A high-voltage DC bypass switch

Abstract

This invention discloses a high-voltage DC bypass switch for improving reliability in areas with strong winds and high seismic intensity. It includes a switch body, a support bushing, and an operating mechanism. To enhance mechanical stability, a parallel insulating support structure is added beside the support bushing. This structure is rigidly connected to the flange at the top of the support bushing via a connecting plate, forming a triangular support frame. For the independent high-voltage node introduced by this structure, a split-type voltage equalization assembly is provided: a first voltage equalization ring is fixed to the top of the insulating support structure, and a second voltage equalization ring is fixed to the flange. Both voltage equalization rings are U-shaped, with opposite openings and electrical isolation, optimizing the electric field at two locations and effectively suppressing partial discharge. This invention synergistically solves the problem of improving the mechanical strength and insulation performance of high-voltage DC switches in harsh environments.

Description

Technical Field

[0001] This invention relates to the field of high-voltage switchgear technology, and specifically to a high-voltage DC bypass switch. Background Technology

[0002] In high-voltage direct current (HVDC) transmission systems, DC bypass switches are used to bypass and commutate current during converter commissioning or decommissioning, ensuring uninterrupted system operation. As voltage levels increase, the insulation requirements for these switches also increase, typically necessitating increased switch height to meet ground insulation requirements. However, in areas with high wind speeds or frequent earthquakes, increasing switch height significantly impacts its mechanical stability and seismic resistance, increasing operational risks.

[0003] Currently, conventional DC bypass switches are mostly single-column double-break structures without additional insulation support devices. They can meet the requirements in general environments, but under extreme climate or geological conditions, their wind and earthquake resistance is insufficient, and they are prone to structural instability or insulation failure.

[0004] Therefore, there is an urgent need for a high-voltage DC bypass switch with excellent mechanical stability and insulation performance to meet engineering requirements in special environments. Summary of the Invention

[0005] In view of the above problems, the present invention provides a high-voltage DC bypass switch that overcomes or at least partially solves the above problems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A high-voltage DC bypass switch includes a switch body and a support bushing. The support bushing is vertically fixed to a ground foundation, and its top is coaxially fixed to the switch body via a flange. The switch body also includes: An insulating support structure vertically installed beside the support sleeve; A connecting assembly, which is horizontally connected between the insulating support structure and the flange; A first equalizing ring and a second equalizing ring are fixed to the top periphery of the insulating support structure and the periphery of the flange, respectively; the first equalizing ring and the second equalizing ring have a semi-enclosed structure and their openings are arranged opposite to each other.

[0007] Preferably, the connecting assembly includes a connecting plate and fasteners, one end of the connecting plate being fixedly connected to the insulating support structure by fasteners, and the other end being fixedly connected to the flange by fasteners.

[0008] Preferably, both the first equalizing ring and the second equalizing ring are U-shaped.

[0009] Preferably, both the first equalizing ring and the second equalizing ring are integrally formed with fixing ears for fixing.

[0010] Furthermore, the first equalizing ring is fixed to the top of the insulating support structure by a fixing lug, and the inner diameter of the first equalizing ring is larger than the top area of ​​the insulating support structure; The second equalizing ring is fixed to the flange by a fixing lug, and the inner diameter of the second equalizing ring is larger than the flange area.

[0011] Preferably, the switch body has a single-column double-break structure.

[0012] Preferably, the insulating support structure is a composite insulator or a ceramic insulator.

[0013] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following: 1. Excellent mechanical stability: The triangular support frame formed by the insulating support structure and connecting components greatly improves the overall anti-overturning ability and structural stability of the switch, making it suitable for heavy-load requirements in high-voltage scenarios; 2. Reliable electrical performance: The equalizing rings are symmetrically arranged and electrically isolated, accurately covering the concentrated electric field area, optimizing the electric field distribution, effectively avoiding partial discharge, and improving the insulation level and operational safety of the switch. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0015] Figure 1 This is a front view of a high-voltage DC bypass switch provided in an embodiment of the present invention; Figure 2 This is a side view of a high-voltage DC bypass switch provided in an embodiment of the present invention; Figure 3 The split-type equalizing ring and its connection method are provided in the embodiments of the present invention; Figure 4 This is a schematic diagram of the connecting plate provided in an embodiment of the present invention; Among them, the switch body-100, the support sleeve-110, the operating mechanism-120, the flange-130, the insulating support structure-200, the connecting plate-300, the first equalizing ring-410, the second equalizing ring-420, the fixing lug-500, and the bolt-600. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0018] like Figure 1 and Figure 2 As shown, the high-voltage DC bypass switch provided by the present invention has the following core structure: a support bushing 110 as the main load-bearing and insulating component, a switch body 100 that performs the breaking function, an operating mechanism 120 that drives the switch body 100, an insulating support structure 200, a mechanical connection assembly, and a split voltage equalization assembly.

[0019] The support bushing 110 is made of high-strength porcelain insulators or composite insulation materials, and its bottom is firmly installed on the concrete foundation by anchor bolts. The switch body 100 adopts a single-column double-break structure, and its lower flange 130 is coaxially connected with the corresponding flange 130 at the top of the support bushing 110, and is fastened with a group of high-strength bolts.

[0020] Arrangement and connection of insulating support structure 200 To cope with the harsh mechanical environment of areas with strong winds (e.g., wind speed ≥34m / s) and high seismic intensity (e.g., intensity VIII and above), this invention provides an insulating support structure 200 parallel to the side of the support sleeve 110. The insulating support structure 200 needs to provide insulation performance and mechanical support strength similar to that of the support sleeve 110. In practical implementation, a support column made of composite insulators or ceramic insulators can be used. Its specific height and mechanical strength need to be matched and selected according to the switch voltage level and seismic and wind resistance design requirements.

[0021] The key connection method of this invention is as follows: one or a group of horizontally arranged connecting plates 300 serve as rigid connecting rods, connecting the insulating support structure 200 and the flange 130. Specifically, as follows... Figure 4 As shown, the solid line represents the connecting plate 300. The left side of the connecting plate 300 is connected to the top of the insulating support structure 200 through 8 holes. The dashed line on the left side of the figure represents the top of the insulating support 200. The right side of the connecting plate 300 is connected to the flange 130 through 3 holes.

[0022] Through this connection, the support sleeve 110, connecting plate 300, and insulating support structure 200 form a stable triangular force-bearing frame. When the switch body 100 is subjected to horizontal wind or seismic forces, the force can be transmitted to the insulating support structure 200 through the flange 130 and connecting plate 300, where both share the bending moment, thereby significantly improving the overall overturning moment resistance of the structure and greatly enhancing its stability.

[0023] In one embodiment, to further enhance installation adaptability and engineering tolerance, elongated holes are provided at both ends of the connecting plate 300. The length of these elongated holes is along the axis of the connecting plate 300 or at a certain angle to the connecting surface. During installation, the bolts can be initially tightened, and then the positions of both ends of the connecting plate 300 relative to the insulating support structure 200 and the flange 130 can be adjusted by slight sliding. This precisely compensates for dimensional deviations caused by foundation construction, column sleeve inclination, or component manufacturing, ensuring optimal geometry and uniform stress distribution of the triangular frame. After adjustment, all fasteners are fully tightened to the specified torque.

[0024] It should be noted that during the on-site installation of high-voltage electrical equipment, minor horizontal errors in the foundation construction of the support sleeve 110, unavoidable tilting during component hoisting, and the accumulation of manufacturing tolerances can lead to a millimeter-level relative positional deviation between the pre-set connection point between the top of the parallel insulation support structure 200 and the side of the flange 130. If a traditional rigid circular hole connection is used, the component will be forcibly fixed under installation stress (or "prestress"), and this stress will affect the structural lifespan and seismic performance over the long term. The design of the elongated circular hole 310 is precisely to absorb and eliminate this installation deviation, achieving stress-free installation.

[0025] The insulation support structure 200 introduces an independent high-voltage node, located at the top of the insulation support structure 200, which is close to the high-voltage potential of the switch body 100. If not properly handled, this node can create a highly uneven electric field with the adjacent flange 130 (typically at ground or intermediate potential), easily triggering corona discharge or surface flashover, endangering insulation safety. To address this issue, this invention employs a split, electrically isolated equalizing ring configuration, specifically as follows... Figure 1 and Figure 3 As shown: The first equalizing ring 410 is an open semi-circular U-shaped ring. It is fastened to the top of the insulating support structure 200 by bolts 600 through its integrally formed fixing lug 500. Its U-shaped opening faces the support sleeve 110.

[0026] The second equalizing ring 420 is also in the shape of a semi-circular U-shape. It is fastened to the flange 130 by bolts 600 through its fixing lug 500, and its U-shaped opening faces the side of the insulating support structure 200.

[0027] Two equalizing rings are arranged symmetrically in space with their openings facing each other. They maintain a certain air gap to achieve electrical isolation. They are not directly electrically connected, but rather optimize the electric field at their respective locations.

[0028] The first equalizing ring 410 effectively shields and homogenizes the electric field of the sharp metal parts at the top of the insulating support structure 200; the second equalizing ring 420 optimizes the electric field at the edge of the flange 130. Together, they smooth and homogenize the electric field distribution between these two spatially close but potentially different regions, controlling the maximum electric field strength below the air breakdown field strength, thereby effectively suppressing partial discharge and improving the overall external insulation level. The pipe diameter, ring diameter, and installation height of the equalizing rings need to be optimized through finite element simulation of the electric field.

[0029] like Figure 3 As shown, the first equalizing ring 410 and the second equalizing ring 420 are U-shaped open ring structures, specifically composed of a semi-circular arc segment and straight arm segments extending symmetrically from both ends of the arc segment in the horizontal direction. The two straight arm segments are of equal length, forming an overall "U" shape, with the inner diameter being the inner diameter of the semi-circular arc segment. The inner diameter of the first equalizing ring is larger than the top region of the insulating support junction (200), and the inner diameter of the second equalizing ring 420 is larger than the region of the flange 130.

[0030] The following section provides a more detailed explanation of this technical solution in conjunction with the assembly process: Foundation and main component installation: Pour concrete foundation and pre-embed anchor bolts. First, hoist the support sleeve 110 and tighten it in place. Then, hoist the insulating support structure 200 to its designed position and initially fix it. Frame Connection: Align one end of the connecting plate 300 with the connection point on the insulating support structure 200 and insert bolts for initial fixation. Then align the other end of the connecting plate 300 with the connection point on the switch flange 130 and fix it for initial fixation as well. Ensure a secure connection without additional stress by adjusting the position within the elongated hole using a laser rangefinder or level. Finally, tighten all connecting bolts to the designed torque value (e.g., 300 N·m). Equalizing ring installation: Install the first equalizing ring 410 to the designated position on top of the insulating support structure 200 and tighten it. Install the second equalizing ring 420 to the designated position on the support sleeve flange 130 and tighten it. Switch body installation: Finally, hoist the switch body 100 to the top of the support sleeve 110, connect it with the flange 130 and tighten it, install the operating mechanism 120 and perform mechanical and electrical debugging.

[0031] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0032] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-voltage DC bypass switch, comprising a switch body (100) and a support bushing (110), wherein the support bushing (110) is vertically fixed to a ground foundation, and its top is coaxially fixedly connected to the switch body (100) via a flange (130), characterized in that, Also includes: An insulating support structure (200) is vertically installed beside the support sleeve (110). A connecting assembly, which is horizontally connected between the insulating support structure (200) and the flange (130); The top periphery of the insulating support structure (200) and the periphery of the flange (130) are respectively fixed with a first equalizing ring (410) and a second equalizing ring (420); the first equalizing ring (410) and the second equalizing ring (420) are semi-enclosed structures with their openings facing each other.

2. The high-voltage DC bypass switch according to claim 1, characterized in that, The connecting assembly includes a connecting plate (300) and fasteners. One end of the connecting plate (300) is fixedly connected to the insulating support structure (200) by fasteners, and the other end is fixedly connected to the flange (130) by fasteners.

3. A high-voltage DC bypass switch according to claim 1, characterized in that, Both the first equalizing ring (410) and the second equalizing ring (420) are U-shaped.

4. A high-voltage DC bypass switch according to claim 1, characterized in that, Both the first equalizing ring (410) and the second equalizing ring (420) are integrally formed with fixing ears (500) for fixing.

5. A high-voltage DC bypass switch according to claim 4, characterized in that, The first equalizing ring (410) is fixed to the top of the insulating support structure (200) by a fixing lug (500), and the inner diameter of the first equalizing ring is larger than the top area of ​​the insulating support structure (200); The second equalizing ring (420) is fixed to the flange (130) by a fixing lug (500), and the inner diameter of the second equalizing ring (420) is larger than the area of ​​the flange (130).

6. A high-voltage DC bypass switch according to claim 1, characterized in that, The switch body (100) has a single-column double-break structure.

7. A high-voltage DC bypass switch according to claim 1, characterized in that, The insulating support structure (200) is a composite insulator or a ceramic insulator.

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