Bushings for medium voltage switchgear
The problem of expensive and difficult to assemble existing sleeves is solved by chamfered design made of polyamide materials and medium-voltage switchgear casing with built-in guides, achieving lighter, cheaper and under condensation conditions Improved drainage performance.
Patent Information
- Application Number
- CN202110158370.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Priority Date
- 2020-02-06
- Filing Date
- 2021-02-04
- Publication Date
- 2024-12-31
- Estimated Expiration
- 2041-02-04
AI Technical Summary
The existing medium-voltage switchgear casing is relatively expensive, difficult to assemble, and has a large volume, and has insufficient drainage performance under condensation conditions.
Using hollow sleeve made of polyamide material, designed with chamfered outer surface, built-in guide and dielectric edges, reduced fastener use, reduced weight and Cost and improve drainage performance through simulation optimization design.
The new casing is lighter and cheaper, simplifies the installation process, improves drainage performance and overall reliability under condensation conditions, while reducing production costs and environmental footprint.
Smart Images
Figure CN113224648B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a bushing for a medium voltage switchgear. Background Art
[0002] In medium voltage switchgear (or switchboard) with metal separators, bushings are an important part of the switchboard. Bushings, which may also be called spouts (1 per phase) or monoblocks (1 for all 3 phases), may be used, for example, with circuit breaker compartments.
[0003] Figure 1 A conventional epoxy resin bushing or nozzle is shown in a partially cut schematic form, wherein the nozzle is mounted to a metal plate (such as a contact support) by means of four screws, for example. This can form a partition between, for example, a circuit breaker compartment and other compartments in a switchgear or switchboard. The nozzle has an insert in the rear wall for fitting T-offs and pins. However, conventional nozzles are relatively expensive, difficult to fit and are large.
[0004] These issues need to be addressed. Summary of the invention
[0005] Therefore, it would be advantageous to have an improved bushing (or nozzle) for a compartment of a medium voltage switchgear, such as an air or gas insulated switchgear.
[0006] The objects of the invention are solved by the subject-matter of the independent claims, wherein further embodiments are incorporated in the dependent claims.It should be noted that the bushing is described for medium voltage air or gas insulated switchgear, but is applicable in other cases for the connection of high voltage current carrying conductors between compartments.
[0007] In one aspect, there is provided a bushing for a metal clad medium voltage switchgear, the bushing comprising:
[0008] -Hollow body;
[0009] The body is made of polyamide. The first end of the body is configured to be connected to a compartment of a medium voltage switchgear. The second end of the body is configured to be connected to a T-off and a pin.
[0010] The new sleeve or nozzle is therefore made of a recyclable polyamide material, which is lighter and cheaper than existing sleeves.
[0011] In an example, the body portion extends from a first end of the body to a second end of the body. The body portion is generally circular about an axis extending from the first end of the body to the second end of the body.
[0012] In an example, an outer surface of the body portion is chamfered such that the outer surface is angled with the axis in a direction from the first end of the body to the second end of the body.
[0013] In other words, the outer surface of the body does not have a constant circular radius, but varies along its length. This improves drainage under condensing conditions.
[0014] In an example, the inner surface of the body portion includes at least one flow conductor.
[0015] The flow guide facilitates the manufacture of the casing.
[0016] In an example, at least one flow leader is in a direction from the first end of the body to the second end of the body.
[0017] In an example, the second end includes a substantially planar portion. At least one T-piece and the pin connection are located within the planar portion.
[0018] In the example, the planar sections have a single T-piece connection and a single pin connection.
[0019] Having a separate T-piece and pin connection makes connection of the sleeve simpler and easier.
[0020] In an example, the inner surface of the planar portion includes at least one flow leader.
[0021] The flow guide facilitates the manufacture of the casing.
[0022] In an example, the inner surface of the planar portion comprises at least one reinforcement portion.
[0023] The one or more reinforcement portions enable the overall thickness of the sleeve to be reduced, wherein the overall weight of the sleeve is also reduced, which also results in a reduction in the cost of the sleeve.
[0024] In an example, the second end includes a dielectric edge.
[0025] The dielectric edge has been found to improve the dielectric properties.
[0026] In an example, the first end of the body is configured to be connected to a compartment of the switchgear via at least one mounting slot.
[0027] The above-described aspects and examples will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Exemplary embodiments will be described below with reference to the following drawings:
[0029] Figure 1 A schematic diagram showing an example of a conventional bushing or nozzle for metal clad medium voltage switchgear;
[0030] Figure 2 An isometric view showing a new bushing or nozzle for metal clad medium voltage switchgear; and
[0031] Figure 3 Shown are front and rear views of a new bushing or nozzle for metal clad medium voltage switchgear. DETAILED DESCRIPTION
[0032] Figures 2 to 3 A new bushing or nozzle for metal-clad medium voltage switchgear. The bushing comprises a hollow body. The body is made of polyamide. A first end of the body is configured to be connected to a compartment of the medium voltage switchgear. A second end of the body is configured to be connected to a T-piece and a pin.
[0033] According to an example, the body portion extends from a first end of the body to a second end of the body.The body portion is generally circular about an axis extending from the first end of the body to the second end of the body.
[0034] According to an example, an outer surface of the body portion is chamfered such that the outer surface is angled with the axis in a direction from the first end of the body to the second end of the body.
[0035] The body portion may be wider at the first end relative to the second end.
[0036] According to an example, the inner surface of the body portion comprises at least one flow conductor.
[0037] According to an example, the at least one flow leader is in a direction from the first end of the body to the second end of the body.
[0038] Thus, as shown, the flow leaders may extend along the shortest distance of the inner surface of the body portion.
[0039] According to an example, the second end comprises a substantially planar portion. At least one T-piece and the pin connection are located within the planar portion.
[0040] According to an example, the planar portion has a separate T-piece connection and a separate pin connection.
[0041] According to an example, the inner surface of the planar portion comprises at least one flow conductor.
[0042] According to an example, the inner surface of the planar portion comprises at least one reinforcement portion.
[0043] According to an example, the second end comprises a dielectric edge.
[0044] According to an example, the first end of the body is configured to be connected to a compartment of the switchgear via at least one mounting groove.
[0045] like Figures 2 to 3As shown in , one end of the bushing as a dielectric edge provides better results in dielectric testing. One or more assembly grooves are provided to enable connection to the compartment of the switchgear without the need for screws or bolts, wherein an internal flow guide extends along the inner surface of the body of the bushing, which facilitates manufacturing. The internal rear surface also has a flow guide, as well as a reinforcement profile designed by simulation, wherein the simulation takes into account the properties of polyamide and results in the optimized design described here. The body of the bushing is slightly tapered or slightly chamfered, thereby providing improved drainage under condensing conditions. A separate T-piece and pin connection is provided on the rear side of the bushing to facilitate connection.
[0046] Therefore, the new bushing or nozzle is made of a recyclable polyamide material, where computer simulation is used to design reinforcements that provide structural integrity maintenance with less overall material. The new design has a phase spacing as low as 133mm, has independent T-piece and pin assemblies, and has flow guides for improved manufacturing. The new bushing features a fastener-free assembly (section) with a built-in dielectric edge with a 1.5% chamfer for improved drainage under condensing conditions. Therefore, the design can be silicone-free and have lower weight and lower cost relative to existing bushings.
[0047] The bushing is an important component of metal clad switchgear. Existing bushings or nozzles are screw mounted and made of epoxy resin. The new bushing offers a partially fastener-free assembly (easier and faster), with advantages in terms of improved drainage (increased reliability), weight (green) and cost, use and recyclable thermoplastics (green).
[0048] Thus, the new sleeve provides a significant improvement over existing epoxy or epoxide sleeves or nozzles.
[0049] The new design of the bushing used simulation and modeling that accounted for the material properties of polyamide, and used the design of reinforcements and flow leaders to provide optimal wall thickness, reduce weight, and increase design strength and aid in manufacturing.
Claims
1. A bushing for a metal-clad medium-voltage switchgear, the bushing comprising: -Hollow body; wherein the body is made of polyamide; wherein the first end of the body is configured to be connected to a compartment of a medium voltage switchgear; and wherein the second end of the body has a separate T-piece connection and a separate pin connection configured to connect to a T-piece and a pin; wherein a body portion extends from the first end of the body to the second end of the body, and wherein the body portion is generally circular about an axis extending from the first end of the body to the second end of the body; Wherein an outer surface of the body portion is chamfered such that the outer surface is angled with respect to the axis in a direction from the first end of the body to the second end of the body to provide drainage under condensing conditions.
2. The sleeve of claim 1, wherein the inner surface of the body portion includes at least one flow conductor. 3 . The sleeve of claim 2 , wherein the at least one flow conductor is in a direction from the first end of the body to the second end of the body.
4. The sleeve according to any one of claims 1 to 3, wherein the second end comprises a substantially planar portion, and wherein at least one T-piece and pin connection is located within the planar portion.
5. The sleeve of claim 4, wherein the inner surface of the planar portion includes at least one flow conductor.
6. The sleeve of claim 4, wherein the inner surface of the planar portion includes at least one reinforced portion.
7. The sleeve of any one of claims 1 to 3, 5 and 6, wherein the second end comprises a dielectric edge.
8. The bushing according to any one of claims 1 to 3, 5 and 6, wherein the first end of the body is configured to be connected to the compartment of the switchgear via at least one mounting groove.