Gas-insulated switchgear

Abstract

A gas-insulated switchgear (100, 101, 102) comprises a lightning arrester (7) that: is provided outside a pressure vessel (1); comprises a conductive lighting arrester grounded shielding layer (7c) that is an outermost layer and a lighting arrester insulating layer (7b) that is covered by the lighting arrester grounded shielding layer (7c); is connected to a principal circuit (2) via a lightning arrester connection bushing (6); and is provided so as to be capable of moving in a prescribed direction to contact / separate from the lightning arrester connection bushing (6). The present invention thereby provides a gas-insulated switchgear (100, 101, 102) that makes it possible to replace a lightning arrester (7) without collecting an insulating gas that is inside a pressure vessel (1).

Description

Gas-insulated switchgear

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

[0002] science fiction ６ Gas-insulated switchgear, in which an insulating gas such as 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 disconnecting switch. A lightning arrester is connected to the main circuit and protects the gas-insulated switchgear from overcurrents 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, overcurrent caused by lightning or the like flows to the lightning arrester, and the lightning arrester can protect the gas-insulated switchgear from the overcurrent.

[0004] International Publication No. 2015 / 019516

[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 supply of electricity to the main circuit is stopped 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 that allows the lightning arrester to be replaced without recovering the insulating gas inside the pressure vessel.

[0007] The gas-insulated switchgear according to the present disclosure is characterized by comprising: a pressure vessel that houses a main circuit and in which insulating gas is sealed; a lightning arrester connection bushing that is connected to the main circuit and has an insulating bushing insulating layer that covers a central conductor; and a lightning arrester that is provided outside the pressure vessel, has an electrically conductive lightning arrester grounding shielding layer as its outermost layer and has a lightning arrester insulating layer covered by the lightning arrester grounding shielding layer, is connected to the main circuit via the lightning arrester connection bushing, and is arranged so that it can be moved toward and away from the lightning arrester connection bushing by moving in a predetermined direction.

[0008] According to the present disclosure, a gas-insulated switchgear is provided outside a pressure vessel, and includes a lightning arrester that has an electrically conductive lightning arrester grounding shielding layer as its outermost layer, a lightning arrester insulating layer covered by the lightning arrester grounding shielding layer, and is connected to a main circuit via a lightning arrester connecting bushing and is arranged so that it can be moved 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.

[0009] Fig. 1 is a schematic cross-sectional view of a gas-insulated switchgear according to embodiment 1. Fig. 2 is a schematic cross-sectional view of the periphery of a lightning arrester in the gas-insulated switchgear according to embodiment 1. Fig. 3 is a schematic cross-sectional view showing a state when the lightning arrester of embodiment 1 has been separated from a bushing. Fig. 4 is a schematic cross-sectional view of a gas-insulated switchgear according to embodiment 2. Fig. 5 is a schematic cross-sectional view of a gas-insulated switchgear according to embodiment 3.

[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 and modified as appropriate. In the drawings, similar components are designated by the same reference numerals. Note that the relative dimensional relationships or shapes of the components in the drawings may differ from those in reality.

[0011] Embodiment 1. A gas-insulated switchgear 100 according to Embodiment 1 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 Embodiment 1. 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 when viewed from the front. FIG. 2 is a schematic cross-sectional view of the area around the lightning arrester 7 in the gas-insulated switchgear 100 according to Embodiment 1. FIG. 3 is a schematic cross-sectional view showing the lightning arrester 7 according to Embodiment 1 when separated from the bushing. In the following description, terms indicating directions such as "up," "down," "right," "left," "front," and "rear" are used as appropriate to facilitate understanding, but these terms do not limit the embodiments. Furthermore, in the embodiments, the terms indicating 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 cable connection bushing 4, a power cable 5, a lightning arrester connection bushing 6, and a lightning 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, SF ６ Gas, N ２ Gas, CO ２ 1 to 5, the pressure vessel 1 is provided below the gas-insulated switchgear 100 and is indicated 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 on the rear surface of the pressure vessel 1 so as to pass through the pressure vessel 1 in an airtight manner toward the rear surface. The cable connection bushing 4 is connected, via a cable head, to a power cable 5 for receiving power from a transmission line.

[0014] As shown in Figure 2, the lightning arrester connection bushing 6 is provided below the pressure vessel 1. The lightning arrester connection bushing 6 is connected to the main circuit 2 via a pressure vessel internal conductor 2a, which is part of the main circuit 2. The lightning arrester connection bushing 6 of the first embodiment is provided so as to pass through the pressure vessel 1 in an airtight manner toward the front surface.

[0015] 2, the lightning arrester connecting bushing 6 includes a center 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 electrically conductive and is covered with a bushing insulating layer 6b. The bushing insulating layer 6b is made of, for example, ethylene propylene rubber, silicone rubber, or epoxy resin. The pressure vessel internal 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 exposed to the outside air outside the pressure vessel 1. The bushing ground shielding layer 6c is made of rubber based on, for example, butyl chloride.

[0018] The lightning arrester 7 is provided outside the pressure vessel 1 and is connected to the main circuit 2 via a lightning arrester connection bushing 6. The zinc oxide elements 7a are composed of stacked disk-shaped elements. When an overvoltage is applied to the zinc oxide elements 7a, their 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 elements 7a are 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 Figure 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, or epoxy resin. Furthermore, the cross-sectional shape of the arrester insulating layer 7b is not limited to a circle; similar effects can be achieved with a polygonal shape such as a square.

[0020] The lightning arrester 7 also has a conductive lightning arrester grounding shielding layer 7c as its outermost layer. That is, the lightning arrester grounding shielding layer 7c is provided outside the pressure vessel 1 and is covered by the outside air. The lightning arrester insulating layer 7b is covered by the lightning arrester grounding shielding layer 7c. The lightning arrester grounding shielding layer 7c is made of rubber with a base material such as butyl chloride, for example.

[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. Furthermore, the lightning arrester insulating layer 7b and the bushing insulating layer 6b are preferably made of materials with different Young's moduli and Poisson's ratios. For example, if one material is ethylene propylene rubber or silicone rubber, the other material is preferably an epoxy resin or the like, which has a higher Young's modulus and a lower Poisson's ratio. This improves the adhesion between the lightning arrester insulating layer 7b and the bushing insulating layer 6b.

[0023] Furthermore, 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 fit 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 into and removed from the lightning arrester connecting bushing 6. Note that the gas-insulated switchgear 100 can achieve the same effects 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 connection 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 moved toward and away from the arrester connection bushing 6 when connecting to and disconnecting from the arrester connection bushing 6.

[0025] When the lightning arrester operating mechanism 9 operates while 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. That is, 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 to the rear of the gas-insulated switchgear 100. At this time, the connection terminal 7d and the center 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, thereby maintaining the insulating performance at the insulating interface.

[0027] Here, the zinc oxide element 7a, lightning arrester grounding shielding layer 7c, and bushing grounding shielding layer 6c are electrically connected to the lightning arrester operating shaft 8. The lightning arrester operating shaft 8 is then grounded. Therefore, the zinc oxide element 7a, lightning arrester grounding shielding layer 7c, and bushing grounding shielding layer 6c are grounded to the ground via the lightning arrester operating shaft 8. This allows the zinc oxide element 7a to pass overcurrent to the ground. Furthermore, the lightning arrester grounding shielding layer 7c and bushing grounding shielding layer 6c can pass the electric charges that have accumulated on the surfaces of the lightning arrester insulating layer 7b and the bushing insulating layer 6b to the ground.

[0028] As described above, 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 its outermost layer, includes the lightning arrester insulating layer 7b covered by 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 that it can be moved toward or away from the lightning arrester connecting bushing 6 by moving in a predetermined direction. With the above configuration, the gas-insulated switchgear 100 has the lightning arrester 7 provided outside the pressure vessel 1, so that the lightning arrester 7 can be replaced without recovering the insulating gas sealed inside the pressure vessel 1. As a result, the time during which 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.

[0029] Furthermore, the gas-insulated switchgear 100 eliminates the need to provide 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 grounding shielding layer 7c and the bushing grounding shielding layer 6c, respectively. With the above configuration, the lightning arrester grounding shielding layer 7c and the bushing grounding shielding layer 6c can ground the electric charges induced by an overcurrent on the surfaces of the lightning arrester insulating layer 7b and the bushing insulating layer 6b. The lightning arrester grounding shielding layer 7c and the bushing grounding shielding layer 6c can also shield the electric field generated from the lightning arrester connecting bushing 6 and the lightning arrester 7.

[0031] Furthermore, 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 infiltration of air at the contact surfaces between the lightning arrester 7 and the lightning arrester connecting bushing 6 by the contact surface pressure at the contact surfaces 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 into 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, improving the workability when installing the gas-insulated switchgear 100.

[0033] Furthermore, the gas-insulated switchgear 100 eliminates the need for an open / close switch to disconnect 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 connection bushing 6, so that even if a short circuit or ground fault occurs in the lightning arrester 7, the effects on the equipment inside the pressure vessel 1 can be suppressed.

[0034] Furthermore, the lightning arrester insulating layer 7b and the bushing insulating layer 6b have different Young's moduli and Poisson's ratios. That is, if 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 if 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 are closely adhered 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 lightning arrester 7 moves has been described as the horizontal direction, but this is not limiting. That is, the lightning arrester 7 can achieve the same effect as long as it can move in a predetermined direction. Here, the "predetermined direction" refers to a certain direction. Therefore, the "predetermined direction" does not only include the horizontal or vertical direction, but also any direction in which the lightning arrester 7 can move toward or away from the lightning arrester connecting bushing 6.

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

[0037] Embodiment 2. A gas-insulated switchgear 101 according to embodiment 2 will be described with reference to FIG. 4 . FIG. 4 is a schematic cross-sectional view of the gas-insulated switchgear 101 according to embodiment 2. In the gas-insulated switchgear 100 according to embodiment 1, the arrester connection bushing 6 is provided outside the pressure vessel 1 and includes a conductive bushing grounding shielding layer 6c that covers the bushing insulating layer 6b. The gas-insulated switchgear 101 according to embodiment 2 differs from the gas-insulated switchgear 100 according to embodiment 1 in that a non-contact region 6d on 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. Components similar to those according to embodiment 1 are denoted by the same reference numerals. Further, detailed description of the components similar to those according to embodiment 1 will be omitted, and the following description will mainly focus on the components different from embodiment 1.

[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 on the surface of the bushing insulating layer 6b that does not contact the lightning arrester 7 is located inside the pressure vessel 1 and is insulated by insulating gas. In addition, a contact area 6e on the surface of the bushing insulating layer that contacts the lightning arrester 7 is located 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 that when the lightning arrester insulating layer 7b and the bushing insulating layer 6b are connected, they penetrate toward the rear surface of the pressure vessel 1. 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 its outermost layer, includes a lightning arrester insulating layer 7b covered by the lightning arrester grounding shielding layer 7c, and includes a lightning arrester 7 connected to the main circuit 2 via a lightning arrester connecting bushing 6 and arranged so as to be able to move toward and away from the lightning arrester connecting bushing 6 by moving in a predetermined direction. With the above configuration, the gas-insulated switchgear 101 has the lightning arrester 7 provided outside the pressure vessel 1, so that the lightning arrester 7 can be replaced without recovering the insulating gas sealed inside the pressure vessel 1. As a result, the time during which 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.

[0041] Furthermore, in the gas-insulated switchgear 101 of embodiment 2, a non-contact region 6d of the surface of the bushing insulating layer 6b that does not come into contact with the lightning arrester 7 is disposed inside the pressure vessel 1 and is insulated by insulating gas. With the above 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 a bushing grounding shielding layer 6c that would otherwise allow charges built up on the surface of the bushing insulating layer 6b to flow to ground. Therefore, the gas-insulated switchgear 101 does not need to provide a bushing grounding shielding layer 6c, and therefore the number of parts and costs can be reduced compared to embodiment 1.

[0042] Embodiment 3. A gas-insulated switchgear 102 according to embodiment 3 will be described with reference to Fig. 5 . Fig. 5 is a schematic cross-sectional view of the gas-insulated switchgear 102 according to embodiment 3. In the gas-insulated switchgear 100 according to embodiment 1, the lightning arrester 7 is arranged to be moved horizontally by the lightning arrester operation mechanism 9. The gas-insulated switchgear 102 according to embodiment 3 differs from the gas-insulated switchgear 100 according to embodiment 1 in that the lightning arrester 7 is arranged to be moved vertically by the lightning arrester operation mechanism 9. The same components as those in embodiment 1 are denoted by the same reference numerals. Further, detailed description of the same components as those in embodiment 1 will be omitted, and the following description will mainly focus on the components that differ from embodiment 1.

[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 region 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 insulating gas, similar to, but not limited to, the second embodiment. That is, in the gas-insulated switchgear 102 of the third embodiment, the lightning arrester connecting bushing 6 may be provided outside the pressure vessel 1 and may include a conductive bushing grounding 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 that is also 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 embodiment 3.

[0045] 5, when the lightning arrester 7 is moved 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, causing the new lightning arrester 7 after replacement to move 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 its outermost layer, includes a lightning arrester insulating layer 7b covered by the lightning arrester grounding shielding layer 7c, is connected to the main circuit 2 via a lightning arrester connecting bushing 6, and is provided with a lightning arrester 7 that is arranged so as to be able to move 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 has the lightning arrester 7 provided outside the pressure vessel 1, so that the lightning arrester 7 can be replaced without recovering the insulating gas sealed inside the pressure vessel 1. As a result, the time during which 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] Furthermore, the gas-insulated switchgear 102 in embodiment 3 has a lightning arrester 7 that is provided so as to be able to move vertically to approach or separate from the lightning arrester connecting bushing 6. With the above configuration, the overall height of the gas-insulated switchgear 102 can be reduced compared to the case where the lightning arrester 7 is provided below the pressure vessel 1 so as to move the lightning arrester 7 horizontally, as in the gas-insulated switchgear 100 in embodiment 1. 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 that includes 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, if the lightning arrester 7 interferes with equipment such as the bus bar 12, maintenance or installation work for the equipment such as the bus bar 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 maintenance or installation work for the equipment such as the bus bar 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 flexibility in the process of maintenance or installation work for the gas-insulated switchgear 102.

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

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

Claims

1. A gas-insulated switchgear, comprising: a pressure vessel that houses a main circuit and is filled with an insulating gas; a bushing for arrester connection that is connected to the main circuit and includes an insulating bushing insulation layer covering a center conductor; an arrester provided outside the pressure vessel, having a conductive arrester grounding shielding layer on an outermost layer, an arrester insulation layer covered by the arrester grounding shielding layer, connected to the main circuit via the bushing for arrester connection, and arranged to be separable from and connectable to the bushing for arrester connection by moving in a predetermined direction.

2. The gas-insulated switchgear according to claim 1, wherein the bushing for arrester connection is provided outside the pressure vessel and further includes a conductive bushing grounding shielding layer covering the bushing insulation layer.

3. The gas-insulated switchgear according to claim 1, wherein a non-contact region of the surface of the bushing insulation layer that does not contact the arrester is arranged inside the pressure vessel, and a contact region of the surface of the bushing insulation layer that contacts the arrester is arranged outside the pressure vessel.

4. The gas-insulated switchgear according to any one of claims 1 to 3, wherein the arrester insulation layer and the bushing insulation layer have a tapered shape that can be fitted to each other.

5. The gas-insulated switchgear according to any one of claims 1 to 4, wherein the arrester insulation layer and the bushing insulation layer have different Young's moduli and Poisson's ratios. When the Young's modulus of the arrester insulation layer is higher than that of the bushing insulation layer, the Poisson's ratio of the arrester insulation layer is lower than that of the bushing insulation layer. When the Young's modulus of the arrester insulation layer is lower than that of the bushing insulation layer, the Poisson's ratio of the arrester insulation layer is higher than that of the bushing insulation layer.

6. The gas-insulated switchgear according to any one of claims 1 to 5, wherein the predetermined direction is a horizontal direction or a vertical direction.

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