Three-phase independent permanent magnet switch cabinet

Abstract

This application relates to a three-phase independent permanent magnet switchgear. The three-phase independent permanent magnet switchgear includes: a cabinet with three mounting interfaces arranged side-by-side on its inner surface; three permanent magnet circuit breakers, corresponding to the three phases of the three-phase circuit, which are mounted side-by-side in the cabinet through the mounting interfaces; each permanent magnet circuit breaker includes: a low-voltage housing with a continuous curvature on its outer circumferential surface; a high-voltage housing, one end of which is fitted onto the outer circumferential surface of the low-voltage housing, with a continuous curvature on its inner circumferential surface; a permanent magnet operating module, which includes at least a moving iron core, and is disposed inside the low-voltage housing; and a power circuit module, which includes at least an arc-extinguishing chamber, and is disposed inside the high-voltage housing. This application can solve the problems of phase deviation, fault location, and single-phase fault linkage in three-phase integrated structures, and reduce the impact of airflow disturbance and electric field distribution on equipment operation.

Description

Technical Field

[0001] This application relates to the field of power technology, and in particular to a three-phase independent permanent magnet switchgear. Background Technology

[0002] With the development of microprocessor technology, power electronics technology, and intelligent control theory, traditional circuit breakers using electromagnetic or spring mechanisms have gradually shown limitations in terms of mechanical complexity and maintenance requirements. Therefore, circuit breakers using permanent magnet mechanisms have emerged. Compared to traditional circuit breakers where the unlocking relies on complex mechanical structures, permanent magnet mechanisms use permanent magnets to maintain the open / closed state, eliminating the need for mechanical latches. This significantly reduces the number of moving parts and effectively solves the problems of numerous components, easy wear, and the need for regular maintenance in traditional circuit breakers.

[0003] Currently, circuit breakers employing permanent magnet mechanisms are widely used in power systems, such as urban distribution network automation systems, smart substations, and digital substations. Modern power grids require circuit breakers to possess intelligent functions such as condition monitoring, fault diagnosis, and synchronous closing. The operation of permanent magnet mechanisms is driven by electronic control systems, offering fast response speeds and low dispersion, providing an ideal material basis for achieving precise and intelligent opening and closing. Therefore, in the operation of power systems, circuit breakers, as core control and protection devices, directly affect the safety and stability of the power grid.

[0004] Existing permanent magnet circuit breakers mostly adopt a three-phase integrated structure, with all three phases sharing a single permanent magnet mechanism and drive shaft. This three-phase integrated design has the following drawbacks: First, phase deviations are prone to occur during the assembly process of the three-phase integrated permanent magnet circuit breaker. Manufacturing and assembly errors can easily lead to synchronicity deviations in opening and closing, thus affecting breaking performance and system stability. Second, fault location is difficult when a permanent magnet circuit breaker malfunctions, and disassembly and repair are difficult and time-consuming. Third, single-pole faults (such as air leakage in the arc-extinguishing chamber or contact wear) can affect the other two phases through mechanical linkage. Fourth, the three-phase linkage shaft has high rigidity, and under strong vibration conditions caused by airflow disturbances, such as in rail transit and wind power environments, stress concentration is easily generated, affecting the accuracy of opening and closing actions. Summary of the Invention

[0005] To overcome the problems existing in related technologies, this application provides a three-phase independent permanent magnet switchgear, which, through phase-separated design and shell structure design, can solve the problems of phase deviation, complex fault location, and mechanical linkage of single-phase faults that are prone to occur in three-phase integrated structures, and reduce the impact of airflow disturbance and electric field distribution on equipment operation.

[0006] This application provides a three-phase independent permanent magnet switchgear, comprising: a cabinet with three mounting interfaces arranged side-by-side on its inner surface; three permanent magnet circuit breakers corresponding to the three phases of a three-phase circuit, wherein the permanent magnet circuit breakers are mounted side-by-side in the cabinet through the mounting interfaces; each permanent magnet circuit breaker includes: a low-voltage section housing, wherein the curvature of the outer peripheral surface of the low-voltage section housing is continuous, and the curvature of the inner peripheral surface of the low-voltage section housing is continuous; the outer peripheral surface of the low-voltage section housing has a curvature inflection point, at the location of this curvature inflection point, the low-voltage section... The curvature directions of adjacent regions on the outer circumferential surface of the housing along the axial direction of the permanent magnet circuit breaker are opposite, and the absolute value of the curvature increases in the direction from the low-voltage housing to the high-voltage housing; the high-voltage housing has one end fitted onto the outer circumferential surface of the low-voltage housing, and the curvature of the inner circumferential surface of the high-voltage housing is continuous; the permanent magnet operating module includes at least a moving iron core, and the permanent magnet operating module is disposed inside the low-voltage housing; the power circuit module includes at least an arc-extinguishing chamber, and the power circuit module is disposed inside the high-voltage housing.

[0007] Preferably, at adjacent positions of the three permanent magnet circuit breakers, the outer peripheral surface of the low-voltage housing and / or the outer peripheral surface of the high-voltage housing have a concave shape.

[0008] Preferably, the low-pressure section shell and the high-pressure section shell are injection molded using modified polymer synthetic materials; the modified polymer synthetic materials use polyhexamethylene adipamide as the base material and are composite modified by adding glass fiber reinforcing agents, halogen-free flame retardants and environmentally friendly toughening agents; the modified polymer synthetic materials meet the following characteristics: tensile strength ≥80MPa, impact strength ≥15kJ / m² and breakdown field strength ≥20kV / mm.

[0009] Preferably, the permanent magnet operating module includes a manual opening and closing mechanism, which includes at least a crank arm assembly and an operating spindle; the operating spindle is movably connected to the moving iron core through the crank arm assembly, so that the operating spindle can drive the moving iron core to move along the axial direction of the permanent magnet circuit breaker.

[0010] Preferably, the crank arm assembly and the operating spindle are fixedly supported by a shaft system formed by a deep groove ball bearing, and the crank arm assembly and the operating spindle are connected by an inter-shaft angular transmission via a universal joint.

[0011] Preferably, the permanent magnet circuit breaker further includes: an insulating link and a moving conductive terminal; the insulating link is disposed inside the low-voltage housing and the high-voltage housing and located at the connection between the two; the moving iron core is connected to the moving conductive terminal through the insulating link; the insulating link is used to transmit the power applied to the moving iron core to the moving conductive terminal, so that the moving conductive terminal moves along the axial direction of the permanent magnet circuit breaker.

[0012] Preferably, the crank arm assembly includes: a U-shaped insertion slot and a transmission arm; the first end of the transmission arm is provided with a cylindrical pin that matches the U-shaped insertion slot, and the second end is connected to the operating spindle; the opening direction of the U-shaped insertion slot is perpendicular to the axial direction of the permanent magnet circuit breaker, the open side of the U-shaped insertion slot is slidably connected to the cylindrical pin, and the closed side of the U-shaped insertion slot is fixed on the moving iron core; under the drive of the operating spindle, the second end of the transmission arm drives the first end of the transmission arm to rotate, causing the cylindrical pin to generate axial and perpendicular displacements, and while the cylindrical pin slides in the U-shaped insertion slot, it drives the U-shaped insertion slot and the moving iron core fixed thereto to move.

[0013] Preferably, the bearing mating parts of the deep groove ball bearing are coated with grease, and the grease meets the following conditions: dropping point ≥ 230℃, pour point ≤ -60℃ and / or viscosity-temperature index ≥ 140.

[0014] Preferably, an elastic sealing ring is provided at the connection between the low-pressure section housing and the high-pressure section housing; the interior of the cabinet is a sealed chamber filled with dry gas.

[0015] The technical solution provided in this application may include the following beneficial effects:

[0016] The three-phase independent permanent magnet switchgear provided in this application contains three independently assembled permanent magnet circuit breakers inside the cabinet. Each of the three permanent magnet circuit breakers corresponds to one of the three phases of the three-phase circuit. Each permanent magnet circuit breaker contains its own permanent magnet operating module and power circuit module, achieving a phase-separated design. Because each of the three permanent magnet circuit breakers has its own corresponding installation interface, they can be assembled independently, achieving structural decoupling. This effectively avoids the phase deviation, complex fault location, and mechanical linkage problems associated with single-phase faults that are common in three-phase integrated structures, improving assembly accuracy and maintenance convenience. Furthermore, the three-phase independent permanent magnet switchgear provided in this application utilizes nested high-voltage and low-voltage housings to independently encapsulate each permanent magnet circuit breaker within a housing, isolating interference between the independent permanent magnet circuit breakers. The outer circumferential surface of the low-voltage housing where the permanent magnet operating module is located adopts a streamlined structure with continuous curved curvature, which can effectively reduce airflow resistance and airflow noise caused by airflow during operation. The inner circumferential surface of the high-voltage housing where the power circuit module is located adopts a streamlined structure with continuous curved curvature, which can optimize the electric field distribution on the housing surface, reduce the maximum electric field strength on the housing surface, and thus avoid corona discharge caused by local electric field concentration, thereby improving the insulation performance and operational safety of the equipment. Attached Figure Description

[0017] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments thereof.

[0018] Figure 1 This is a schematic diagram of the structure of a three-phase independent permanent magnet switchgear shown in the embodiments of this application.

[0019] Figure 2 This is another structural schematic diagram of a three-phase independent permanent magnet switchgear shown in the embodiments of this application.

[0020] Figure 3 This is a schematic diagram of the permanent magnet circuit breaker shown in the embodiments of this application.

[0021] Figure 4 This is a schematic diagram of the internal structure of a permanent magnet circuit breaker shown in an embodiment of this application.

[0022] Marker explanation:

[0023] 10-Cabinet; 20-Permanent magnet circuit breaker; 11-Installation interface; 21-Low voltage section housing; 22-High voltage section housing; 23-Permanent magnet operating module; 24-Power circuit module; 25-Insulating connecting rod; 231-Moving iron core; 232-Crank arm assembly; 233-Operating spindle; 241-Arc extinguishing chamber; 2321-U-shaped insertion slot; 2322-Transmission arm; 2323-Cylindrical pin. Detailed Implementation

[0024] Preferred embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0025] Three-phase integrated permanent magnet circuit breakers are prone to assembly phase deviations, making fault location difficult in the event of a fault. The mechanical linkage structure causes a single-phase fault to affect the other two phases, which is detrimental to power supply continuity and makes it difficult to adapt to special operating conditions with strong airflow interference.

[0026] To address the aforementioned issues, this application provides a three-phase independent permanent magnet switchgear. The technical solution of this application embodiment is described in detail below with reference to the accompanying drawings.

[0027] Figure 1 This is a schematic diagram of the structure of a three-phase independent permanent magnet switchgear shown in the embodiments of this application. Figure 2This is another structural schematic diagram of a three-phase independent permanent magnet switchgear shown in the embodiments of this application.

[0028] See Figure 1 and Figure 2 The three-phase independent permanent magnet switch cabinet includes a cabinet 10 and three permanent magnet circuit breakers 20. The three permanent magnet circuit breakers 20 correspond to the three phases of the three-phase circuit. Three mounting interfaces 11 are arranged side by side on the inner surface of the cabinet 10 to guide the assembly of the three permanent magnet circuit breakers 20, so that the three permanent magnet circuit breakers 20 are assembled side by side in the cabinet 10 through the mounting interfaces.

[0029] Furthermore, during assembly, the three permanent magnet circuit breakers are fixed to the mounting interface using high-precision guide pins and bolts. This independent structure not only improves assembly accuracy but also facilitates later maintenance and repair. When a permanent magnet circuit breaker corresponding to a certain phase fails, it can be disassembled and replaced individually without disassembling the entire equipment, achieving modular assembly and effectively reducing maintenance costs and downtime.

[0030] In some embodiments, anti-loosening devices, such as anti-loosening nuts, spring washers, and thread-locking adhesive, can be provided at key connection points to prevent loosening of connections under long-term vibration conditions.

[0031] See Figure 3 and Figure 4 In this embodiment, each permanent magnet circuit breaker 20 has an independent permanent magnet operating module 23 and an electrical circuit module 24. The permanent magnet operating module 23 is the core power and position control unit of the permanent magnet circuit breaker 20, which realizes the power output for opening and closing by receiving control commands and transmitting action status. The electrical circuit module 24 is the core execution unit in the permanent magnet circuit breaker 20 that realizes the switching of the power supply circuit. It is a key component for realizing the switching of the circuit and the extinguishing of the fault arc. It receives the mechanical power of the permanent magnet operating module to complete the normal opening and closing of the circuit, and at the same time, it quickly extinguishes the arc and cuts off the fault current in the event of faults such as short circuits, so as to ensure the insulation of the power system and the safety of the equipment.

[0032] Specifically, the permanent magnet operating module 23 includes at least a moving iron core 231, and the power circuit module 24 includes at least an arc-extinguishing chamber 241. The permanent magnet operating module 23, through mechanical transmission and a limiting structure, precisely transmits the linear motion of the moving iron core 231 to the arc-extinguishing chamber 241. After receiving the closing power from the permanent magnet operating module 23, the power circuit module 24 drives the moving conductive end (not shown in the figure) inside the arc-extinguishing chamber 241 to make close contact with the stationary conductive end (not shown in the figure), forming a closed conductive circuit and connecting the power supply side and the load side circuit to achieve power transmission. If the power circuit module 24 receives the opening power, then after receiving the opening power from the permanent magnet operating module 23, the power circuit module 24 drives the moving conductive end inside the arc-extinguishing chamber 241 to quickly separate from the stationary conductive end, cutting off power transmission. In addition, during line short circuits / overloads, the power circuit module 24 quickly extinguishes the arc and prevents arc reignition, cutting off the fault current.

[0033] In practical applications, the permanent magnet operating module also includes a stationary iron core, a permanent magnet, a coil, and inner and outer magnetic yokes. The stationary iron core forms the fixed magnetic poles of the magnetic circuit and works with the moving iron core to form a low magnetic resistance magnetic circuit. When the coil is energized, the magnetic field generated is superimposed on the magnetic field of the permanent magnet, forming a magnetic force that acts on the moving iron core. The moving iron core, as the direct force-bearing body of the magnetic force, converts the magnetic force into linear mechanical power, driving the mechanical components fixed to the moving iron core to move linearly along the axis of the permanent magnet circuit breaker. The inner and outer magnetic yokes enclose the permanent magnet, the coil, and the stationary iron core to form a cavity, guiding the direction of the magnetic field and reducing magnetic leakage.

[0034] Furthermore, the permanent magnet circuit breaker 20 also includes an insulating link 25 and a moving conductive terminal. The insulating link 25 is disposed inside the low-voltage housing 21 and the high-voltage housing 22 and is located at the connection between the two. The moving iron core 231 is connected to the moving conductive terminal through the insulating link 25. The insulating link 25 is used to transmit the power applied to the moving iron core 231 to the moving conductive terminal, so that the moving conductive terminal moves along the axial direction of the permanent magnet circuit breaker 20.

[0035] In permanent magnet circuit breakers, the insulating link is a mechanical transmission and electrical insulation component connecting the permanent magnet operating module and the power circuit module. It undertakes the dual core functions of precise power transmission and high-voltage electrical isolation, serving as the insulating link in the mechanical transmission chain of the permanent magnet circuit breaker. As an example, the insulating link can have the following parts: metal connectors at both ends and an insulating rod body in the middle. The metal connectors are hinged to the moving iron core and the moving conductive end via a ball joint / fisheye hinge structure to compensate for minor coaxiality deviations during assembly and operation. The insulating rod body is the core insulation and load-bearing part and can be used as a high-voltage insulation component.

[0036] Based on the functional differences between the permanent magnet operating module 23 and the power circuit module 24 described above, and using the electrical attributes of the two functional modules as the dividing line, in the permanent magnet circuit breaker 20, the permanent magnet operating module 23 is regarded as the low-voltage section, receiving the signal control voltage used to realize the opening and closing drive and status control; the power circuit module 24 is regarded as the high-voltage section, receiving the rated operating voltage of the power grid.

[0037] Based on the difference in the voltage between the two functional modules mentioned above, the embodiment of this application divides the housing of the permanent magnet circuit breaker into two parts: a low-voltage housing 21 and a high-voltage housing 22. The permanent magnet operating module 23 is located inside the low-voltage housing 21, and the power circuit module 24 is located inside the high-voltage housing 22.

[0038] Understandably, the insulating connecting rod 25 is located at the connection between the low-voltage housing 21 and the high-voltage housing 22, at the boundary between the high-voltage and low-voltage sections of the permanent magnet circuit breaker 20. One end of it is connected to the transmission mechanism in the permanent magnet operating module 23, and the other end is connected to the moving conductive terminal in the arc-extinguishing chamber 241. This achieves lossless power transmission and isolates the electrical connection between the high-voltage and low-voltage sections, preventing high-voltage electricity from being conducted to the permanent magnet operating module and its control system, which could cause equipment short circuits or personal safety accidents.

[0039] Furthermore, in this embodiment of the application, the structure of the low-pressure housing 21 and the high-pressure housing 22 has been optimized for the internal functional modules of the low-pressure housing 21 and the high-pressure housing 22: the curvature of the outer peripheral surface of the low-pressure housing 21 is continuous, and the curvature of the inner peripheral surface of the high-pressure housing 22 is continuous.

[0040] In this embodiment, the core function of the permanent magnet operating module 23 within the low-voltage housing 21 is mechanical transmission. This mechanical transmission is susceptible to environmental vibrations, which can cause deviations in the power transmission path, leading to insufficient opening stroke / insufficient closing overtravel of the moving conductive terminal within the arc-extinguishing chamber. Insufficient opening stroke results in inadequate insulation distance, while insufficient closing overtravel leads to insufficient contact pressure at the conductive terminal, causing overheating and ablation. To address these issues, the low-voltage housing 21 in this embodiment employs a streamlined design with continuous curvature on adjacent areas of its outer periphery. This design reduces the interference and impact of vibrations caused by air disturbances in the external environment on the mechanical transmission chain within the permanent magnet operating module. Furthermore, compared to traditional angular housing structures, it also reduces airflow noise by 10-20 dB.

[0041] In this embodiment, the core function of the power circuit module 24 within the high-voltage housing 22 is to control the on / off state of the power transmission circuit and extinguish fault arcs. Due to the high electric field strength in its location, especially in high-voltage power distribution scenarios, the maximum local surface electric field strength can reach 3kV / mm. Based on this, the high-voltage housing 22 shown in this embodiment, through a streamlined design with continuous curvature in adjacent areas of its inner circumference, optimizes the electric field distribution on the inner surface of the high-voltage housing, reducing the maximum local surface electric field strength to as low as 1.8kV / mm. This effectively avoids corona discharge caused by concentrated local electric fields, improving the insulation performance and operational safety of the permanent magnet circuit breaker.

[0042] Furthermore, given that the moving iron core 231 in the permanent magnet operating module 23 achieves linear motion under the action of electromagnetic force, some embodiments of this application have optimized the inner circumferential surface structure of the low-pressure section housing 21 where the permanent magnet operating module 23 is located: the curvature of adjacent areas on the inner circumferential surface of the low-pressure section housing 21 is continuous. Through the streamlined design of the inner surface of the low-pressure section housing 21, the magnetic field distribution can be optimized, magnetic circuit loss can be reduced, and magnetic field distortion can be reduced, ensuring the stability and power transmission efficiency of the permanent magnet drive chain in the permanent magnet operating module 23.

[0043] In addition, there is a curvature inflection point on the outer peripheral surface of the low-voltage housing 21. At the location of this curvature inflection point, the curvature directions of the regions adjacent to the permanent magnet circuit breaker along the axial direction of the low-voltage housing 21 are opposite, and the absolute value of the curvature increases in the direction from the low-voltage housing 21 to the high-voltage housing 22.

[0044] For ease of understanding, assume that the center of the sphere containing the curved surface at a certain position W on the outer peripheral surface of the low-voltage section housing is O. If the direction from position W to the center O is from the outside of the low-voltage section housing to the inside, then the curvature of the surface at position W is considered positive, and the surface at position W is convex; conversely, it is negative, and the surface at position W is concave. In this embodiment, the curvature of the outer peripheral surface of the low-voltage section housing changes from positive to negative at the curvature inflection point. In other words, along the axial direction of the permanent magnet circuit breaker, the outer peripheral surface of the low-voltage section housing transitions from a convex shape to a concave shape.

[0045] In some embodiments, given that the three permanent magnet circuit breakers 20 are assembled side-by-side in the cabinet, and considering the miniaturization design of the permanent magnet switchgear, the three permanent magnet circuit breakers 20 are compactly arranged in the cabinet to minimize the volume of the permanent magnet switchgear, facilitating installation in a small distribution cabinet. Meanwhile, to ensure sufficient clearance between the three permanent magnet circuit breakers 20 and prevent interference from air vibrations during operation of adjacent permanent magnet circuit breakers, the outer peripheral surface of the low-voltage housing 21 and / or the outer peripheral surface of the high-voltage housing 22 at adjacent positions of the three permanent magnet circuit breakers 20 has a concave shape, thereby providing a certain gap for adjacent permanent magnet circuit breakers and reducing electromagnetic interference between adjacent permanent magnet circuit breakers.

[0046] In some embodiments, the low-pressure housing 21 and the high-pressure housing 22 are each provided with an extended step, and the connection between the two is mutually limited by the extended steps to prevent the low-pressure housing 21 and the high-pressure housing 22 from separating. An elastic sealing ring is provided between the extended steps of the low-pressure housing and the high-pressure housing, which serves two purposes: firstly, to dampen vibrations during the axial movement of the moving iron core, and secondly, to seal the connection between the low-pressure housing and the high-pressure housing.

[0047] In addition, to prevent humid air and dust from entering the permanent magnet switch cabinet and causing the internal components to malfunction due to oxidation, corrosion or foreign object jamming, the cabinet is equipped with a sealed chamber filled with dry gas.

[0048] The above describes ways to improve the performance of permanent magnet circuit breakers by optimizing the housing structure. In other embodiments, the performance of permanent magnet circuit breakers can also be optimized by optimizing the housing material.

[0049] In this embodiment, the low-voltage housing and the high-voltage housing are injection molded using modified polymer synthetic materials. The modified polymer synthetic material uses polyhexamethylene adipamide (PA66) as the base material and undergoes composite modification treatment by adding glass fiber reinforcement, halogen-free flame retardant, and environmentally friendly toughening agent. The modified polymer synthetic material meets the following characteristics: tensile strength ≥ 80 MPa, impact strength ≥ 15 kJ / m², and breakdown field strength ≥ 20 kV / mm, which can meet the stringent operating requirements of high-voltage electrical equipment.

[0050] Furthermore, the glass fiber reinforcement uses an epoxy-based silane coupling agent, such as silane coupling agent KH560. PA66 is a polar crystalline resin with hygroscopic properties. The epoxy groups in KH560 undergo a ring-opening reaction with the amide bonds of PA66 to form chemical bonds, resulting in strong interfacial bonding. This improves tensile strength and impact strength while reducing interfacial voids. Since interfacial voids reduce the breakdown field strength, the composite of KH560 and PA66 can ensure the shell's breakdown resistance by reducing interfacial voids, while also taking into account mechanical and electrical properties.

[0051] Halogen-free flame retardants can be one or more of the following materials: phosphorus-based flame retardants, silicone-based flame retardants, and phosphorus-nitrogen composite flame retardants. Taking phosphorus-nitrogen composite flame retardants as an example, a flame retardant can be obtained by compounding melamine polyphosphate (MPP) and melamine cyanurate (MCA) in a ratio of 1:1 to 1:1.5. MPP and MCA have high-temperature resistance and good compatibility with PA66. MPP is a hydrophobic material that can improve the moisture absorption properties of PA66.

[0052] Environmentally friendly toughening agents can be grafted to ensure compatibility with PA66, such as maleic anhydride grafted POE (POE-g-MAH). The grafting rate of POE-g-MAH ranges from 1.0% to 1.3MA%, exhibiting good compatibility with PA66. The resulting interfacial bonding after reacting with the amide bonds of PA66 is strong, and it can reduce the water absorption of the PA66 substrate and enhance the bond between the glass fiber and the substrate. This toughening effect does not reduce rigidity or electrical properties.

[0053] For environmental reasons, modified polymer synthetic materials do not contain heavy metals such as lead, mercury, and cadmium, and can be recycled through pyrolysis after disposal to meet the requirements of RoHS environmental directives and green manufacturing and sustainable development.

[0054] The above describes the structure of a three-phase independent permanent magnet switchgear that automatically controls opening and closing via a control circuit. In some embodiments, the three-phase independent permanent magnet switchgear also has a manual opening and closing mechanism to meet the opening and closing operation requirements in emergency situations.

[0055] See Figure 4 In this embodiment, the permanent magnet operating module 23 includes a manual opening and closing mechanism. This mechanism includes at least a crank arm assembly 232 and an operating spindle 233. The operating spindle 233 is movably connected to the moving iron core 231 via the crank arm assembly 232, allowing the operating spindle 233 to drive the moving iron core 231 to move axially along the permanent magnet circuit breaker 20. Furthermore, the operating spindle 233 is connected to an external transmission mechanism outside the permanent magnet circuit breaker. The operator drives the operating spindle 233 through this external transmission mechanism. Under the drive of the operating spindle 233, the crank arm assembly 232 moves the moving iron core 231, thereby causing the moving conductive end of the other end of the insulating connecting rod 25 to perform the opening and closing operation.

[0056] As an example, the crank arm assembly 232 and the operating spindle 233 are fixedly supported by a shaft system formed by deep groove ball bearings, and an inter-shaft angular transmission connection is formed between the crank arm assembly 232 and the operating spindle 233 by a universal joint. The universal joint connection can compensate for minor coaxiality errors generated during assembly, ensuring smooth power transmission. By using the rolling friction of deep groove ball bearings to replace the sliding friction in traditional transmission mechanisms, the mechanical friction coefficient during the opening and closing process can be reduced from 0.3-0.5 to 0.001-0.003, thus reducing the mechanical resistance of the opening and closing operation.

[0057] The crank arm assembly 232 includes a U-shaped insertion groove 2321 and a transmission arm 2322. The first end of the transmission arm 2322 is provided with a cylindrical pin 2323 that matches the U-shaped insertion groove 2321, and the second end is connected to the operating spindle 233. The opening direction of the U-shaped insertion groove 2321 is perpendicular to the axial direction of the permanent magnet circuit breaker. The open side of the U-shaped insertion groove 2321 is slidably connected to the cylindrical pin 2323, and the closed side of the U-shaped insertion groove 2321 is fixed on the moving iron core 231.

[0058] Driven by the main shaft 233, the second end of the transmission arm 2322 drives the first end of the transmission arm 2322 to rotate, causing the cylindrical pin 2323 to produce axial and perpendicular displacement. While the cylindrical pin 2323 slides in the U-shaped insertion groove 2321, it drives the U-shaped insertion groove 2321 and the moving iron core 231 fixed thereto to move.

[0059] In practical applications, after the operator drives the operating spindle through the external transmission mechanism, the torque is transmitted across the angle from the operating spindle to the transmission arm under the action of the universal joint. As the transmission arm rotates, the cylindrical pin at one end of the transmission arm simultaneously generates displacement in the axial direction of the permanent magnet circuit breaker and in the direction perpendicular to the axial direction. The displacement in the direction perpendicular to the axial direction corresponds to the position generated by the cylindrical pin sliding in the U-shaped insertion groove. Due to the limiting effect of the groove sidewall of the U-shaped insertion groove on the cylindrical pin, the axial movement of the cylindrical pin will drive the U-shaped insertion groove to move in the axial direction of the permanent magnet circuit breaker, which in turn drives the moving iron core fixed to the U-shaped insertion groove to move in the axial direction of the permanent magnet circuit breaker, thereby driving the moving conductive end at the other end of the insulating connecting rod to perform the opening and closing operation.

[0060] Furthermore, the bearing mating surfaces of the deep groove ball bearing are coated with grease that meets the following conditions: dropping point ≥ 230℃, pour point ≤ -60℃, and / or viscosity-temperature index ≥ 140. This grease maintains stable lubrication performance within a temperature range of -40℃ to 120℃, preventing lubrication failure due to temperature changes.

[0061] For example, the grease uses a compound system of polyalphaolefin-polyol ester base oil, compound lithium-based thickener and insulating additive.

[0062] The polyalphaolefin-polyol ester composite base oil uses a compounding system with polyalphaolefin (PAO) as the main component and polyol ester as the auxiliary component. The compounding ratio of polyol ester to PAO ranges from 2:8 to 3:7. PAO has a viscosity-temperature index (VI) ≥ 135, maintains low viscosity even at -40℃, has low evaporation loss at 120℃, and exhibits good chemical stability. PAO has a pour point ≤ -60℃ and excellent low-temperature fluidity.

[0063] Thickeners can be either complex lithium-based thickeners or polyurea thickeners. In practical applications, complex lithium-based thickeners are preferred. Complex lithium-based thickeners are composed of lithium 12-hydroxystearate and sebacic acid / azelic acid, which significantly improves the dropping point of the grease and provides excellent water resistance, rust prevention, and corrosion protection. Furthermore, complex lithium-based greases maintain good colloidal stability and fluidity at low temperatures, effectively enhancing the lubrication performance of the grease in both high and low temperature environments.

[0064] Insulating additives can effectively fill the microscopic gaps in the grease matrix, forming a barrier that hinders the passage of current, ensuring that it does not conduct electricity under high voltage conditions. They can also enhance the grease's resistance to oxidation, aging, and weak acids and alkalis, enabling it to maintain stable insulation properties and physical form, thereby extending the service life of permanent magnet circuit breakers in high-voltage power distribution scenarios.

[0065] The compound system of ester oil and lithium complex has good compatibility with PA66 material and can effectively avoid the swelling and cracking problems of PA66 material caused by additives in grease.

[0066] By improving the type of frictional resistance and using lubricating grease, the maximum resistance of the opening and closing operation of the permanent magnet circuit breaker can be controlled within 50N, ensuring an operation response delay of ≤1ms and stabilizing the opening time within the range of 4.2-4.8ms. This significantly improves the speed and reliability of fault current interruption and provides a strong guarantee for the rapid clearing of power grid faults.

[0067] Anti-loosening devices, such as anti-loosening nuts, spring washers, and thread locking adhesive, are installed at key connection points of the permanent magnet drive chain in the permanent magnet operating module to prevent the structure in the drive chain from becoming loose under long-term vibration conditions, thus affecting the stability and safety of the transmission process.

[0068] The solution of this application has been described in detail above with reference to the accompanying drawings. In the above embodiments, the descriptions of each embodiment have different emphases; parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments. Those skilled in the art should also understand that the actions and modules involved in the specification are not necessarily essential to this application. Furthermore, it is understood that the steps in the method of this application embodiment can be adjusted, combined, and deleted according to actual needs, and the modules in the device of this application embodiment can be combined, divided, and deleted according to actual needs.

[0069] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A three-phase self-contained permanent magnet switchgear, characterized by, include: The cabinet (10) has three mounting interfaces (11) arranged side by side on its inner surface. Three permanent magnet circuit breakers (20) are installed side by side in the cabinet (10) through the mounting interface (11) for the three phases of the three-phase circuit. The permanent magnet circuit breaker (20) includes: a low-voltage housing (21), the curvature of the outer peripheral surface of the low-voltage housing (21) is continuous, the curvature of the inner peripheral surface of the low-voltage housing (21) is continuous, the outer peripheral surface of the low-voltage housing (21) has a curvature inflection point, at the location of the curvature inflection point, the curvature directions of the regions adjacent to the permanent magnet circuit breaker axis on the outer peripheral surface of the low-voltage housing (21) are opposite, and the absolute value of the curvature increases in the direction from the low-voltage housing (21) to the high-voltage housing (22); The high-pressure housing (22) has one end fitted onto the outer circumferential surface of the low-pressure housing (21), and the curvature of the inner circumferential surface of the high-pressure housing (22) is continuous. A permanent magnet operating module (23) includes at least a moving iron core (231), and the permanent magnet operating module (23) is disposed inside the low-pressure housing (21); The power circuit module (24) includes at least an arc-extinguishing chamber (241), and the power circuit module (24) is disposed inside the high-voltage housing (22).

2. The three-phase self-contained permanent magnet switchgear according to claim 1, characterized in that, At adjacent positions of the three permanent magnet circuit breakers (20), the outer peripheral surface of the low-voltage housing (21) and / or the outer peripheral surface of the high-voltage housing (22) have a concave shape.

3. The three-phase self-contained permanent magnet switchgear according to claim 1, characterized in that, The low-pressure housing (21) and the high-pressure housing (22) are injection molded from modified polymer synthetic materials; The modified polymer synthetic material uses polyhexamethylene adipamide as the base material and undergoes composite modification treatment by adding glass fiber reinforcing agent, halogen-free flame retardant and environmentally friendly toughening agent; The modified polymer synthetic material meets the following characteristics: tensile strength ≥ 80 MPa, impact strength ≥ 15 kJ / m², and breakdown field strength ≥ 20 kV / mm.

4. The three-phase self-contained permanent magnet switchgear according to claim 1, characterized in that, The permanent magnet operating module (23) includes: a manual opening and closing mechanism, which includes at least a crank arm assembly (232) and an operating spindle (233). The operating spindle (233) is movably connected to the moving iron core (231) through the crank arm assembly (232), so that the operating spindle (233) can drive the moving iron core (231) to move along the axial direction of the permanent magnet circuit breaker (20).

5. The three-phase self-contained permanent magnet switchgear according to claim 4, characterized in that, The crank arm assembly (232) and the operating spindle (233) are fixedly supported by a shaft system through a deep groove ball bearing, and the crank arm assembly (232) and the operating spindle (233) are connected by an inter-shaft angle transmission through a universal joint.

6. The three-phase self-contained permanent magnet switchgear according to claim 1, characterized in that, The permanent magnet circuit breaker also includes: an insulating connecting rod (25) and a moving conductive terminal; The insulating link (25) is disposed inside the low-voltage housing (21) and the high-voltage housing (22) and located at the connection between them. The moving iron core (231) is connected to the moving conductive end through the insulating link (25). The insulating link (25) is used to transmit the power applied to the moving iron core (231) to the moving conductive end, so that the moving conductive end moves along the axial direction of the permanent magnet circuit breaker (20).

7. The three-phase self-contained permanent magnet switchgear according to claim 4, characterized in that, The crank arm assembly (232) includes: a U-shaped insertion slot (2321) and a transmission arm (2322); The first end of the transmission arm (2322) is provided with a cylindrical pin (2323) that matches the U-shaped insertion groove (2321), and the second end is connected to the operating spindle (233). The opening direction of the U-shaped plug groove (2321) is perpendicular to the axial direction of the permanent magnet circuit breaker. The open side of the U-shaped plug groove (2321) is slidably connected to the cylindrical pin (2323). The closed side of the U-shaped plug groove (2321) is fixed on the moving iron core (231). Driven by the operating spindle (233), the second end of the transmission arm (2322) drives the first end of the transmission arm (2322) to rotate, causing the cylindrical pin (2323) to produce axial and perpendicular displacement. While the cylindrical pin (2323) slides in the U-shaped insertion groove (2321), it drives the U-shaped insertion groove (2321) and the moving iron core (231) fixed thereto to move.

8. The three-phase self-contained permanent magnet switchgear of claim 5, wherein, The bearing mating parts of the deep groove ball bearing are coated with grease, and the grease meets the following conditions: dropping point ≥ 230℃, pour point ≤ -60℃ and / or viscosity-temperature index ≥ 140.

9. The three-phase self-contained permanent magnet switchgear according to claim 1, characterized in that, An elastic sealing ring is provided at the connection between the low-pressure housing (21) and the high-pressure housing (22); The interior of the cabinet (10) is a sealed chamber filled with dry gas.

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