A vacuum arc extinguishing device

Abstract

The application discloses a vacuum arc extinguishing device, and belongs to the technical field of high-voltage direct-current switch equipment insulation technology. The vacuum arc extinguishing device comprises a multilayer shell which is coaxially sleeved and has an insulation function. An arc extinguishing cavity is arranged in the innermost shell of the multilayer shell. The arc extinguishing cavity is used for accommodating a contact group. The shell located at the inner layer directly faces the vacuum environment and the arc radiation area inside the arc extinguishing cavity, and bears the functions of vacuum sealing and arc ablation resistance. The shell located at the outer layer serves as an external main insulation layer, and provides additional surface insulation length and mechanical strength protection. Through the combined mode of the multilayer shell, the shell located at the inner layer can not only prevent the arc from not being completely isolated, but also avoid the influence of the external environment on the shell located at the inner layer through the shell located at the outer layer.

Description

Technical Field

[0001] This invention relates to the field of insulation technology for high-voltage DC switchgear, and in particular to a vacuum arc-extinguishing device. Background Technology

[0002] With the rapid development of new energy power systems and long-distance, high-capacity power transmission technologies, high-voltage direct current (HVDC) transmission has become the backbone of modern power grids due to its core advantages such as large transmission capacity, low line loss, and strong system stability. Vacuum arc-extinguishing devices, as core functional components of HVDC switchgear, play a crucial role in circuit connection, fault current interruption, and long-term insulation pressure resistance. Their insulation performance and electric field distribution characteristics directly determine the operational reliability, insulation margin, and overall service life of the switchgear, making them a core component ensuring the safe and stable operation of HVDC transmission systems.

[0003] Currently, vacuum arc-extinguishing devices adapted to high-voltage direct current (HVDC) applications generally use ceramic as the insulating shell. Ceramic materials possess advantages such as high insulation strength, good airtightness, high temperature resistance, and stable mechanical properties, meeting the basic requirements of long-term vacuum sealing and high-voltage insulation for vacuum arc-extinguishing devices. They are the mainstream material for the insulating shells of current HVDC vacuum arc-extinguishing devices and are widely used in various HVDC circuit breakers, disconnectors, and other switching equipment. However, under the special operating conditions of a constant electric field in HVDC, the inherent structural defects of the ceramic shell are continuously amplified, giving rise to a series of technical problems that restrict the insulation performance and operational stability of the equipment, making it difficult to adapt to the development needs of high-voltage, high-capacity, and long-life DC power transmission.

[0004] Unlike the periodic alternating distribution of alternating current electric fields, under a high-voltage direct current (HVDC) steady-state electric field, the electric field distribution of the insulating medium is mainly affected by factors such as resistivity, temperature, and space charge. Under the long-term action of a high DC electric field, a single-layer homogeneous ceramic shell exhibits a severely uneven electric field distribution along its wall thickness. Specifically, the electric field strength on the inner surface of the arc-extinguishing chamber ceramic is significantly higher than that on the outer surface, with electric stress highly concentrated in the inner region of the shell, while the withstand voltage performance of the outer insulating material cannot be fully utilized. This extreme imbalance in electric field distribution leads to the ineffective utilization of the intrinsic breakdown strength of the ceramic insulating material, resulting in a significant waste of the overall insulation margin of the equipment and an inability to fully match the inherent insulation potential of the ceramic material.

[0005] Under long-term high-voltage direct current (HVDC) operation, the aforementioned electric field distribution defects can trigger a chain reaction of insulation hazards. The inner high-electric-field region is prone to problems such as excessive local field strength, micro-charge accumulation, and partial discharge. Long-term accumulation can lead to aging of the ceramic dielectric and degradation of insulation performance, significantly increasing the risk of insulation breakdown in the arc-extinguishing chamber, severely shortening equipment lifespan, and drastically reducing the operational reliability and adaptability of HVDC switchgear. Current technologies, which conventionally improve insulation performance by increasing the ceramic shell wall thickness and optimizing the external shielding structure, can only slightly improve the overall withstand voltage level and cannot fundamentally solve the core problems of uneven DC electric field distribution and imbalance in the utilization of internal and external insulation performance. These methods have drawbacks such as limited improvement potential, low material utilization, and increased equipment size and cost.

[0006] Existing technological research and engineering practice have verified that actively controlling the dielectric constant distribution of the insulating medium to precisely optimize the DC electric field distribution is the core breakthrough path to fundamentally improve the insulation performance of vacuum arc-extinguishing devices, increase insulation margin, and avoid the problem of local electric field concentration. Currently, the industry has not yet developed a mature dielectric constant-controlled ceramic insulation structure suitable for high-voltage DC operating conditions, and lacks effective technical solutions to address the uneven electric field distribution and wasted insulation margin of the ceramic shell.

[0007] Therefore, developing an insulation structure for a vacuum arc extinguishing device that can optimize the distribution of high-voltage DC electric field, fully utilize the intrinsic properties of insulating materials, and improve the insulation reliability and service life of equipment has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to solve the above-mentioned technical problems and provide a vacuum arc extinguishing device. The vacuum arc extinguishing device includes a coaxially sleeved housing with insulating function. An arc extinguishing cavity is opened in the innermost housing to accommodate the contact assembly. By wrapping the contact assembly with multiple layers of housing, even if the inner or outer housing is damaged, the outer or inner housing can still protect and isolate the arc extinguishing cavity, thereby improving the overall insulation and protection function of the device for the arc extinguishing cavity.

[0009] To achieve the above objectives, the present invention provides the following solution: a vacuum arc extinguishing device, comprising a multi-layered housing coaxially sleeved and having an insulating function, wherein an arc extinguishing cavity is formed in the innermost layer of the multi-layered housing, and the arc extinguishing cavity is used to accommodate a contact assembly.

[0010] Preferably, the multilayer housing includes two housing layers with a receiving space between the two housing layers, and the receiving space is filled with dielectric material.

[0011] Preferably, the multi-layered housing further includes three housing layers, with a receiving space provided between each two adjacent housing layers, and each receiving space being filled with the dielectric material.

[0012] Preferably, the multilayer housing further includes four housing layers, with each adjacent housing layer having a receiving space, and each receiving space being filled with the dielectric material.

[0013] Preferably, the dielectric constant of the dielectric material in adjacent accommodating spaces increases or decreases sequentially from the inside to the outside.

[0014] Preferably, the dielectric constant of the dielectric material located in the innermost layer and the dielectric constant of the dielectric material located in the outermost layer are both less than or greater than the dielectric constant of the dielectric material located in the middle layer.

[0015] Preferably, the dielectric constant of the dielectric material gradually increases or decreases along the arrangement direction perpendicular to the accommodating space.

[0016] Preferably, the dielectric constant of the dielectric material is distributed in a pattern of high on both sides and low in the middle, or low on both sides and high in the middle, along the arrangement direction perpendicular to the accommodating space.

[0017] Preferably, all the multiple shells share the same top wall and the same side wall, and the side walls of each shell are coaxially fitted together.

[0018] Preferably, the materials of the multi-layered shell are all aluminum nitride ceramic or other highly insulating materials.

[0019] The present invention achieves the following technical effects compared to the prior art: The inner shell directly faces the vacuum environment and arc radiation area inside the arc-extinguishing chamber, undertaking the functions of vacuum sealing and arc erosion resistance. The outer shell serves as the external main insulation layer, providing additional surface insulation length and mechanical strength protection. This multi-layered shell structure prevents the inner shell from failing to completely isolate the arc while also preventing external environmental influences from affecting the inner shell through the outer shell. This multi-layered shell structure forms a "cooperative" insulation barrier; even if the inner shell experiences localized micro-cracks or surface damage, the outer shell can still independently maintain its insulation function, preventing single-point failure. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained by analyzing these drawings without creative effort.

[0021] Figure 1 This is a cross-sectional view of the vacuum arc-extinguishing device in an embodiment of the present invention; Figure 2 This is a top view of the vacuum arc-extinguishing device in an embodiment of the present invention; Figure 3 This is a schematic diagram showing the change (gradual increase) of the dielectric constant of the dielectric material in different accommodating spaces from the inside to the outside, with the arc-extinguishing cavity as the reference, when the number of accommodating spaces is three in an embodiment of the present invention. Figure 4 This is a schematic diagram showing the change (gradually decreasing) of the dielectric constant of the dielectric material in different accommodating spaces from the inside to the outside, with the arc-extinguishing cavity as the reference, when the number of accommodating spaces is three in an embodiment of the present invention. Figure 5 This is a schematic diagram showing the change in dielectric constant of the dielectric material in different accommodating spaces from the inside to the outside (higher in the middle than on the sides) when the number of accommodating spaces is three, with the arc-extinguishing cavity as the reference. Figure 6 This is a schematic diagram showing the change in dielectric constant of the dielectric material in different accommodating spaces from the inside to the outside (the middle is lower than the sides) when the number of accommodating spaces is three, with the arc-extinguishing cavity as the reference. Figure 7 This is a schematic diagram of the dielectric constant of a dielectric material in a certain accommodating space changing (gradually increasing (including both straight and curved forms)) along the radial direction of the accommodating space in an embodiment of the present invention. Figure 8 This is a schematic diagram showing the change (gradual decrease, including both straight and curved forms) of the dielectric constant of the dielectric material in a certain accommodating space along the radial direction of the accommodating space in an embodiment of the present invention.

[0022] Explanation of reference numerals in the attached drawings: 1. Central conductive rod; 2. Housing; 3. Dielectric material; 4. Arc extinguishing cavity; 5. Contact group; 51. Upper contact; 52. Lower contact. Detailed Implementation

[0023] 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 a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments analyzed and obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] The purpose of this invention is to provide a vacuum arc-extinguishing device to solve the problems existing in the prior art. The vacuum arc-extinguishing device includes a coaxially sleeved housing with an insulating function. An arc-extinguishing cavity is opened in the innermost housing to accommodate the contact assembly. By wrapping the contact assembly with multiple layers of housing, even if the inner or outer housing is damaged, the outer or inner housing can still protect and isolate the arc-extinguishing cavity, thus ensuring the overall insulation of the arc-extinguishing cavity and avoiding single-point failure.

[0025] To achieve the above objectives, the present invention provides the following solution: like Figures 1 to 8 As shown, this embodiment provides a vacuum arc extinguishing device, including a multi-layered housing 2 coaxially sleeved and having an insulating function. An arc extinguishing cavity 4 is formed in the innermost housing 2, which is used to accommodate the contact group 5. The inner housing 2 directly faces the vacuum environment and arc radiation area inside the arc extinguishing cavity 4, and undertakes the functions of vacuum sealing and anti-arc erosion. The outer housing 2 serves as the external main insulation layer, providing additional surface insulation length and mechanical strength protection.

[0026] In one embodiment, the contact assembly 5 includes an upper contact 51 and a lower contact 52, both located within the arc-extinguishing cavity 4. The upper contact 51 and lower contact 52 are spatially isolated to ensure arc extinguishing requirements. One end of the central conductive rod 1 penetrates the top and bottom of the housing 2 from its upper and lower sides, respectively, into the arc-extinguishing cavity 4 and is electrically connected to the upper contact 51 and lower contact 52, respectively. The other end of the central conductive rod 1 is connected to electrical equipment or power lines.

[0027] In one embodiment, the multilayer housing 2 includes two housings 2, with a receiving space between the two housings 2. The receiving space is filled with dielectric material 3. Both housings 2 have insulating capabilities, and the dielectric material 3 located between the two housings 2 also has insulating capabilities. The contact group 5 is isolated from the external environment by using a three-layer insulation method.

[0028] In one embodiment, the multilayer housing 2 further includes a three-layer housing 2, with a receiving space between each two adjacent housing layers 2, and each receiving space is filled with dielectric material 3. Similarly, the three-layer housing 2 and the two dielectric materials 3 in the two receiving spaces between the three-layer housing 2 also have insulating capabilities.

[0029] In one embodiment, the multilayer housing 2 further includes four housing layers 2, with a receiving space provided between each pair of adjacent housing layers 2, and each receiving space is filled with dielectric material 3. Similarly, the four housing layers 2 and the three dielectric materials 3 in the three receiving spaces all have insulating capabilities.

[0030] In one embodiment, the multi-layer housing 2 includes N layers of housing 2, all of which are arranged in a coaxial nesting manner. There is a receiving space between adjacent housing layers, and the receiving space is filled with dielectric material 3. Those skilled in the art can choose the number of layers of housing 2 according to the actual situation.

[0031] Of course, those skilled in the art can choose to provide a receiving space between two adjacent shell layers 2 or not. Furthermore, when a receiving space is provided between two adjacent shell layers 2, those skilled in the art can provide dielectric material 3 in all receiving spaces, or not provide dielectric material 3 in any receiving spaces, or selectively provide dielectric material 3 in some receiving spaces, or not provide dielectric material 3 in some receiving spaces. Regarding the number of shell layers 2, the number of receiving spaces, and whether or not dielectric material 3 is provided in the receiving spaces, those skilled in the art can make their own choices based on the actual situation, and no further limitations are imposed here.

[0032] In one embodiment, when the number of accommodating spaces is not less than two, the dielectric constant of the dielectric material 3 in adjacent accommodating spaces increases or decreases sequentially from the inside to the outside, that is, the dielectric constant of the dielectric material 3 closer to the arc-extinguishing cavity 4 is higher or lower than the dielectric constant of the dielectric material 3 farther away from the arc-extinguishing cavity 4.

[0033] In one embodiment, when the number of accommodating spaces is not less than two, the dielectric constant of the innermost dielectric material 3 and the dielectric constant of the outermost dielectric material 3 are both less than or greater than the dielectric constant of the dielectric material 3 in the middle layer. That is, the dielectric constant of the dielectric material 3 near the arc-extinguishing cavity 4 and the dielectric constant of the dielectric material 3 far from the arc-extinguishing cavity 4 are both greater than or less than the dielectric constant of the dielectric material 3 in the middle position. By distributing dielectric materials 3 with different dielectric constants in different accommodating spaces, the peak electric field in the arc-extinguishing cavity 4 is transferred to a specific region inside the dielectric material 3 or in the wall of the housing 2, thereby deeply optimizing the distribution of the electric field and improving the overall insulation performance of the device.

[0034] In one embodiment, with the arrangement direction of the accommodating space as the transverse direction, the dielectric constant of the dielectric material 3 gradually increases or decreases within the accommodating space in a direction perpendicular to the transverse direction. That is, within a certain accommodating space, with the radial direction of the dielectric material 3 as a reference, the dielectric constant of the dielectric material 3 gradually increases or decreases, so that the dielectric constant is distributed in a straight line or curve.

[0035] In one embodiment, with the arrangement direction of the accommodating space as the transverse direction, the dielectric constant of the dielectric material 3 is distributed in the accommodating space in a shape that is high on both sides and low in the middle, or low on both sides and high in the middle, along a direction perpendicular to the transverse direction. Under this embodiment, when the dielectric constant of the dielectric material 3 follows a curve that is low on both sides and high in the middle, this arrangement of the dielectric material 3 can transfer some of the electric field stress from the interface region to the interior of the dielectric material 3, thereby reducing the local electric field strength at the interface between the shell 2 and the dielectric material 3.

[0036] In one implementation, the dielectric material 3 is not limited to a specific chemical composition or phase, and can be pre-selected or designed according to actual application requirements. The dielectric material 3 can be a solid (oxide ceramic nanoparticles and polymer matrix) composite, a liquid (such as high dielectric constant insulating oil), or a solid-liquid mixture system. The dielectric constant can be high or low; for example, a high dielectric constant can be obtained by using a ferroelectric ceramic / polymer composite material, or a low dielectric constant can be obtained by using a hollow microsphere / silicone rubber composite material. By controlling the type, ratio, and spatial distribution of the dielectric material 3, the equivalent dielectric constant of the dielectric material 3 can vary radially according to a preset distribution curve, such as monotonically decreasing, monotonically increasing, high in the middle and low at both ends, or other optimized forms. The dielectric constant distribution is not limited to a monotonically changing radial direction; a gradient change can also be achieved in the axial direction (along the height direction of the ceramic shell), forming a two-dimensional functional gradient. This allows the electric field peak to be transferred to a specific region inside the containment space or in the wall of the shell 2, deeply optimizing the electric field distribution and greatly improving the insulation performance.

[0037] In one embodiment, the dielectric material 3, in addition to its dielectric strength function, can also be selected by choosing a filler with low thermal conductivity (such as...). Hollow microspheres, etc.) or high thermal conductivity fillers (such as...) , (e.g., etc.) can respectively achieve heat insulation or heat dissipation functions, which can be dynamically adjusted by those skilled in the art according to actual thermal management needs. The synergistic effect of gradient dielectric and thermal management functions enhances the long-term reliability of the structure under high voltage and high current conditions.

[0038] In one embodiment, the material of the housing 2 is not limited to 95 ceramic or 99 ceramic (95 and 99 represent the alumina content in the alumina ceramic, 95 ceramic represents an alumina content of 95%, and 99 ceramic represents an alumina content of 99%), but can also be other high-insulation ceramics.

[0039] In one embodiment, the multi-layer shells 2 all share the same top wall and the same side wall, and the side walls of each shell 2 are coaxially fitted together.

[0040] In one embodiment, a method for adjusting the dielectric constant of the dielectric material 3 is included, specifically: Option 1: Multi-level Discrete Approximation The containment space is divided radially into several annular sub-layers, each using a different filler ratio. For example: First layer: High dielectric constant filler volume fraction is 40%; Second layer: Volume fraction is 30%; Third layer: Volume fraction is 20%; Fourth layer: Volume fraction is 10%.

[0041] By layer-by-layer infusion, curing, or assembly, the constant of dielectric material 3 in each layer changes in a stepwise manner. Increasing the number of sublayers allows the stepwise distribution to gradually approximate a continuous curve. The listed 40%, 30%, 20%, and 10% ratios are merely examples illustrating the gradient construction method and do not represent a fixed optimal ratio for all material systems; specific ratios should be determined through material testing and electric field optimization. Option 2: Continuous gradient By controlling the packing sedimentation, centrifugal molding, layered casting, additive manufacturing, or inducing the migration and self-assembly of the packing with an external electric field, the packing concentration can be continuously varied, thereby forming a continuous dielectric constant. An external AC electric field is used to make the packing particles form a chain structure in the high field strength region, thereby increasing the local dielectric constant and reducing the local electric field peak.

[0042] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A vacuum arc-extinguishing device, characterized in that: The device includes a multi-layered housing that is coaxially fitted and has an insulating function. The innermost housing in the multi-layered housing has an arc-extinguishing cavity, which is used to accommodate the contact assembly.

2. The vacuum arc-extinguishing device according to claim 1, characterized in that: The multi-layered housing includes two housing layers with a receiving space between them, and the receiving space is filled with dielectric material.

3. The vacuum arc-extinguishing device according to claim 2, characterized in that: The multi-layered housing also includes three housing layers, with a receiving space provided between each two adjacent housing layers, and each receiving space is filled with the dielectric material.

4. The vacuum arc-extinguishing device according to claim 3, characterized in that: The multi-layered housing also includes four housing layers, with a receiving space provided between each two adjacent housing layers, and each receiving space is filled with the dielectric material.

5. The vacuum arc-extinguishing device according to any one of claims 3-4, characterized in that: The dielectric constant of the dielectric material in adjacent accommodating spaces increases or decreases sequentially from the inside to the outside.

6. The vacuum arc-extinguishing device according to claim 4, characterized in that: The dielectric constant of the dielectric material located in the innermost layer and the dielectric constant of the dielectric material located in the outermost layer are both less than or greater than the dielectric constant of the dielectric material located in the middle layer.

7. The vacuum arc-extinguishing device according to claim 5, characterized in that: The dielectric constant of the dielectric material gradually increases or decreases along the arrangement direction perpendicular to the accommodating space.

8. The vacuum arc-extinguishing device according to claim 5, characterized in that: The dielectric constant of the dielectric material is distributed in a pattern of high on both sides and low in the middle, or low on both sides and high in the middle, along the arrangement direction perpendicular to the accommodating space.

9. The vacuum arc-extinguishing device according to claim 1, characterized in that: All the multi-layered shells share the same top wall and the same side wall, and the side walls of each shell are coaxially fitted together.

10. The vacuum arc-extinguishing device according to claim 1, characterized in that: The materials used for the multi-layered shell are all aluminum nitride ceramic or other highly insulating materials.

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