Isolating switch and contact shielding structure thereof

Abstract

The utility model relates to an isolating switch and a contact shielding structure thereof, the isolating switch comprises a moving contact, a static contact and a fracture shielding structure, the fracture shielding structure comprises a moving contact shielding structure and a static contact shielding structure, and at least one of the two contact shielding structures comprises a shielding cover. The shielding cover is fixedly connected with a shielding ring with a smooth surface, the shielding ring is arranged at the front end of the shielding cover, the outer diameter of the shielding ring is not smaller than that of the shielding cover, and the inner diameter of the shielding ring is larger than that of the shielding cover. In this way, the shielding effect can be further improved, and the situation that when the isolation switch opens and closes small capacitive current, electric arcs generated at the moment of contact gap breakdown drift to the shell, then parts of the isolation switch are ablated and damaged, and the insulation performance is affected is prevented.

Description

Technical Field

[0001] This utility model relates to the field of high voltage switchgear application technology, and in particular to a disconnecting switch and its contact shielding structure. Background Technology

[0002] Current investigations worldwide have revealed in IEC60071-2:2023 and GB / T311.2-2013 that during disconnection switch operation, the rapid breakdown of the gas gap and the almost unattended propagation of the shock wave within the GIS can generate an ultra-fast transient overvoltage, namely VFTO.

[0003] With the widespread application of GIS equipment in power systems, especially when disconnecting switches to handle small capacitive currents, such as when using disconnecting switches to open and close unloaded busbars, multiple breakdowns can occur in the contact gaps, leading to VFTO (Voltage-Free Overvoltage). VFTO has a steep rise and high amplitude, reaching up to 3 p.u. Particularly in ultra-high voltage (800 / 1100kV) levels, high overvoltages inevitably place higher demands on insulation performance, significantly increasing the difficulty and cost of insulation design. This also has a substantial impact on the stable operation of the power system. Therefore, certain methods and measures must be adopted in ultra-high voltage GIS to suppress VFTO.

[0004] like Figure 1 As shown, existing disconnect switches typically have shielding covers at the moving contact 2 and stationary contact 4 to prevent the arc generated by the contact gap breakdown from drifting. However, the shielding effect of the shielding cover alone is limited. After the contact gap breaks down, when the arc intensity is large, the arc is affected by the electric field intensity and extends to the outer shell to form a discharge, which will cause ablation damage to the components of the disconnect switch and affect the insulation performance. Utility Model Content

[0005] The purpose of this invention is to provide a contact shielding structure to address the problem that existing disconnecting switches have limited shielding effectiveness when handling small capacitive currents, resulting in arcing and contact gap breakdown. Another purpose of this invention is to provide a disconnecting switch that solves the aforementioned problems.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution.

[0007] A contact shielding structure includes a shielding cover, wherein a smooth shielding ring is fixedly connected to the shielding cover, the shielding ring is disposed at the front end of the shielding cover, the outer diameter of the shielding ring is not less than the outer diameter of the shielding cover, and the inner diameter of the shielding ring is greater than the inner diameter of the shielding cover.

[0008] Furthermore, the shielding cover is a moving-side shielding cover.

[0009] Furthermore, the shielding ring and the shielding cover are fixedly connected together by welding.

[0010] Furthermore, the shielding ring and the shielding cover are integrally cast structures.

[0011] Furthermore, the cross-sectional profile of the shielding ring is circular.

[0012] The beneficial effects of adopting the above technical solution are as follows: This utility model proposes an improved contact shielding structure, including a shielding cover, wherein the shielding cover is also fixedly connected with a smooth shielding ring. The shielding ring is set at the front end of the shielding cover. The outer diameter of the shielding ring is not less than the outer diameter of the shielding cover, and the inner diameter of the shielding ring is greater than the inner diameter of the shielding cover. This can further improve the shielding effect and prevent the arc generated at the moment of contact gap breakdown when the disconnecting switch is opened and closed with a small capacitive current from drifting to the outer shell, thereby causing burn damage to the components of the disconnecting switch and affecting the insulation performance.

[0013] A disconnecting switch includes a moving contact, a stationary contact, and a break shielding structure. The break shielding structure includes a moving contact shielding structure and a stationary contact shielding structure. At least one of the two contact shielding structures includes a shielding cover. The shielding cover is fixedly connected to a shielding ring with a smooth surface. The shielding ring is disposed at the front end of the shielding cover. The outer diameter of the shielding ring is not less than the outer diameter of the shielding cover, and the inner diameter of the shielding ring is greater than the inner diameter of the shielding cover.

[0014] Furthermore, the shielding ring is mounted on the moving side shielding cover and is fixedly connected to the moving side shielding cover.

[0015] Furthermore, the shielding ring and the shielding cover are fixedly connected together by welding.

[0016] Furthermore, the shielding ring and the shielding cover are integrally cast structures.

[0017] Furthermore, the cross-sectional profile of the shielding ring is circular.

[0018] The above technical solution offers the following advantages: This utility model provides an improved disconnecting switch, including a break-out shielding structure. The break-out shielding structure comprises a moving contact shielding structure and a stationary contact shielding structure. At least one of the two contact shielding structures includes a shielding cover. A smooth-surfaced shielding ring is fixedly connected to the shielding cover, positioned at the front end of the shielding cover. The outer diameter of the shielding ring is not less than the outer diameter of the shielding cover, and the inner diameter of the shielding ring is greater than the inner diameter of the shielding cover. This further improves the shielding effect, preventing the arc generated during the contact gap breakdown when the disconnecting switch is opened and closed with a small capacitive current from drifting to the outer casing, thus avoiding burn-through damage to the disconnecting switch components and affecting insulation performance. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of an existing fracture shielding structure;

[0020] Figure 2 This is a schematic diagram of one embodiment of the break-out shielding structure of this utility model;

[0021] Figure 3 This is a diagram showing the electric field distribution of the disconnecting switch before arc breakdown.

[0022] Figure 4 This is a diagram showing the electric field distribution during arc breakdown of the disconnecting switch.

[0023] Figure 5 A schematic diagram of the electric field intensity of the arc in the traditional break shielding structure of a disconnector switch;

[0024] Figure 6 A schematic diagram of the arc electric field strength of the break shielding structure of this utility model used for disconnecting switches.

[0025] In the diagram: 1. Housing; 2. Moving contact; 3. Moving side shield; 4. Stationary contact; 5. Stationary side shield; 6. Shielding ring; Z. Breakdown zone. Detailed Implementation

[0026] The features and performance of this utility model will be further described in detail below with reference to the embodiments.

[0027] This utility model proposes a contact shielding structure, including a shielding cover. By setting a smooth shielding ring on the shielding cover, the outer diameter of the shielding ring is not less than the outer diameter of the shielding cover, and the inner diameter of the shielding ring is greater than the inner diameter of the shielding cover. This can further improve the shielding effect and prevent the arc generated at the moment of contact gap breakdown when the disconnecting switch is opened and closed with a small capacitive current from drifting to the outer shell, thereby causing burn damage to the components of the disconnecting switch and affecting the insulation performance.

[0028] Based on the above concept, this utility model provides various embodiments of disconnecting switches for illustration.

[0029] In a basic embodiment, such as Figure 2 As shown, the disconnecting switch includes a housing 1, inside which a moving contact 2 and a stationary contact 4 are fixedly installed. A moving-side shielding cover 3 is fixedly installed on the moving contact 2, and a stationary-side shielding cover 5 is fixedly installed on the stationary contact 4. The disconnecting switch also includes a break shielding structure, which includes a moving contact shielding structure and a stationary contact shielding structure. The contact shielding structure includes a shielding cover, and a smooth-surfaced shielding ring 6 is fixedly connected to the shielding cover. The shielding ring 6 is located at the front end of the shielding cover. The outer diameter of the shielding ring 6 is not less than the outer diameter of the shielding cover, and the inner diameter of the shielding ring 6 is greater than the inner diameter of the shielding cover.

[0030] Based on the above embodiments, the shielding ring 6 can be fixedly connected to the stationary side shielding cover 5, or the shielding ring 6 can be fixedly connected to both the moving side shielding cover 3 and the stationary side shielding cover 5. The outer diameter of the shielding ring 6 is not less than the outer diameter of the shielding cover, and the inner diameter of the shielding ring 6 is greater than the inner diameter of the shielding cover. In a preferred embodiment, such as... Figure 2 As shown, the shielding ring 6 is fixedly connected to the moving side shielding cover 3. Its outer diameter is not less than the outer diameter of the moving side shielding cover 3, and its inner diameter is greater than the inner diameter of the moving side shielding cover 3. This structure is relatively simple and easy to manufacture, and can also play the role of enhancing the shielding effect.

[0031] Based on the above embodiments, the shielding ring 6 is a sheet metal part formed by rolling a thin-walled plate. It can be fixedly connected to the moving-side shielding cover 3 by welding. It is only necessary to ensure that the weld seam is smooth after welding. In a preferred embodiment, the shielding ring 6 and the moving-side shielding cover 3 are integrally cast structures, which can ensure the integrity of the contact shielding structure and make the shielding effect better.

[0032] Based on the above embodiments, the cross-sectional shape of the shielding ring 6 can be set as a shape formed by connecting straight segments and arc segments, with a smooth connection at the junction of the straight segments and the arc segments, and the arc of the arc segment facing the front end of the moving side shielding cover 3, or it can be set as an ellipse. In a preferred embodiment, such as Figure 2 As shown, the cross-sectional shape of the shielding ring 6 is set to an arc shape, which further enhances the shielding effect.

[0033] When a disconnecting switch uses a traditional break-shielded structure, such as Figure 1 As shown, a moving-side shield 3 and a stationary-side shield 5 are respectively provided on the moving contact 2 and the stationary contact 4. When the disconnecting switch is used, the electric field distribution therein is as follows: Figure 3 The diagram shows the electric field distribution of the disconnecting switch before arcing breakdown. When the disconnecting switch experiences a small capacitive current and arcing breakdown, the electric field distribution is as follows: Figure 4 The diagram shows the electric field distribution during arc breakdown of the disconnecting switch. The electric field strength at the breakdown zone Z is significantly greater than that in other areas. When the arc intensity is high, the arc is affected by the electric field strength and extends towards the casing 1 to form a discharge, which will cause ablation damage to the components of the disconnecting switch and affect the insulation performance.

[0034] The disconnection switch of this utility model has a break shielding structure, which is achieved by setting the moving contact shielding structure as a moving-side shielding cover 3 and a shielding ring 6 fixedly connected. The outer diameter of the shielding ring 6 is not less than the outer diameter of the moving-side shielding cover 3, and the inner diameter of the shielding ring 6 is greater than the inner diameter of the moving-side shielding cover 3. Figure 2As shown, by using a design method for a disconnecting switch break disclosed in Chinese invention patent application CN117133583A, published on November 28, 2023, it can be calculated that the maximum value of the arc electric field intensity of the disconnecting switch using the existing break shielding structure is 9.31 kV / mm. Figure 5 As shown; when using the disconnecting switch of this utility model, the highest value of the arc electric field intensity is 4.1KV / mm, as... Figure 6 As shown, the intensity of the arc electric field is reduced by 56% compared to the existing disconnecting switch, and the electric field around the contact area is significantly reduced.

[0035] The contact shielding structure of this utility model is consistent with the contact shielding structure in the break shielding structure of the above-mentioned disconnecting switch embodiment, and will not be described again in this article.

[0036] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. The patent protection scope of the present utility model shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present utility model shall also be included within the protection scope of the present utility model.

Claims

1. A contact shielding structure, comprising a shielding cover, characterized in that, The shielding cover is fixedly connected to a smooth shielding ring, which is located at the front end of the shielding cover. The outer diameter of the shielding ring is not less than the outer diameter of the shielding cover, and the inner diameter of the shielding ring is greater than the inner diameter of the shielding cover.

2. The contact shielding structure according to claim 1, characterized in that, The shielding cover is a moving-side shielding cover.

3. The contact shielding structure according to claim 1, characterized in that, The shielding ring and the shielding cover are fixedly connected together by welding.

4. The contact shielding structure according to claim 1, characterized in that, The shielding ring and shielding cover are integrally cast structures.

5. The contact shielding structure according to any one of claims 1-4, characterized in that, The cross-sectional profile of the shielding ring is circular.

6. A disconnecting switch, comprising a moving contact, a stationary contact, and a break shielding structure, characterized in that, The break shielding structure includes a moving contact shielding structure and a stationary contact shielding structure. At least one of the two contact shielding structures includes a shielding cover. The shielding cover is fixedly connected to a shielding ring with a smooth surface. The shielding ring is located at the front end of the shielding cover. The outer diameter of the shielding ring is not less than the outer diameter of the shielding cover, and the inner diameter of the shielding ring is greater than the inner diameter of the shielding cover.

7. The disconnecting switch according to claim 6, characterized in that, The shielding ring is installed on the moving side shield and is fixedly connected to the moving side shield.

8. The disconnecting switch according to claim 6, characterized in that, The shielding ring and the shielding cover are fixedly connected together by welding.

9. The disconnecting switch according to claim 6, characterized in that, The shielding ring and shielding cover are integrally cast structures.

10. The disconnecting switch according to any one of claims 6-9, characterized in that, The cross-sectional profile of the shielding ring is circular.

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