A gas insulated switchgear with partial pressure sealed tank

Abstract

The application discloses a kind of gas insulation switchgear with partial pressure sealing box, including first partial pressure box and second partial pressure box;First partial pressure box is arranged in the inside of second partial pressure box;First partial pressure box is fixedly connected by box connecting piece between second partial pressure box;First partial pressure box and second partial pressure box are sealed;First partial pressure box is filled with insulating gas, and second partial pressure box is filled with filling medium, and the pressure of insulating gas is greater than the pressure of filling medium;Box connecting piece includes insulating support and conducting part;Insulating support is arranged at the both ends of conducting part;Conducting part passes through first partial pressure box and second partial pressure box, and the insulating support of both ends is arranged between first partial pressure box and second partial pressure box, and the both ends of insulating support are fixedly connected first partial pressure box and second partial pressure box respectively;High-voltage element is arranged on the conducting part in first partial pressure box.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of gas insulated switchgear, and particularly relates to a voltage division sealing box body for a gas insulated switchgear. BACKGROUND

[0002] The main feature of a gas insulated high-voltage alternating-current metal-enclosed switchgear is that, except for the connection of the primary incoming and outgoing lines and the compartment unit, the main branch bus and switch elements of the switch cabinet are all in a sealed gas chamber of low-pressure SF6 or mixed gas. Since the shape of the switch cabinet is generally made into a cabinet shape, it is also called a cabinet type gas insulated switch cabinet (C-GIS). The connection between the incoming and outgoing lines and the gas chamber of the C-GIS adopts a stress cone cable plug connector or a bus connector, and the entire main circuit is not affected by the external environment.

[0003] Since the insulation strength of SF6 gas is high, the pressure of SF6 gas filled in the medium-voltage gas insulated switchgear does not need to be very high. At present, the filling pressure of the SF6 gas insulated switchgear is 1.4 bar (absolute value), and the pressure borne by the sealing box body is about 0.4 bar, plus the external atmospheric pressure of the sealing box body. Since this pressure is not very high, the sealing box body used in the current medium-voltage SF6 gas insulated switch cabinet is welded from stainless steel sheets, which is relatively simple in processing difficulty and manufacturing process and has a lower cost.

[0004] Since the SF6 gas used in the switchgear has a relatively high greenhouse effect index, with the increasing emphasis on environmental protection, a gas with a relatively small greenhouse effect index is used as the insulation gas of the switchgear in the research and development process. However, the insulation performance of the insulation gas is relatively poor compared with that of SF6 gas. In order to meet the insulation requirements of the switchgear, the filling pressure of the switchgear must be increased. The sealing box body used in the current medium-voltage SF6 gas insulated switch cabinet is welded from stainless steel sheets. After the filling pressure of the insulation gas is increased, the sealing box body welded from stainless steel sheets is subjected to a large gas pressure, which causes the sealing box body to be severely deformed. After the sealing box body is severely deformed, the welding seam is cracked to form a gas leakage point. After the sealing box body is severely deformed, the use of the switchgear with multiple cabinets is also affected. Since the sealing box body is the installation reference of all internal components, the deformation of the sealing box body will affect the stress deformation of the internal components and change the internal electric field distribution, which affects the operation reliability of the switchgear. In order to reduce the deformation of the box body, a reinforcing rib is welded on the sheet. When the reinforcing rib is welded inside the box body, the internal electric field of the switchgear is changed to affect the insulation strength. When the reinforcing rib is welded outside the box body, the size of the switchgear is increased, which affects the appearance of the switchgear.

[0005] In order to achieve the case of bearing pressure invariability needs to increase the thickness of the sheet or change the shape of the box, so the existing switchgear manufacturing equipment, processing technology need to change. Due to the increase of gas pressure to ensure the sealing performance of the original sealing structure also need to be redesigned. SUMMARY

[0006] In order to solve the problems in the prior art, the application provides a gas insulated switchgear pressure distribution sealing box, which can meet the original switchgear manufacturing equipment, processing technology and sealing structure, without changing the manufacturing equipment, process requirements and sealing design difficulty.

[0007] To achieve the above object, the application provides the following technical scheme:

[0008] A gas insulated switchgear pressure distribution sealing box, comprising a first pressure distribution box and a second pressure distribution box;

[0009] The first pressure distribution box is arranged in the second pressure distribution box; the first pressure distribution box and the second pressure distribution box are fixedly connected through a box connecting piece; the first pressure distribution box and the second pressure distribution box are both sealed;

[0010] The first pressure distribution box is filled with insulating gas, and the second pressure distribution box is filled with filling medium; the pressure of the insulating gas is greater than that of the filling medium;

[0011] The box connecting piece comprises an insulating support and a conductive piece; the insulating support is arranged at both ends of the conductive piece; the conductive piece passes through the first pressure distribution box and the second pressure distribution box, and the insulating supports at both ends are arranged between the first pressure distribution box and the second pressure distribution box; the insulating supports at both ends are fixedly connected to the first pressure distribution box and the second pressure distribution box, respectively; and an internal high-voltage element is arranged on the conductive piece in the first pressure distribution box;

[0012] The first pressure distribution box is a floating potential, and the second pressure distribution box is grounded as a ground potential.

[0013] Preferably, the first pressure distribution box is provided with a first gas inlet, and the second pressure distribution box is provided with a second gas inlet.

[0014] Preferably, the first pressure distribution box and the second pressure distribution box are box bodies of the same structure but different sizes.

[0015] Preferably, the first pressure distribution box comprises a right plate, a left plate, an upper plate, a lower plate, a front plate and a rear plate, and the right plate, the left plate, the upper plate, the lower plate, the front plate and the rear plate are welded into a sealed box body.

[0016] Preferably, the insulating support and the conductive piece are in a one-time casting structure.

[0017] Preferably, the insulating support is provided with a plurality of mounting connectors; the mounting connectors are bolt mounting inserts, the first pressure dividing box and the second pressure dividing box are provided with openings, the bolt mounting inserts are installed in the openings, the bolt mounting inserts are embedded in the openings and fixed with bolts, and the bolt mounting inserts are located inside the sealing ring.

[0018] Preferably, the insulating support is provided with a plurality of mounting connectors; the mounting connectors are bolt mounting holes, studs are welded on the first and second pressure dividing boxes, the studs pass through the bolt mounting holes and are fixedly installed with nuts, and the bolt mounting holes are located outside the sealing ring.

[0019] Preferably, the insulating support member has a first sealing groove and a second sealing groove at both ends; a first sealing ring and a second sealing ring are respectively provided inside the first sealing groove and the second sealing groove.

[0020] Preferably, the box connector is provided with a climbing skirt.

[0021] Preferably, the first voltage divider box is made of metal or insulating material, and the second voltage divider box is made of metal.

[0022] Compared with the prior art, the present invention has the following beneficial technical effects:

[0023] This invention provides a pressure-dividing sealing enclosure for gas-insulated switchgear. By employing a first pressure-dividing enclosure and a second pressure-dividing enclosure, the first enclosure is filled with insulating gas at the required pressure, while the second enclosure is filled with a filling medium at a lower pressure than the first enclosure. This reduces the internal and external pressures of the first and second enclosures, minimizing deformation of the sealing housing when the insulating gas filling pressure of the switchgear increases. Other gases or liquids can be filled between the first and second enclosures, reducing the amount of insulating gas used. The reduced pressure between the first and second enclosures also reduces leakage of the insulating gas. Furthermore, when internal arcing occurs in the switchgear, the first enclosure, being at a floating potential, is less likely to ignite the arc between the high-voltage conductor and the enclosure, reducing the possibility of the sealing enclosure being burned through by the arc and improving the switchgear's protection capabilities.

[0024] Furthermore, the first voltage divider box is at a floating potential, while the second voltage divider box is grounded to ground potential. Since the first voltage divider box is at a floating potential, the potential distribution inside and outside the first voltage divider box can be improved, thereby improving the insulation performance of the switchgear.

[0025] Furthermore, creepage skirts are installed on the edges of the enclosure connectors to increase the creepage distance. Attached Figure Description

[0026] Figure 1This is a schematic diagram of the overall structure of a pressure-dividing sealing housing for a gas-insulated switchgear according to the present invention;

[0027] Figure 2 This is a schematic diagram of the first / second pressure-dividing box of the present invention;

[0028] Figure 3 This is a front view of the box-type connector.

[0029] Figure 4 This is a cross-sectional view of the box-type connecting parts;

[0030] In the attached diagram: 1 is the first pressure dividing box; 2 is the second pressure dividing box; 3 is the box connector; 4 is the second air inlet; 5 is the first air inlet; 6 is the right plate; 7 is the left plate; 8 is the upper plate; 9 is the lower plate; 10 is the front plate; 11 is the rear plate; 12 is the insulating gas; 13 is the filling medium; 14 is the natural atmosphere; 15 is the internal high-voltage component; 16 is the insulating support component; 17 is the conductive component; 18 is the first sealing ring; 19 is the second sealing ring; 20 is the creepage skirt; 21 is the mounting connector; 22 is the first sealing groove; 23 is the second sealing groove. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0032] Example

[0033] like Figure 1 As shown, a pressure-dividing sealing enclosure for a gas-insulated switchgear according to the present invention includes a first pressure-dividing enclosure 1, a second pressure-dividing enclosure 2, and an enclosure connector 3.

[0034] The first pressure dividing chamber 1 is connected and fixed to the second pressure dividing chamber 2 via a chamber connector 3. The chamber connector 3 is connected to the internal high-voltage component 15. Each of the first and second pressure dividing chambers has a first inflation port 5 and a second inflation port 4 for filling the sealed chamber with gas / liquid. During inflation, the inflation port is connected to the inside of the sealed chamber; after inflation, the inflation port closes itself to maintain a seal. The first pressure dividing chamber is filled with insulating gas 12, and the second pressure dividing chamber (intermediate layer) is filled with other gas (insulating gas) / liquid 13. The outside of the second pressure dividing chamber is the natural atmosphere 14. The pressure of the insulating gas 12 is greater than the pressure of the intermediate layer 13, and the pressure of the intermediate layer 13 is greater than the pressure of the natural atmosphere 14.

[0035] like Figure 2As shown, the first pressure-reducing chamber 1 and the second pressure-reducing chamber 2 are chambers with the same structure but different sizes. Both the first pressure-reducing chamber 1 and the second pressure-reducing chamber 2 are assembled and welded together from six plates: right plate 6, left plate 7, upper plate 8, lower plate 9, front plate 10, and rear plate 11. The welded chambers must ensure their sealing performance. The first pressure-reducing chamber 1 and the second pressure-reducing chamber 2 can also be welded together from three (one rolled into a cylinder or ellipse and two end plates) or more plates (with hexagonal or octagonal cross-sections).

[0036] like Figure 3 As shown, the housing connector 3 includes an insulating support 16 and a conductive component 17. The insulating support 16 is located at both ends of the conductive component 17, and the insulating support 16 and the conductive component 17 are cast in one piece. The insulating support 16 is used to connect the first voltage divider housing 1 and the second voltage divider housing 2. At each end of the insulating support 16, there are several mounting connectors 21. The mounting connectors 21 are bolt mounting inserts or bolt mounting holes. If studs are welded to the sealing housing, the bolt mounting holes are used for fixing with nuts, and the mounting holes are outside the sealing ring. If holes are opened on the sealing housing, the bolt mounting inserts are used for fixing with bolts, and the mounting inserts are inside the sealing ring. The bolts fix the insulating support 16 between the first voltage divider housing 1 and the second voltage divider housing 2 through the bolt mounting inserts or bolt mounting holes. The insulating support 16 can be circular or other shapes.

[0037] like Figure 4 As shown, the insulating support 16 has a first sealing groove 22 and a second sealing groove 23 at both ends; a first sealing ring 18 and a second sealing ring 19 are respectively provided inside the first sealing groove 22 and the second sealing groove 23. The first sealing ring 18 and the second sealing ring 19 are used to seal the first voltage divider housing 1 and the second voltage divider housing 2, respectively. A creepage skirt 20 is provided on the edge of the housing connector 3 to increase the creepage distance.

[0038] The first pressure-dividing chamber 1 is filled with insulating gas at the required pressure, while the second pressure-dividing chamber 2 is filled with air (which has no impact on the environment) or other gases at a lower pressure than the first pressure-dividing chamber 1. Since the pressure borne by the first pressure-dividing chamber 1 is the pressure difference between the internal gas pressure and the intermediate layer gas pressure, and the pressure borne by the second pressure-dividing chamber 2 is the pressure difference between the intermediate layer gas pressure and the external atmospheric pressure, the internal and external pressures of the first and second pressure-dividing chambers 1 and 2 are lower than the pressure borne by a single chamber. This reduces the deformation of the sealing shell when the insulating gas filling pressure of the switchgear increases. The filling medium 13 can be air (which has no impact on the environment), other gases, or insulating liquids.

[0039] In this invention, the first voltage divider box 1 is at a floating potential, and the second voltage divider box 2 is grounded at a ground potential. Since the first voltage divider box 1 is at a floating potential, the potential distribution inside and outside the first voltage divider box can be improved, thereby improving the insulation performance of the switching equipment.

[0040] Other gases (non-insulating gases) or liquids can be filled between the first pressure dividing box 1 and the second pressure dividing box 2. The insulating gas that originally needed to be filled between the first pressure dividing box 1 and the second pressure dividing box 2 (intermediate layer) can be replaced by other gases / liquids, which can reduce the amount of insulating gas used.

[0041] Previously, a single sealed enclosure had higher internal and external air pressures, requiring more stringent sealing structures and rings, and increasing the likelihood of leakage. However, with the reduced pressure between the first and second pressure-dividing enclosures (1 and 2), the requirements for the sealing structure and rings remain the same as current products, reducing the leakage of insulating gas from the switchgear. If the first pressure-dividing enclosure (1) leaks, the internal insulating gas pressure will only decrease slightly, without affecting the internal insulation. Similarly, if the second pressure-dividing enclosure (2) leaks, the internal pressure of the first pressure-dividing enclosure (1) will not change, and the internal insulation will not be affected.

[0042] When an internal arc occurs in the switchgear, the first voltage divider housing 1 is at a floating potential, making it less likely for the arc to burn between the high-voltage conductor and the first housing. This reduces the possibility of the sealed housing being burned through by the arc, thus improving the switchgear's protection capability. Even if the arc burns between the first voltage divider housing 1 and the high voltage, and burns through the first voltage divider housing 1, the presence of the second voltage divider housing 2 ensures that the internal arc and high-temperature gas will not affect the outside environment.

[0043] This invention can satisfy existing switchgear manufacturing equipment, processing technology, and sealing structure without changing the manufacturing equipment, process requirements, or sealing design complexity. Both the first voltage divider housing 1 and the second voltage divider housing 2 have gas-sealing performance and can share gas pressure; the first voltage divider housing 1 is at a floating potential, and the second voltage divider housing 2 is at ground potential, capable of sharing voltage; the first voltage divider housing 1 can be made of metal or insulating material, and the second voltage divider housing 2 is made of metal.

[0044] The first voltage divider box 1 and the second voltage divider box 2 can both be ground potential schemes, but the first voltage divider box 1 will not have the function of changing the electric field. In order to achieve the condition that the pressure-bearing box remains unchanged, it is necessary to increase the thickness of the thin plate, increase the number of reinforcing ribs, or change the shape of the box (circular or elliptical). At this time, the box may be made of three or more plates welded together.

Claims

1. A pressure-dividing sealed enclosure for a gas-insulated switchgear, characterized in that, It includes a first pressure dividing box (1) and a second pressure dividing box (2); The first pressure dividing box (1) is disposed inside the second pressure dividing box (2); the first pressure dividing box (1) and the second pressure dividing box (2) are fixedly connected by a box connector (3); both the first pressure dividing box (1) and the second pressure dividing box (2) are sealed. The first pressure divider box (1) is filled with insulating gas (12), and the second pressure divider box (2) is filled with filling medium (13). The pressure of the insulating gas (12) is greater than the pressure of the filling medium (13). The housing connector (3) includes an insulating support (16) and a conductive component (17); the insulating support (16) is disposed at both ends of the conductive component (17); the conductive component (17) passes through the first voltage divider housing (1) and the second voltage divider housing (2), and the insulating support (16) at both ends is disposed between the first voltage divider housing (1) and the second voltage divider housing (2), and the two ends of the insulating support (16) are respectively fixedly connected to the first voltage divider housing (1) and the second voltage divider housing (2); an internal high-voltage component (15) is disposed on the conductive component (17) inside the first voltage divider housing (1); The first voltage divider box (1) is at a floating potential, and the second voltage divider box (2) is grounded at a ground potential.

2. The pressure-dividing sealed enclosure for a gas-insulated switchgear according to claim 1, characterized in that, The first pressure divider box (1) is provided with a first air inlet (5); the second pressure divider box (2) is provided with a second air inlet (4).

3. The pressure-dividing sealed enclosure for a gas-insulated switchgear according to claim 1, characterized in that, The first pressure dividing box (1) and the second pressure dividing box (2) are boxes with the same structure but different sizes.

4. The pressure-dividing sealed enclosure for a gas-insulated switchgear according to claim 1, characterized in that, The first pressure-dividing box (1) includes a right plate (6), a left plate (7), an upper plate (8), a lower plate (9), a front plate (10), and a rear plate (11), which are welded together to form a sealed box.

5. A pressure-dividing sealed enclosure for a gas-insulated switchgear according to claim 1, characterized in that, The insulating support (16) and the conductive component (17) are formed by one-time casting.

6. The voltage divider sealing housing for gas-insulated switchgear according to claim 1, characterized in that, The insulating support (16) is provided with a plurality of mounting connectors (21); the mounting connectors (21) are bolt mounting inserts, the first pressure dividing box (1) and the second pressure dividing box (2) are provided with openings, the bolt mounting inserts are installed in the openings, the bolt mounting inserts are embedded in the openings and fixed with bolts, and the bolt mounting inserts are located inside the sealing ring.

7. The pressure-dividing sealed enclosure for a gas-insulated switchgear according to claim 1, characterized in that, The insulating support (16) is provided with a plurality of mounting connectors (21); the mounting connectors (21) are bolt mounting holes, and studs are welded on the first pressure dividing box (1) and the second pressure dividing box (2). The studs pass through the bolt mounting holes and are fixedly installed with nuts. The bolt mounting holes are located outside the sealing ring.

8. A pressure-dividing sealed enclosure for a gas-insulated switchgear according to claim 1, characterized in that, The insulating support (16) has a first sealing groove (22) and a second sealing groove (23) at both ends; a first sealing ring (18) and a second sealing ring (19) are respectively provided inside the first sealing groove (22) and the second sealing groove (23).

9. A pressure-dividing sealed enclosure for a gas-insulated switchgear according to claim 1, characterized in that, The box connector (3) is provided with a climbing skirt (20).

10. A pressure-dividing sealed enclosure for a gas-insulated switchgear according to claim 1, characterized in that, The first voltage divider box (1) is made of metal or insulating material, and the second voltage divider box (2) is made of metal.

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