Inflatable switch cabinet double-shielding sleeve

Abstract

The utility model provides an inflatable switch cabinet double-shielding sleeve, which relates to the technical field of power equipment and comprises a conductive rod, an insulating sleeve, a grounding end, a first shielding layer and a second shielding layer. The insulating sleeve is a cylindrical sleeve made of an insulating material and sleeves the outer side of the conductive rod, and the grounding end is embedded into the insulating sleeve; the first shielding layer and the second shielding layer are of cylindrical structures, and the diameter of the first shielding layer is smaller than that of the second shielding layer; the first shielding layer and the second shielding layer are arranged in the insulating sleeve and sleeve the conductive rod, and the first shielding layer, the second shielding layer and the conductive rod are coaxially arranged; the first shielding layer is fixedly connected with the conductive rod, and the second shielding layer is fixedly connected with the grounding end. According to the scheme, the problem that the shielding net of the outgoing line sleeve needs to be overlapped and matched with the semiconductor shielding layer of the separable connector to achieve a good shielding effect can be solved.

Description

Technical Field

[0001] The utility model relates to the technical field of electric power equipment, in particular to a double-shielding bushing of an inflatable switch cabinet. Background Art

[0002] Gas-insulated metal split switchgear is a widely used power equipment, which is installed in a closed metal insulation cabinet or assembled into a compartmentalized ring network power supply unit. It has the advantages of simple structure, small size and low price. Due to its fully enclosed structure, good interchangeability, easy installation, perfect operating performance and anti-misoperation function, convenient inspection and maintenance, it has been widely used in distribution stations and box-type substations in urban residential areas, high-rise buildings, large public buildings, factories and enterprises and other load centers.

[0003] With the increasing number of applications of 10kV~40.5kV gas-insulated metal split switchgear, the increasing running time, the uneven quality of manufacturers and the ineffective market supervision, the gas-insulated metal split switchgear has exposed more and more problems and hidden dangers during operation and use. These problems are of various types, such as faults in the gas box caused by unreasonable structural design of the cabinet, faults in the gas box caused by reduced insulation capacity due to gas box leakage, cable bin faults caused by design and manufacturing defects of detachable connectors, faults in the gas box or cable bin caused by manufacturing defects of insulating parts, and faults at the connection between cabinets caused by improper cabinet combination and assembly, etc. However, the detachable connector failure in the cable bin has the most problems, the highest failure rate and the most serious accidents. After statistical analysis, the main cause of detachable connector failure is poor matching between the connector and the outlet bushing and unreasonable shielding design.

[0004] After further analysis and research, it is found that the structures of the grounding shielding layers at the ends of the detachable connectors currently on the market are significantly different, mainly including two structures: the first grounding shielding layer structure has two layers at the end, the inner layer is a silicone rubber layer, and the outer layer is a semi-conductive rubber layer; the second grounding shielding layer structure has only one layer at the end, that is, the semi-conductive silicone rubber layer is in direct contact with the sleeve; however, after simulation research and analysis, when the end of the detachable connector is a double-layer structure, the shielding layer of the detachable connector and the shielding net of the sleeve are offset and overlapped, and the air electric field strength in the end area is reduced. When the shielding is offset by 5mm, the air electric field strength value in the local area is 0.528kV / mm, and when the shielding overlaps by 5mm, the air electric field strength value in the local area is 0.0682kV / mm. The electric field value in the key area is 8.5 times the electric field value in the key area of ​​shield overlap, indicating that the external grounded semiconductor shielding layer of the detachable connector and the grounded shielding mesh of the outlet bushing must be overlapped; and when the end of the detachable connector is a single-layer structure, the shielding layer of the detachable connector and the shielding mesh of the bushing change from staggered to overlap, and the air electric field strength in the end area is reduced. When the shield is staggered by 5mm, the air electric field strength value in the key area is 0.456kV / mm, and when the shield overlaps by 5mm, the air electric field strength value in the key area is 0.0511kV / mm. The electric field value in the key area of ​​shield staggered is 8.9 times the electric field value in the key area of ​​shield overlap, indicating that the external grounded semiconductor shielding layer of the detachable connector and the grounded shielding mesh of the outlet bushing must be overlapped.

[0005] It can be seen that no matter what structure the separable connector has, it requires the external grounded semiconductor shielding layer to overlap with the grounded shielding mesh ring of the outlet bushing to ensure a good shielding effect. However, there are no matching size requirements for separable connectors and outlet bushings in the current manufacturing standards, and usually the manufacturers of outlet bushings will not produce separable connectors, and the manufacturers of separable connectors will not produce outlet bushings. They have different understandings of key dimensions and insulation structure design. Therefore, it is difficult to ensure that separable connectors and outlet bushings have appropriate matching requirements in the current market, which will still lead to partial discharge phenomenon and poor shielding effect of separable connectors and outlet bushings. Utility Model Content

[0006] In view of this, in order to address the above shortcomings, it is necessary to propose a double shielding bushing for an inflatable switch cabinet to solve the problem that the shielding net of the outlet bushing needs to overlap with the semiconductor shielding layer of the detachable connector to achieve a good shielding effect.

[0007] The utility model provides a double-shielding sleeve of an inflatable switch cabinet, comprising: a conductive rod, an insulating sleeve, a grounding end, a first shielding layer and a second shielding layer; the insulating sleeve is a cylindrical sleeve made of insulating material, which is sleeved on the outside of the conductive rod, and the grounding end is embedded in the insulating sleeve; the first shielding layer and the second shielding layer are both cylindrical structures, and the diameter of the first shielding layer is smaller than the diameter of the second shielding layer; the first shielding layer and the second shielding layer are both arranged inside the insulating sleeve, sleeved on the outside of the conductive rod, and the first shielding layer, the second shielding layer and the conductive rod are coaxially arranged; the first shielding layer is fixedly connected to the conductive rod, and the second shielding layer is fixedly connected to the grounding end.

[0008] Preferably, the first shielding layer and the second shielding layer are arranged opposite to each other.

[0009] Preferably, an annular protrusion is provided on the outer surface of the insulating sleeve, and the grounding end is embedded in the insulating sleeve from the annular protrusion.

[0010] Preferably, the double-shielded sleeve of the inflatable switch cabinet also includes a mounting plate, which is provided with a through hole. The mounting plate is sleeved on one side of the sleeve for connecting to the front insertion end of the cabinet through the through hole, and is fixedly mounted to the side of the annular protrusion.

[0011] Preferably, the first shielding layer and the second shielding layer are both cylindrical metal meshes.

[0012] Preferably, the first shielding layer and the conductive rod are fixedly connected via fixing studs.

[0013] Preferably, the second shielding layer and the grounding end are fixedly connected via a fixing stud.

[0014] Preferably, both ends of the first shielding layer and the second shielding layer are provided with folded edges.

[0015] Preferably, the folded edge is spherical.

[0016] Preferably, the mesh diameter of the cylindrical metal mesh is not greater than 1.2 mm.

[0017] It can be seen from the above technical scheme that the double shielding sleeve of the inflatable switch cabinet provided by the embodiment of the utility model includes a conductive rod, an insulating sleeve, a grounding terminal, a first shielding layer and a second shielding layer. The cylindrical insulating sleeve is arranged on the outside of the conductive rod, and the grounding terminal is embedded in the insulating sleeve. The outer side of the conductive rod is provided with a cylindrical first shielding layer and a second shielding layer. The inner first shielding layer is fixedly connected to the conductive rod, and the outer second shielding layer is fixedly connected to the grounding terminal. It can be seen that the present scheme is to separately set a double-layer shielding structure on the outlet sleeve, and by optimizing the electric field distribution on the surface of the outlet sleeve, the local discharge fault caused by excessive electric field is reduced, that is, the outlet sleeve itself can obtain a good shielding effect, and there is no need to rely on the overlapping cooperation of the sleeve grounding shielding net ring and the semiconductor shielding layer of the detachable connector to achieve a good shielding effect. In other words, the outlet sleeve provided by the present scheme can be applied to the detachable connector produced by any manufacturer, and it only needs to meet the overlapping cooperation requirements to have a good shielding effect. In addition, the double-layer shielding net provided by the present scheme is a cylindrical structure, which can be sleeved on the outer surface of the conductive rod and fixedly connected, with a simple structure and convenient installation and disassembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of a double-shielded bushing for an inflatable switch cabinet provided in an embodiment of the utility model.

[0019] Figure 2 A cross-sectional view of a double-shielded bushing of an inflatable switch cabinet provided in an embodiment of the utility model.

[0020] Figure 3 for Figure 2 Partial view at point A in the middle.

[0021] In the figure: a conductive rod 1, an insulating sleeve 2, a grounding terminal 3, a first shielding layer 4, a second shielding layer 5, an annular protrusion 6, a mounting plate 7, a fixing stud 8, and a folded edge 9. DETAILED DESCRIPTION

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] See also Figure 1-3The embodiment of the utility model provides a double shielding sleeve of an inflatable switch cabinet, comprising: a conductive rod 1, an insulating sleeve 2, a grounding terminal 3, a first shielding layer 4 and a second shielding layer 5; the insulating sleeve 2 is a cylindrical sleeve made of insulating material, which is sleeved on the outside of the conductive rod 1, and the grounding terminal 3 is embedded in the insulating sleeve 2; the first shielding layer 4 and the second shielding layer 5 are both cylindrical structures, and the diameter of the first shielding layer 4 is smaller than the diameter of the second shielding layer 5; the first shielding layer 4 and the second shielding layer 5 are both arranged inside the insulating sleeve 2, sleeved on the outside of the conductive rod 1, and the first shielding layer 4, the second shielding layer 5 and the conductive rod 1 are coaxially arranged; the first shielding layer 4 is fixedly connected to the conductive rod 1, and the second shielding layer 5 is fixedly connected to the grounding terminal 3.

[0024] In this embodiment, a double-layer shielding structure is considered to be separately set on the outlet bushing. By optimizing the electric field distribution on the surface of the outlet bushing, the local discharge fault caused by excessive electric field is reduced, that is, the outlet bushing itself can obtain a good shielding effect, and there is no need to rely on the overlapping cooperation of the bushing grounding shielding mesh ring and the semiconductor shielding layer of the detachable connector to achieve a good shielding effect. Moreover, since condensation, foreign matter adsorption, tip discharge, etc. are prone to occur on the surface of the bushing, the electric field on the surface of the bushing can be reduced by the double-layer shielding structure, thereby reducing the occurrence of partial discharge faults, and the double-layer shielding will also perform better in terms of mechanical stress. In addition, the double-layer shielding nets provided in this solution are all cylindrical structures, which can be mounted on the outer surface of the conductive rod 1 and fixedly connected. The structure is simple and easy to install and disassemble.

[0025] The first shielding layer 4 and the second shielding layer 5 can be arranged opposite to each other, so that the specifications and standards of the shielding net are more consistent, and the installation is more convenient and quick. The second shielding layer 5 needs to be fixedly connected to the ground terminal 3. After the position is determined, the first shielding layer 4 and the second shielding layer 5 are installed opposite to each other and fixedly connected on the conductive rod 1. The first shielding layer 4 and the second shielding layer 5 can both be cylindrical metal meshes, and the mesh diameter of the cylindrical metal mesh is not greater than 1.2 mm, so that the double-layer shielded outlet bushing can achieve a better shielding effect.

[0026] In one embodiment, an annular protrusion 6 is provided on the outer surface of the insulating sleeve 2, and the ground terminal 3 is embedded in the insulating sleeve 2 from the annular protrusion 6. In this way, the second shielding layer 5 can be connected to the ground terminal 3, and the ground terminal 3 is prevented from being exposed.

[0027] In one embodiment, the double-shielding bushing of the inflatable switch cabinet further includes a mounting plate 7, which is provided with a through hole, and the mounting plate 7 is sleeved on one side of the bushing for connecting the front insertion end of the cabinet through the through hole, and is fixedly installed with the side of the annular protrusion 6. In this way, the outlet bushing can be fixedly installed in the inflatable switch cabinet through the mounting plate 7.

[0028] In one embodiment, the first shielding layer 4 and the conductive rod 1 are fixedly connected by the fixing studs 8, and the second shielding layer 5 and the grounding terminal 3 can also be fixedly connected by the fixing studs 8, so that the first shielding layer 4 and the second shielding layer 5 can be quickly installed. Moreover, by adjusting the screwing amount of the fixing studs 8, the spacing between the first shielding layer 4 and the second shielding layer 5 can be adjusted as needed.

[0029] Furthermore, folded edges 9 are provided at both ends of the first shielding layer 4 and the second shielding layer 5, so as to avoid the formation of sharp points at both ends of the first shielding layer 4 and the second shielding layer 5, which may cause discharge at the sharp points. Specifically, since the circular electric field is more uniform, the folded edge 9 may be spherical.

[0030] Next, the effect of the double-layer shielding bushing of the inflatable switch cabinet provided by this solution is further explained in combination with a specific simulation experiment.

[0031] The double-layer shielding bushing provided by the optimal embodiment of the present solution was used as the experimental object for the simulation test, and four schemes including high-voltage network suspension, no shielding network, only low-voltage shielding network and only high-voltage shielding network were used as control experiments for the simulation experiment. The loaded voltage was 95kV, and the maximum field strength in the epoxy resin of the outlet bushing, the lower umbrella of the air, the upper umbrella of the air and the inner side of the air were simulated respectively.

[0032] Table 1 below shows the maximum field strength in various media for various schemes, in kV / mm.

[0033] Table 1

[0034]

[0035] As can be seen from Table 1, in the double-layer shielding scheme provided by this scheme, the electric field distribution is more uniform, and the maximum field strength values ​​of the air lower umbrella, air upper umbrella and air inner side are all relatively low overall, so the double-layer shielding sleeve provided by this scheme can have a better shielding effect. For example, the required field strength of air is 2.0-2.5kV / mm, while the maximum field strength of the air inner side of the high-voltage net suspension scheme reaches 3.22kV / mm, and the maximum field strength of the air upper umbrella of the non-shielded net scheme reaches 12.5kV / mm. Only the maximum field strength of the air lower umbrella of the low-voltage shielding net scheme reaches 3.37kV / mm, and only the maximum field strength of the air upper umbrella of the high-voltage shielding net scheme reaches 22.4kV / mm, which are far higher than the required field strength range of air. Therefore, partial discharge is very likely to occur during normal operation of the product. Moreover, in the high-voltage suspension scheme, the maximum field strength in the epoxy resin is only 2.30kV / mm, which greatly reduces the utilization rate of the epoxy resin and the insulation effect of the epoxy resin is not fully reflected.

[0036] The modules or units in the device of the embodiment of the utility model can be combined, divided and deleted according to actual needs. The above disclosure is only the preferred embodiment of the utility model, and of course it cannot be used to limit the scope of the rights of the utility model. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments are implemented, and equivalent changes made according to the claims of the utility model still fall within the scope of the utility model.

Claims

1. A double shielding bushing for an inflatable switch cabinet, characterized in that: include: A conductive rod, an insulating sleeve, a grounding terminal, a first shielding layer and a second shielding layer; the insulating sleeve is a cylindrical sleeve made of insulating material, which is sleeved on the outside of the conductive rod, and the grounding terminal is embedded in the insulating sleeve; the first shielding layer and the second shielding layer are both cylindrical structures, and the diameter of the first shielding layer is smaller than the diameter of the second shielding layer; the first shielding layer and the second shielding layer are both arranged inside the insulating sleeve and sleeved on the outside of the conductive rod, and the first shielding layer, the second shielding layer and the conductive rod are coaxially arranged; the first shielding layer is fixedly connected to the conductive rod, and the second shielding layer is fixedly connected to the grounding terminal.

2. The double shielding bushing of the inflatable switch cabinet according to claim 1 is characterized in that: The first shielding layer and the second shielding layer are arranged opposite to each other.

3. The double shielding bushing of the inflatable switch cabinet according to claim 1 is characterized in that: An annular protrusion is arranged on the outer surface of the insulating sleeve, and the grounding end is embedded into the insulating sleeve from the annular protrusion.

4. The double shielding bushing of the inflatable switch cabinet according to claim 3 is characterized in that: The double-shielded sleeve of the inflatable switch cabinet also includes a mounting plate, which is provided with a through hole. The mounting plate is sleeved on one side of the sleeve for connecting to the front insertion end of the cabinet through the through hole, and is fixedly mounted on the side of the annular protrusion.

5. The double shielding bushing of the inflatable switch cabinet according to claim 1, characterized in that: The first shielding layer and the second shielding layer are both cylindrical metal meshes.

6. The double shielding bushing of the inflatable switch cabinet according to claim 5, characterized in that: The first shielding layer and the conductive rod are fixedly connected via fixing studs.

7. The double shielding bushing of the inflatable switch cabinet according to claim 5, characterized in that: The second shielding layer is fixedly connected to the grounding end via a fixing stud.

8. The double shielding bushing of the inflatable switch cabinet according to claim 5, characterized in that: Both ends of the first shielding layer and the second shielding layer are provided with folded edges.

9. The double shielding bushing of the inflatable switch cabinet according to claim 8, characterized in that: The folded edge is spherical.

10. The double shielding bushing of the inflatable switch cabinet according to claim 5, characterized in that: The mesh diameter of the cylindrical metal mesh is not greater than 1.2 mm.

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