Grounding device for gas insulated switchgear

Abstract

The utility model discloses a grounding device for a gas-insulated switchgear, which comprises a grounding conductor main body arranged on the outer wall of a gas chamber shell, a fixed flange arranged on the inner wall of the gas chamber shell, an inner grounding bar and an outer grounding bar, the grounding conductor main body is composed of two sections of concentric reducing cylinders with small upper parts and large lower parts, the lower section of cylinder is connected with one end of the outer grounding bar, and the other end of the outer grounding bar is connected with the fixed flange. The other end of the external grounding bar is connected with an equipment grounding point, the fixing flange is a short cylinder with a central through hole, and the upper section cylinder of the grounding conductor main body penetrates through the air chamber shell, extends into the central through hole of the fixing flange, is fixed and extends out by a section to be connected with one end of the internal grounding bar; and the other end of the inner grounding bar is connected with a main switch grounding bar in the gas tank. According to the utility model, not only can the sealing performance of the air chamber be ensured, but also the short-time endurance capability and continuity of a grounding loop can be ensured, a stable and reliable fault current discharge channel is provided when a grounding fault occurs in the switch equipment or manual grounding maintenance is needed, and the device is convenient to disassemble and assemble.

Description

Technical Field

[0001] This utility model relates to the grounding technology of main switches for metal-enclosed switchgear and control equipment in the power industry, and specifically to the structural design of the transition point of the grounding circuit between the inner and outer grounding circuits of box-type gas-insulated switchgear and control equipment, and particularly to a grounding device for gas-insulated switchgear. Background Technology

[0002] The short-time withstand capability of the equipment grounding circuit is one of the core indicators in the safety design of power systems, directly affecting the reliability and safety of equipment under extreme fault conditions. When a grounding fault occurs inside the ring main unit or manual grounding maintenance is required, the grounding circuit is the only channel for discharging the fault current. If the short-time withstand capability of the circuit is insufficient, when a fault occurs, before the circuit breaker can trip and cut off the fault current, the high-impedance conductor will melt, preventing the fault current from being discharged. This can easily lead to arc reignition or equipment explosion, endangering personal safety. The ring main unit grounding circuit has become a crucial component for ensuring the safe and stable operation of the power system.

[0003] Gas-insulated switchgear and control equipment are widely used in power systems due to their fully enclosed, modular, compact, highly safe, intelligent, low-maintenance, environmentally friendly, and highly reliable characteristics. The fully enclosed nature of these devices improves operational reliability but also increases the design complexity of the grounding circuit within the gas chamber. This requires ensuring the gas chamber's airtightness, the short-time withstand capability and continuity of the grounding circuit, and the convenience of the grounding device. Considering these requirements, there are currently three main methods for grounding the gas chamber and its surrounding environment:

[0004] Method 1: The grounding circuit passes through the gas chamber location, with studs welded face-to-face. The main switch inside the gas chamber is connected to the grounding system through the grounding busbar inside the gas box, studs, the gas box wall, and the grounding busbar outside the gas box. Its advantages are: convenient installation and guaranteed gas chamber sealing; its disadvantages are: a high impedance point appears in the grounding circuit, and when a large fault current passes through, the grounding copper part at the grounding point is prone to melting, and the fault current cannot be discharged.

[0005] Method 2: The grounding circuit passes through an opening in the gas chamber, with a copper block welded in the middle. The main switch inside the gas chamber is connected to the grounding system via the grounding busbar inside the gas box, the welded copper block, and the grounding busbar outside the gas box. Its advantages are: convenient installation and no high-impedance points in the grounding circuit; its disadvantages are: the welding of the copper parts to the stainless steel gas box wall requires high welding technology, it is not easy to disassemble, it is very easy to leak air, and the sealing is difficult to guarantee.

[0006] Method 3: The grounding circuit passes through an opening in the gas chamber, with a stainless steel component welded in the middle. The main switch inside the gas chamber is connected to the grounding system via the grounding busbar inside the gas box, the stainless steel component, and the grounding busbar outside the gas chamber. Its advantages are: the stainless steel component is welded to the stainless steel gas box wall, making welding easy and ensuring the gas chamber's sealing performance; its disadvantages are: it is difficult to disassemble, high impedance points appear in the grounding circuit, and the grounding copper component at the grounding point is prone to melting when a large fault current passes through, preventing the fault current from being discharged. Utility Model Content

[0007] The purpose of this invention is to provide a grounding device for gas-filled cabinets that ensures the short-term withstand capability and continuity of the grounding circuit while guaranteeing the airtightness of the gas chamber, and is easy to disassemble and replace.

[0008] The purpose of this utility model is achieved through the following technical measures: A grounding device for a gas-filled cabinet, characterized in that it includes a grounding conductor body disposed on the outer wall of the gas chamber shell, a fixing flange disposed on the inner wall of the gas chamber shell, an inner grounding busbar and an outer grounding busbar. The grounding conductor body is composed of two concentric columns of different diameters, one smaller at the top and one larger at the bottom. The lower column is connected to one end of the outer grounding busbar, and the other end of the outer grounding busbar is connected to the equipment grounding point. The fixing flange is a short column with a central through hole. The upper column of the grounding conductor body passes through the gas chamber shell, extends into the central through hole of the fixing flange, is fixed, and extends out to connect to one end of the inner grounding busbar. The other end of the inner grounding busbar is connected to the main switch grounding busbar inside the gas chamber.

[0009] This invention ensures both the airtightness of the gas chamber and the short-term withstand capability and continuity of the grounding circuit, providing a stable and reliable fault current discharge channel for grounding faults occurring inside switchgear or requiring manual grounding maintenance. This avoids risks such as equipment explosions and further escalation of faults leading to personal injury and economic losses due to insufficient short-term withstand capability of the grounding circuit. Furthermore, the device is easy to install and disassemble.

[0010] The present invention provides sealing structures between the bottom surface of the fixed flange and the inner wall of the gas chamber shell, and between the lower column of the grounding conductor body and the outer wall of the gas chamber shell.

[0011] The sealing structures between the bottom surface of the fixed flange and the inner wall of the gas chamber shell, and between the top surface of the lower column of the grounding conductor body and the outer wall of the gas chamber shell, of this utility model are both inner and outer annular sealing grooves and sealing rings. The inner sealing ring is a U-shaped cross-section high-temperature resistant metal sealing ring, and the outer sealing ring is an O-shaped cross-section polytetrafluoroethylene sealing ring.

[0012] The upper column of the grounding conductor body of this utility model has threads on its side, and the central through hole of the fixed flange is a threaded hole. The upper column of the grounding conductor body is threadedly connected to the central through hole of the fixed flange.

[0013] The surface of the grounding conductor body of this utility model, except for the threaded surface of the upper column, is galvanized or silver-plated.

[0014] The bottom surface of the lower column of the grounding conductor body of this utility model is provided with a first threaded hole. The external grounding busbar is fixed to the grounding conductor body by means of bolting and screwing into the first threaded hole. The top surface of the upper column of the grounding conductor body is provided with a second threaded hole. The internal grounding busbar is fixed to the grounding conductor body by means of bolting and screwing into the second threaded hole.

[0015] The upper and lower columns of the grounding conductor body of this utility model are integrally formed. The upper column is a cylinder and the lower column is a regular hexagonal prism. The top surface of the upper column is a plane, which is also the overlapping surface with the inner grounding busbar. The bottom surface of the lower column is a plane, which is also the overlapping surface with the outer grounding busbar.

[0016] The outer wall surface of the fixed flange of this utility model has at least one set of two opposing planes, and a pair of radially arranged third threaded holes are provided on one set of planes. The third threaded holes allow flat-end set screws to pass through and press tightly against the upper column of the grounding conductor body, effectively preventing it from loosening due to vibration or electrodynamic force.

[0017] The fixed flange and the grounding conductor body of this utility model are both made of copper.

[0018] Compared with the prior art, the present invention has the following significant advantages:

[0019] (1) The main body of this utility model is made of T2 copper. The conductor cross-section design fully meets the requirements of national and industry standards for the short-time withstand capability of the main switch grounding circuit, and the structure is reliable.

[0020] (2) The grounding conductor body and the fixed flange of this utility model are connected by threaded locking, which is reliable, easy to disassemble and assemble, and does not require copper-copper or copper-stainless steel welding processes. It is easy to construct and easy to replace.

[0021] (3) The present invention has a double sealing surface structure, that is, both the inner and outer sides of the gas chamber wall are sealing surfaces. During operation, as long as one of the sealing surfaces is normal, the airtightness of the gas chamber can be guaranteed, and the risk of arc extinguishing and leakage of insulating medium in the gas chamber is reduced.

[0022] (4) The grounding conductor body and fixed flange of this utility model are combined in a combined manner. In fact, only the integrated copper grounding conductor body runs through the inside and outside of the gas box. The contact resistance and transmission resistance are extremely small, which can effectively eliminate the high impedance point in the grounding circuit.

[0023] (5) This utility model changes the design from axial sealing to static end face radial sealing. The grounding conductor body runs through the inside and outside of the gas box. The grounding conductor body and the flange that were originally to be sealed are transferred to static end face sealing between the grounding conductor body, the fixed flange and the gas chamber wall through the double sealing surface structure, which is more reliable.

[0024] (6) The double-ring sealing design at the sealing surface of this utility model ensures the sealing effect of the surface if one ring is normal. The inner ring adopts a high-temperature resistant metal sealing ring with an annular U-shaped cross section, and the outer ring adopts a polytetrafluoroethylene sealing ring to reduce the impact of the thermal effect of fault current on the sealing performance at this point.

[0025] (7) The fixed flange of this utility model adopts a flat-end set bolt installation method to prevent loosening, thereby reducing the impact of current dynamic effect on the sealing effect at this location.

[0026] (8) This utility model meets the requirements of relevant standards for short-time withstand capability of grounding circuits in power switchgear and control equipment. Through theoretical calculation and careful design, compared with grounding methods such as grounding studs, gas box shells, stainless steel weldments, and copper grounding block assemblies, this utility model has high reliability, good sealing performance, and convenient installation without affecting the airtightness of the gas chamber. It can be applied to most box-type gas-filled metal-enclosed switchgear and control equipment in medium and low voltage. Attached Figure Description

[0027] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0028] Figure 1 This is a schematic diagram of the structure of this utility model installed on the air chamber shell;

[0029] Figure 2 yes Figure 1 S-direction view;

[0030] Figure 3 This is a top view of the fixed flange of this utility model;

[0031] Figure 4 This is the front view of the fixed flange of this utility model;

[0032] Figure 5 This is a top view of the grounding conductor body of this utility model;

[0033] Figure 6 This is a front view of the grounding conductor body of this utility model.

[0034] In the diagram: 1-Inner grounding busbar, 2-Fixed flange, 3-First sealing ring, 4-Second sealing ring, 5-Gas chamber shell, 6-Fourth sealing ring, 7-Third sealing ring, 8-Grounding conductor body, 9-External grounding busbar, 10-Main switch grounding busbar, 11-Lower column, 12-Central through hole, 13-Upper column, 14-First threaded hole, 15-Second threaded hole, 16-Flat surface, 17-Third threaded hole, 18-First annular sealing groove, 19-Second annular sealing groove, 20-Third annular sealing groove, 21-Fourth annular sealing groove, 22-Flat-end set screw. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the embodiments and accompanying drawings to help those skilled in the art better understand the inventive concept of the present invention. However, the scope of protection of the claims of the present invention is not limited to the following embodiments. For those skilled in the art, all other embodiments obtained without creative effort without departing from the inventive concept of the present invention are within the scope of protection of the present invention.

[0036] like Figures 1-6 As shown, this utility model discloses a grounding device for an inflatable cabinet, comprising a grounding conductor body 8 disposed on the bottom surface of the outer wall of the gas chamber shell 5, a fixing flange 2 disposed on the bottom surface of the inner wall of the gas chamber shell 5, an inner grounding busbar 1, and an outer grounding busbar 9. The fixing flange 2 and the grounding conductor body 8 are both made of copper. The grounding conductor body 8 is composed of two concentric columns of different diameters, one smaller at the top and one larger at the bottom. The lower column 11 is connected to one end of the outer grounding busbar 9, and the other end of the outer grounding busbar 9 is connected to the equipment grounding point. The fixing flange 2 is a short column with a central through hole 12. The upper column 13 of the grounding conductor body 8 passes through the gas chamber shell 5, extends into the central through hole 12 of the fixing flange 2, is fixed, and extends out to connect to one end of the inner grounding busbar 1. The other end of the inner grounding busbar 1 is connected to the main switch grounding busbar 10 inside the gas chamber.

[0037] In this embodiment, the upper column 13 of the grounding conductor body 8 has threads on its side, and the central through hole 12 of the fixing flange 2 is a threaded hole. The upper column 13 of the grounding conductor body 8 is threadedly connected to the central through hole 12 of the fixing flange 2.

[0038] Except for the threaded surface of the upper column 13, the surface of the grounding conductor body 8 is galvanized or silver-plated to prevent rust and reduce contact resistance.

[0039] The bottom surface of the lower column 11 of the grounding conductor body 8 is provided with a first threaded hole 14. The external grounding busbar 9 is fixed to the grounding conductor body 8 by bolting it into the first threaded hole 14. The top surface of the upper column 13 of the grounding conductor body 8 is provided with a second threaded hole 15. The internal grounding busbar 1 is fixed to the grounding conductor body 8 by bolting it into the second threaded hole 15.

[0040] The upper column 13 and the lower column 11 of the grounding conductor body 8 are integrally made. The upper column 13 is a cylinder and the lower column 11 is a regular hexagonal prism. The top surface of the upper column 13 is a plane, which is also the overlapping surface with the inner grounding busbar 1. The bottom surface of the lower column 11 is a plane, which is also the overlapping surface with the outer grounding busbar 9. The top surface of the lower column 11 is a sealing surface with double sealing grooves.

[0041] The top surface of the fixed flange 2 is flat, and the lower surface is a sealing surface with double sealing grooves. The outer wall surface of the fixed flange 2 has at least one set of two opposing planes 16 (for fastening with locking tools). A pair of radially arranged third threaded holes 17 are provided on one set of planes 16. The third threaded holes 17 allow flat-end set screws 22 to pass through and press tightly against the upper column 13 of the grounding conductor body 8. The flat-end set screw installation method is designed to prevent loosening and reduce the impact of current dynamics on the sealing effect at this location.

[0042] In this embodiment, a sealing structure is provided between the bottom surface of the fixed flange 2 and the inner wall surface of the gas chamber shell 5, and between the top surface of the lower column 11 of the grounding conductor body 8 and the outer wall surface of the gas chamber shell 5. The sealing structure consists of two annular sealing grooves and sealing rings, one inside and one outside. The two annular sealing grooves on the fixed flange 2 are the first annular sealing groove 18 on the inner ring and the second annular sealing groove 19 on the outer ring. The first sealing ring 3 of the inner ring installed in the first annular sealing groove 18 is a high-temperature resistant annular U-shaped cross-section metal sealing ring, which is the first sealing line of the double sealing surface. The second sealing ring 4 of the outer ring installed in the second annular sealing groove 19 is a high-temperature resistant annular O-shaped cross-section polytetrafluoroethylene sealing ring, which is the second sealing line of the double sealing surface. The two annular sealing grooves on the lower column 11 of the grounding conductor body 8 are the third annular sealing groove 20 on the inner ring and the fourth annular sealing groove 21 on the outer ring. The third sealing ring 7 of the inner ring installed in the third annular sealing groove 20 is a high-temperature resistant annular U-shaped cross-section metal sealing ring, which is the first sealing line of the double sealing surface. The fourth sealing ring 6 of the outer ring installed in the fourth annular sealing groove 21 is a high-temperature resistant annular O-shaped cross-section polytetrafluoroethylene sealing ring, which is the second sealing line of the double sealing surface.

[0043] In this invention, the fixed flange 2 and the grounding conductor body 8 are respectively placed inside and outside the gas chamber shell, and are mechanically connected by threaded locking. A double-sealing surface and double-sealing structure ensure the airtightness of the gas chamber. After locking, the upper column end face of the grounding conductor body extends beyond the upper end face of the fixed flange by a certain distance. One end of the grounding busbar 1 inside the gas chamber is connected to the main switch grounding busbar 10 inside the gas chamber, and the other end is connected to the grounding conductor body 8 by bolts. One end of the grounding busbar 2 outside the gas chamber is connected to the equipment grounding point, and the other end is connected to the grounding conductor body 8 by bolts, thereby achieving the connection between the internal and external grounding conductors of the gas chamber. After the above installation is completed, the fixed flange 2 is fixed and prevented from loosening using flat-end set screws 22.

Claims

1. A grounding device for a gas-insulated switchgear, characterized in that: It includes a grounding conductor body disposed on the outer wall of the gas chamber shell, a fixed flange disposed on the inner wall of the gas chamber shell, an inner grounding busbar and an outer grounding busbar. The grounding conductor body is composed of two concentric columns of different diameters, one smaller at the top and one larger at the bottom. The lower column is connected to one end of the outer grounding busbar, and the other end of the outer grounding busbar is connected to the equipment grounding point. The fixed flange is a short column with a central through hole. The upper column of the grounding conductor body passes through the gas chamber shell, extends into the central through hole of the fixed flange, is fixed, and extends out to connect to one end of the inner grounding busbar. The other end of the inner grounding busbar is connected to the main switch grounding busbar inside the gas box.

2. The grounding device for a gas-insulated switchgear according to claim 1, characterized in that: A sealing structure is provided between the bottom surface of the fixed flange and the inner wall surface of the gas chamber shell, and between the top surface of the lower column of the grounding conductor body and the outer wall surface of the gas chamber shell.

3. The grounding device for a gas-insulated switchgear according to claim 2, characterized in that: The sealing structures between the bottom surface of the fixed flange and the inner wall of the gas chamber shell, and between the top surface of the lower column of the grounding conductor body and the outer wall of the gas chamber shell, are both inner and outer annular sealing grooves and sealing rings. The inner sealing ring is a U-shaped high-temperature resistant metal sealing ring, and the outer sealing ring is an O-shaped polytetrafluoroethylene sealing ring.

4. The grounding device for a gas-insulated switchgear according to claim 3, characterized in that: The upper column of the grounding conductor body has threads on its side, and the central through hole of the fixed flange is a threaded hole. The upper column of the grounding conductor body is threadedly connected to the central through hole of the fixed flange.

5. The grounding device for a gas-insulated switchgear according to claim 4, characterized in that: Except for the threaded surface of the upper column, the main surface of the grounding conductor is galvanized or silver-plated.

6. The grounding device for a gas-insulated switchgear according to claim 5, characterized in that: The bottom surface of the lower column of the grounding conductor body is provided with a first threaded hole. The external grounding busbar is fixed to the grounding conductor body by means of bolting and screwing it into the first threaded hole. The top surface of the upper column of the grounding conductor body is provided with a second threaded hole. The internal grounding busbar is fixed to the grounding conductor body by means of bolting and screwing it into the second threaded hole.

7. The grounding device for a gas-insulated switchgear according to claim 6, characterized in that: The upper and lower column sections of the grounding conductor body are integrally formed. The upper column section is a cylinder, and the lower column section is a regular hexagonal prism. The top surface of the upper column section is a plane, which is also the overlapping surface with the inner grounding busbar. The bottom surface of the lower column section is a plane, which is also the overlapping surface with the outer grounding busbar.

8. The grounding device for a gas-insulated switchgear according to claim 7, characterized in that: The outer wall surface of the fixed flange has at least one set of two opposing planes, and a pair of radially arranged third threaded holes are provided on one set of planes. The third threaded holes allow flat-end set screws to pass through and press tightly against the upper column of the grounding conductor body.

9. The grounding device for a gas-insulated switchgear according to claim 8, characterized in that: Both the fixed flange and the grounding conductor body are made of copper.

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