Gas-insulated switchgear

Abstract

Provided is a gas-insulated switchgear capable of ensuring a necessary insulation distance between a tank and a switch while keeping a space for flange fastening work. A gas-insulated switchgear according to the present disclosure is characterized by comprising switches, and a plurality of tanks that store the switches and an insulating gas and that each have a flange at an opening, and is characterized in that: the plurality of tanks are each attached to, with the flange thereof fastened by means of a bolt, the flange of another one of the tanks; and the inner diameter of at least one of the plurality of tanks decreases as the opening is approached.

Description

Gas-insulated switchgear

[0001] The present disclosure relates to a connection structure for a plurality of tanks of a gas-insulated switchgear.

[0002] A gas-insulated switchgear is configured by storing switches such as circuit breakers, disconnecting switches, and earthing switches in a tank filled with insulating gas. The gas-insulated switchgear can improve the insulation performance of the switches by filling the tank with dry air, SF6, or the like. This configuration allows the gas-insulated switchgear to shorten the distance (insulation distance) required to insulate the switches from the grounded tank, thereby making it possible to miniaturize the device.

[0003] A gas-insulated switchgear is attached to a plurality of tanks, and a switch is disposed inside the connected plurality of tanks. Patent Document 1 discloses a technology for connecting the plurality of tanks by fastening flanges provided at the openings of the plurality of tanks with bolts or the like.

[0004] JP 2014-003755 A

[0005] However, when multiple tanks are installed, space is required around the flanges where bolts and other components are placed to allow for tightening. Because tightening requires a space larger than the outer diameter of the flanges, ensuring sufficient space for tightening restricts the tank's outer dimensions. Therefore, when a switchgear is stored inside a tank, if there are dimensional restrictions on the space available for installing the gas-insulated switchgear, it becomes difficult to ensure the required insulation distance between the tank and the switchgear.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a gas-insulated switchgear that can ensure the necessary insulation distance between the tank and the switchgear while maintaining space for the flange tightening operation.

[0007] 1. A gas-insulated switchgear comprising: a switchgear; and a plurality of tanks each containing the switchgear and insulating gas and each having a flange at an opening, wherein the flanges of the plurality of tanks are attached to the flanges of other tanks by being fastened with bolts, and at least one of the plurality of tanks has an inner diameter that becomes smaller as it approaches the opening.

[0008] According to the gas-insulated switchgear of the present disclosure, the inner diameter of the tank becomes smaller as it approaches the opening, so that the necessary insulation distance can be secured between the tank and the switchgear while maintaining space for the flange tightening operation.

[0009] Fig. 1 is a perspective view showing a gas-insulated switchgear according to a first embodiment of the present disclosure; Fig. 2 is a cross-sectional view showing a tank connection portion in the gas-insulated switchgear according to the first embodiment of the present disclosure; Fig. 3 is a cross-sectional view showing the size relationship between the tank and the flange of the gas-insulated switchgear according to the first embodiment of the present disclosure; Fig. 4 is a cross-sectional view showing a tank connection portion in a gas-insulated switchgear according to a second embodiment of the present disclosure; Fig. 5 is a cross-sectional view showing a tank connection portion in a gas-insulated switchgear according to a third embodiment of the present disclosure;

[0010] Hereinafter, a gas-insulated switchgear according to a first embodiment of the present disclosure will be described with reference to the drawings.

[0011] Embodiment 1. Fig. 1 is a perspective view showing the configuration of a gas-insulated switchgear according to embodiment 1 of the present disclosure. The gas-insulated switchgear 100 according to embodiment 1 of the present disclosure includes a switchgear and a plurality of tanks. Note that the switchgear is not shown in Fig. 1 . Tank 1, tank 2, tank 7, and tank 8 store switchgears and insulating gas, and flanges are provided at the openings of each tank. As shown in Fig. 1 , the plurality of tanks are connected via flanges, and each tank is supported by a support member 25. The plurality of tanks are grounded, and the switchgear is provided in the tank in consideration of an insulation distance, which is a distance required to insulate the switchgear from the grounded tank.

[0012] As shown in Fig. 1, lids 18 are provided on the ends of tanks 1 and 8 located at the ends of the gas-insulated switchgear 100, and the flanges of the tanks and the lids 18 are fastened together with bolts or the like. The configuration of the gas-insulated switchgear 100 shown in Fig. 1 is merely an example, and the gas-insulated switchgear 100 may be configured by appropriately changing the order in which the tanks are arranged or the number of tanks.

[0013] FIG. 2 is a cross-sectional view showing a tank connection portion in a gas-insulated switchgear according to embodiment 1 of the present disclosure. Here, FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1 , showing an enlarged view of the connection portion between tank 1 and tank 2. Below, the connection portion between tank 1 and tank 2, among the multiple tanks of gas-insulated switchgear 100 according to embodiment 1 of the present disclosure, will be described as an example. As shown in FIG. 2 , tank 1 is provided with a flange 3, and tank 2 is provided with a flange 4. Tank 1 and tank 2 are connected by fastening flanges 3 and 4 provided at opening 17 with bolts 5 and nuts 6. In FIG. 2 , tank 1 and tank 2 are cylindrical, and flanges 3 and 4 are circular. A sufficient number of bolts 5 and nuts 6 are provided to fasten flanges 3 and 4 circumferentially around tank 1 and tank 2.

[0014] As shown in FIG. 2 , the inner diameter of the tank 1 of the gas-insulated switchgear 100 according to the first embodiment of the present disclosure decreases toward the opening 17 where the flange 3 is provided. Because the inner diameter of the tank 1 decreases toward the opening 17, the outer wall surface of the tank 1 of the gas-insulated switchgear according to the first embodiment of the present disclosure has a tapered shape that slopes downward toward the flange 3. The tank 2 has the same shape as the tank 1, and the same slope is formed between the outer wall surface of the tank 2 and the flange 4. The formation of such slopes creates a difference in height between the wall surface of the tank 1 and the flange 3, and between the wall surface of the tank 2 and the flange 4, and ensures space around the flanges 3 and 4 where the bolts 5 and nuts 6 can be tightened. The space where the tightening operation is performed only needs to be large enough to accommodate the bolts 5 and nuts 6 and to allow the use of tools such as wrenches. Therefore, in the gas-insulated switchgear 100 according to the first embodiment of the present disclosure, it is not necessary to secure a space greater than the outer diameter of the flanges 3 and 4 around the flanges when performing the tightening work of the flanges 3 and 4, and the dimensions of the tanks 1 and 2 are not limited by the outer diameter of the flanges. Furthermore, in the gas-insulated switchgear 100 according to the first embodiment of the present disclosure, the dimensions of the tanks are not limited by the outer diameter of the flanges, so it is possible to widen the space inside the tanks and sufficiently secure the insulation distance required for the switchgear.

[0015] FIG. 3 is a cross-sectional view showing the size relationship between the tank and flange of the gas-insulated switchgear according to the first embodiment of the present disclosure. Because tank 1 and tank 2 have the same shape, tank 1 will be described below as an example. In FIG. 2, the outer diameter of tank 1 is the same as the outer diameter of flange 3. However, in FIG. 3, the outer diameter of flange 3 in the gas-insulated switchgear 100 according to the first embodiment of the present disclosure is slightly smaller than the outer diameter of tank 1. Even in this case, the outer wall surface of tank 1 has a shape that slopes downward toward flange 3. Therefore, tank 1 of the gas-insulated switchgear 100 according to the first embodiment of the present disclosure can ensure the required insulation distance between tank 1 and the switchgear while maintaining the tightening operation of bolts 5 and nuts 6 around flange 3.

[0016] 3 illustrates a case in which the outer diameter of the flange 3 is slightly smaller than the outer diameter of the tank 1, but the outer diameter of the flange 3 may be slightly larger than the outer diameter of the tank 1. In other words, in the gas-insulated switchgear 100 according to the first embodiment of the disclosure, it is sufficient that the outer diameter of the flange 3 is approximately the same as the outer diameter of the tank 1. Note that "approximately the same" in this disclosure means that the necessary insulation distance between the tank 1 and the switchgear is ensured within the tank 1 while maintaining space for the tightening operation of the flange 3 at the tank connection portion, and that the outer diameter of the tank 1 and the outer diameter of the flange 3 are the same or approximately the same. Note that, although only the relationship between the outer diameter of the tank 1 and the outer diameter of the flange 3 has been described here, this relationship may also be established for the other tanks in the gas-insulated switchgear 100 of the present disclosure.

[0017] 2 and 3 , the interiors of the tanks 1 and 2 of the gas-insulated switchgear 100 according to the first embodiment of the present disclosure are inclined in an arc-like manner. Here, the inclination in an arc-like manner means that the interiors of the tanks 1 and 2 are not angular. If the interiors of the tanks 1 and 2 were angular, a ground fault would occur between the tanks and the switchgear, originating from the angular portion. If a ground fault occurs between the switchgear and the tanks in the gas-insulated switchgear 100, a sufficient insulation distance between the tanks and the switchgear would not be obtained, and the function of the gas-insulated switchgear 100 would be impaired. The gas-insulated switchgear 100 according to the first embodiment of the present disclosure is effective in addressing such issues, as the interiors of the multiple tanks are inclined in an arc-like manner, thereby preventing ground faults and ensuring a sufficient insulation distance between the tanks and the switchgear.

[0018] As described above, the gas-insulated switchgear 100 according to the first embodiment of the present disclosure includes a switchgear, and a plurality of tanks that store the switchgear and insulating gas and have flanges at the opening 17. The plurality of tanks are attached to the flanges of the other tanks by fastening the flanges with bolts, and the inner diameter of at least one of the plurality of tanks becomes smaller as it approaches the opening 17.

[0019] According to the gas-insulated switchgear 100 of the first embodiment of the present disclosure, the inner diameter of at least one of the multiple tanks becomes smaller as it approaches the opening 17, so that the necessary insulation distance can be secured between the tank and the switchgear while maintaining space for the flange tightening operation.

[0020] Furthermore, according to the gas-insulated device 100 of embodiment 1 of the present disclosure, the outer diameter of the tank is approximately the same as the outer diameter of the flange, so that the outer diameter of the tank can be set to the maximum value relative to the size of the gas-insulated switchgear 100, and the space inside the tank can also be maximized.

[0021] Furthermore, in the gas-insulated switchgear 100 according to the first embodiment of the present disclosure, only the connected tanks having the same shape have been described, but the connected tanks may be configured such that the inner diameters of only some of the tanks become smaller as they approach the opening 17. Even in such a case, it is possible to ensure the necessary insulation distance between the tank and the switchgear while maintaining a space for performing the tightening operation.

[0022] Second Embodiment In a second embodiment, the same components as those in the first embodiment of the present disclosure are designated by the same reference numerals, and descriptions of the same or corresponding parts will be omitted. Hereinafter, a gas-insulated switchgear according to the second embodiment will be described with reference to the drawings.

[0023] FIG. 4 is a cross-sectional view showing a tank connection portion in a gas-insulated switchgear according to a second embodiment of the present disclosure. Below, a description will be given of an example of a connection portion between tank 1 and tank 11, among the multiple tanks of the gas-insulated switchgear according to the second embodiment of the present disclosure. In the first embodiment, tank 1 and tank 2 are connected by fastening flanges 3 and 4 with bolts 5 and nuts 6. In contrast, in the gas-insulated switchgear according to the second embodiment of the present disclosure, in addition to the configuration of the first embodiment, tank 11 has a flange 9 with threaded holes 12. With this configuration, flange 9 is attached to flange 3 of tank 1 with bolts 5 and threaded holes 12, as shown in FIG. 4 . Because tank 11 is provided with flange 9 with threaded holes 12, the side surface of tank 11 becomes thicker toward opening 17.

[0024] The gas-insulated apparatus according to the second embodiment of the present disclosure has a configuration similar to that of the first embodiment, and therefore can ensure the insulation distance required for the switchgear while maintaining space for the flange tightening operation. Furthermore, whereas the tanks are connected to each other using bolts 5 and nuts 6 in the first embodiment, the gas-insulated apparatus according to the second embodiment of the present disclosure uses only bolts 5. Therefore, the gas-insulated apparatus according to the second embodiment of the present disclosure can also reduce the number of parts required to connect the tanks to each other compared to the first embodiment.

[0025] In the gas insulated apparatus according to the second embodiment of the present disclosure, the tank 1 and the tank 11 can be connected simply by inserting the bolt 5 into the threaded hole 12 from the tank 1 side and tightening it. Therefore, the gas insulated apparatus according to the second embodiment of the present disclosure has the effect of facilitating the work of connecting the tanks together.

[0026] Furthermore, in the gas insulated apparatus according to the second embodiment of the present disclosure, some of the multiple tanks may be attached to other tanks with bolts 5 and nuts 6, and other parts of the multiple tanks may be attached to other tanks with bolts 5 and threaded holes 12. With this configuration, in the gas insulated apparatus according to the second embodiment of the present disclosure, the number of parts required to connect some of the multiple tanks to each other can be reduced, and the connection work for some of the multiple tanks can be facilitated.

[0027] Furthermore, in a structure such as the gas-insulated apparatus according to the second embodiment of the present disclosure, if the bolt 5 and the threaded hole 12 are not electrically connected, the bolt 5 becomes a floating electrode. Here, a floating electrode is generated by induced voltage from live parts inside and outside the tank. The presence of this floating electrode can generate a surge between the grounded outer jacket, causing a ground fault or short circuit in the main circuit inside the tank and damaging components and equipment outside the tank. In contrast, in the gas-insulated apparatus according to the second embodiment of the present disclosure, the threaded hole 12 is left unpainted, thereby electrically connecting the bolt 5 and the threaded hole 12. With this configuration, the threads of the bolt 5 come into contact with the unpainted portion of the threaded hole 12, ensuring electrical contact. Therefore, the gas-insulated apparatus according to the second embodiment of the present disclosure can prevent the bolt 5 from becoming a floating electrode and can also prevent damage to components and equipment due to surges.

[0028] Embodiment 3 In embodiment 3, the same components as those in embodiment 1 of the present disclosure are designated by the same reference numerals, and descriptions of the same or corresponding parts will be omitted. Hereinafter, a gas insulated apparatus according to embodiment 3 will be described with reference to the drawings.

[0029] FIG. 5 is a cross-sectional view showing a tank connection portion in a gas-insulated switchgear according to a third embodiment of the present disclosure. Below, a description will be given of an example of a connection portion between tank 14 and tank 15, among the multiple tanks of the gas-insulated switchgear according to the third embodiment of the present disclosure. As shown in FIG. 5 , the gas-insulated switchgear according to the third embodiment of the present disclosure has, in addition to the configuration of the first embodiment, a flange 10 provided inside tank 14 and a flange 16 provided inside tank 15. With this configuration, during tightening work, bolts 5 can be inserted into threaded holes 13 from inside tank 14, so the gas-insulated switchgear according to the third embodiment of the present disclosure does not require tightening work on the outsides of tanks 14 and 15. However, a configuration such as that of the gas-insulated switchgear according to the third embodiment of the present disclosure is effective only when there is a margin in the electric field design between the connected tanks.

[0030] As described above, the gas-insulated switchgear according to the third embodiment of the present disclosure has the same configuration as that of the first embodiment, and therefore can ensure the insulation distance required for the switchgear while maintaining space for the flange tightening operation. Furthermore, the gas-insulated switchgear according to the third embodiment of the present disclosure has the flange provided inside the tank, which eliminates the need for work outside the tank and eliminates restrictions on structures to be placed around the tank.

[0031] Although the tank in the first to fourth embodiments of the present disclosure has a cylindrical shape and the flange has a circular shape, the tank and flange may be approximately cylindrical (e.g., elliptical) or rectangular, as long as they are strong enough to withstand the pressure of the insulating gas that is sealed inside.

[0032] In the gas insulated switchgear according to the first to fourth embodiments of the present disclosure, the switchgear stored in the tank includes a circuit breaker, a disconnecting switch, a grounding switch, etc. Furthermore, the insulating gas stored in the tank may be dry air, SF6, etc.

[0033] The configurations described in the above embodiments are merely examples of the contents of the present disclosure, and may be combined with other known techniques. Furthermore, parts of the configurations may be omitted or modified without departing from the scope of the present disclosure.

[0034] 1 2 7 8 11 14 15 Tank, 3 4 9 10 16 Flange, 5 Bolt, 6 Nut, 12 13 Screw hole, 17 Opening, 18 Lid, 100 Gas insulated switchgear

Claims

1. A gas-insulated switchgear comprising a switch and a plurality of tanks for storing the switch and an insulating gas, the plurality of tanks being provided with flanges at their openings, and the plurality of tanks being attached to the flanges of other tanks by tightening the flanges with bolts, wherein at least one of the plurality of tanks is characterized in that the inner diameter of the tank becomes smaller as it approaches the opening.

2. The gas-insulated switchgear according to claim 1, characterized in that the outer diameter of the flange is approximately the same as the outer diameter of the tank.

3. The gas-insulated switchgear according to claim 1 or 2, characterized in that the inner surfaces of the plurality of tanks are inclined in an arc shape.

4. The gas-insulated switchgear according to any one of claims 1 to 3, characterized in that the tank has a threaded hole in the flange, and the flange is attached to the flanges of other tanks by the bolts and the threaded hole.

5. The gas-insulated switchgear according to claim 4, characterized in that some of the plurality of tanks are attached to other tanks by bolts and nuts, and some of the plurality of tanks are attached to other tanks by bolts and the threaded holes.

6. The gas-insulated switchgear according to claim 4 or 5, characterized in that the bolts and the threaded holes are electrically connected.

7. The gas-insulated switchgear according to any one of claims 1 to 6, characterized in that the flange is provided inside the tank.

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