Gas insulated switchgear

Abstract

The gas-insulated switchgear (100, 101, 102) is provided outside the pressure vessel (1), includes a conductive lightning arrester grounding shielding layer (7c) as the outermost layer, includes a lightning arrester insulating layer (7b) covered with the lightning arrester grounding shielding layer (7c), is connected to the main circuit (2) via a lightning arrester connecting bushing (6), and includes a lightning arrester (7) arranged so as to be movable toward and away from the lightning arrester connecting bushing (6) by moving in a predetermined direction. This makes it possible to provide the gas-insulated switchgear (100, 101, 102) that allows the lightning arrester (7) to be replaced without recovering the insulating gas inside the pressure vessel (1).

Description

[Technical field]

[0001] The present disclosure relates to gas-insulated switchgear. [Background technology]

[0002] Gas-insulated switchgear, in which insulating gas such as SF6 gas is sealed inside a pressure vessel, is used as electrical equipment housing power-receiving equipment in power facilities such as substations and power plants. Inside the pressure vessel, a main circuit is installed between the connection of the power cable that receives power from the transmission line and the disconnector. The lightning arrester is connected to the main circuit and protects the gas-insulated switchgear from overcurrent caused by lightning, etc.

[0003] For example, in the invention described in Patent Document 1, a lightning arrester is provided inside a pressure vessel. Therefore, the connection between the lightning arrester and the main circuit is insulated by insulating gas sealed inside the pressure vessel. As a result, an overcurrent caused by lightning or the like flows to the lightning arrester, so that the lightning arrester can protect the gas-insulated switchgear from the overcurrent. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2015 / 019516 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the invention described in Patent Document 1, since a lightning arrester is provided inside the pressure vessel, it is necessary to recover the insulating gas inside the pressure vessel when replacing the lightning arrester. In this case, the main circuit is de-energized until the insulating gas is refilled into the pressure vessel, and improving workability has been an issue.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a gas-insulated switchgear in which a lightning arrester can be replaced without recovering the insulating gas inside the pressure vessel. [Means for solving the problem]

[0007] The gas-insulated switchgear according to the present disclosure comprises: a pressure vessel in which a main circuit is housed and in which insulating gas is sealed; a lightning arrester connecting bushing connected to the main circuit and having an insulating bushing insulating layer covering a central conductor; and a lightning arrester provided outside the pressure vessel, having an electrically conductive lightning arrester grounding shielding layer as its outermost layer and having an arrester insulating layer covered by the lightning arrester grounding shielding layer, connected to the main circuit via the lightning arrester connecting bushing, and arranged so as to be able to approach and separate from the lightning arrester connecting bushing by moving in a predetermined direction. The lightning arrester connecting bushing is provided outside the pressure vessel and further includes a conductive bushing ground shielding layer covering the bushing insulating layer. It is characterized by: Effect of the Invention

[0008] According to the present disclosure, a gas-insulated switchgear is provided outside a pressure vessel, includes a conductive lightning arrester grounding shielding layer as an outermost layer, includes a lightning arrester insulating layer covered by the lightning arrester grounding shielding layer, is connected to a main circuit via a lightning arrester connecting bushing, and is arranged so as to be able to move in a predetermined direction to be connected to or separated from the lightning arrester connecting bushing. This makes it possible to provide a gas-insulated switchgear that allows the lightning arrester to be replaced without recovering the insulating gas inside the pressure vessel. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic cross-sectional view of a gas-insulated switchgear according to a first embodiment. [Diagram 2] 1 is a schematic cross-sectional view of the periphery of a lightning arrester in a gas-insulated switchgear according to a first embodiment. [Diagram 3] 4 is a schematic cross-sectional view showing a state in which the lightning arrester of the first embodiment is separated from the bushing. FIG. [Figure 4] FIG. 11 is a schematic cross-sectional view of a gas-insulated switchgear according to a second embodiment. [Diagram 5] FIG. 11 is a schematic cross-sectional view of a gas-insulated switchgear according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Gas-insulated switchgear according to embodiments will be described below with reference to the drawings. The following embodiments are merely examples, and the embodiments can be combined as appropriate and each embodiment can be modified as appropriate. In the drawings, similar components are given the same reference numerals. Note that the relative dimensional relationship or shape of each component may differ from the actual ones in each drawing.

[0011] Embodiment 1 A gas-insulated switchgear 100 according to the first embodiment will be described with reference to Figs. 1, 2, and 3. Fig. 1 is a schematic cross-sectional view of the gas-insulated switchgear 100 according to the first embodiment. Fig. 1 is a right side view of the gas-insulated switchgear 100, and the left side of Fig. 1 is the front of the gas-insulated switchgear 100. Fig. 2 is a schematic cross-sectional view of the lightning arrester 7 and its surroundings in the gas-insulated switchgear 100 according to the first embodiment. Fig. 3 is a schematic cross-sectional view showing a state in which the lightning arrester 7 according to the first embodiment is separated from the bushing. In the following description, for ease of understanding, terms expressing directions such as "up", "down", "right", "left", "front", and "rear" are appropriately used, but this does not limit the embodiments. In the embodiments, the terms expressing the above directions are used when the gas-insulated switchgear 100 is viewed from the front.

[0012] As shown in Fig. 1, the gas-insulated switchgear 100 includes a pressure vessel 1, a main circuit 2, a disconnecting switch 3, a bushing 4 for connecting a cable, a power cable 5, a bushing 6 for connecting an arrester, and an arrester 7. The pressure vessel 1 is an airtight tank filled with insulating gas. The pressure vessel 1 is made of, for example, metal, and is grounded to the ground using a conductor or the like. The insulating gas is, for example, SF6 gas, N2 gas, CO2 gas, dry air, or the like. In Figs. 1 to 5, the pressure vessel 1 is provided at the bottom of the gas-insulated switchgear 100, and is illustrated by a thick line.

[0013] A main circuit 2 and a disconnecting switch 3 are housed inside the pressure vessel 1. The main circuit 2 connects the disconnecting switch 3 and a cable connection bushing 4 via a connector. The cable connection bushing 4 is provided at the rear surface of the pressure vessel 1 so as to pass through airtightly in the rear direction of the pressure vessel 1. The cable connection bushing 4 is connected, via a cable head, to a power cable 5 for receiving power from a power transmission line.

[0014] 2, the lightning arrester connecting bushing 6 is provided below the pressure vessel 1. The lightning arrester connecting bushing 6 is connected to the main circuit 2 via a conductor 2a inside the pressure vessel, which is part of the main circuit 2. The lightning arrester connecting bushing 6 of the first embodiment is provided so as to penetrate airtightly toward the front surface of the pressure vessel 1.

[0015] 2, the lightning arrester connecting bushing 6 includes a central conductor 6a, a bushing insulating layer 6b, and a bushing ground shielding layer 6c. The lightning arrester 7 includes a zinc oxide element 7a, a lightning arrester insulating layer 7b, a lightning arrester ground shielding layer 7c, and a connection terminal 7d.

[0016] The central conductor 6a is conductive and is provided so as to be covered with the bushing insulating layer 6b. The material of the bushing insulating layer 6b is, for example, ethylene propylene rubber, silicone rubber, or epoxy resin. The pressure vessel inner conductor 2a, the central conductor 6a, and the zinc oxide element 7a are electrically connected. This allows the gas-insulated switchgear 100 to pass an overcurrent from the main circuit 2 to the lightning arrester 7.

[0017] The bushing insulating layer 6b is covered with a conductive bushing ground shielding layer 6c. The bushing ground shielding layer 6c is connected to the pressure vessel 1 and is covered with the outside air outside the pressure vessel 1. The bushing ground shielding layer 6c is, for example, a rubber based on butyl chloride or the like.

[0018] The lightning arrester 7 is provided outside the pressure vessel 1 and is connected to the main circuit 2 via a lightning arrester connecting bushing 6. The zinc oxide element 7a is composed of stacked disk-shaped elements. When an overvoltage is applied to the zinc oxide element 7a, the impedance decreases, allowing the overcurrent to flow to the ground side. This allows the lightning arrester 7 to protect the gas-insulated switchgear 100 from overcurrent.

[0019] The zinc oxide element 7a is covered with a cylindrical insulating arrester insulating layer 7b. This allows the arrester 7 to maintain its insulating performance even when placed outside the pressure vessel 1 as shown in Fig. 1, and to withstand impact when an overvoltage is applied. The material of the arrester insulating layer 7b is, for example, ethylene propylene rubber, silicone rubber, epoxy resin, or the like. In addition, the cross-sectional shape of the arrester insulating layer 7b is not limited to a circle, and a polygonal shape such as a square can also provide the same effect.

[0020] The lightning arrester 7 also includes a conductive lightning arrester ground shielding layer 7c as the outermost layer. That is, the lightning arrester ground shielding layer 7c is provided outside the pressure vessel 1 and is covered by the outside air. The lightning arrester insulating layer 7b is also covered by the lightning arrester ground shielding layer 7c. The lightning arrester ground shielding layer 7c is, for example, a rubber based on butyl chloride or the like.

[0021] Furthermore, the connection terminal 7d is electrically connected to the central conductor 6a. The connection terminal 7d is provided between the central conductor 6a and the zinc oxide element 7a. The central conductor 6a has a recess into which the connection terminal 7d can be fitted. This allows the connection terminal 7d to electrically connect the zinc oxide element 7a and the central conductor 6a, and also connect the lightning arrester 7 to the lightning arrester connecting bushing 6.

[0022] The lightning arrester insulating layer 7b and the bushing insulating layer 6b are arranged to adhere to each other in order to maintain the insulating performance of the lightning arrester 7. The lightning arrester insulating layer 7b and the bushing insulating layer 6b are preferably made of materials with different Young's modulus and Poisson's ratio. For example, when one material is ethylene propylene rubber or silicone rubber, the other material is preferably epoxy resin or the like having a higher Young's modulus and a lower Poisson's ratio than these. This enhances the adhesion between the lightning arrester insulating layer 7b and the bushing insulating layer 6b.

[0023] Moreover, the lightning arrester insulating layer 7b has, for example, a convex tapered shape at one end that comes into close contact with the bushing insulating layer 6b. The bushing insulating layer 6b has, at one end that comes into close contact with the lightning arrester insulating layer 7b, a concave tapered shape that can be fitted into the tapered shape of the lightning arrester insulating layer 7b. This gives the lightning arrester 7 a plug-in structure that allows it to be easily inserted and removed from the lightning arrester connecting bushing 6. The gas-insulated switchgear 100 can achieve the same effect even if the lightning arrester insulating layer 7b has a concave tapered shape and the bushing insulating layer 6b has a convex tapered shape.

[0024] An arrester operating shaft 8 is provided at the other end of the arrester 7 that is not connected to the arrester connecting bushing 6. The arrester operating shaft 8 is supported by a flange 10. This allows the arrester 7 to be held so that it can move horizontally. In addition, an arrester operating mechanism 9 is provided on the arrester operating shaft 8. The arrester operating mechanism 9 can move the arrester 7 horizontally via the arrester operating shaft 8. This allows the arrester 7 to be structured so that it can be brought into contact with and separated from the arrester connecting bushing 6 when connecting to and disconnecting from the arrester connecting bushing 6.

[0025] When the lightning arrester operation mechanism 9 operates in a state in which the connection terminal 7d and the central conductor 6a are in contact with each other as shown in Fig. 2, the lightning arrester 7 moves forward and horizontally of the gas-insulated switchgear 100 as shown in Fig. 3. At this time, the connection terminal 7d and the central conductor 6a are separated from each other. In other words, the lightning arrester 7 and the lightning arrester connecting bushing 6 are separated from each other. This makes it possible to replace the lightning arrester 7.

[0026] Then, the lightning arrester operation mechanism 9 operates, causing the new replaced lightning arrester 7 to move horizontally backward of the gas-insulated switchgear 100. At this time, the connection terminal 7d and the central conductor 6a of the new lightning arrester 7 come into contact. This connects the new lightning arrester 7 to the lightning arrester connection bushing 6. At this time, the lightning arrester operation mechanism 9 applies sufficient contact surface pressure to the contact surfaces of the lightning arrester 7 and the lightning arrester connection bushing 6. This allows the lightning arrester operation mechanism 9 to suppress the intrusion of air into the contact surfaces of the lightning arrester 7 and the lightning arrester connection bushing 6, and maintain the insulating performance at the insulating interface.

[0027] Here, the zinc oxide element 7a, the lightning arrester ground shielding layer 7c, and the bushing ground shielding layer 6c are electrically connected to the lightning arrester operation shaft 8. The lightning arrester operation shaft 8 is grounded to the ground. Therefore, the zinc oxide element 7a, the lightning arrester ground shielding layer 7c, and the bushing ground shielding layer 6c are grounded to the ground via the lightning arrester operation shaft 8. This allows the zinc oxide element 7a to pass overcurrent to the ground. Also, the lightning arrester ground shielding layer 7c and the bushing ground shielding layer 6c can pass the electric charges on the surface of the lightning arrester insulating layer 7b and the surface of the bushing insulating layer 6b to the ground.

[0028] In this way, the gas-insulated switchgear 100 of the first embodiment includes the lightning arrester 7, which is provided outside the pressure vessel 1, includes a conductive lightning arrester grounding shielding layer 7c as the outermost layer, includes the lightning arrester insulating layer 7b covered with the lightning arrester grounding shielding layer 7c, is connected to the main circuit 2 via the lightning arrester connecting bushing 6, and is arranged so as to be able to approach and separate from the lightning arrester connecting bushing 6 by moving in a predetermined direction. With the above configuration, the gas-insulated switchgear 100 can replace the lightning arrester 7 without recovering the insulating gas sealed inside the pressure vessel 1, since the lightning arrester 7 is provided outside the pressure vessel 1. As a result, the time during which the power supply to the main circuit 2 is stopped when replacing the lightning arrester 7 can be reduced compared to the configuration of the conventional art in which the lightning arrester 7 is provided inside the pressure vessel 1.

[0029] Furthermore, the gas-insulated switchgear 100 eliminates the need to provide a space for the lightning arrester 7 inside the pressure vessel 1, allowing the pressure vessel 1 to be made smaller. As a result, the gas-insulated switchgear 100 can reduce the cost of manufacturing the pressure vessel 1.

[0030] The lightning arrester insulating layer 7b and the bushing insulating layer 6b are covered by the lightning arrester ground shielding layer 7c and the bushing ground shielding layer 6c, respectively. With the above configuration, the lightning arrester ground shielding layer 7c and the bushing ground shielding layer 6c can ground the electric charge induced by an overcurrent on the surface of the lightning arrester insulating layer 7b and the surface of the bushing insulating layer 6b. The lightning arrester ground shielding layer 7c and the bushing ground shielding layer 6c can also shield the electric field generated from the lightning arrester connection bushing 6 and the lightning arrester 7.

[0031] In addition, the lightning arrester insulating layer 7b and the bushing insulating layer 6b have tapered shapes that allow them to fit together. With the above configuration, the lightning arrester operation mechanism 9 can suppress the intrusion of air into the contact surface between the lightning arrester 7 and the lightning arrester connecting bushing 6 by the contact surface pressure between the lightning arrester 7 and the lightning arrester connecting bushing 6, thereby maintaining the insulating performance at the insulating interface.

[0032] Furthermore, the lightning arrester insulating layer 7b and the bushing insulating layer 6b have a plug-in structure that allows the lightning arrester 7 to be easily inserted and removed from the lightning arrester connecting bushing 6, thereby improving the workability when replacing the lightning arrester 7. As a result, the gas-insulated switchgear 100 has a configuration in which the lightning arrester 7 can be easily removed, thereby improving the workability when installing the gas-insulated switchgear 100.

[0033] Furthermore, the gas-insulated switchgear 100 does not require an opening / closing switch for disconnecting the lightning arrester 7 from the main circuit 2 from outside the pressure vessel 1, thereby reducing the number of parts and costs. Furthermore, the gas-insulated switchgear 100 allows the lightning arrester 7 to be easily disconnected from the lightning arrester connecting bushing 6, so that even if a short circuit or ground fault occurs in the lightning arrester 7, the effect on the equipment inside the pressure vessel 1 can be suppressed.

[0034] In addition, the lightning arrester insulating layer 7b and the bushing insulating layer 6b have different Young's modulus and Poisson's ratio. That is, when the Young's modulus of the lightning arrester insulating layer 7b is higher than that of the bushing insulating layer 6b, the Poisson's ratio of the lightning arrester insulating layer 7b is lower than that of the bushing insulating layer 6b, and when the Young's modulus of the lightning arrester insulating layer 7b is lower than that of the bushing insulating layer 6b, the Poisson's ratio of the lightning arrester insulating layer 7b is higher than that of the bushing insulating layer 6b. With the above configuration, the lightning arrester insulating layer 7b and the bushing insulating layer 6b have high adhesion to each other, so that the insulating performance of the lightning arrester 7 can be maintained even if the lightning arrester 7 is provided outside the pressure vessel 1.

[0035] In the first embodiment, the direction in which the arrester 7 moves has been described as the horizontal direction, but this is not limiting. That is, the arrester 7 can achieve the same effect as long as it can move in a predetermined direction. Here, the predetermined direction means a certain direction. Therefore, the predetermined direction includes not only the horizontal direction or the vertical direction, but also any direction in which the arrester 7 can move toward or away from the arrester connection bushing 6.

[0036] In addition, the grounding method of the lightning arrester ground shielding layer 7c and the bushing ground shielding layer 6c is not limited to the above. For example, the lightning arrester ground shielding layer 7c and the bushing ground shielding layer 6c may be grounded to the ground by a conductor.

[0037] Embodiment 2 A gas-insulated switchgear 101 according to the second embodiment will be described with reference to FIG. 4. FIG. 4 is a schematic cross-sectional view of the gas-insulated switchgear 101 according to the second embodiment. In the gas-insulated switchgear 100 according to the first embodiment, the arrester connection bushing 6 is provided outside the pressure vessel 1 and includes a conductive bushing ground shielding layer 6c covering the bushing insulating layer 6b. The gas-insulated switchgear 101 according to the second embodiment differs from the gas-insulated switchgear 100 according to the first embodiment in that a non-contact area 6d of the surface of the bushing insulating layer 6b that does not contact the arrester 7 is insulated by insulating gas inside the pressure vessel 1. The same reference numerals are used for the same configurations as those according to the first embodiment. Further, detailed description of the same configurations as those according to the first embodiment will be omitted, and the configurations different from those according to the first embodiment will be mainly described.

[0038] 4, the lightning arrester connecting bushing 6 in the second embodiment is airtightly connected to the pressure vessel 1 via the bushing insulating layer 6b. Here, a non-contact area 6d of the surface of the bushing insulating layer 6b that does not contact the lightning arrester 7 is disposed inside the pressure vessel 1 and is insulated by an insulating gas. Also, a contact area 6e of the surface of the bushing insulating layer that contacts the lightning arrester 7 is disposed outside the pressure vessel 1 and is exposed to the outside air when not connected to the lightning arrester insulating layer 7b.

[0039] Furthermore, the lightning arrester 7 is provided so as to penetrate toward the rear surface of the pressure vessel 1 when the lightning arrester insulating layer 7b and the bushing insulating layer 6b are connected. Even in this case, the lightning arrester insulating layer 7b and the bushing insulating layer 6b are arranged so as to be in close contact with each other, so that the insulating performance of the lightning arrester 7 is maintained.

[0040] As in the first embodiment, the gas-insulated switchgear 101 of the second embodiment is provided outside the pressure vessel 1, includes a conductive lightning arrester grounding shielding layer 7c as the outermost layer, includes a lightning arrester insulating layer 7b covered with the lightning arrester grounding shielding layer 7c, is connected to the main circuit 2 via a lightning arrester connecting bushing 6, and includes a lightning arrester 7 arranged so as to be able to approach and separate from the lightning arrester connecting bushing 6 by moving in a predetermined direction. With the above configuration, the gas-insulated switchgear 101 can replace the lightning arrester 7 without recovering the insulating gas sealed inside the pressure vessel 1, since the lightning arrester 7 is provided outside the pressure vessel 1. As a result, the time during which the power supply to the main circuit 2 is stopped when replacing the lightning arrester 7 can be reduced compared to the configuration of the conventional art in which the lightning arrester 7 is provided inside the pressure vessel 1.

[0041] In the gas-insulated switchgear 101 of the second embodiment, a non-contact area 6d of the surface of the bushing insulating layer 6b that does not contact the lightning arrester 7 is disposed inside the pressure vessel 1 and insulated by the insulating gas. With the above-mentioned configuration, the electric field generated from the lightning arrester connecting bushing 6 is insulated by the insulating gas. As a result, the gas-insulated switchgear 101 can be configured without providing the bushing ground shielding layer 6c for discharging the electric charge on the surface of the bushing insulating layer 6b to the ground. Therefore, since the gas-insulated switchgear 101 does not need to provide the bushing ground shielding layer 6c, the number of parts and the cost can be reduced compared to the first embodiment.

[0042] Embodiment 3 A gas-insulated switchgear 102 according to the third embodiment will be described with reference to Fig. 5. Fig. 5 is a schematic cross-sectional view of the gas-insulated switchgear 102 according to the third embodiment. In the gas-insulated switchgear 100 according to the first embodiment, the lightning arrester 7 is provided so as to be moved in the horizontal direction by the lightning arrester operation mechanism 9. The gas-insulated switchgear 102 according to the third embodiment differs from the gas-insulated switchgear 100 according to the first embodiment in that the lightning arrester 7 is provided so as to be moved in the vertical direction by the lightning arrester operation mechanism 9. The same components as those according to the first embodiment are denoted by the same reference numerals. Further, detailed description of the components similar to those according to the first embodiment will be omitted, and components different from those according to the first embodiment will be mainly described.

[0043] As shown in Fig. 5, the lightning arrester connecting bushing 6 is provided above the pressure vessel 1. In the gas-insulated switchgear 102 shown in Fig. 5, a non-contact area 6d of the surface of the bushing insulating layer 6b that does not contact the lightning arrester 7 is disposed inside the pressure vessel 1 and insulated by an insulating gas, similar to the second embodiment, but is not limited thereto. That is, in the gas-insulated switchgear 102 in the third embodiment, the lightning arrester connecting bushing 6 may be provided outside the pressure vessel 1 and include a conductive bushing ground shielding layer 6c that covers the bushing insulating layer 6b, similar to the first embodiment.

[0044] The lightning arrester 7 is provided outside the pressure vessel 1 and is supported by a support 11 provided above the exterior of the pressure vessel 1. When the lightning arrester operating mechanism 9 operates in the state shown in Fig. 5, the lightning arrester 7 moves vertically above the gas-insulated switchgear 102. As described above, the direction in which the lightning arrester 7 moves is not limited to the horizontal direction, and the same effect can be achieved as long as the lightning arrester 7 can move in a predetermined direction. Therefore, the same effect can be achieved even with a configuration in which the lightning arrester 7 moves vertically, as in the gas-insulated switchgear 102 of the third embodiment.

[0045] 5, when the lightning arrester 7 moves vertically above the gas-insulated switchgear 102, the lightning arrester 7 and the lightning arrester connecting bushing 6 are separated from each other. This makes it possible to replace the lightning arrester 7.

[0046] Then, the lightning arrester operating mechanism 9 operates to move the new lightning arrester 7 after replacement vertically below the gas-insulated switchgear 102. At this time, the new lightning arrester 7 is connected to the lightning arrester connecting bushing 6.

[0047] As in the first embodiment, the gas-insulated switchgear 102 of the third embodiment is provided outside the pressure vessel 1, includes a conductive lightning arrester grounding shielding layer 7c as the outermost layer, includes a lightning arrester insulating layer 7b covered with the lightning arrester grounding shielding layer 7c, is connected to the main circuit 2 via a lightning arrester connecting bushing 6, and includes a lightning arrester 7 arranged so as to be movable toward and away from the lightning arrester connecting bushing 6 by moving in a predetermined direction. With the above configuration, the gas-insulated switchgear 102 can replace the lightning arrester 7 without recovering the insulating gas sealed inside the pressure vessel 1, since the lightning arrester 7 is provided outside the pressure vessel 1. As a result, the time during which the power supply to the main circuit 2 is stopped when replacing the lightning arrester 7 can be reduced compared to the configuration of the prior art in which the lightning arrester 7 is provided inside the pressure vessel 1.

[0048] Moreover, the gas-insulated switchgear 102 in the third embodiment has the lightning arrester 7 that is provided so as to be capable of being brought into contact with and separated from the lightning arrester connecting bushing 6 by moving in the vertical direction. With the above configuration, the overall height of the gas-insulated switchgear 102 can be made lower than when the lightning arrester 7 is provided below the pressure vessel 1 in order to move the lightning arrester 7 in the horizontal direction, as in the gas-insulated switchgear 100 in the first embodiment. As a result, even if there is a height restriction in the space in which the gas-insulated switchgear 102 is installed, the gas-insulated switchgear 102 including the lightning arrester 7 provided outside the pressure vessel 1 can be employed.

[0049] Also in the third embodiment, the lightning arrester 7 has a plug-in structure that allows it to be easily inserted and removed from the lightning arrester connecting bushing 6. Therefore, in the gas-insulated switchgear 102, when the lightning arrester 7 interferes with equipment such as the busbar 12, the maintenance work or installation work of the equipment such as the busbar 12 can be performed with the lightning arrester 7 removed from the lightning arrester connecting bushing 6. This makes it possible to prevent the lightning arrester 7 provided above the pressure vessel 1 from interfering with the maintenance work or installation work of the equipment such as the busbar 12. In this way, since the lightning arrester 7 has a plug-in structure that allows it to be easily inserted and removed from the lightning arrester connecting bushing 6, it is possible to provide a degree of freedom to the process during the maintenance work or installation work of the gas-insulated switchgear 102.

[0050] The direction in which the arrester 7 moves is not limited to the horizontal or vertical direction. The arrester 7 in the third embodiment may be provided so as to move in a direction offset from the vertical direction by about 45° toward the rear of the pressure vessel 1. That is, the arrester 7 may be provided so as to move in a direction diagonally upward and toward the rear of the pressure vessel 1. The angle by which the direction in which the arrester 7 moves is set arbitrarily. With the above configuration, it is possible to prevent the arrester 7 provided above the pressure vessel 1 from interfering with equipment such as the busbar 12. Therefore, the gas-insulated switchgear 102 can improve the work efficiency during maintenance or installation of equipment such as the busbar 12. [Explanation of symbols]

[0051] 100, 101, 102 Gas-insulated switchgear, 1 Pressure vessel, 2 Main circuit, 2a Conductor inside pressure vessel, 3 Disconnector, 4 Bushing for connecting cable, 5 Power cable, 6 Bushing for connecting lightning arrester, 6a Central conductor, 6b Bushing insulating layer, 6c Bushing ground shielding layer, 6d Non-contact area, 6e Contact area, 7 Lightning arrester, 7a Zinc oxide element, 7b Lightning arrester insulating layer, 7c Lightning arrester ground shielding layer, 7d Connection terminal, 8 Lightning arrester operating shaft, 9 Lightning arrester operating mechanism, 10 Flange, 11 Support, 12 Busbar

Claims

1. a pressure vessel in which a main circuit is housed and in which an insulating gas is sealed; a lightning arrester connecting bushing connected to the main circuit and including an insulating bushing insulating layer covering a central conductor; a lightning arrester provided outside the pressure vessel, comprising an electrically conductive lightning arrester grounding shielding layer as an outermost layer, a lightning arrester insulating layer covered with the lightning arrester grounding shielding layer, connected to the main circuit via the lightning arrester connecting bushing, and arranged so as to be capable of being brought into contact with and separated from the lightning arrester connecting bushing by moving in a predetermined direction; The lightning arrester connection bushing is provided outside the pressure vessel and further includes a conductive bushing ground shielding layer covering the bushing insulating layer.

1. A gas-insulated switchgear comprising:

2. The arrester insulating layer and the bushing insulating layer have tapered shapes that can be fitted together.

2. The gas-insulated switchgear according to claim 1 .

3. The arrester insulating layer and the bushing insulating layer have different Young's modulus and Poisson's ratio, When the Young's modulus of the surge arrester insulating layer is higher than the Young's modulus of the bushing insulating layer, the Poisson's ratio of the surge arrester insulating layer is lower than the Poisson's ratio of the bushing insulating layer; When the Young's modulus of the surge arrester insulating layer is lower than that of the bushing insulating layer, the Poisson's ratio of the surge arrester insulating layer is higher than that of the bushing insulating layer.

2. The gas-insulated switchgear according to claim 1 .

4. The predetermined direction is a horizontal direction or a vertical direction.

2. The gas-insulated switchgear according to claim 1 .