Vacuum composite contact structure suitable for frequent reactive switching and short circuit opening and closing

Abstract

The present invention relates to a vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing. Type A contacts and type B contacts are paired to form a vacuum interrupter, which is sealed in a shell in a vacuum environment. The type A contact seat is surrounded by a mounting cavity, and the type A auxiliary movable contact is slidably arranged in the mounting cavity. The type A main contact is arranged at the top of the type A contact seat. When the vacuum interrupter is in the opening position, the top surface of the type A auxiliary movable contact is higher than the top surface of the type A contact. The type B main contact and the type B auxiliary stationary contact are both arranged at the end of the type B contact seat, and the type B auxiliary stationary contact is located at the geometric center position of the type B main contact. The top surface of the type B auxiliary stationary contact is flush with the top surface of the type B main contact. Such an arrangement solves the technical problem that high-frequency arcs easily cause point erosion on the contact surface and destroy the alloy structure on the basis of taking into account the original short-circuit and high-current interruption, and ensures an extremely low probability of restrike during vacuum interruption.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum composite contacts, and in particular to a vacuum composite contact structure suitable for frequent reactive power switching and short circuit opening and closing. Background Art

[0002] At present, the new power system with a high proportion of new energy such as wind power and photovoltaic power connected to the grid is developing rapidly. In particular, photovoltaic power generation varies with the intensity of solar radiation, which is extremely random and volatile. The frequent connection and disconnection of photovoltaic capacity can easily lead to more frequent disconnection and connection of the station-side shunt capacitor bank for reactive power compensation, which requires an average of 1000 open and close times per day. times, average annual opening and closing Second-rate.

[0003] At present, traditional vacuum circuit breakers used as switches for switching capacitor banks are prone to heavy breakdown and have poor reliability. At present, 40.5kV and 126kV switches for switching capacitor banks on site generally use circuit breakers with plug-in contact structures and SF6 gas as the arc extinguishing medium. Although SF6 circuit breakers have good reactive switching performance, their short-circuit and high current switching capabilities are relatively weak. With the rapid development of new power systems, the requirements for reactive power and short-circuit and high current performance are simultaneously improved, and they are required to be green, environmentally friendly and maintenance-free. Vacuum circuit breakers are mainly composed of an operating mechanism and a vacuum interrupter. The vacuum interrupter is an important component for opening and closing circuits in vacuum circuit breakers, such as Figures 1 to 3 As shown, the traditional vacuum interrupter structure is mainly composed of a static flat contact and a moving flat contact. The flat contact structure generally adopts a truncated cone flat contact structure, which is mainly composed of CuCr alloy contact pieces and Cu support parts. Taking the reactive load of the capacitor bank as an example, Figure 1 As shown in the figure, when the vacuum interrupter is closed, the moving and static flat contacts of the vacuum interrupter are in the open position, and the moving flat contact moves upward and approaches the static flat contact. When it approaches a certain small gap, pre-breakdown will occur, and high-frequency surge arc points will be generated on the surfaces of the moving and static flat contacts to burn the CuCr alloy contact pieces. When the moving and static contacts are in contact, there is no more arc burning on the entire contact, and the entire circuit is connected; when the vacuum interrupter is opened, the moving and static flat contacts of the vacuum interrupter are in the closed position, and the moving flat contact moves downward and away from the static flat contact. At the moment of separation, a small power frequency current arc will be generated to burn the contact surface. When the moving flat contact moves to the rated opening distance, the power frequency arc is extinguished, and both ends of the contact are subjected to the power frequency recovery voltage formed by the sum of the power supply side voltage and the load residual voltage, and the entire circuit is disconnected.

[0004] However, the above-mentioned prior art solutions have the following defects:

[0005] 1. The alloy contact sheet welded on the surface of the existing contact structure adopts a Cr content of The contact is made of CuCr alloy. The electric field of the cone-shaped contact is concentrated at the edge of the cone, which easily causes the initial arc root of the high-frequency arc to be concentrated at the edge of the cone. After frequent switching, the high-frequency arc will track and further ablate and degrade the contact, causing damage to the contact surface tissue.

[0006] 2. The existing CuCr alloy contact pieces have poor ablation resistance, especially the high-frequency inrush arc generated by the pre-breakdown during typical reactive power closing, which severely ablates the surface of the contact piece. After multiple ablations, the surface alloy structure of the contact piece will be destroyed. When closing, the moving and static contacts are prone to welding and adhesion, and when opening, heavy breakdown is likely to occur between the two contacts. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing. Its advantage is that it can solve the technical problem that high-frequency arcs easily cause point erosion on the contact surface and destroy the alloy structure; and ensure an extremely low probability of re-breakdown during vacuum breaking.

[0008] The above-mentioned invention object of the present invention is achieved through the following technical solutions: a vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing, comprising a type A contact and a type B contact; the type A contact and the type B contact are paired to form a vacuum interrupter, and the vacuum interrupter is sealed in a shell in a vacuum environment; when the vacuum interrupter is in the open position, a preset space is left between the type A contact and the type B contact; when the vacuum interrupter is in the closed position, the type A contact and the type B contact are in contact; the type A contact comprises a type A auxiliary movable contact, a type A main contact and a type A contact seat, and the type A contact The head seat is arranged to form a mounting cavity, the type A auxiliary movable contact can be slidably arranged in the mounting cavity, the type A main contact is arranged at the top of the type A contact seat, and when the vacuum interrupter is in the opening position, the top surface of the type A auxiliary movable contact is higher than the top surface of the type A contact; the type B contact includes a type B auxiliary stationary contact, a type B main contact and a type B contact seat, the type B main contact and the type B auxiliary stationary contact are both arranged at the end of the type B contact seat, the type B auxiliary stationary contact is located at the geometric center position of the type B main contact, and the top surface of the type B auxiliary stationary contact is flush with the top surface of the type B main contact.

[0009] Preferably, the present invention provides a vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing. The type A auxiliary movable contact includes a connecting rod and a contact part. The contact part is arranged at the top end of the connecting rod, and an arc-shaped surface is provided at the end of the contact part away from the connecting rod; when the vacuum interrupter is in the open position, the arc-shaped surface is higher than the top surface of the type A contact.

[0010] Preferably, the vacuum composite contact structure provided by the present invention is suitable for frequent reactive switching and short-circuit opening and closing, and the contact part and the type B auxiliary stationary contact are both made of any one of copper-tungsten alloy, copper-tungsten alloy added with graphene and nano-tungsten carbide, copper-molybdenum alloy, alloy containing Sb, Te, Fe, Co and alloy containing Mo.

[0011] Preferably, the vacuum composite contact structure provided by the present invention is suitable for frequent reactive power switching and short-circuit opening and closing, and both the type A main contact and the type B main contact are made of copper-chromium alloy material.

[0012] Preferably, the present invention provides a vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing, the A-type contact also includes a damping spring and a limit snap ring, the installation cavity includes a first chamber, a second chamber and a third chamber, the first chamber, the second chamber and the third chamber are arranged in sequence from top to bottom, the first chamber is connected to the third chamber through the second chamber, the damping spring is arranged in the third chamber, the limit snap ring is arranged in the second chamber, the limit snap ring is threadedly connected to the A-type contact seat, and a through hole is provided on the limit snap ring; the bottom end of the connecting rod is inserted into the third chamber and connected to the top end of the damping spring, the top end of the connecting rod is inserted into the first chamber through the through hole, and the connecting rod can slide relative to the limit snap ring; a limit boss is provided on the outer peripheral wall near the bottom end of the connecting rod, and the limit boss cooperates with the limit snap ring to limit the extension and contraction amount of the A-type auxiliary movable contact.

[0013] Preferably, the present invention provides a vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing. The type A contact also includes an I-type support tube, which is inserted into the first chamber and sleeved on the connecting rod. The connecting rod can slide relative to the I-type support tube, and the top of the I-type support tube is connected to the type A main contact through an annular plate.

[0014] Preferably, the present invention provides a vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing. The type A contact also includes a type A magnetic focusing ring. The I-shaped support tube and the inner wall of the first cavity together constitute a accommodating cavity. The type A magnetic focusing ring is installed in the accommodating cavity. The type A magnetic focusing ring is used to ensure that the concentrated arc is quickly transformed into a diffused state during the opening operation.

[0015] Preferably, the present invention provides a vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing. The type B contact also includes an I-type double-support assembly and a B-type magnetic focusing ring. The top of the type B contact seat is provided with an accommodating cavity. The type I double-support assembly and the type B magnetic focusing ring are both arranged in the accommodating cavity. The type B auxiliary stationary contact and the type B main contact are both connected to the top of the type I double-support assembly through the circular ring plate; the type B magnetic focusing ring is used to ensure that the concentrated arc is quickly transformed into a diffused state during the opening operation.

[0016] Preferably, the present invention provides a vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing. The I-type double support assembly includes a first I-type support sleeve and a second I-type support sleeve. The first I-type support sleeve is sleeved on the second I-type support sleeve. The first I-type support sleeve and the inner circumferential wall of the accommodating cavity together constitute a fixed chamber, and the B-type magnetic ring is installed in the fixed chamber; the B-type main contact is arranged corresponding to the first I-type support sleeve, and the B-type auxiliary stationary contact is arranged corresponding to the second I-type support sleeve.

[0017] Preferably, the vacuum composite contact structure provided by the present invention is suitable for frequent reactive switching and short circuit opening and closing, and the damping spring can withstand high temperature.

[0018] In summary, the beneficial technical effects of the present invention are as follows: the vacuum composite contact structure provided by the present application is suitable for frequent reactive switching and short-circuit opening and closing, including type A contact and type B contact; type A contact and type B contact are paired to form a vacuum interrupter, and the vacuum interrupter is sealed in a shell in a vacuum environment; when the vacuum interrupter is in the open position, a preset space is left between type A contact and type B contact; when the vacuum interrupter is in the closed position, type A contact and type B contact are in contact; type A contact includes type A auxiliary movable contact, type A main contact and type A contact seat, type A contact seat is surrounded by a mounting cavity, type A auxiliary movable contact is slidably arranged in the mounting cavity, a The type A main contact is arranged at the top of the type A contact seat. When the vacuum interrupter is in the open position, the top surface of the type A auxiliary movable contact is higher than the top surface of the type A contact; the type B contact includes a type B auxiliary stationary contact, a type B main contact and a type B contact seat. The type B main contact and the type B auxiliary stationary contact are both arranged at the end of the type B contact seat. The type B auxiliary stationary contact is located at the geometric center of the type B main contact, and the top surface of the type B auxiliary stationary contact is flush with the top surface of the type B main contact; this arrangement solves the technical problem that high-frequency arcs easily cause point erosion on the contact surface and destroy the alloy structure on the basis of taking into account the original short-circuit and high-current interruption; it ensures an extremely low probability of restrike during vacuum interruption. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1It is a structural diagram of a traditional vacuum interrupter.

[0020] Figure 2 It is a structural diagram of a traditional flat contact.

[0021] Figure 3 It is a schematic diagram of the structure of traditional CuCr alloy contact sheet.

[0022] Figure 4 It is a structural schematic diagram of type A contacts in a vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing, provided by an embodiment of the present invention.

[0023] Figure 5 It is a structural schematic diagram of a type B contact in a vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing, provided by an embodiment of the present invention.

[0024] Figure 6 This is a structural schematic diagram of the vacuum interrupter in a vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing, provided by an embodiment of the present invention (opening position).

[0025] Figure 7 This is a structural schematic diagram of the vacuum interrupter in a vacuum composite contact structure suitable for frequent reactive power switching and short-circuit opening and closing, provided by an embodiment of the present invention (closing position).

[0026] In the figure, 1, vacuum interrupter; 10, type A contact; 11, type A auxiliary movable contact; 111, connecting rod; 1111, limiting boss; 112, contact part; 1121, arc surface; 12, type A main contact; 121, through hole; 13, type A contact seat; 131, mounting cavity; 1311, first chamber; 1312, second chamber; 1313, third chamber; 14, damping spring; 15, limiting Snap ring; 16. Type I support cylinder; 17. Ring plate; 18. Type A magnetic focusing ring; 19. Accommodating chamber; 20. Type B contact; 21. Type B auxiliary stationary contact; 22. Type B main contact; 221. Fixing hole; 23. Type B contact seat; 231. Accommodating cavity; 24. Type I double support assembly; 241. First Type I support sleeve; 242. Second Type I support sleeve; 25. Type B magnetic focusing ring; 26. Fixed chamber. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to the accompanying drawings.

[0028] Reference Figures 4 to 7, disclosed in the present invention, is a vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing, including a type A contact 10 and a type B contact 20; the type A contact 10 and the type B contact 20 are paired to form a vacuum interrupter 1, and the vacuum interrupter 1 is sealed in a shell in a vacuum environment; when the vacuum interrupter 1 is in the open position, a preset space is left between the type A contact 10 and the type B contact 20; when the vacuum interrupter 1 is in the closed position, the type A contact 10 and the type B contact 20 are in contact.

[0029] Specifically, the vacuum interrupter 1 is sealed in a ceramic housing in a 10-4 vacuum environment. Figure 6 Taking the shown orientation as an example, the a-type contact 10 is located at the bottom and the b-type contact 20 is located at the top.

[0030] Among them, in this embodiment, the type A contact 10 includes a type A auxiliary movable contact 11, a type A main contact 12 and a type A contact seat 13, the type A contact seat 13 is surrounded by a mounting cavity 131, the type A auxiliary movable contact 11 is slidably arranged in the mounting cavity 131, and the type A main contact 12 is arranged at the top of the type A contact seat 13. When the vacuum interrupter 1 is in the open position, the top surface of the type A auxiliary movable contact 11 is higher than the top surface of the type A contact 10; the type B contact 20 includes a type B auxiliary stationary contact 21, a type B main contact 22 and a type B contact seat 23, and the type B main contact 22 and the type B The auxiliary stationary contacts 21 are all arranged at the end of the type B contact seat 23. The type B auxiliary stationary contact 21 is located at the geometric center of the type B main contact 22. The top surface of the type B auxiliary stationary contact 21 is flush with the top surface of the type B main contact 22. Among them, the type A auxiliary movable contact 11 and the type B auxiliary stationary contact 21 are arranged opposite each other, and the type A main contact 12 and the type B main contact 22 are arranged opposite each other. This arrangement solves the technical problem that high-frequency arcs are prone to point-ablation of the contact surface and destruction of the alloy structure on the basis of taking into account the original short-circuit and high-current interruption; it ensures an extremely low probability of re-breakdown during vacuum interruption.

[0031] Specifically, both the A-type main contact 12 and the B-type main contact 22 are circular flat plates. A through-hole 121 is defined at the geometric center of the A-type main contact 12. The through-hole 121 extends through the A-type main contact 12. The top of the A-type auxiliary movable contact 11 is located within the through-hole 121, with a gap between the outer wall of the A-type auxiliary movable contact 11 and the inner wall of the through-hole 121. Furthermore, a fixing hole 221 is defined at the geometric center of the B-type main contact 22. The fixing hole 221 extends through the B-type main contact 22. The B-type auxiliary stationary contact 21 is located within the fixing hole 221, with a gap between the outer wall of the B-type auxiliary stationary contact 21 and the inner wall of the fixing hole 221.

[0032] The type a main contact 12 and the type b main contact 22 are both made of copper-chromium alloy (CuCr) with a strong current carrying capacity.

[0033] Furthermore, in this embodiment, the type A auxiliary movable contact 11 includes a connecting rod 111 and a contact part 112. The contact part 112 is arranged at the top end of the connecting rod 111, and an arc surface 1121 is provided at the end of the contact part 112 away from the connecting rod 111; when the vacuum interrupter 1 is in the open position, the arc surface 1121 is higher than the top surface of the type A contact 10.

[0034] In this embodiment, the contact part 112 and the type B auxiliary stationary contact 21 are made of any one of copper-tungsten alloy (CuW) with strong ablation resistance, copper-tungsten alloy (CuW) added with graphene and nano-tungsten carbide, copper-molybdenum alloy, alloy containing Sb, Te, Fe, Co and alloy containing Mo; such a setting can guide the high-frequency arc to ablate on the type A auxiliary movable contact 11 and the type B auxiliary stationary contact 21, thereby greatly improving the reactive load switching capacity.

[0035] Specifically, using graphene and nano-tungsten carbide as added phases can synergistically strengthen copper-tungsten alloy (CuW).

[0036] Furthermore, in this embodiment, the A-type contact 10 also includes a damping spring 14 and a limiting snap ring 15. The installation cavity 131 includes a first chamber 1311, a second chamber 1312, and a third chamber 1313. The first chamber 1311, the second chamber 1312, and the third chamber 1313 are arranged in sequence from top to bottom. The first chamber 1311 is connected to the third chamber 1313 through the second chamber 1312. The damping spring 14 is arranged in the third chamber 1313, and the limiting snap ring 15 is arranged in the second chamber 1312. The limiting snap ring 15 is threadedly connected to the type A contact seat 13, and a through hole is provided on the limiting snap ring 15; the bottom end of the connecting rod 111 is inserted into the third chamber 1313 and is connected to the top end of the damping spring 14, and the top end of the connecting rod 111 is inserted into the first chamber 1311 through the through hole, and the connecting rod 111 can slide relative to the limiting snap ring 15; a limiting boss 1111 is provided on the outer peripheral wall near the bottom end of the connecting rod 111, and the limiting boss 1111 cooperates with the limiting snap ring 15 to limit the extension and contraction amount of the type A auxiliary movable contact 11.

[0037] Specifically, Figure 4 Taking the shown orientation as an example, the first chamber 1311 , the second chamber 1312 and the third chamber 1313 are arranged in sequence from top to bottom, wherein the diameter of the first chamber 1311 is larger than the diameter of the second chamber 1312 , and the diameter of the second chamber 1312 is larger than the diameter of the third chamber 1313 .

[0038] The bottom end of the damping spring 14 is connected to the bottom end of the third chamber 1313, and the top end of the damping spring 14 is connected to the bottom end of the connecting rod 111. The outer circumferential wall of the limiting snap ring 15 is provided with external threads, and the inner circumferential wall of the second chamber 1312 is provided with internal threads that match the external threads. The limiting snap ring 15 is screwed into the second chamber 1312. The limiting boss 1111 provided on the connecting rod 111 is located in the third chamber 1313. The limiting boss 1111 cooperates with the limiting snap ring 15 to limit the extension and contraction of the A-type auxiliary movable contact 11, while ensuring that the damping spring 14 is always in a preloaded state.

[0039] It should be noted that the structure of the damping spring 14 depends on the size of the third chamber 1313 and the output characteristic requirements. The damping spring 14 can be a cylindrical compression spring, a rectangular compression spring or a disc spring.

[0040] Among them, the damping spring 14 can withstand high temperature.

[0041] Furthermore, in this embodiment, the type A contact 10 also includes an I-type support tube 16, which is inserted into the first chamber 1311 and sleeved on the connecting rod 111. The connecting rod 111 can slide relative to the I-type support tube 16, and the top of the I-type support tube 16 is connected to the type A main contact 12 through the annular plate 17; by setting the I-type support tube 16, it is ensured that the type A main contact 12 does not undergo mechanical deformation during the closing operation.

[0042] It should be noted that a space is left between the inner peripheral wall of the I-shaped support cylinder 16 and the outer peripheral wall of the connecting rod 111 .

[0043] The type A main contact 12 is welded to the top surface of the annular plate 17 .

[0044] Furthermore, in this embodiment, the type A contact 10 also includes a type A magnetic focusing ring 18, the type I support tube 16 and the inner circumferential wall of the first cavity together constitute a accommodating cavity 19, and the type A magnetic focusing ring 18 is installed in the accommodating cavity 19; the type A magnetic focusing ring 18 is used to ensure that the concentrated arc is quickly transformed into a diffused state during the opening operation.

[0045] The a-type contact seat 13 , the b-type contact seat 23 and the limiting clamping ring 15 are all made of pure copper or copper alloy.

[0046] Continue to refer to Figure 5In this embodiment, the B-type contact 20 also includes an I-type double-support component 24 and a B-type magnetic focusing ring 25. A accommodating cavity 231 is provided at the top of the B-type contact seat 23. The I-type double-support component 24 and the B-type magnetic focusing ring 25 are both arranged in the accommodating cavity 231. The B-type auxiliary stationary contact 21 and the B-type main contact 22 are both connected to the top of the I-type double-support component 24 through a circular ring plate; the B-type magnetic focusing ring 25 is used to ensure that the concentrated arc is quickly transformed into a diffuse state during the opening operation; by setting the I-type double-support component 24, it is ensured that the B-type main contact 22 does not undergo mechanical deformation during the closing operation.

[0047] The b-type auxiliary stationary contact 21 and the b-type main contact 22 are both welded on the annular plate.

[0048] Furthermore, in this embodiment, the I-type double support assembly 24 includes a first I-type support sleeve 241 and a second I-type support sleeve 242. The first I-type support sleeve 241 is sleeved on the second I-type support sleeve 242. The first I-type support sleeve 241 and the inner circumferential wall of the accommodating cavity 231 together constitute a fixed chamber 26, and the B-type magnetic ring 25 is installed in the fixed chamber 26; the B-type main contact 22 is arranged corresponding to the first I-type support sleeve 241, and the B-type auxiliary stationary contact 21 is arranged corresponding to the second I-type support sleeve 242.

[0049] Among them, the center line of the first I-shaped support sleeve 241 is set parallel to the center line of the second I-shaped support sleeve 242. In some feasible methods, the center line of the first I-shaped support sleeve 241 and the center line of the second I-shaped support sleeve 242 are set collinearly.

[0050] Specifically, both the A-type magnetic concentrator 18 and the B-type magnetic concentrator 25 are made of either 45# steel, 10# steel, or electrical pure iron. Arc shape is regulated as needed to enhance short-circuit and capacitive load switching capabilities. To further improve current flow capacity during opening and closing, spring fingers can be added to the A-type auxiliary movable contact 11 and the B-type auxiliary stationary contact 21, depending on actual conditions.

[0051] Compared to conventional vacuum interrupters 1 currently used in power grids, the novel vacuum interrupter 1, featuring a complete set of paired composite contacts, significantly improves its ability to withstand high-frequency inrush arc erosion caused by pre-breakdown during circuit breaker closing. It also ensures that the high-frequency arc erosion transforms from traditional spot erosion to uniform surface erosion, ultimately guiding the arc to erode on the auxiliary contacts. This resolves a problem that has plagued my country's power industry for over a decade. Specific experimental verification demonstrates that, under the most demanding C2-level back-to-back capacitive switching test (GB1984) for high-voltage AC circuit breakers, a conventional vacuum interrupter 1 experienced a restrike after 40 CO cycles with a peak inrush current of 20kA and a frequency of 4250Hz. However, under the same standard, the novel vacuum interrupter 1, under the most demanding C2-level back-to-back capacitive switching test (GB1984) for high-voltage AC circuit breakers, experienced no restrike after 80 CO cycles with a peak inrush current of 20kA and a frequency of 4250Hz. In the near term, this achievement can directly cover 12kV, 40.5kV, and 126kV vacuum environmental circuit breakers, and in the long term, 252kV, 500kV, and 800kV vacuum environmental circuit breakers. Details are shown in Table 1 below.

[0052] Table 1 Capacitive opening and closing test results

[0053]

[0054] Continue to refer to Figure 6 and Figure 7 The working principle of the vacuum composite contact structure provided in this embodiment, which is suitable for frequent reactive switching and short-circuit opening and closing, is as follows: when the vacuum interrupter 1 is in the open position, the type A contact 10 and the type B contact 20 are at a certain opening distance, wherein the arc surface 1121 of the contact part 112 of the type A auxiliary movable contact 11 in the type A contact 10 is higher than the plane of the type A main contact 12, and the damping spring 14 is in an extended state. At the same time, the extension amount of the damping spring 14 is limited by the limit clamp 15, thereby ensuring and accurately positioning the extension amount of the type A auxiliary movable contact 11.

[0055] When the vacuum interrupter 1 is closed and a reactive load is applied, both the type A contact 10 and the type B contact 20 can be used as moving parts. The type A contact 10 serves as the movable contact. When closing, the type A contact 10 rapidly moves upward, approaching the stationary type B contact 20. When it reaches a certain small vacuum gap just before closing, a pre-breakdown arc is generated between the type A contact 10 and the type B contact 20, generating a high-frequency inrush current. The arc rotates and moves under the action of the magnetic field, eventually transferring to the contact portion 112 of the type A auxiliary movable contact 11 and the type B auxiliary stationary contact 21 of the type B contact 20, where it ablates for less than 1ms. Immediately after the type A contact 10 and the type B contact 20 close, the type A auxiliary movable contact 11 contracts due to the downward pressure of the type B contact 20. Finally, the main contacts of the type A contact 10 and the type B contact 20 fully contact, ensuring that the vacuum interrupter 1 is in the closed position.

[0056] When the vacuum interrupter 1 is in the closed position, the raised arc portion of the type A auxiliary movable contact 11 is pressed by the type B contact 20. Under the force of the damping spring 14, the type A auxiliary movable contact 11 contracts and becomes flush with the surface of the type A main contact 12. At the same time, the type A main contact 12 and the type B main contact 22 are in full contact and in the closed state.

[0057] When the vacuum interrupter 1 is opened to cut off the reactive load, the type A contact 10 moves downward rapidly and separates from the static side type B contact 20. When it moves to a certain small vacuum gap just after opening, an industrial frequency arc will be generated between the type A contact 10 and the type B contact 20. Under the combined action of the longitudinal magnetism on the contact surface and the auxiliary enhancement of the magnetic focusing ring, the arc rotates and moves rapidly until it crosses zero and is extinguished. The vacuum interrupter 1 completes the circuit breaking. Finally, the type A contact 10 moves to the opening position to ensure that the vacuum interrupter 1 is in the opening position.

[0058] The present application provides a vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing, including a type A contact 10 and a type B contact 20; the type A contact 10 and the type B contact 20 are paired to form a vacuum interrupter 1, and the vacuum interrupter 1 is sealed in a shell in a vacuum environment; when the vacuum interrupter 1 is in the open position, a preset space is left between the type A contact 10 and the type B contact 20; when the vacuum interrupter 1 is in the closed position, the type A contact 10 and the type B contact 20 are in contact; the type A contact 10 includes a type A auxiliary movable contact 11, a type A main contact 12 and a type A contact seat 13, the type A contact seat 13 is surrounded by a mounting cavity 131, the type A auxiliary movable contact 11 is slidably arranged in the mounting cavity 131, and the type A main contact 1 2 is arranged at the top of the type A contact seat 13. When the vacuum interrupter 1 is in the open position, the top surface of the type A auxiliary movable contact 11 is higher than the top surface of the type A contact 10. The type B contact 20 includes a type B auxiliary stationary contact 21, a type B main contact 22 and a type B contact seat 23. The type B main contact 22 and the type B auxiliary stationary contact 21 are both arranged at the end of the type B contact seat 23. The type B auxiliary stationary contact 21 is located at the geometric center of the type B main contact 22. The top surface of the type B auxiliary stationary contact 21 is flush with the top surface of the type B main contact 22. This arrangement solves the technical problem of high-frequency arc easily causing point erosion of the contact surface and destruction of the alloy structure on the basis of taking into account the original short-circuit and high-current interruption; and ensures an extremely low probability of restrike during vacuum interruption.

[0059] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0060] Finally, it should be noted that the above embodiments are merely examples for the purpose of illustrating the present invention and are not intended to limit the embodiments. Those skilled in the art will readily appreciate that other variations or modifications based on the above description are possible. It is not necessary and impossible to provide an exhaustive list of all embodiments. However, obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing, characterized by: Including type a contact and type b contact; The type A contact and the type B contact are paired to form a vacuum interrupter, which is sealed in a housing in a vacuum environment; when the vacuum interrupter is in the open position, a preset space is left between the type A contact and the type B contact; when the vacuum interrupter is in the closed position, the type A contact and the type B contact are in contact; The type A contact comprises an type A auxiliary movable contact, a type A main contact and an type A contact seat, wherein the type A contact seat is arranged to form a mounting cavity, the type A auxiliary movable contact is slidably arranged in the mounting cavity, the type A main contact is arranged at the top of the type A contact seat, and when the vacuum interrupter is in the open position, the top surface of the type A auxiliary movable contact is higher than the top surface of the type A contact; The B-type contact includes a B-type auxiliary stationary contact, a B-type main contact and a B-type contact seat. The B-type main contact and the B-type auxiliary stationary contact are both arranged at the end of the B-type contact seat. The B-type auxiliary stationary contact is located at the geometric center of the B-type main contact. The top surface of the B-type auxiliary stationary contact is flush with the top surface of the B-type main contact. The B-type contact also includes an I-type double-support assembly and a B-type magnetic focusing ring. The top of the B-type contact seat is provided with an accommodating cavity. The I-type double-support assembly and the B-type magnetic focusing ring are both arranged in the accommodating cavity. The B-type auxiliary stationary contact and the B-type main contact are both connected to the top of the I-type double-support assembly through a circular ring plate. The I-shaped double support assembly includes a first I-shaped support sleeve and a second I-shaped support sleeve, the first I-shaped support sleeve is sleeved on the second I-shaped support sleeve, the first I-shaped support sleeve and the inner peripheral wall of the accommodating cavity together form a fixed chamber, and the B-type magnetic focusing ring is installed in the fixed chamber; The b-type main contact is arranged correspondingly to the first I-type supporting sleeve, and the b-type auxiliary stationary contact is arranged correspondingly to the second I-type supporting sleeve.

2. The vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing according to claim 1 is characterized in that: The type A auxiliary movable contact includes a connecting rod and a contact part, the contact part is arranged at the top end of the connecting rod, and an arc surface is provided at the end of the contact part away from the connecting rod; when the vacuum interrupter is in the open position, the arc surface is higher than the top surface of the type A contact.

3. The vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing according to claim 2 is characterized in that: The contact part and the B-type auxiliary stationary contact are both made of any one of copper-tungsten alloy, copper-tungsten alloy added with graphene and nano-tungsten carbide, copper-molybdenum alloy, alloy containing Sb, Te, Fe, Co and alloy containing Mo.

4. The vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing according to claim 1 is characterized in that: The type A main contact and the type B main contact are both made of copper-chromium alloy material.

5. The vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing according to claim 2 is characterized in that: The A-type contact further includes a damping spring and a limiting snap ring. The mounting cavity includes a first chamber, a second chamber, and a third chamber. The first chamber, the second chamber, and the third chamber are arranged sequentially from top to bottom. The first chamber is connected to the third chamber through the second chamber. The damping spring is arranged in the third chamber, and the limiting snap ring is arranged in the second chamber. The limiting snap ring is threadedly connected to the A-type contact seat, and a through hole is opened on the limiting snap ring. The bottom end of the connecting rod is inserted into the third chamber and connected to the top end of the damping spring. The top end of the connecting rod passes through the through hole and is inserted into the first chamber. The connecting rod can slide relative to the limiting clamp ring. A limiting boss is provided on the outer peripheral wall near the bottom end of the connecting rod, and the limiting boss cooperates with the limiting clamping ring to limit the extension and contraction amount of the A-type auxiliary movable contact.

6. The vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing according to claim 5, characterized in that: The type A contact also includes an I-type support tube, which is inserted into the first chamber and sleeved on the connecting rod. The connecting rod can slide relative to the I-type support tube, and the top end of the I-type support tube is connected to the type A main contact through an annular plate.

7. The vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing according to claim 6, characterized in that: The A-type contact also includes an A-type magnetic focusing ring. The I-type support cylinder and the inner peripheral wall of the first chamber together form an accommodating cavity, and the A-type magnetic focusing ring is installed in the accommodating cavity.

8. The vacuum composite contact structure suitable for frequent reactive switching and short-circuit opening and closing according to claim 5 is characterized in that: The damping spring can withstand high temperatures of 700°C to 900°C.

Images