Load switch and ring main unit

Abstract

The application belongs to the technical field of ring main units, and particularly relates to a load switch and a ring main unit. The load switch comprises a fixed support assembly, a switching-on assembly and an electric field shielding assembly. The fixed support assembly comprises a fixed plate, a static end electrically conductive part and a dynamic end electrically conductive part. The static end electrically conductive part and the dynamic end electrically conductive part are arranged on the fixed plate along a first direction. The surface of the fixed plate is provided with protruding ribs. The switching-on assembly comprises a dynamic contact bridge part and a driving part. The dynamic contact bridge part moves along the first direction under the driving of the driving part to have a first position in contact with the static end electrically conductive part to switch on a circuit and a second position separated from the static end electrically conductive part to switch off the circuit. The electric field shielding assembly comprises a static end shielding cover covering the connection part of the static end electrically conductive part and the fixed plate and a dynamic end shielding cover covering the connection part of the dynamic end electrically conductive part and the fixed plate. The application realizes high insulation reliability of the load switch in a compact volume and is suitable for reducing the use of SF6 gas by using environment-friendly gas.

Description

Technical Field

[0001] This application belongs to the field of ring main unit technology, specifically relating to a load switch and a ring main unit. Background Technology

[0002] Ring main units (RNBs) are key equipment in power distribution networks, undertaking the core functions of power distribution, control, and protection. They are widely used in urban power grids, industrial and mining enterprises, and renewable energy access points, and their reliability directly affects the continuity and quality of regional power supply. Among them, load switches are the core components for realizing line connection and disconnection, load switching, and grounding protection.

[0003] To meet the requirements of compact structure and high insulation performance of ring main units, existing technologies generally fill the insulation cavity of load switches with sulfur hexafluoride (SF6) gas. Due to its excellent insulation and arc-extinguishing properties, SF6 gas can effectively withstand 24kV operating voltage and fault current in a small space, making it a key technology for miniaturizing load switches.

[0004] However, SF6 is a strong greenhouse gas, and its application faces severe environmental pressure. Therefore, in order to reduce the use of SF6 gas, the development of environmentally friendly switchgear has begun. However, load switches in related technologies generally have inherent defects such as large size, uneven electric field distribution, and low insulation reliability. After switching to environmentally friendly insulating media, their performance is difficult to meet the insulation strength requirements at the 24kV voltage level, which seriously restricts the miniaturization development of environmentally friendly switchgear. Utility Model Content

[0005] The purpose of this application is to solve the technical problem in the related technology that the load switch cannot meet the insulation strength requirements under the 24kV voltage level after the use of environmentally friendly insulating medium.

[0006] This application provides a load switch, comprising: a fixed support assembly including a fixed plate, a stationary conductive element, and a moving conductive element, wherein the stationary conductive element and the moving conductive element are spaced apart on the fixed plate along a first direction, and the surface of the fixed plate has protruding ribs; a switching assembly including a moving contact bridge and a driving component, wherein the moving contact bridge moves along the first direction under the drive of the driving component to have a first position of contacting the stationary conductive element to connect the circuit, and a second position of separating from the stationary conductive element to disconnect the circuit; and an electric field shielding assembly including a stationary shielding cover at the connection between the stationary conductive element and the fixed plate, and a moving shielding cover at the connection between the moving conductive element and the fixed plate.

[0007] In an exemplary embodiment of this application, the driving component includes a guide rod extending in the first direction, and the movable contact bridge is movably sleeved on the guide rod and is capable of linear reciprocating motion along the axial direction of the guide rod.

[0008] In one exemplary embodiment of this application, the driving component further includes an operating shaft and a transmission member. The operating shaft extends along a second direction, which intersects with the first direction. The operating shaft is connected to the moving contact bridge member via the transmission member to convert rotational motion into linear motion of the moving contact bridge member.

[0009] In one exemplary embodiment of this application, the connection component further includes a crossbeam extending along the second direction, and the guide rod is fixed to the crossbeam.

[0010] In one exemplary embodiment of this application, the surface of the crossarm has protruding ribs, and a plurality of the ribs are arranged at intervals in the second direction.

[0011] In one exemplary embodiment of this application, both the stationary end shield and the moving end shield are arc-shaped covers.

[0012] In one exemplary embodiment of this application, the stationary conductive element and the moving conductive element are respectively connected to the fixed plate by fasteners, and the stationary shield and the moving shield cover the respective fasteners.

[0013] In one exemplary embodiment of this application, the fixing plate includes a first fixing structure and a second fixing structure, the first fixing structure and the second fixing structure are parallel to each other and spaced apart, and the stationary end conductive element and the moving end conductive element are sandwiched between the first fixing structure and the second fixing structure.

[0014] A second aspect of this application provides a ring main unit, comprising: a grounding switch; and a load switch as described in any of the preceding claims, wherein the grounding stationary terminal of the grounding switch is electrically connected to the moving conductive component of the load switch via a connecting conductor.

[0015] In one exemplary embodiment of this application, a shield is provided on the outer periphery of both the grounding moving end and the grounding stationary end of the grounding switch.

[0016] The load switch and ring main unit proposed in this application have at least the following beneficial effects: The load switch of this application includes a fixed support assembly, a switching assembly, and an electric field shielding assembly. The fixed support assembly includes a fixed plate and a stationary conductive element and a moving conductive element disposed on the fixed plate. The switching assembly includes a moving contact bridging element and a driving component. The moving contact bridging element moves along a first direction under the drive of the driving component to bridge or separate the stationary conductive element and the moving conductive element. The electric field shielding assembly includes a stationary shielding cover disposed at the connection between the stationary conductive element and the fixed plate, and a moving shielding cover disposed at the connection between the moving conductive element and the fixed plate. By integrating the stationary and moving conductive components onto a ribbed fixed plate and employing a direct-acting connection assembly, a compact and miniaturized structure is achieved. A shield precisely positioned at the connection point between the conductive components and the fixed plate effectively homogenizes high electric field areas. The ribs on the fixed plate extend the creepage distance, and the shield optimizes the electric field; together, they form a double insulation guarantee. This allows the load switch to simultaneously meet the stringent requirements of miniaturization and high insulation reliability by using only environmentally friendly insulating media such as dry air or nitrogen, without requiring sulfur hexafluoride (SF6) gas.

[0017] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part by practice of this application.

[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0020] Figure 1 Schematic diagrams of load switches and grounding switches provided in some embodiments are shown.

[0021] Figure 2 A schematic diagram of the structure of the fixing plate provided in some embodiments is shown.

[0022] Figure 3 A schematic diagram of the load switch in the closed state provided in some embodiments is shown.

[0023] Figure 4 A schematic diagram of the load switch in the open state provided in some embodiments is shown.

[0024] Figure 5 A schematic diagram of the crossarm provided in some embodiments is shown.

[0025] Figure 6 A front view schematic diagram of the load switch and grounding switch provided in some embodiments is shown.

[0026] Figure 7 Structural schematic diagrams of the cabinets provided in some embodiments are shown.

[0027] Explanation of reference numerals in the attached figures: 10. Ring main unit; 100. Load switch; 110. Fixed support assembly; 111. Fixing plate; 111a. First fixing structure; 111b. Second fixing structure; 1110. Rib; 112. Stationary conductive component; 113. Moving conductive component; 120. Connecting assembly; 121. Moving contact bridge component; 122. Drive component; 1220. Guide rod; 1221. Operating shaft; 1222. Transmission component; 123. Crossarm; 1230. Rib; 131. Stationary shielding cover; 132. Moving shielding cover; 200, Cabinet; 300, Grounding switch; 310, Grounding moving end; 320, Grounding stationary end; 330, Support plate; 340, First shielding plate; 350, Second shielding plate; 360, Connecting conductor. Detailed Implementation

[0028] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0029] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0030] In this application, unless otherwise expressly specified and limited, the terms "assembly," "connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0031] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0032] See Figure 1 As shown, this application provides a load switch 100, which can adopt a modular structure design. It includes a fixed support component 110, a connection component 120 and an electric field shielding component. Through optimized cooperation between the components, high insulation reliability is achieved in a compact space.

[0033] In some embodiments, see Figure 1 and Figure 2 As shown, the fixed support assembly 110 constitutes the mechanical support and insulation base of the entire switch. The fixed support assembly 110 may include a fixing plate 111. The fixing plate 111 may be integrally molded from epoxy resin or unsaturated polyester molding compound through a molding process. This material not only has excellent insulation properties, but also has sufficient mechanical strength to withstand the mechanical stress generated during switch operation.

[0034] In some embodiments, see Figures 1 to 4 As shown, the fixed support assembly 110 may further include a stationary conductive element 112 and a moving conductive element 113. The stationary conductive element 112 and the moving conductive element 113 are fixed to the fixed plate 111 at intervals along a first direction X (i.e., the vertical direction). In actual installation, the first direction X usually corresponds to the vertical direction. This arrangement is beneficial for using gravity to assist in the tripping operation and also facilitates the arrangement of electrical connections. The spacing between the two conductive elements must ensure sufficient insulation distance while also taking into account the overall size limitations of the switch.

[0035] In some embodiments, see Figure 2 As shown, the surface of the fixing plate 111 has protruding ribs 1110. The ribs 1110 are designed with a specific geometry, such as a ring structure.

[0036] In some embodiments, the rib 1110 may be integrally formed with the fixing plate 111 and protrude from the surface of the fixing plate 111. The height of the rib 1110 may be between 3-8 mm, the width between 2-5 mm, and the spacing between adjacent ribs 1110 may be between 10-20 mm, so as to maximize the creepage distance within a limited space. For example, the height of the rib 1110 may be 5 mm, the width may be 3 mm, and the spacing between adjacent ribs 1110 may be 15 mm.

[0037] By integrating the stationary conductive element 112 and the moving conductive element 113 onto the same fixed plate 111, a compact structure is achieved. The ribs 1110 on the surface of the fixed plate 111 not only significantly extend the creepage distance by increasing the surface area, but also enhance the mechanical strength of the component, enabling it to better withstand the impact of electrodynamic forces and mechanical vibrations. This design increases the creepage distance ratio from 12 mm / kV in related technologies to 18 mm / kV, far exceeding the standard requirement of 14 mm / kV for the 24 kV voltage level, laying a solid structural foundation for improving overall insulation performance.

[0038] In some embodiments, see Figure 1 and Figure 3 As shown, the switching assembly 120 includes a moving contact bridge 121 and a driving component 122. The moving contact bridge 121 can be made of a copper alloy material with high conductivity. Its structure is cylindrical, and its inner wall is precision machined to ensure good contact with the stationary conductive element 112. Under the drive of the driving component 122, the moving contact bridge 121 moves precisely in a first direction X, so that it has a first position (i.e., closed state) to contact the stationary conductive element 112 to connect the circuit, and a second position (i.e., open state) to separate from the stationary conductive element 112 to disconnect the circuit.

[0039] Understandably, adopting a direct-acting switching scheme in a single direction offers advantages such as a short transmission path, precise operation, and no lateral force interference. This design effectively reduces contact wear during closing and opening processes, extending electrical life. Furthermore, the direct-acting structure is more compact than the rotary structure in related technologies, making a crucial contribution to the overall miniaturization of the switch.

[0040] For example, the overall volume of the load switch 100 using this structure is reduced by more than 20% compared to related circuit breaker solutions.

[0041] In some embodiments, see Figure 1As shown, the electric field shielding assembly includes a stationary shield 131 and a moving shield 132. The stationary shield 131 is fixed by stainless steel clips or corrosion-resistant bolts and completely covers the connection between the stationary conductive element 112 and the fixing plate 111. Similarly, the moving shield 132 is also fixedly covered at the connection between the moving conductive element 113 and the fixing plate 111 in the same manner.

[0042] By precisely shielding the connection area between the conductive component and the fixed plate 111, the electric field concentration phenomenon caused by structural abrupt changes such as bolts and sharp corners is effectively eliminated. The smooth arc-shaped surface of the shielding cover evenly disperses the strong electric field, making the electric field distribution more uniform. After installing the shielding component, the maximum electric field strength on the surface of the stationary conductive component 112 and the moving conductive component 113 of the load switch 100 can be reduced to below 3kV / mm, which fully meets the insulation requirements of dry air at a voltage level of 24kV and solves the partial discharge problem when using environmentally friendly gas insulation.

[0043] In some embodiments, the shielding cover may be made of aluminum alloy, and its surface may be specially anodized to enhance arc resistance. Its thickness is between 1-2 mm, which ensures sufficient mechanical strength while achieving a lightweight design.

[0044] Understandably, the ribs 1110 on the surface of the fixed plate 111 greatly enhance the insulating components' ability to resist surface flashover, enabling them to effectively block leakage current formed along the insulating surface in harsh environments such as humidity and dirt. This characteristic perfectly compensates for the low insulation strength of environmentally friendly insulating media such as dry air and nitrogen, and together with the electric field shielding components, it forms a dual guarantee of body insulation and surface insulation. This allows the load switch 100 to achieve a compact design while eliminating SF6 gas and maintaining high reliability.

[0045] Furthermore, during the circuit breaker tripping process, dry air or nitrogen can effectively extinguish the arc through a self-powered air-blowing principle. The extremely high energy of the electric arc instantly heats and ionizes the surrounding environmentally friendly gas, causing it to rapidly expand and form high pressure within the sealed arc chamber. This high pressure drives a high-speed airflow to be directionally ejected along a direct-acting "pipe-casing" structure, powerfully cooling, elongating, and dispersing the arc plasma, while simultaneously introducing a cold medium to promote deionization. This synergistic effect of combining arc energy utilization with mechanical structural reinforcement enables ordinary environmentally friendly gases to reliably extinguish arcs generated by load currents, successfully replacing SF6 gas.

[0046] In some embodiments, see Figure 3 As shown, the drive component 122 may include a guide rod 1220. The guide rod 1220 may be made of stainless steel and its surface is precision ground to ensure straightness and surface finish.

[0047] In some embodiments, the guide rod 1220 extends in the first direction X (vertical direction), and its length can be precisely designed according to the travel requirements of the switch, for example, 100 mm, 120 mm, or 150 mm. The moving contact bridge 121 is movably sleeved on the guide rod 1220 via a bearing or a self-lubricating bushing, so that it can perform linear reciprocating motion along the axial direction of the guide rod 1220.

[0048] In some embodiments, the installation position of the guide rod 1220 needs to ensure that the moving contact bridge 121 remains aligned with the stationary conductive element 112 during movement. The diameter of the guide rod 1220 can be designed according to the force conditions, for example, it can be 8mm, 10mm, 12mm or 15mm, so as to ensure sufficient rigidity and avoid excessive movement resistance.

[0049] Understandably, the guide rod 1220 provides precise guidance and support for the moving contact bridge component 121, ensuring its straightness and stability during closing and opening. The guide rod 1220 effectively prevents the moving contact bridge component 121 from skewing or jamming during movement, thus ensuring accurate and reliable contact with the stationary conductive component 112. Furthermore, this guide rod 1220 significantly improves contact quality, avoiding excessive temperature rise or arc erosion caused by poor contact, and extending the switch's service life.

[0050] In some embodiments, see Figure 1 As shown, the drive component 122 may further include an operating shaft 1221 and a transmission component 1222. The operating shaft 1221 may be made of alloy structural steel and its surface is hardened to improve wear resistance. The operating shaft 1221 extends along a second direction Y (i.e., the front-to-back direction), which intersects perpendicularly with the first direction X (i.e., the up-down direction). This orthogonal arrangement makes full use of three-dimensional space and optimizes the overall structural layout of the switch.

[0051] In some embodiments, the operating shaft 1221 is connected to the moving contact bridge 121 via a transmission member 1222. The transmission member 1222 can take various forms such as a linkage mechanism, a gear and rack mechanism, or a cam mechanism.

[0052] For example, the transmission element 1222 can be a rocker arm linkage mechanism. The transmission element 1222 includes a rocker arm fixedly connected to the operating shaft 1221 and a push rod connected to the moving contact bridge 121. The length and angle design of the rocker arm can ensure that the rotational motion of the operating shaft 1221 is efficiently converted into the linear motion of the moving contact bridge 121.

[0053] In some embodiments, the end of the operating shaft 1221 is provided with an operating interface, which can be connected to a manual operating mechanism or an electric operating mechanism.

[0054] For example, in manual operation, the operating shaft 1221 is driven to rotate by rotating the handle. In electric operation, the operating shaft 1221 is driven to rotate by a motor reduction mechanism. The rotation angle of the operating shaft 1221 is typically designed to be 90° or 180°, corresponding to the fully open and closed positions of the moving contact bridge connector 121.

[0055] By decoupling the power input direction (second direction Y) from the contact movement direction (first direction X) through the operating shaft 1221 and the transmission component 1222, the drive mechanism can be flexibly arranged in the optimal position of the switch, optimizing the internal space utilization of the switch. This arrangement is particularly advantageous for achieving lateral arrangement within the narrow-body ring main unit 10, further supporting the miniaturization design of the equipment. Simultaneously, the conversion of rotary motion into linear motion results in smoother operating torque, lower operating force, and improved controllability and reliability of operation.

[0056] In some embodiments, see Figure 1 As shown, the switching assembly 120 may further include a crossarm 123. The crossarm 123 may be made of the same insulating material as the fixing plate 111 and integrally molded using a molding process. The crossarm 123 extends along the second direction Y (i.e., the front-to-back direction), and its length is determined according to the overall width of the switch, for example, 200mm, 260mm, or 300mm. Both ends of the crossarm 123 are fixed to the switch's support frame using high-strength insulating bolts, forming a stable support structure.

[0057] In some embodiments, the guide rod 1220 can be fixed to the crossarm 123 by a clamp with an anti-loosening design to ensure that it will not loosen under long-term vibration. The crossarm 123 is provided with multiple mounting holes to facilitate adjustment of the installation position of the guide rod 1220 according to different specifications of switches. The crossarm 123 can adopt an I-shaped or box-shaped structure to minimize weight while ensuring sufficient rigidity.

[0058] The crossarm 123 provides a stable mounting base for the guide rod 1220, enhancing the structural rigidity and stability of the entire moving-side actuator assembly. This design allows the switch to maintain structural integrity and prevent component deformation or damage when subjected to the enormous electrodynamic impact of short-circuit current. The insulating properties of the crossarm 123 also provide an inter-phase insulation barrier, further enhancing the switch's insulation performance.

[0059] In some embodiments, see Figure 1 and Figure 5As shown, the surface of the crossarm 123 has protruding ribs 1230. These ribs 1230 can be manufactured using a process that integrally forms the crossarm 123 body, ensuring the integrity of the structure and its mechanical strength. Multiple ribs 1230 are arranged at intervals in the second direction Y. The height of the ribs 1230 can be 3-6 mm, the width can be 2-4 mm, and the spacing between adjacent ribs 1230 is 8-15 mm. The orientation of the ribs 1230 can be optimized according to the electric field distribution, adopting different forms such as straight lines, wavy lines, or serrated lines.

[0060] For example, the height of the rib 1230 can be 4mm, the width can be 3mm, and the spacing between adjacent ribs 1230 can be 10mm.

[0061] It should be noted that the cross-sectional shape of the rib 1230 can be specially designed, with a rounded transition at the top to avoid creating new electric field concentration points. The arrangement density of the rib 1230 is adjusted according to the differences in electric field strength at various parts of the crossarm 123. The density of the rib 1230 is appropriately increased in areas with higher electric field strength and appropriately decreased in areas with lower electric field strength to achieve optimal material utilization.

[0062] In addition, the design of the raised rib 1230 can reduce the electric field intensity on the surface of the crossarm 123, effectively preventing the occurrence of surface flashover.

[0063] Understandably, the raised ribs 1230 on the surface of the crossarm 123 and the ribs 1110 on the fixing plate 111 work together to enhance its mechanical strength and further extend the insulation creepage distance. This double insulation barrier design significantly improves the insulation redundancy and operational reliability of the switch.

[0064] In some embodiments, see Figure 1 As shown, both the stationary end shield 131 and the moving end shield 132 are arc-shaped covers adapted to the shape of the corresponding conductive components. The shields can adopt a composite curved surface design, including a combination of spherical, cylindrical, and transitional curved surfaces. The radius of curvature of the shield can be determined according to the electric field strength at its location, with a larger radius of curvature used in high electric field regions and a smaller radius of curvature used in low electric field regions.

[0065] It should be noted that the edges of the shielding cover can use a large rounded transition, with a radius of not less than 3mm, to avoid electric field concentration at the edges. The opening size of the shielding cover must ensure complete coverage of the area to be shielded while avoiding interference with moving parts. The wall thickness of the shielding cover should be uniformly distributed to ensure uniform electric field distribution.

[0066] Understandably, the optimized arc-shaped shielding design minimizes the formation of new electric field concentration points within the shield itself, ensuring optimal electric field optimization. This streamlined structure not only improves the electric field distribution but also facilitates placement in a compact space, reducing the overall size of the switch. With this shielding design, the switch's power frequency withstand voltage and lightning impulse withstand voltage under dry air insulation conditions fully meet the insulation requirements for the 24kV voltage level.

[0067] In some embodiments, the stationary conductive element 112 and the moving conductive element 113 are respectively connected to the fixed plate 111 by stainless steel fasteners. The fasteners may employ an anti-loosening design, including nuts with locking function and anti-loosening washers, to ensure the reliability of the connection under long-term vibration environment. The material and surface treatment of the fasteners are matched with the conductive elements to avoid electrochemical corrosion caused by material differences.

[0068] In some embodiments, the fasteners can be installed symmetrically to ensure uniform stress. Each conductive component typically uses 4-6 fasteners, with the tightening torque strictly controlled according to process requirements to ensure sufficient contact pressure without damaging the insulation material. The fastener heads are countersunk to reduce installation height and facilitate the installation of the shielding cover.

[0069] In some embodiments, the design dimensions of the stationary end shield 131 and the moving end shield 132 ensure that they completely cover their respective fastener mounting locations. The mating gap between the shield and the conductive component can be controlled within the range of 0.5-1mm, which ensures both ease of installation and avoids excessive gaps that could affect the shielding effect.

[0070] Understandably, by using the stationary end shield 131 and the moving end shield 132 to shield the metal fasteners such as bolt heads and nuts that are most prone to electric field concentration, the potential discharge points are reduced. The design of the stationary end shield 131 and the moving end shield 132 allows the switch to maintain stable insulation performance even after long-term operation.

[0071] In some embodiments, see Figure 1 As shown, the fixing plate 111 may include a first fixing structure 111a and a second fixing structure 111b. Both the first fixing structure 111a and the second fixing structure 111b can be made of the same material and have the same structure. They are parallel to each other and spaced apart, with the spacing determined according to the size of the conductive component and insulation requirements, for example, 30mm, 40mm, or 50mm. The two fixing structures can be connected by reinforcing ribs to form a stable frame structure.

[0072] The stationary conductive element 112 and the moving conductive element 113 are clamped and fixed between the first fixing structure 111a and the second fixing structure 111b by fasteners. This sandwich structure ensures that the conductive elements are subjected to uniform clamping force, avoiding stress concentration that may occur with unilateral fixing.

[0073] Understandably, the mounting plate 111 has mounting flanges around its perimeter to facilitate the installation of the entire load switch 100 onto the switch cabinet frame. The mounting flanges have multiple mounting holes, which can be designed as elongated holes to facilitate position adjustment during installation.

[0074] Furthermore, this sandwich structure makes the installation of conductive components more secure and able to withstand greater electrodynamic impacts. At the same time, the structure itself increases the complexity of the insulation path, objectively extending the creepage distance and providing a strong guarantee for the long-term reliable operation of the switch.

[0075] See Figure 6 and Figure 7 As shown in the figure, this application embodiment also provides a ring main unit 10, which includes a cabinet 200, a load switch 100 and a grounding switch 300.

[0076] The cabinet 200 can be made of cold-rolled steel sheet with anti-corrosion treatment, achieving an overall protection level of IP4X. The width of the cabinet 200 is optimized according to the dimensions of the load switch 100, with a minimum width of 400mm, making it particularly suitable for installations with limited space.

[0077] It is understood that the load switch 100 can adopt the structure described in the above embodiments, and is fixed to the frame of the cabinet 200 by the mounting flange of the fixing plate 111. The stationary conductive element 112 of the load switch 100 is connected to the incoming circuit through a busbar, and the moving conductive element 113 is connected to the outgoing circuit through a connecting conductor 360. All live parts are enclosed in an insulating chamber, which is filled with dry air or nitrogen as an insulating medium.

[0078] In addition, see Figure 1 and Figure 6 As shown, the grounding switch 300 can adopt a knife switch structure. It may include a grounding moving end 310, a grounding stationary end 320, and a support plate 330 as a supporting structure. The grounding moving end 310 is rotatably mounted on the support plate 330 via a rotating shaft, and its structure is a rotary knife switch. The grounding stationary end 320 is connected to the end of the connecting conductor 360 away from the moving conductive part 113 of the load switch 100 by bolts. The connecting conductor 360 can be a connecting copper busbar, which can be connected to the crossarm 123 by fasteners to further enhance the stability of the connecting conductor 360.

[0079] It should be noted that the grounding switch 300 is equipped with an independent operating mechanism, which is connected to the operating mechanism of the load switch 100 through a mechanical interlocking device. This ensures that the grounding switch 300 can only be operated when the load switch 100 is open, preventing accidental operation of closing the grounding wire while it is energized.

[0080] By integrating the load switch 100 and the grounding switch 300 into the ring main unit 10, a complete, fully functional, and environmentally friendly switchgear is formed. This design ensures reliable and safe grounding through the grounding switch 300 after the load switch 100 is tripped, fully meeting the safety operation specifications of the power distribution system. This ring main unit 10 has advantages such as small size, good insulation performance, reliable operation, and convenient maintenance. Moreover, this ring main unit 10 can reduce the use of SF6 gas, thereby reducing greenhouse gas emissions and achieving significant environmental benefits. At the same time, the compact design reduces the footprint of the ring main unit 10, greatly saving installation space.

[0081] Understandably, this ring main unit 10 also has an operating mechanism connected to the grounding switch 300, which is independently set up from the operating mechanism of the load switch 100. When closing, the operating mechanism of the grounding switch 300 drives the moving grounding terminal 310 to rotate around the axis of the support plate 330 until the moving grounding terminal 310 is tightly fitted with the stationary grounding terminal 320 fixed and connected to the conductor 360, forming a grounding circuit. At this time, the load switch 100 is in the open state, preventing live grounding. When opening, the operating mechanism drives the moving grounding terminal 310 to rotate in the opposite direction, completely separating it from the stationary grounding terminal 320, switching the grounding circuit, and the equipment can be restored to normal operation preparation state. The knife switch structure has a clear opening and closing angle, a large contact area, and strong current carrying capacity. After opening, it has a clear isolation gap, meeting the requirements for disconnection points in the composite ionization safety specifications, thus improving the safety of maintenance operations.

[0082] In some embodiments, see Figure 1 and Figure 6 As shown, the grounding moving end 310 and grounding stationary end 320 of the grounding switch 300 are both provided with dedicated shielding components on their outer peripheries, which may include a first shielding plate 340 and a second shielding plate 350. The first shielding plate 340 and the second shielding plate 350 can be manufactured using the same materials and processes as the shielding cover of the load switch 100 to ensure the consistency of electric field characteristics.

[0083] In some embodiments, see Figure 1 and Figure 6As shown, the second shielding plate 350 is fixed on both sides of the grounding stationary end 320, and it is used to shield the stationary end contact and its connection with the connecting conductor 360. The first shielding plate 340 can be fixedly installed on the mounting base or support plate 330 of the grounding moving end 310, and the first shielding plate 340 is provided with an opening for the grounding moving end 310 to rotate, so that the grounding moving end 310 can rotate toward the grounding stationary end 320 to close the circuit or rotate away from the grounding stationary end 320 to open the circuit. The design position of the first shielding plate 340 ensures that during the closing process of the grounding switch 300, when the grounding moving end 310 rotates to contact the grounding stationary end 320, the first shielding plate 340 can effectively cover and shield the electric field concentration area at the root of the grounding moving end 310.

[0084] In some embodiments, see Figure 1 and Figure 6 As shown, a smooth electric field transition is formed between the first shielding plate 340 and the second shielding plate 350. The edges of the shielding plates adopt a large arc design, and all sharp corners are rounded with a radius of not less than 5mm. The shielding plates have uniform thickness and a surface finish of Ra0.8 or higher to ensure the uniformity of the electric field distribution.

[0085] Understandably, shielding protection is also applied to the conductive components of the grounding switch 300, achieving full-loop electric field optimization from the load switch 100 to the grounding switch 300. This ensures the long-term operational safety and reliability of the entire switchgear in a purely environmentally friendly gas-insulated environment. The full-loop shielding design effectively improves the overall insulation level of the ring main unit 10.

[0086] This application adopts a compact integration of a direct-acting load switch 100 and a knife-type grounding switch 300. The layout of each component is optimized and there is no redundant structure. The overall volume is reduced by more than 20% compared with the circuit breaker solution of related technologies. It can be directly embedded in a narrow-body environmentally friendly switch cabinet with a width of ≤400mm, which greatly saves installation space and is suitable for the narrow installation environment of power distribution scenarios.

[0087] The full-circuit electric field shielding design of the moving end shield 132, the stationary end shield 131, the first shielding plate 340 and the second shielding plate 350, combined with the ribs 1110 of the load switch 100 fixing plate 111 and the protruding ribs 1230 on the crossarm 123 to extend the creepage distance, provides double insulation protection so that the equipment can stably adapt to environmentally friendly insulating media such as dry air and nitrogen, and reduce the use of SF6 gas.

[0088] The components are connected by modular methods such as bolts and clips, eliminating the need for complex welding or precision debugging, resulting in shorter assembly time and reduced manufacturing and on-site installation costs. At the same time, the modular design facilitates later maintenance and component replacement, reducing equipment downtime.

[0089] The direct-acting operation reduces wear on the moving contact bridge 121 and the stationary conductive part 112 of the load switch 100. The knife-type grounding switch 300 has stable current carrying capacity and reliable contact. The optimized electric field avoids aging of insulation components, extends equipment life, reduces failure rate, and lowers long-term operation and maintenance costs.

[0090] In the description of this specification, references to terms such as "some embodiments," "exemplarily," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. The illustrative expressions of the above terms in this specification do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0091] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application. Therefore, any changes or modifications made in accordance with the claims and description of this application should fall within the scope of this patent application.

Claims

1. A load switch, characterized in that, include: A fixed support assembly includes a fixed plate, a stationary conductive element, and a moving conductive element. The stationary conductive element and the moving conductive element are spaced apart on the fixed plate along a first direction. The surface of the fixed plate has protruding ribs. The connection component includes a movable contact bridge and a driving component. The movable contact bridge moves along the first direction under the drive of the driving component to have a first position to contact the stationary conductive element to connect the circuit, and a second position to separate from the stationary conductive element to disconnect the circuit. An electric field shielding assembly includes a stationary shielding cover disposed at the connection between the stationary conductive element and the fixed plate, and a moving shielding cover disposed at the connection between the moving conductive element and the fixed plate.

2. The load switch according to claim 1, characterized in that, The driving component includes a guide rod that extends in the first direction. The movable contact bridge is movably sleeved on the guide rod and is capable of linear reciprocating motion along the axial direction of the guide rod.

3. The load switch according to claim 2, characterized in that, The driving component further includes an operating shaft and a transmission component. The operating shaft extends along a second direction, which intersects with the first direction. The operating shaft is connected to the moving contact bridge component via the transmission component to convert rotational motion into linear motion of the moving contact bridge component.

4. The load switch according to claim 3, characterized in that, The connection component also includes a crossbeam, which extends along the second direction, and the guide rod is fixed to the crossbeam.

5. The load switch according to claim 4, characterized in that, The surface of the crossarm has protruding ribs, and multiple ribs are arranged at intervals in the second direction.

6. The load switch according to claim 1, characterized in that, Both the stationary end shield and the moving end shield are arc-shaped covers.

7. The load switch according to claim 1, characterized in that, The stationary conductive element and the moving conductive element are respectively connected to the fixed plate by fasteners, and the stationary shield and the moving shield cover the fasteners respectively.

8. The load switch according to claim 7, characterized in that, The fixing plate includes a first fixing structure and a second fixing structure. The first fixing structure and the second fixing structure are parallel to each other and spaced apart. The stationary end conductive element and the moving end conductive element are sandwiched between the first fixing structure and the second fixing structure.

9. A ring main unit, characterized in that, include: Grounding switch; According to any one of claims 1 to 8, the grounding stationary terminal of the grounding switch is electrically connected to the moving conductive component of the load switch via a connecting conductor.

10. The ring main unit according to claim 9, characterized in that, Both the moving grounding terminal and the stationary grounding terminal of the grounding switch are provided with shielding components on their outer periphery.

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