioned as far left as possible by the operating mechanism 3 within the movable range of the opening / closing shaft 20. As shown in Figure 1C, the lateral separation distance between the ground electrode 43 and the left-side disconnect electrode 42 is set to be shorter than the length of the movable contact 23. As a result, the movable contact 23 makes contact with the ground electrode 43 and the left-side disconnect electrode 42 simultaneously, and the ground electrode 43 and the left-side disconnect electrode 42 are electrically connected via the movable contact 23. This connection results in a grounded state where the load is grounded through the disconnect electrode 42, the movable contact 23, and the ground electrode 43. In this way, by changing which electrode 40 is electrically connected to the movable contact 23 among the multiple electrodes 40, it is possible to switch between energized state, disconnected state, and grounded state.

[0036] In the grounded state shown in Figure 1C, the insulating portion 22 of the opening / closing shaft 20 is positioned and held within the holding portion 30, while the left-side region, which is part of the insulating portion 22, is positioned outside the housing 10 from the holding portion 30.

[0037] Thus, in the above embodiment, in the grounded state shown in Figure 1C, the insulating portion 22 of the opening / closing shaft 20 penetrates the holding portion 30 and protrudes to the outside of the housing 10. In the conventional structure, the size of the housing was set so that the entire insulating portion would fit inside the housing in all states, including the grounded state, so it was essential to enlarge the housing in the direction of extension of the opening / closing shaft.

[0038] In this respect, in the above embodiment, the insulating portion 22 protrudes to the outside of the housing 10 when grounded, and by the length of this protrusion, the housing 10 can be made smaller compared to the conventional structure. More specifically, a layout can be adopted in which the position of the partition wall 11 of the housing 10 is shifted to the right in Figure 1C, and the dimensions of the housing 10 in the left-right direction (the direction in which the opening / closing shaft 20 extends) can be reduced. Moreover, in the above embodiment, the amount of insulating gas sealed in the housing 10 can be reduced by making the housing 10 smaller.

[0039] In this embodiment, the switchgear 1 equipped with a grounding disconnection function is grounded when performing maintenance, etc., so the frequency of grounding is reduced compared to the energized and disconnected states, and the duration (time) is also shortened. Therefore, by providing good airtightness between the holding part 30 and the connecting part 21 in the energized and disconnected states, even if the airtightness between the holding part 30 and the insulating part 22 in the grounded state changes slightly, the overall airtightness of the housing 10 can be ensured.

[0040] Furthermore, since the insulating portion 22 is formed by a core material 22a and a surface layer 22b, both dimensional stability of the core material 22a and frictional strength of the surface layer 22b can be obtained, allowing the switchgear 1 to be used stably over a long period of time.

[0041] Furthermore, since the surface layer 22b is formed spanning the insulating portion 22 and the connecting portion 21, the material and properties of the outer surface at their boundary are made common, allowing the boundary portion to slide smoothly within the holding portion 30.

[0042] Furthermore, by forming a recessed portion 21b in the connecting portion 21, it becomes easier to form a surface layer 22b on the connecting portion 21 as well, while also making it easier to form the same diameter dimensions for the connecting portion 21 and the insulating portion 22, thereby maintaining good airtightness between the insulating portion 22 and the holding portion 30 in the grounded state.

[0043] It should be noted that the present invention is not limited to the embodiments described above, and can be implemented with various modifications. In the embodiments described above, the size, shape, orientation, etc., shown in the accompanying drawings are not limited thereto, and can be appropriately modified within the scope that allows the present invention to exert its effects. Furthermore, it can be implemented with appropriate modifications as long as it does not deviate from the scope of the objectives of the present invention.

[0044] In the above embodiment, the connecting portion 21 and the insulating portion 22, and the insulating portion 22 and the movable contact 23 on the opening / closing shaft 20 are screw-connected. However, other connecting structures may be used as long as they provide the same functionality as in the above embodiment.

[0045] Furthermore, while the insulating portion 22 may be formed from a single material, laminating the surface layer 22b onto the core material 22a is advantageous because it allows for multiple functions to be performed as described above.

[0046] Furthermore, although the case where two cutting electrodes 42 are provided has been described, one may be used instead. [Explanation of Symbols]

[0047] 1: Switchgear (gas-insulated switchgear) 3: Operation mechanism 10: Cabinet 20: Opening / closing axis 21:Connection part 21b: Recessed area 22: Insulation part 22a: Core material 22b: Surface layer 23: Movable contact 30: Holding part 40: Electrode 41: Input electrode 42: Cutting electrode 43: Ground electrode

Claims

1. A housing filled with insulating gas, An opening / closing shaft is provided through the aforementioned housing, An operating mechanism provided on the outside of the housing for driving the opening and closing shaft, A holding part that holds the opening / closing shaft at a position through the housing while maintaining airtightness inside the housing, A gas-insulated switchgear comprising a plurality of electrodes arranged inside the housing on the same axis as the opening / closing shaft, the electrodes whose electrical connection to the opening / closing shaft is switched by the driving of the opening / closing shaft, The opening / closing shaft has a connecting portion that is connected to the operating mechanism on the outside of the housing, A movable contact that contacts the plurality of electrodes and conducts current, The system includes an insulating portion provided between the connecting portion and the movable contact, and by driving the opening / closing shaft, the electrode that is electrically connected to the movable contact among the plurality of electrodes changes, thereby switching between energized state, disconnected state and grounded state. In the energized state and the disconnected state, the entire insulating part is positioned inside the housing. A gas-insulated switchgear characterized in that, in the aforementioned grounded state, a portion of the insulating part is positioned outside the housing from the holding part.

2. The gas-insulated switchgear according to claim 1, characterized in that the insulating portion comprises a axial core material and a surface layer provided on the outer circumferential surface of the core material.

3. The gas-insulated switchgear according to claim 2, characterized in that the surface layer is formed across the outer circumference of the connecting portion.

4. The gas-insulated switchgear according to claim 3, characterized in that a recess is formed at the surface layer formation position in the connecting portion.

5. A male threaded portion is formed at the end of the insulating portion on the connecting portion side. The gas-insulated switchgear according to claim 4, characterized in that a female thread portion that screws into the male thread portion is formed at the end of the connecting portion on the insulating portion side, and the recess portion surrounds the female thread portion around its axis.