Circuit breaker contact structure integrated with permanent magnet and vacuum circuit breaker

Abstract

The invention discloses a circuit breaker contact structure integrated with a permanent magnet and a vacuum circuit breaker, and relates to the technical field of vacuum circuit breakers, the circuit breaker contact structure integrated with the permanent magnet comprises a contact piece, a contact cup, an insulation sleeve, a permanent magnet ring and a conducting rod, the contact piece and the conducting rod are arranged at the two ends of the contact cup respectively, the insulation sleeve is sleeved outside the contact cup, the permanent magnet ring is sleeved outside the insulation sleeve, and the contact cup is provided with a spiral slot. The vacuum circuit breaker adopts a circuit breaker contact structure integrated with a permanent magnet. Through innovative structural design and material application, the problems that in an existing vacuum circuit breaker contact structure, magnetic field phase lag and residual magnetism affect arc extinguishing are effectively solved, the longitudinal magnetic field control effect is enhanced at the current peak value, the residual magnetism is restrained at the current zero passage, coordination and cooperation of the two are achieved, and the service life of the vacuum circuit breaker is prolonged. The breaking performance and reliability of the vacuum circuit breaker are improved, and the breaking reliability of the vacuum circuit breaker is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum circuit breakers, and in particular to a circuit breaker contact structure with integrated permanent magnets and a vacuum circuit breaker. Background Art

[0002] Vacuum circuit breakers, due to their low cost, high breaking capacity, and high reliability, have been widely used in medium-voltage power switchgear. These devices are gradually evolving towards higher voltage levels, becoming a mainstream research direction. Effective arc control between contacts has become a key research focus during the development of vacuum circuit breakers. In particular, longitudinal magnetic field control technology has developed rapidly in recent years and has been widely adopted. The longitudinal magnetic field not only maintains a diffuse state in high-current vacuum arcs, preventing cathode spots from migrating to the cathode surface, but also reduces arc voltage and the erosion rate of the cathode and anode electrodes. However, the forced zero-crossing technique used in vacuum circuit breakers induces severe eddy currents within the conductors, causing significant hysteresis in the inter-electrode magnetic field, which affects effective arc interruption. When the current rapidly decreases from a DC state to zero, the frequency of the decrease is extremely high, generating strong eddy currents within the contacts, resulting in a lag in the magnetic field response in the arc region. At the peak current moment, the arc region's magnetic field strength is insufficient, resulting in poor arc control. Furthermore, at zero current crossings, residual magnetism remains in the arc region, further exacerbating the magnetic field lag. The effective distribution of the longitudinal magnetic field at the peak current moment further decreases, while the residual magnetism at zero current crossings significantly increases. This places higher demands on the precise control of the inter-polar longitudinal magnetic field.

[0003] To achieve precise control of the longitudinal magnetic field distribution of vacuum circuit breakers at high current interruption frequencies and address the magnetic field phase lag problem, design approaches to optimizing the contact structure of circuit breakers with integrated permanent magnets have been gradually adopted in recent years. Traditional solutions typically introduce an iron core inside the contact cup to significantly enhance the strength of the longitudinal magnetic field between the poles, thereby increasing the proportion of effective longitudinal magnetic field distribution. However, the iron core itself also generates eddy currents, resulting in excessive residual magnetism between the poles at the moment the current passes through zero, which affects the effective extinction of the arc. In addition, installing an iron core inside the contact cup also introduces new challenges to the insulation performance, production costs, and assembly process of the contacts. Therefore, how to enhance the longitudinal magnetic field control effect at the current peak while suppressing the residual magnetism effect at the current zero passage, and achieve coordinated coordination between the two, has become a key challenge facing the optimized design of the contact structure of circuit breakers with integrated permanent magnets.

[0004] Therefore, the existing technology needs to be improved. Summary of the Invention

[0005] The present invention aims to provide a circuit breaker contact structure and a vacuum circuit breaker with an integrated permanent magnet. Through innovative structural design and combined with material application, the present invention effectively solves the problems of magnetic field phase lag and residual magnetism affecting arc extinction in the circuit breaker contact structure with an integrated permanent magnet in existing vacuum circuit breakers. The invention enhances the longitudinal magnetic field control effect at the current peak and suppresses the residual magnetism when the current passes through zero, achieving coordinated cooperation between the two and improving the breaking performance and reliability of the vacuum circuit breaker.

[0006] The present invention is achieved through the following technical solutions: In a first aspect, the present invention provides a circuit breaker contact structure with an integrated permanent magnet, which includes a contact piece, a contact cup, an insulating and heat-insulating sleeve, a permanent magnet ring, and a conductive rod. The contact piece and the conductive rod are respectively arranged at both ends of the contact cup, the insulating and heat-insulating sleeve is sleeved on the outside of the contact cup, the permanent magnet ring is sleeved on the outside of the insulating and heat-insulating sleeve, and the contact cup is provided with spiral grooves.

[0007] In the above technical solution, the longitudinal magnetic field is actively generated by the permanent magnet ring, and the design of the spiral grooves of the contact cup and the strip holes of the contact piece is combined to effectively enhance the magnetic field strength in the arc zone at the current peak, improve the effective distribution ratio of the longitudinal magnetic field, better maintain the arc diffusion state, prevent the migration of cathode spots, and improve the arc control effect.

[0008] Furthermore, in the present invention, the contact piece is provided with a strip hole 1 extending from the edge toward the center, and the outer end of the strip hole 1 corresponds to the port of the spiral groove.

[0009] In the above technical solution, the connection between the strip-shaped hole and the spiral slot is equivalent to extending the spiral slot, thereby generating a stronger longitudinal magnetic field.

[0010] Furthermore, in the present invention, the number of the spiral grooves and the strip-shaped holes is the same and are evenly distributed around the center.

[0011] Furthermore, in the present invention, the strip-shaped hole 1 is configured as a straight strip-shaped hole 1.

[0012] Furthermore, in the present invention, a second strip hole extending from the edge toward the center is provided on the bottom surface of one end of the contact cup away from the contact piece, and the outer end of the second strip hole corresponds to the end of the spiral groove.

[0013] In the above technical solution, the second strip-shaped hole serves to extend the length of the spiral slot, thereby generating a stronger longitudinal magnetic field.

[0014] Furthermore, in the present invention, the two symmetrical circuit breaker contact structures with integrated permanent magnets are respectively configured as a moving contact and a stationary contact, and the spiral direction of the spiral groove in the moving contact is consistent with the spiral direction of the spiral groove in the stationary contact.

[0015] In the above technical solution, the spiral direction of the spiral groove in the moving contact is consistent with the spiral direction of the spiral groove in the static contact. This design can ensure that during the opening and closing process of the vacuum circuit breaker, the magnetic field distribution between the moving contact and the static contact is uniform and stable, which is conducive to the stable control and effective extinguishing of the arc.

[0016] Furthermore, in the present invention, the conductive rods are made of copper.

[0017] In the above technical solution, the conductive rod is configured to be made of copper material to ensure that the current can smoothly pass through the circuit breaker contact structure with the integrated permanent magnet.

[0018] Furthermore, in the present invention, the permanent magnet ring is made of neodymium iron boron material.

[0019] In the above technical solution, NdFeB material has the characteristics of high remanence, high coercive force and high magnetic energy product, providing a stable and high-intensity magnetic field.

[0020] Furthermore, in the present invention, the above-mentioned insulating and heat-insulating sleeve is configured as aluminum nitride material.

[0021] In the above technical solution, aluminum nitride has good thermal conductivity and can effectively dissipate the heat generated by the circuit breaker contact structure with integrated permanent magnets during operation, thereby ensuring stable operation of the circuit breaker contact structure with integrated permanent magnets.

[0022] In a second aspect, the present invention further provides a vacuum circuit breaker, which adopts a circuit breaker contact structure with an integrated permanent magnet.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects: The magnetic field optimization effect is significant: the longitudinal magnetic field is actively generated by the permanent magnet ring. Combined with the design of the spiral slots in the contact cup and the strip holes in the contact piece, it can effectively enhance the magnetic field strength in the arc zone at the current peak, improve the effective distribution ratio of the longitudinal magnetic field, better maintain the arc diffusion state, prevent the migration of cathode spots, and improve the arc control effect.

[0024] Suppressing the residual magnetism problem: It avoids the problem of excessive residual magnetism at the zero-crossing moment caused by eddy current in traditional iron cores. The insulating and thermal insulation sleeve is made of aluminum nitride material, which effectively isolates external magnetic field interference and suppresses eddy current heating. When the current passes through zero, the magnetic field can be quickly attenuated, promoting the effective extinction of the arc and improving the breaking reliability of the vacuum circuit breaker.

[0025] Balance between performance and cost: No complex iron core structure is required inside the contact cup, which simplifies the assembly process and reduces production costs. At the same time, it avoids the impact of the iron core on the insulation performance of the contact, achieving a good balance between performance improvement and cost control. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the examples. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort. In the drawings: Figure 1 This is a schematic diagram of the appearance of a circuit breaker contact structure with integrated permanent magnets according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the internal structure of a circuit breaker contact structure with an integrated permanent magnet according to an embodiment of the present invention; Figure 3 Schematic diagram of the contact cups in the moving contact and the static contact according to an embodiment of the present invention.

[0027] The marks and corresponding parts names in the accompanying drawings are: 1-contact piece, 101-bar hole 1, 2-contact cup, 201-spiral slot, 3-insulating and thermal insulation sleeve, 4-permanent magnet ring, 5-conductive rod. DETAILED DESCRIPTION

[0028] In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and drawings. The schematic embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention. The following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] It should be noted that similar numbers and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in the subsequent figures. In the description of the embodiments of the present invention, it should be noted that if the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate an orientation or position relationship based on the orientation or position relationship shown in the figures, or the orientation or position relationship in which the invented product is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", "third" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0030] Furthermore, the use of terms such as "horizontal," "vertical," and "overhanging" does not necessarily imply that a component must be absolutely horizontal or overhanging; rather, it may be slightly tilted. For example, "horizontal" simply refers to a more horizontal orientation relative to "vertical," not to a completely horizontal structure; rather, it may be slightly tilted. In the description of the embodiments of the present invention, "multiple" means at least two.

[0031] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0032] Example 1 Reference Figure 1 and Figure 2 As shown, the circuit breaker contact structure with integrated permanent magnets according to the embodiment of the present invention mainly consists of five parts: a contact piece 1 , a contact cup 2 , an insulating and heat-insulating sleeve 3 , a permanent magnet ring 4 and a conductive rod 5 .

[0033] The contact blade 1 is made of a high-temperature-resistant, highly conductive copper-tungsten alloy. Its surface is provided with strip-shaped holes 101 extending from the edge toward the center. Six of these holes 101 are evenly distributed around the center of the contact blade 1 and are arranged as straight strips. Their outer ends correspond to the ends of the spiral slots 201 in the contact cup 2. The design of these holes 101 not only helps extend the spiral slots 201 but also reduces the weight of the contact blade 1 to a certain extent, optimizing the overall performance of the circuit breaker contact structure with integrated permanent magnets.

[0034] The contact cup 2 is a key component of the circuit breaker contact structure with integrated permanent magnets. It is made of a copper-chromium alloy with excellent magnetic and electrical conductivity. The sidewalls of the contact cup 2 are provided with six spiral slots 201, the same number as the strip-shaped holes 101 in the contact blade 1, and are evenly distributed. The spiral angle of the spiral slots 201 has been precisely calculated and optimized to effectively guide the magnetic field generated by the permanent magnet ring 4, forming a uniform and appropriately strong longitudinal magnetic field in the arc region.

[0035] It should be noted that, in some embodiments, the contact cup 2 may be provided with a strip hole 2 extending from the edge toward the center on the bottom surface of the end away from the contact piece 1, and the outer ends of the strip hole 2 correspond to the ports of the spiral groove 201, further extending the spiral groove 201.

[0036] In some implementations of this embodiment, Figure 1 and Figure 2 As shown, the insulating sleeve 3 is mounted on the outside of the contact cup 2 and is made of aluminum nitride. Aluminum nitride has excellent thermal conductivity and can effectively dissipate the heat generated by the circuit breaker contact structure with integrated permanent magnets during operation, suppressing eddy current heating and ensuring stable operation of the circuit breaker contact structure with integrated permanent magnets.

[0037] Combine Figure 1 and Figure 2 As shown, a permanent magnet ring 4 is mounted on the exterior of the insulating sleeve 3. Made of neodymium iron boron (NdFeB), NdFeB permanent magnets possess high remanence, high coercivity, and high magnetic energy product, providing a stable and high-intensity longitudinal magnetic field for the circuit breaker contact structure incorporating permanent magnets. The inner diameter of the permanent magnet ring 4 matches the outer diameter of the insulating sleeve 3 and is secured to the sleeve through a precise assembly process, ensuring that the magnetic field it generates accurately impacts the interior of the contact.

[0038] The conductive rod 5 is made of copper material with good conductivity. One end of the conductive rod is connected to the contact cup 2 and the other end is used to connect to the external circuit to ensure that the current can smoothly pass through the circuit breaker contact structure with integrated permanent magnet.

[0039] During assembly, first weld the conductive rod 5 to one end of the contact cup 2 to ensure a secure connection and good conductivity. Then, place the insulating sleeve 3 over the contact cup 2, ensuring a tight fit and avoiding gaps that could affect insulation and heat isolation. Next, place the permanent magnet ring 4 over the insulating sleeve 3 and secure it in place using a specific fixing method (such as bonding or mechanical fastening). Finally, assemble the contact piece 1 with the other end of the contact cup 2, ensuring that the strip hole 101 of the contact piece 1 precisely aligns with the spiral slot 201 of the contact cup 2.

[0040] Example 2 Combine Figure 3 As shown, this embodiment demonstrates the practical application of the circuit breaker contact structure with integrated permanent magnets in a vacuum circuit breaker, and configures two symmetrical circuit breaker contact structures with integrated permanent magnets as a moving contact and a static contact, respectively.

[0041] The structural composition of the moving contact and the static contact is consistent with the circuit breaker contact structure with integrated permanent magnets described in Example 1, and both include a contact piece 1, a contact cup 2, an insulating and thermally insulating sleeve 3, a permanent magnet ring 4, and a conductive rod 5. The spiral direction of the spiral slot 201 in the moving contact is consistent with the spiral direction of the spiral slot 201 in the static contact. This design ensures a uniform and stable magnetic field distribution between the moving and static contacts during the opening and closing of the vacuum circuit breaker, which is conducive to stable control and effective extinguishing of the arc.

[0042] It should be noted that the design can be further optimized, and the contact pieces 1 of the moving contact and the static contact are used for contact and conduction of current. A conductive arch structure can be provided on the end face of one of the contact pieces 1 for contact, and a conductive groove structure can be provided on the end face of the other contact piece 1 for contact. The arch structure can be configured as a circular drum piece, and the groove structure can be configured as a circular groove. The circular drum piece can be configured to have a certain elasticity or deformation ability. When the moving contact and the static contact are close to each other, the arch structure and the groove structure are in stable contact, and the conductive effect is better.

[0043] When the vacuum circuit breaker is operating, as current passes through the moving and stationary contacts, the longitudinal magnetic field generated by the permanent magnet ring 4 cooperates with the magnetic field guided by the spiral slots 201 in the contact cup 2 and the strip-shaped holes 101 in the contact blade 1. At current peaks, a longitudinal magnetic field of sufficient strength is formed in the arc region between the contacts, maintaining the arc in a diffuse state, preventing cathode spot migration, and effectively controlling the arc. When the current passes through zero, the magnetic field rapidly decays, facilitating the rapid extinction of the arc, significantly improving the interrupting performance and reliability of the vacuum circuit breaker, by avoiding the residual magnetism caused by eddy currents generated by traditional iron cores.

[0044] The working principles of the circuit breaker contact structure with integrated permanent magnet and the vacuum circuit breaker of the present invention are as follows: When the circuit breaker contact structure with integrated permanent magnet and vacuum circuit breaker is opened, a vacuum arc will be formed between the poles. Since the contact cup 2 adopts the structure of spiral slot 201, the current will flow along the contact cup 2 in a circular direction. According to Ampere's loop law, a longitudinal control magnetic field A will be generated between the poles. Figure 3As shown, the circuit breaker contact structure and vacuum circuit breaker with integrated permanent magnets of the present invention have an S-pole permanent magnet ring 4 surrounding the outside of the anode contact cup 2, and an N-pole permanent magnet ring 4 surrounding the outside of the cathode contact cup 2. The permanent magnet ring 4 is made of neodymium iron boron material. A strong magnetic field B opposite to the magnetic field A is generated between the contacts. After superposition, the composite longitudinal magnetic field can cause the high-current vacuum arc to maintain a diffuse state, prevent the cathode spots from migrating on the cathode surface, and thus reduce the arc voltage and electrode erosion rate.

[0045] In the initial stages of disconnection, as the moving and stationary contacts begin to separate, the gap between them is small. The opposing magnetic field B generated by the permanent magnet ring 4 surrounding the contact cup 2 is strong, while magnetic field A is relatively weak due to the small vacuum arc. At this point, the composite magnetic field is directed downward, providing sufficient restraint at the current peak to stabilize the arc. As the disconnection process progresses, the gap between the moving and stationary contacts increases, and the strength of magnetic field B gradually weakens. At this point, magnetic field B reduces magnetic field A. The combined effect of magnetic field B and magnetic field A effectively suppresses the residual magnetism at current zero crossings, until the two fields almost completely cancel each other out at this point. This improves plasma diffusion conditions and prevents arc reignition after the current crosses zero.

[0046] The surrounding insulating and heat-insulating sleeve 3 of the present invention is made of aluminum nitride material, which has high strength and good wear resistance and corrosion resistance. In this process, it not only plays the role of insulation and heat insulation to prevent the permanent magnet ring 4 from overheating, but also ensures the mechanical structure strength of the circuit breaker contact structure with integrated permanent magnets and the vacuum circuit breaker, thereby improving their service life.

[0047] In summary, the present invention provides a circuit breaker contact structure with an integrated permanent magnet, comprising a contact piece 1, a contact cup 2, an insulating and heat-insulating sleeve 3, a permanent magnet ring 4, and a conductive rod 5. The contact piece 1 and the conductive rod 5 are respectively disposed at both ends of the contact cup 2, the insulating and heat-insulating sleeve 3 is sleeved on the outside of the contact cup 2, and the permanent magnet ring 4 is sleeved on the outside of the insulating and heat-insulating sleeve 3. The contact cup 2 is provided with a spiral groove 201. The contact piece 1 is provided with a strip hole 101 extending from the edge toward the center, and the outer end of the strip hole 101 corresponds to the end of the spiral groove 201. The number of spiral grooves 201 and strip holes 101 is the same and is evenly distributed around the center. The strip holes 101 are configured as straight strip holes 101. The bottom surface of the end of the contact cup 2 away from the contact piece 1 is provided with a strip hole 2 extending from the edge toward the center, and the outer end of the strip hole 2 corresponds to the end of the spiral groove 201. Two symmetrical circuit breaker contact structures with integrated permanent magnets are configured as a moving contact and a stationary contact, respectively. The spiral direction of the spiral slot 201 in the moving contact is consistent with the spiral direction of the spiral slot 201 in the stationary contact. The conductive rod 5 is configured as copper. The permanent magnet ring 4 is configured as neodymium iron boron material. The insulating and thermal insulation sleeve 3 is configured as aluminum nitride material.

[0048] The present invention also provides a vacuum circuit breaker, characterized by adopting the circuit breaker contact structure with integrated permanent magnet as claimed in claim 1.

[0049] Therefore, the circuit breaker contact structure and vacuum circuit breaker with integrated permanent magnets of the present invention effectively solve the problems of magnetic field phase lag and residual magnetism affecting arc extinction in the existing vacuum circuit breaker contact structure through innovative structural design and combined material application. It enhances the longitudinal magnetic field control effect at the current peak and suppresses the residual magnetism when the current passes through zero, achieving coordinated cooperation between the two and improving the breaking performance and reliability of the vacuum circuit breaker.

[0050] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A circuit breaker contact structure with an integrated permanent magnet, characterized in that: It comprises a contact piece (1), a contact cup (2), an insulating heat-insulating sleeve (3), a permanent magnet ring (4) and a conductive rod (5), The contact piece (1) and the conductive rod (5) are respectively arranged at two ends of the contact cup (2); the insulating heat-insulating sleeve (3) is sleeved on the outside of the contact cup (2); the permanent magnet ring (4) is sleeved on the outside of the insulating heat-insulating sleeve (3); and the contact cup (2) is provided with a spiral groove (201).

2. The circuit breaker contact structure with integrated permanent magnet according to claim 1, characterized in that: The contact piece (1) is provided with a strip hole (101) extending from the edge toward the center, and the outer end of the strip hole (101) corresponds to the end of the spiral groove (201).

3. The circuit breaker contact structure with integrated permanent magnet according to claim 2, characterized in that: The spiral slots (201) and the strip holes (101) are of the same number and are evenly distributed around the center.

4. The circuit breaker contact structure with integrated permanent magnet according to claim 3, characterized in that: The strip-shaped hole one (101) is configured as a straight strip-shaped hole one (101).

5. The circuit breaker contact structure with integrated permanent magnet according to claim 4, characterized in that: A second strip hole extending from the edge toward the center is provided on the bottom surface of one end of the contact cup (2) away from the contact piece (1), and the outer end of the second strip hole corresponds to the end of the spiral slot (201).

6. The circuit breaker contact structure with integrated permanent magnet according to claim 1, characterized in that: The two symmetrical circuit breaker contact structures with integrated permanent magnets are respectively configured as a moving contact and a stationary contact, and the spiral direction of the spiral slot (201) in the moving contact is consistent with the spiral direction of the spiral slot (201) in the stationary contact.

7. The circuit breaker contact structure with integrated permanent magnet according to claim 1, characterized in that: The conductive rod (5) is made of copper material.

8. The circuit breaker contact structure with integrated permanent magnet according to claim 1, characterized in that: The permanent magnet ring (4) is configured as a neodymium iron boron material.

9. The circuit breaker contact structure with integrated permanent magnet according to claim 1, characterized in that: The insulating and heat-insulating sleeve (3) is configured as aluminum nitride material.

10. A vacuum circuit breaker, characterized in that: A circuit breaker contact structure with an integrated permanent magnet as claimed in claim 1 is used.

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