JP2024063576A - Gas insulated switchgear pressure vessel - Google Patents

Abstract

[Problem] To provide a pressure vessel for a gas-insulated switchgear that can prevent the pressure vessel from bursting even if the internal pressure rises without releasing insulating gas into the atmosphere. [Solution] The pressure vessel for a gas-insulated switchgear according to the present invention comprises a vessel body 1 filled with insulating gas, a conductor 3 housed in the vessel body 1, an insulating spacer 6 positioned on the outer periphery of the conductor 3 to support the conductor 3, and a flange 5 positioned between the insulating spacer 6 and the vessel body 1 to fix the insulating spacer 6 to the vessel body 1. The flange 5 comprises a through hole 14 and a rupture disk 11 that is curved in a convex shape and closes the opening of the through hole 14. [Selected Figure] Figure 1

Description

The present invention relates to a pressure vessel for a gas-insulated switchgear.

Gas-insulated switchgear, which is a high-voltage device installed in a power system, is configured by housing devices such as a circuit breaker, a disconnecting switch, a grounding switch, and a busbar in a pressure vessel. The pressure vessel is filled with an insulating gas such as sulfur hexafluoride gas ( _SF6 gas).

When a fault such as a ground fault occurs inside a pressure vessel, an arc discharge can occur. This arc discharge can cause the insulating gas to expand or decompose to produce a different gas, which can increase the pressure of the insulating gas sealed inside the vessel and cause the pressure vessel to burst. For this reason, pressure vessels are prevented from bursting by either having the mechanical strength to withstand the increase in internal pressure, or by being equipped with a pressure relief device that releases insulating gas to the outside (into the atmosphere) if the internal pressure rises above a certain pressure.

An example of technology to prevent a pressure vessel from bursting when the internal pressure of the pressure vessel rises is described in Patent Document 1. The pressure vessel described in Patent Document 1 has a through hole that connects the internal space of the pressure vessel to the outside, and a rupture disc that closes the through hole. With the technology in Patent Document 1, when the pressure difference between the internal space and the outside reaches a predetermined rupture pressure, the rupture disc bursts and the insulating gas flows out from the through hole to the outside, reducing the rise in internal pressure and preventing the pressure vessel from bursting.

JP 2017-60214 A

_SF6 gas, which is mainly used as an insulating gas in gas-insulated switchgear, has a global warming potential of 22,800 times that of _CO2 . For this reason, there are concerns that if the internal pressure of a pressure vessel increases, as in the case of the pressure vessel described in Patent Document 1, and the internal pressure is reduced by releasing the insulating gas into the atmosphere, this will have a significant impact on the environment.

The object of the present invention is to provide a pressure vessel for a gas-insulated switchgear that can prevent the pressure vessel from bursting even if the internal pressure rises, without releasing insulating gas into the atmosphere.

The pressure vessel of the gas-insulated switchgear according to the present invention comprises a vessel body filled with insulating gas, a conductor housed in the vessel body, an insulating spacer positioned on the outer periphery of the conductor to support the conductor, and a flange positioned between the insulating spacer and the vessel body to fix the insulating spacer to the vessel body. The flange comprises a through hole and a rupture disk that is curved in a convex shape and closes the opening of the through hole.

The present invention provides a pressure vessel for a gas-insulated switchgear that can prevent the pressure vessel from bursting even if the internal pressure rises, without releasing insulating gas into the atmosphere.

FIG. 2 is a cross-sectional view showing an example of the configuration of a pressure vessel of a gas-insulated switchgear according to FIG. 2 is an enlarged cross-sectional view of a portion A in FIG. 1, showing the configuration of a pressure relief device.

The pressure vessel of the gas-insulated switchgear according to the present invention comprises a vessel body filled with insulating gas, an insulating spacer, a flange, and a pressure relief device that prevents the vessel body from bursting. The pressure vessel has an internal space divided into multiple compartments by the insulating spacer and the flange. The pressure relief device comprises a convex rupture disc that closes the opening of the through hole provided in the flange.

In the pressure vessel of the present invention, when the internal pressure rises, the rupture disk of the pressure relief device ruptures, releasing insulating gas through the through hole in the flange into an adjacent compartment in the pressure vessel, thereby reducing the internal pressure and preventing the pressure vessel from bursting without releasing insulating gas into the atmosphere.

Hereinafter, a pressure vessel for a gas-insulated switchgear according to an embodiment of the present invention will be described with reference to the drawings. Note that in the drawings used in this specification, identical or corresponding components are given the same reference numerals, and repeated explanations of these components may be omitted.

Figure 1 is a cross-sectional view showing an example of the configuration of a pressure vessel of a gas-insulated switchgear according to this embodiment.

The pressure vessel comprises a vessel body 1, a conductor 3, an insulating spacer 6, a flange 5, an embedded conductor 7, and a pressure relief device 10.

The container body 1 is a cylindrical metal member, and is made of, for example, an aluminum alloy, iron, or stainless steel. The container body 1 is made up of a plurality of joined parts, and the internal space 8 is divided into a plurality of compartments. FIG. 1 shows two parts constituting the container body 1, that is, a container body 1a and a container body 1b joined to the container body 1a. In the example shown in FIG. 1, the internal space 8 of the container body 1 is divided into two compartments, that is, an internal space 8a of the container body 1a and an internal space 8b of the container body 1b. An insulating gas such as SF ₆ gas having a predetermined pressure (for example, 0.2 MPa to 1.0 MPa) is sealed in the container body 1 (1a, 1b).

The container body 1 houses the conductor 3, the insulating spacer 6, the flange 5, the embedded conductor 7, and the pressure relief device 10. A portion of the flange 5 is located inside the container body 1.

The conductor 3 is a busbar through which the load current of the power transmission and substation system flows. The conductor 3 is made of metal (e.g., aluminum alloy, etc.) and extends in the longitudinal direction of the pressure vessel. In the example shown in FIG. 1, the conductor 3 is configured by connecting the conductor 3a located in the internal space 8a and the conductor 3b located in the internal space 8b to each other.

The insulating spacer 6 is made of, for example, resin, and is positioned on the outer periphery of the conductor 3 to support the conductor 3.

The flange 5 is located between the insulating spacer 6 and the container body 1 and fixes the insulating spacer 6 to the container body 1.

The embedded conductor 7 is embedded in the center of the insulating spacer 6 and connects the conductors 3a and 3b to each other.

The insulating spacer 6 and the flange 5 divide the internal space 8 of the container body 1 into multiple compartments. In the example shown in Figure 1, the insulating spacer 6 and the flange 5 divide the internal space 8 of the container body 1 into internal space 8a and internal space 8b.

The pressure relief device 10 is installed in a portion of the flange 5 that is located inside the container body 1. The pressure relief device 10 is a device that prevents the container body 1 from bursting, and includes a rupture disk 11 that closes the through hole 14 in the flange 5, as described below.

Figure 2 is an enlarged cross-sectional view of part A in Figure 1, showing the configuration of the pressure relief device 10.

The flange 5 has a surface 5a facing the internal space 8a and a surface 5b facing the internal space 8b. Furthermore, the flange 5 has a through hole 14 that connects the internal space 8a and the internal space 8b, and the surface 5a and the surface 5b each have an opening for the through hole 14. The shape of the through hole 14 and its position on the flange 5 can be determined arbitrarily.

The flange 5 has an opening for the through hole 14 and a rupture disc 11a that covers and closes this opening on the surface 5a facing the internal space 8a, and has an opening for the through hole 14 and a rupture disc 11b that covers and closes this opening on the surface 5b facing the internal space 8b.

The pressure relief device 10 includes a rupture disc 11 (11a, 11b), fixing brackets 12 (12a, 12b), and packings 13 (13a, 13b), and is installed to cover both sides of the through hole 14 in the flange 5. The rupture disc 11 is a thin metal plate-like member, and is fixed to the flange 5. An existing rupture disc can be used for the rupture disc 11. The fixing brackets 12 are members that fix the rupture disc 11 to the flange 5. The packings 13 are members that maintain the airtightness of the internal space 15 of the through hole 14, and are provided at the fixing portion of the rupture disc 11 to the flange 5.

The rupture disc 11 is dome-shaped and curved in a convex shape. That is, the rupture disc 11 has a convex surface and a concave surface that is the reverse surface of the convex surface. In general, the rupture disc 11 ruptures when the difference between the pressure applied to one surface and the pressure applied to the other surface reaches a predetermined value (burst pressure). In the convexly curved rupture disc 11, the burst pressure differs between the convex surface and the concave surface, and the burst pressure of the convex surface is greater than the burst pressure of the concave surface. For this reason, in the convexly curved rupture disc 11, the convex surface is usually arranged to face the space where the pressure is higher.

In the pressure vessel according to this embodiment, the rupture discs 11a and 11b are arranged so that their convex surfaces face the internal space 8a and the internal space 8b, respectively. That is, the rupture disc 11a provided on the surface 5a of the flange 5 is curved in a convex shape toward the internal space 8a in contact with the surface 5a, and the rupture disc 11b provided on the surface 5b of the flange 5 is curved in a convex shape toward the internal space 8b in contact with the surface 5b. The concave surfaces of the rupture discs 11a and 11b face the internal space 15 of the through hole 14.

The through hole 14 is filled with gas in the internal space 15 that is blocked by the rupture discs 11a and 11b. This gas is, for example, dry air or an insulating gas that is sealed in the container body 1. When dry air is sealed in the internal space 15, the pressure in the internal space 15 can be made the same as atmospheric pressure, which has the advantage that the rupture disc 11 can be designed and installed in the same way as a conventional rupture disc that ruptures due to the difference between atmospheric pressure and insulating gas pressure.

In the pressure vessel according to this embodiment, the pressure of the insulating gas rises in the internal space 8a, and when the difference between the pressure of this insulating gas and the pressure of the gas sealed in the internal space 15 reaches the rupture pressure, the rupture disc 11a ruptures. As described above, in the rupture disc 11 curved in a convex shape, the rupture pressure of the convex surface is greater than the rupture pressure of the concave surface. Therefore, when the rupture disc 11a ruptures on the convex surface (i.e., the surface facing the internal space 8a), the rupture disc 11b ruptures on the concave surface (i.e., the surface facing the internal space 15 of the through hole 14). As a result, the insulating gas in the internal space 8a is released into the internal space 8b through the through hole 14 of the flange 5, and the pressure of the increased insulating gas can be reduced.

When the pressure of the insulating gas rises in the internal space 8b and the difference between the pressure of this insulating gas and the pressure of the gas sealed in the internal space 15 reaches the rupture pressure, the rupture disc 11b ruptures at the convex surface (i.e., the surface facing the internal space 8b), and the rupture disc 11a ruptures at the concave surface (i.e., the surface facing the internal space 15 of the through hole 14). This allows the insulating gas in the internal space 8b to be released into the internal space 8a through the through hole 14 of the flange 5, reducing the rising pressure of the insulating gas.

In this way, the pressure vessel of this embodiment can prevent the pressure vessel from bursting without releasing insulating gas into the atmosphere even if the internal pressure rises.

The shape of the through hole 14 can be determined arbitrarily, but it is preferable that it be circular so that the rupture disc 11 can rupture effectively. In addition, in this embodiment, one flange 5 is provided with one pressure relief device 10, but one flange 5 may be provided with multiple pressure relief devices 10.

Conventional pressure vessels are equipped with a pressure relief device on the outer surface of the vessel, and when the difference between atmospheric pressure and the pressure inside the vessel reaches the rupture pressure, the rupture disc ruptures, releasing insulating gas into the atmosphere. This has raised concerns that it could have a significant impact on the environment.

In the pressure vessel of this embodiment, insulating gas is released into adjacent compartments within the pressure vessel to reduce the internal pressure, preventing the pressure vessel from bursting without releasing insulating gas into the atmosphere, and causing no impact on the environment.

The present invention is not limited to the above-mentioned examples, and various modifications are possible. For example, the above-mentioned examples have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to an embodiment having all of the configurations described. It is also possible to replace part of the configuration of one example with the configuration of another example. It is also possible to add the configuration of another example to the configuration of one example. It is also possible to delete part of the configuration of each example, or to add or replace other configurations.

1, 1a, 1b...container body, 3, 3a, 3b...conductor, 5...flange, 5a, 5b...surface, 6...insulating spacer, 7...embedded conductor, 8, 8a, 8b...internal space, 10...pressure relief device, 11, 11a, 11b...rupture disc, 12, 12a, 12b...fixing bracket, 13, 13a, 13b...packing, 14...through hole, 15...internal space.

Claims (4)

A container body in which an insulating gas is sealed;
A conductor accommodated in the container body;
an insulating spacer positioned on an outer periphery of the conductor to support the conductor;
a flange located between the insulating spacer and the container body to fix the insulating spacer to the container body;
Equipped with
The flange includes a through hole and a rupture disk that is curved in a convex shape and closes an opening of the through hole.
2. A pressure vessel for a gas-insulated switchgear comprising: The insulating spacer and the flange divide an internal space of the container body,
The flange has one surface facing one of the divided internal spaces of the container body and another surface facing the other of the divided internal spaces,
The flange includes the opening of the through hole and the rupture disc closing the opening on each of the one surface and the other surface.
2. A pressure vessel for gas-insulated switchgear according to claim 1. The rupture disk provided on the one surface of the flange is curved in a convex shape toward the one internal space,
The rupture disc provided on the other surface of the flange is curved in a convex shape toward the other internal space.
A pressure vessel of gas-insulated switchgear according to claim 2. The through hole is sealed with dry air inside the through hole sealed with the rupture disc.
A pressure vessel of gas-insulated switchgear according to claim 2.

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