A load switch with improved electrical insulation performance and a design method

Abstract

This application relates to a load switch and its design method for improving electrical insulation performance. The load switch includes a frame; a main stationary contact located at the top of the frame and fastened with a first mounting insulator by bolts; a grounding contact located at the bottom of the frame; a moving contact assembly including a connecting post fastened with a second mounting insulator by bolts and located above the second mounting insulator, and a moving contact with one end hinged to the connecting post; a driving component, one end of which is connected to the frame, and the other end of which is connected to the moving contact via an arc-shaped push rod to drive the other end of the moving contact to swing, thereby dynamically connecting with the main stationary contact or the grounding contact; the shed spacing on the first and second mounting insulators is arranged according to a preset spacing. This achieves a systematic improvement in the power frequency withstand voltage, lightning impulse withstand voltage, and partial discharge level at 24kV, enhancing the electrical insulation stability of the load switch.

Description

Technical Field

[0001] This invention relates to the technical field of load switch design, and more particularly to a load switch and design method for improving electrical insulation performance. Background Technology

[0002] Currently, with the increase in voltage levels of power distribution systems, the application of 24kV SF6 load switches in medium-voltage power distribution systems is gradually increasing. Most existing 24kV SF6 load switches are based on the original 10kV load switch structure, with the increase in cabinet gas chamber space and structural margin to meet the electrical insulation requirements of higher voltage levels, rather than being specifically designed and systematically optimized for the 24kV voltage level.

[0003] In existing technologies, the contact seat of the fixed moving contact is typically mounted on a plastic crossbeam, which in turn is mounted on a metal crossbeam. The plastic crossbeam bears the main insulating support function of the contact. This type of structure mainly relies on the basic insulation performance of the plastic material itself and the structural dimensional margin to achieve electrical isolation. However, during long-term operation, the electrical insulation performance of the plastic crossbeam is greatly affected by factors such as material aging, environmental humidity, and electric field distribution, which can easily lead to fluctuations in overall insulation performance. This makes it difficult to consistently meet the stringent requirements of the State Grid and Southern Power Grid for indicators such as power frequency withstand voltage, lightning impulse withstand voltage, and partial discharge level.

[0004] To compensate for the above deficiencies, some existing technical solutions improve insulation margin by further increasing the space of the cabinet gas box and increasing the internal insulation gap. However, this approach inevitably leads to an increase in equipment size, which is not only detrimental to the miniaturization and compact layout of power distribution equipment, but also increases manufacturing costs and installation difficulty, making it difficult to meet the current application requirements of power distribution equipment for both high voltage levels and compact structures. Summary of the Invention

[0005] To address the issues of existing 24kV SF load switches, such as the reliance on space for insulation structure expansion, insufficient insulation performance of plastic crossbeams, limited creepage distance, and difficulty in balancing equipment size, this application provides a load switch and design method that improves electrical insulation performance.

[0006] A load switch with improved electrical insulation performance, the load switch comprising: Frame; The main blade stationary contact is located at the top of the frame and is secured with a first mounting insulator by bolts; The grounding contact is located at the bottom of the frame. The moving contact assembly includes a connecting post on which a second mounting insulator is fastened by bolts and located on the upper part of the second mounting insulator of the frame, and a moving contact at one end of which is hinged to the connecting post; The driving component has one end rotatably connected to the frame and the other end connected to the moving contact via an arc-shaped push rod, so as to drive the other end of the moving contact to swing, thereby dynamically connecting with the main blade stationary contact or the grounding contact; The spacing between the sheds on the first and second mounting insulators is arranged according to a preset spacing, and the number of shed groups on the first and second mounting insulators is set as a preset number of groups.

[0007] By adopting the above technical solution, and by setting installation insulators on the frame to support the stationary and moving contacts of the main blade, the live contacts no longer rely on the plastic crossbeam for insulation isolation. Instead, they are directly separated from the metal frame by independent insulating components. This structurally increases the electrical distance between the live parts and the grounded parts, avoiding the problem of unstable insulation performance caused by the height limitation or material aging of the plastic crossbeam. At the same time, it provides a more stable structural foundation for reliable insulation under high voltage levels.

[0008] Preferably, the driving component includes a driving mechanism, a main shaft, a collar, and an arc-shaped push rod. The main shaft is rotatably mounted on the frame and connected to the driving end of the driving mechanism. One end of the collar is sleeved with the main shaft, and the other end of the collar is hinged with one end of the arc-shaped push rod. The other end of the arc-shaped push rod is hinged with the moving contact. When the driving end of the driving mechanism drives the main shaft to rotate relative to the frame, the collar rotates with the rotation of the main shaft and pushes and pulls the other end of the moving contact through the arc-shaped push rod, so that the other end of the moving contact swings.

[0009] By adopting the above technical solution, the linkage drive structure consisting of the drive mechanism, main shaft, collar and arc-shaped push rod enables the moving contact to swing smoothly along a predetermined trajectory during the switching process, realizing reliable engagement and separation with the main blade stationary contact or grounding contact. This ensures that the contact position change is controlled under different working conditions, avoids contact offset or insulation gap fluctuation caused by unstable drive, and helps maintain the spatial insulation stability under the opening state.

[0010] Preferably, both the first mounting insulator and the second mounting insulator include an integrally formed insulating column and a plurality of skirt groups arranged sequentially on the insulating column, wherein the preset number of skirt groups is 3-5.

[0011] By adopting the above technical solution, and by using an integrated molded insulating column and multiple sets of shed structures on the installed insulator, the insulating component forms a continuous and extended surface creepage path within a limited axial dimension, thereby effectively improving the ability of the insulating component to suppress surface leakage current and creepage discharge, and enhancing the insulation reliability of the load switch under high voltage level and long-term operating conditions.

[0012] Preferably, the skirt spacing is the distance between two adjacent skirt groups, and the ratio between the preset spacing and the diameter of the insulating column is 1 / 5 to 1 / 4.

[0013] By adopting the above technical solution, and by establishing a proportional relationship between the spacing of the umbrella skirts and the diameter of the insulating column, the distribution of the umbrella skirts in the axial and radial directions is made more reasonable. This helps to optimize the electric field distribution on the surface of the insulating component, reduce the phenomenon of local electric field concentration, and improve the utilization efficiency of the creepage distance while taking into account the processing feasibility and structural compactness of the insulating component.

[0014] Preferably, the straight-line distance between the main blade stationary contact and the moving contact, and the straight-line distance between the grounding contact and the moving contact are defined as the contact opening distance, and each contact opening distance is greater than 60mm.

[0015] By adopting the above technical solution, and by clearly defining the minimum contact distance between the main blade stationary contact and the moving contact, as well as between the grounding contact and the moving contact, the components with different potentials always maintain sufficient spatial separation distance in the open state, thereby effectively reducing the risk of spatial breakdown and flashover, and improving the withstand voltage capacity and operational safety of the load switch under the disconnection condition.

[0016] Preferably, the grounding contact includes a first contact end and a second contact end formed by bending and integral molding. Both the first contact end and the second contact end are placed vertically at the bottom of the frame. The second contact end is connected to a baffle extending upward from the bottom of the frame. The first contact end is dynamically fitted and connected to the other end of the moving contact.

[0017] By adopting the above technical solution and using a bent, integrated grounding contact structure, the grounding contact can maintain a stable geometric shape and a reliable conductive path while dynamically fitting with the moving contact. This achieves the grounding function while avoiding insulation dead angles or electric field distortions caused by complex structures, which helps maintain the stability of the overall electrical structure.

[0018] A design method for a load switch to improve electrical insulation performance, applied to a load switch with improved electrical insulation performance, the design method comprising: Based on the predetermined design requirements, the corresponding target voltage level and environmental conditions are obtained. Based on the target voltage level, the electrical insulation performance target that the load switch needs to meet under at least one disconnection condition is determined. According to the electrical insulation performance target and the environmental conditions, the corresponding constraints are determined. The constraints include at least creepage distance constraints and minimum spatial separation distance constraints. Based on the creepage distance constraint, the surface creepage path characteristics of the insulating component are determined; Based on the minimum spatial separation distance constraint and the surface creepage path characteristics, the separation spacing characteristics of the insulating components are determined. Based on the surface creepage path characteristics and the separation spacing characteristics, a corresponding target insulating component is designed, and a corresponding load switch is designed based on the target insulating component. The target insulating component includes at least a first mounting insulator and a second mounting insulator.

[0019] By adopting the above technical solutions and introducing a systematic design process that starts with design requirements, the target voltage level and environmental conditions are transformed into electrical insulation performance targets, and further into constraints such as creepage distance and spatial separation distance. This transforms the insulation structure design of load switches from empirical adjustments to engineering design based on constraints, thereby improving the overall controllability and consistency of the insulation scheme.

[0020] Preferably, the step of determining the corresponding constraints based on the electrical insulation performance target and the environmental conditions includes: Based on the electrical insulation performance targets, determine the maximum permissible surface electric field strength and maximum spatial electric field strength of the insulating component under disconnection conditions; Based on the maximum surface electric field intensity, the minimum surface path length required to avoid creepage discharge along the surface of the insulating member is determined, and the minimum surface path length is determined as the creepage distance constraint condition. Based on the maximum spatial electric field strength and the relative geometric state between the contacts under the disconnection condition, the minimum spatial gap required under the disconnection condition is derived. Based on the minimum spatial gap and the environmental conditions, the corresponding minimum spatial separation distance constraint is determined.

[0021] By adopting the above technical solutions, the insulation risks are analyzed from two dimensions: surface electric field and spatial electric field. Based on this, the creepage distance constraints and minimum spatial separation distance constraints are derived, enabling the insulation design to simultaneously take into account both surface creepage discharge risks and spatial breakdown risks, thereby forming a more comprehensive and reliable insulation constraint system.

[0022] In summary, this application includes at least one of the following beneficial technical effects: This application fundamentally changes the technical approach of relying on plastic crossbeams and enlarged gas chamber space to meet high-voltage insulation requirements by comprehensively reconstructing the contact support and insulation structure of the load switch. Specifically, this application no longer establishes the insulation support of the moving or stationary contacts on the plastic crossbeam. Instead, by setting a first mounting insulator and a second mounting insulator on the frame, the main stationary and moving contacts are directly supported and electrically isolated by independent mounting insulators. This structurally increases the insulation distance between the live parts and the metal frame, and avoids the insulation instability problem caused by the limited material properties and structural height of the plastic crossbeam. At the same time, by integrating multiple sets of sheds on the aforementioned mounting insulators and uniformly planning the spacing and number of sheds, the insulating components form a longer and more continuous surface creepage path within the limited installation space. Thus, without relying on enlarged gas chamber space, the creepage distance and electric field withstand capability of the load switch under opening conditions are effectively improved. Based on this, the moving contact, under the action of the driving component, can reliably switch between the main blade stationary contact and the grounding contact. Its contact spacing is limited by both the insulation structure and spatial layout, ensuring sufficient spatial separation between components at different potentials when disconnected. Without significantly increasing the overall size of the equipment, a systematic improvement is achieved in the power frequency withstand voltage, lightning impulse withstand voltage, and partial discharge levels at the 24kV level. This significantly enhances the electrical insulation stability and long-term operational reliability of the load switch, effectively solving the problems of insufficient insulation margin, limited creepage distance, and difficulty in balancing compactness requirements in existing technologies. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the specific structure of a load switch for improving electrical insulation performance in one embodiment of this application; Figure 2 This is a front view of a load switch with improved electrical insulation performance according to an embodiment of this application; Figure 3 This is a schematic side view of a load switch with improved electrical insulation performance in the open state according to an embodiment of this application; Figure 4 This is a schematic side view of a load switch with improved electrical insulation performance in the closed state according to an embodiment of this application; Figure 5 This is a schematic side view of a load switch with improved electrical insulation performance in a grounded state according to an embodiment of this application; Figure 6 This is a flowchart of a design method for a load switch to improve electrical insulation performance according to an embodiment of this application.

[0024] Explanation of reference numerals in the attached figures: 1. Frame; 2. Main blade stationary contact; 3a. First mounting insulator; 3b. Second mounting insulator; 31. Insulating column; 32. Umbrella skirt assembly; 4. Grounding contact; 41. First contact end; 42. Second contact end; 5. Moving contact assembly; 51. Connecting column; 52. Moving contact; 6. Drive component; 61. Main shaft; 62. Collar; 63. Arc-shaped push rod. Detailed Implementation

[0025] The present application will be further described in detail below with reference to the accompanying drawings.

[0026] In one embodiment, such as Figures 1-5 As shown, this application discloses a load switch with improved electrical insulation performance. The load switch with improved electrical insulation performance includes: Frame 1; The main blade stationary contact 2 is located at the top of the frame 1 and is fastened with the first mounting insulator 3a by bolts; Grounding contact 4 is located at the bottom of frame 1; The moving contact assembly 5 includes a connecting post 51 on which a second mounting insulator 3b is fastened by bolts and located on the upper part of the second mounting insulator 3b, and a moving contact 52 with one end hinged to the connecting post 51. The drive component 6 is rotatably connected to the frame 1 at one end and connected to the moving contact 52 via an arc-shaped push rod at the other end, so as to drive the other end of the moving contact 52 to swing, thereby dynamically connecting with the main blade stationary contact 2 or the grounding contact 4. The spacing between the sheds on the first mounting insulator 3a and the second mounting insulator 3b is arranged according to a preset spacing, and the number of shed groups on the first mounting insulator 3a and the second mounting insulator 3b is set as a preset number of groups.

[0027] In this embodiment, a load switch with improved electrical insulation performance is integrally mounted on a frame 1. The frame 1 serves as the basic load-bearing structure for the load switch, providing mechanical support and relative positional constraints for each functional component, and also acts as the main frame connecting the entire unit to the external switchgear structure. The main blade stationary contact 2 is located in the top area of ​​the frame 1, and is electrically isolated and fixedly connected to the frame 1 via a first mounting insulator 3a. The first mounting insulator 3a provides mechanical support for the main blade stationary contact 2 and forms a stable insulating isolation path between the main blade stationary contact 2 and the frame 1, thereby preventing the high potential at the main blade stationary contact 2 from being directly conducted to the frame 1. The first mounting insulator 3a has an axially extending structure, and its outer surface is integrally provided with multiple sets of umbrella skirt structures. The umbrella skirts are arranged sequentially along the axial direction at a preset interval, effectively improving the creepage distance and pollution flashover resistance in this area by extending the surface creepage path between the main blade stationary contact 2 and the frame 1.

[0028] The grounding contact 4 is located at the bottom of the frame 1 and is electrically connected to the frame 1. It provides a reliable grounding path for the moving contact 52 when the load switch is in the grounding condition. Since the grounding contact 4 is located at the bottom of the frame 1, its position is spatially separated from the main blade stationary contact 2, providing a clear direction of movement and spatial reference for the switching of the moving contact 52 between different positions.

[0029] The moving contact 52 is hinged to the connecting post 51 mounted on the upper part of the second mounting insulator, allowing the moving contact 52 to rotate relative to the frame 1. The second mounting insulator 3b establishes a stable electrical insulation structure between the moving contact 52 and the frame 1, preventing potential changes of the moving contact 52 under different operating conditions from directly affecting the frame 1. The outer surface of the second mounting insulator 3b is also integrally provided with multiple sets of shed structures, and the number of sheds and the spacing between adjacent sheds are uniformly configured according to preset parameters, ensuring that the moving contact 52 maintains a sufficient surface creepage distance with the frame 1 during swinging, thereby ensuring insulation reliability in the open and transition states.

[0030] One end of the driving component 6 is rotatably connected to the frame 1, and the other end is connected to the moving contact 52. The driving component 6 provides a controlled mechanical driving force to the moving contact 52, enabling the moving contact 52 to swing around the hinge axis formed by the second mounting insulator 3b. When the driving component 6 is activated, the free end of the moving contact 52 moves along a predetermined trajectory in space, thereby forming a conductive connection with the main blade stationary contact 2 under the closing condition, a conductive connection with the grounding contact 4 under the grounding condition, and maintaining spatial separation from both the main blade stationary contact 2 and the grounding contact 4 under the opening condition. By controlling the movement process of the moving contact 52 through the driving component 6, it can be ensured that the movement path, termination position, and contact opening distance of the moving contact 52 are all controllable during the switching of various operating conditions, thereby avoiding problems such as insufficient insulation gap or electric field concentration caused by motion instability.

[0031] Through the above structural configuration, the first mounting insulator 3a and the second mounting insulator 3b independently support and insulate the main blade stationary contact 2 and the moving contact 52, respectively. Furthermore, by integrating multiple sets of umbrella-shaped structures on their outer surfaces and arranging them at preset intervals, the creepage path between the critical live components and the frame 1 is effectively extended without significantly increasing the overall size of the frame 1. Simultaneously, the moving contact 52, driven by the driving component 6, swings controlled between the main blade stationary contact 2 and the grounding contact 4, ensuring that the load switch can simultaneously meet the requirements of electrical connection reliability and electrical insulation safety under different operating conditions. This comprehensively improves the electrical insulation performance and operational stability of the load switch under high-voltage conditions.

[0032] Furthermore, such as Figures 2-3 As shown, the drive component 6 includes a drive mechanism, a main shaft 61, a collar 62, and an arc-shaped push rod 63. The main shaft 61 is rotatably mounted on the frame 1 and connected to the drive end of the drive mechanism. One end of the collar 62 is fixedly engaged with the main shaft 61, and the other end of the collar 62 is hinged to one end of the arc-shaped push rod 63. The other end of the arc-shaped push rod 63 is hinged to the moving contact. When the drive end of the drive mechanism drives the main shaft 61 to rotate relative to the frame 1, the collar 62 rotates with the rotation of the main shaft 61 and pushes and pulls the other end of the moving contact 52 through the arc-shaped push rod 63, so that the other end of the moving contact 52 swings.

[0033] In this embodiment, the drive component 6 provides stable and controllable driving power to the moving contact 52. It is composed of a drive mechanism, a main shaft 61, a collar 62, and an arc-shaped push rod 63. These components are interconnected through rotational and hinged connections to form a continuous force and displacement transmission link. The main shaft 61 is rotatably mounted on the frame 1. On one hand, the main shaft 61 forms a stable rotational support relationship with the frame 1 through bearings or an equivalent rotational support structure. On the other hand, it is directly connected to the drive end of the drive mechanism, allowing the rotational torque output by the drive mechanism to be transmitted to the main shaft 61 without interruption, thus enabling the main shaft 61 to rotate in a controlled manner relative to the frame 1. By making the main shaft 61 a rotating component, the rotational motion of the drive mechanism is clearly limited to a fixed axis relative to the frame 1, which helps ensure the stability and repeatability of the subsequent transmission process.

[0034] The collar 62 is fixedly mounted on the main shaft 61. The collar 62 rotates synchronously with the main shaft 61 and, through its structural design, provides a stable hinge point for subsequent linkage mechanisms. This fixed fit between the collar 62 and the main shaft 61 ensures that the collar 62, while bearing the force of the arc-shaped push rod 63, will not experience axial movement or angular displacement relative to the main shaft 61, thus guaranteeing that the force transmission path always revolves around the main shaft 61. The other end of the collar 62 is hinged to one end of the arc-shaped push rod 63. This hinged fit allows the arc-shaped push rod 63 to change angle relative to the collar 62, converting the rotational motion of the collar 62 into the pushing and pulling motion of the arc-shaped push rod 63.

[0035] The other end of the arc-shaped push rod 63 is hinged to the moving contact 52. This hinge structure allows the arc-shaped push rod 63 to adapt to the swing trajectory changes of the moving contact 52 during the pushing and pulling process, avoiding additional stress or movement jamming caused by rigid connection. When the drive end of the drive mechanism drives the main shaft 61 to rotate relative to the frame 1, the main shaft 61 drives the collar 62 to rotate synchronously. During the rotation, the collar 62 applies a pushing or pulling force to the moving contact 52 through the arc-shaped push rod 63, causing the moving contact 52 to swing around the hinge position between it and the frame 1. Since the arc-shaped push rod 63 has an overall arc-shaped structure, its movement trajectory matches the swing trajectory of the moving contact 52, thus maintaining a relatively constant lever arm relationship throughout the movement, making the movement of the moving contact 52 smoother and more controllable.

[0036] Furthermore, such as Figure 2 As shown, both the first mounting insulator 3a and the second mounting insulator 3b include an integrally formed insulating column 31 and multiple skirt groups 32 arranged sequentially on the insulating column 31, with a preset number of 3-5 skirt groups 32.

[0037] In this embodiment, the first mounting insulator 3a and the second mounting insulator 3b adopt the same insulation configuration in terms of structure. Both are composed of an integrally formed insulating column 31 and multiple shed groups 32 arranged sequentially on the outer surface of the insulating column 31. The insulating column 31 serves as the main load-bearing structure of the first mounting insulator 3a and the second mounting insulator 3b. Its axial direction is used to bear the mechanical load transmitted by the main stationary contact 2 or the moving contact 52, and electrically isolates the corresponding contact from the frame 1, thereby forming a stable basic insulation channel. By designing the insulating column 31 as an integrally formed structure, the interface defects and electric field concentration problems caused by multi-segment splicing can be avoided, which is beneficial to improving the overall mechanical strength and electrical reliability of the insulation components.

[0038] Multiple skirt groups 32 are arranged sequentially along the axial direction of the insulating column 31 and are integrally formed with the insulating column 31, so that the first mounting insulator 3a and the second mounting insulator 3b form a continuously extending surface structure within a limited axial height. Each skirt group 32, by changing the path shape of the outer surface of the insulating member, forces the leakage current that may form on the insulating surface to detour, thereby significantly extending the effective creepage path length between the live contact and the frame 1. By limiting the preset number of skirt groups 32 to 3-5, a balance is achieved between the insulating performance and structural dimensions of the insulating member. On the one hand, it can meet the creepage distance requirements under high voltage levels, and on the other hand, it avoids the increased structural complexity, manufacturing difficulty, or risk of local contamination caused by an excessive number of skirts.

[0039] Since the first mounting insulator 3a and the second mounting insulator 3b are used to support the main knife stationary contact 2 and the moving contact 52 via the connecting post 51, respectively, they undertake insulation tasks in different spatial positions. However, the number and arrangement of their shed groups 32 are consistent, which helps to ensure that the key insulation parts inside the load switch maintain consistency in electric field distribution characteristics and creepage performance, thereby avoiding weak insulation points caused by differences in the performance of different insulation components. Through the above structural design, the first mounting insulator 3a and the second mounting insulator 3b not only play a role in mechanical support and electrical isolation, but also, through the coordinated configuration of the shed groups 32, effectively suppress the risk of surface creepage discharge, thereby improving the overall electrical insulation stability and long-term reliability of the load switch under high-voltage operating conditions.

[0040] Furthermore, the skirt spacing is the distance between two adjacent skirt groups 32, and the ratio between the preset spacing and the diameter of the insulating column 31 is 1 / 5 to 1 / 4.

[0041] In this embodiment, the skirt spacing is defined as the distance between two adjacent skirt groups 32 in the axial direction of the insulating column 31. This skirt spacing, as a crucial structural parameter affecting the creepage performance of the first mounting insulator 3a and the second mounting insulator 3b, establishes a clear proportional relationship with the diameter of the insulating column 31. Specifically, the ratio between the preset spacing and the diameter of the insulating column 31 is limited to the range of 1 / 5 to 1 / 4. This proportional constraint ensures that the distribution of the skirt groups 32 in the axial direction is neither too dense nor too sparse, thereby forming a reasonably extended surface creepage path within the limited length of the insulating column 31. When the skirt spacing relative to the diameter of the insulating column 31 remains within the aforementioned proportional range, it effectively avoids problems such as dirt accumulation, water accumulation, or local electric field superposition caused by excessively small spacing between the skirt groups 32. Simultaneously, it prevents the formation of excessively short straight leakage paths on the insulating surface due to excessively large spacing, thus affecting the overall utilization efficiency of the creepage distance.

[0042] By proportionalizing the skirt spacing with the diameter of the insulating column 31, the first mounting insulator 3a and the second mounting insulator 3b maintain relatively consistent electric field distribution characteristics and creepage path morphology under different size specifications, thereby improving the versatility and scalability of the insulating components in different types of load switches. Simultaneously, this proportional relationship facilitates full utilization of the outer surface space of the insulating column 31 while ensuring a reasonable configuration of the number of skirt groups 32. This effectively lengthens the leakage current path that may form along the insulation surface and causes multiple reversals, thereby reducing the probability of surface creepage discharge. Through the aforementioned proportional setting of the skirt spacing, the first mounting insulator 3a and the second mounting insulator 3b achieve synergistic optimization of creepage distance and electric field uniformity without significantly increasing structural dimensions, further improving the electrical insulation stability and reliability of the load switch under high-voltage operating conditions.

[0043] Furthermore, such as Figure 3 As shown, the straight-line distance between the main blade stationary contact 2 and the moving contact 52, and the straight-line distance between the grounding contact 4 and the moving contact 52 are defined as the contact opening distance, and the opening distance of each contact is greater than 60mm.

[0044] In this embodiment, the straight-line distance between the main stationary contact 2 and the moving contact 52, and the straight-line distance between the grounding contact 4 and the moving contact 52 are uniformly defined as the contact gap. The contact gap is used to characterize the minimum spatial separation between contacts at different potentials under the opening condition of the load switch. By defining the contact gap as a straight-line distance, the spatial relationship between the main stationary contact 2, the grounding contact 4, and the moving contact 52 can be evaluated based on the geometric distance in the most unfavorable direction, thereby avoiding underestimation of the actual insulation gap due to differences in contact shape or installation angle. In terms of structural design, the contact gap of each contact is limited to greater than 60mm, so that after the moving contact 52 is separated from the main stationary contact 2 or the grounding contact 4, a sufficient air gap is formed in space to reduce the risk of spatial breakdown or flashover under high voltage conditions.

[0045] Because the moving contact 52 swings around the hinged position of the connecting column 51 under the action of the driving component 6, its spatial position relative to the main stationary contact 2 and the grounding contact 4 in the open state is determined by the movement trajectory. By uniformly limiting the lower limit of the contact opening distance, it can be ensured that when the moving contact 52 reaches the open termination position, it can maintain the minimum spatial separation distance that meets the insulation requirements with the main stationary contact 2 and the grounding contact 4, thereby avoiding local electric field concentration or discharge along the air path under high voltage. Through the above-mentioned setting of the contact opening distance, not only is the withstand voltage capability and operational safety of the load switch under the disconnection condition improved, but the insulation design is also transformed from relying solely on the performance of the insulation material to a comprehensive insulation method that combines material insulation and spatial insulation. Thus, without significantly increasing the overall structural size, the electrical insulation stability and reliability of the load switch under high voltage level operating conditions are further improved.

[0046] Furthermore, such as Figure 1 As shown, the grounding contact 4 includes a first contact end 41 and a second contact end 42 formed by bending and integral molding. Both the first contact end 41 and the second contact end 42 are placed vertically at the bottom of the frame 1. The second contact end 42 is connected to the baffle extending upward from the bottom of the frame 1. The first contact end 41 is dynamically attached to the other end of the moving contact 52.

[0047] In this embodiment, the grounding contact 4 adopts a bent, integrated molding structure, which includes a first contact end 41 and a second contact end 42. Both the first contact end 41 and the second contact end 42 are arranged vertically in the bottom area of ​​the frame 1, effectively controlling the lateral and longitudinal space occupied by the grounding contact 4 inside the frame 1. This facilitates the arrangement of the grounding function without increasing the overall size of the frame 1. The second contact end 42 is connected to a baffle extending upward from the bottom of the frame 1, forming a stable fixed relationship between the grounding contact 4 and the frame 1 in terms of mechanical structure. At the same time, the baffle structure limits the installation position of the second contact end 42, thereby ensuring that the installation height and posture of the grounding contact 4 in space are consistent with the overall layout of the machine, and avoiding the impact of positional deviation on the internal insulation spacing distribution.

[0048] The first contact end 41 is located on the other side of the grounding contact 4. Its position and orientation are adjusted according to the swing trajectory of the moving contact 52, so that the first contact end 41 can dynamically fit and connect with the other end of the moving contact 52 when the moving contact 52 reaches the grounding condition. By matching the movement trajectory of the first contact end 41 with that of the moving contact 52, the moving contact 52 can smoothly enter the grounding position during swing. In the non-grounding condition, the first contact end 41 can maintain sufficient space separation from the moving contact 52 and other live parts, thereby avoiding the formation of insulation dead corners with narrow local spaces or concentrated electric fields inside the frame 1. Since the first contact end 41 and the second contact end 42 adopt a bent integrated molding structure, the grounding contact 4 can achieve continuous conductivity while its overall shape can be compactly arranged according to the internal space of the frame 1. This is beneficial to limit the overall structure of the load switch within the size range required by the State Grid standardized SF610kV switchgear, while meeting the requirements of grounding function and electrical safety.

[0049] Through the structural and positional design of the grounding contact 4, the grounding function, the movement path of the moving contact 52, and the internal spatial layout of the frame 1 are coordinated. Without increasing the additional installation space, the reliability of grounding and the safety of electrical insulation are taken into account, thereby effectively improving the spatial adaptability of the load switch under high voltage conditions and the stability of the overall insulation performance.

[0050] like Figure 6 As shown, a design method for a load switch to improve electrical insulation performance is described. The method, applied to a load switch with improved electrical insulation performance, includes: S10. Based on the predetermined design requirements, obtain the corresponding target voltage level and environmental conditions. Based on the target voltage level, determine the electrical insulation performance target that the load switch needs to meet under at least one disconnection condition. Based on the electrical insulation performance target and environmental conditions, determine the corresponding constraints. The constraints shall include at least the creepage distance constraint and the minimum spatial separation distance constraint. S20. Based on the creepage distance constraint, determine the surface creepage path characteristics of the insulating component; In this embodiment, the process of determining the surface creepage path characteristics of the insulating component based on creepage distance constraints is a process of transforming the creepage distance constraints into the design process of the geometric parameters of the outer surface of the insulating component. Specifically, firstly, based on the creepage distance constraints, the minimum effective surface path length required to be formed along the surface of the insulating component from the high potential end to the low potential end is determined, and this minimum effective surface path length is used as the lower limit constraint for the outer surface structure design of the insulating component. On this basis, taking the axial direction of the insulating component as the main development direction, a segmented structural design is carried out on its outer surface, so that the surface path does not extend along a straight line, but extends through multiple folding paths.

[0051] In the specific implementation process, multiple outwardly extending structural units are sequentially arranged along the axial direction on the outer surface of the insulating component, creating axial gaps between adjacent structural units. This forces the leakage path propagating along the surface of the insulating component to change direction multiple times as it passes through each structural unit. By adjusting the number of structural units arranged in the axial direction and the spacing between adjacent structural units, the cumulative path length formed along the surface of the insulating component reaches or exceeds the minimum value limited by the creepage distance constraint. Finally, the outer surface structural morphology that satisfies the cumulative surface path length requirement is determined as the surface creepage path characteristic of the insulating component.

[0052] S30. Based on the minimum spatial separation distance constraint and surface creepage path characteristics, determine the separation spacing characteristics of the insulating components; In this embodiment, the process of determining the separation distance characteristics of the insulating components based on the minimum spatial separation distance constraint and surface creepage path characteristics is a design process that transforms spatial insulation safety requirements into the specific installation position and geometric spacing of the insulating components within the overall structure. Specifically, firstly, based on the minimum spatial separation distance constraint, the minimum safe space gap that must be maintained between the insulating components and adjacent live or grounded components under disconnection conditions is determined, and this minimum safe space gap is used as the lower limit constraint for the spatial arrangement of the insulating components. Based on this, combined with the determined surface creepage path characteristics, the installation height, radial position, and relative orientation of the insulating components within the frame are comprehensively determined, ensuring that while meeting the minimum safe space gap, the creepage path formed on the outer surface of the insulating components is not obstructed or compressed by adjacent structures.

[0053] In the specific implementation process, the position of the insulating component in space is adjusted to form a stable and continuous spatial separation region with the corresponding contact under the disconnection condition. It is ensured that the spatial distance along any possible straight line direction leading to a breakdown path is not less than the minimum value limited by the minimum spatial separation distance constraint. Simultaneously, when determining the separation distance characteristics of the insulating component, the unfolding direction of the surface creepage path of the insulating component is also checked to avoid overlap or shortening of the surface creepage path and spatial gap in local areas due to improper spatial arrangement. Finally, the spatial positional relationship of the insulating component determined under the premise of satisfying the spatial separation distance constraint and without destroying the surface creepage path characteristics is determined as the separation distance characteristic of the insulating component.

[0054] S40. Based on the surface creepage path characteristics and separation distance characteristics, design the corresponding target insulation component, and design the corresponding load switch based on the target insulation component. The target insulation component includes at least a first mounting insulator and a second mounting insulator.

[0055] In this embodiment, the process of designing the target insulation component based on surface creepage path characteristics and separation distance characteristics, and then designing the corresponding load switch based on the target insulation component, is the process of translating the aforementioned insulation design results from the parameter level into a specific structural scheme and completing the overall integration. Specifically, firstly, using the determined surface creepage path characteristics as the basis for shape design, the axial length, outer surface contour, and axially unfolded structural form of the target insulation component are determined, so that the target insulation component can form a continuous creepage path on its outer surface that satisfies the creepage distance constraint. Simultaneously, using the determined separation distance characteristics as the basis for spatial arrangement, the installation position, installation height, and relative distance between the target insulation component and adjacent contacts and the frame are determined, so that the target insulation component can meet the minimum spatial separation distance constraint in the overall structure.

[0056] In the specific implementation process, the structural form and installation interface of the target insulating component are designed according to the above two types of characteristic parameters, so that the target insulating component, as an independent structural component, simultaneously possesses the geometric characteristics to meet the surface creepage path requirements and spatial separation requirements. Based on this, the target insulating component is configured as a first mounting insulator and a second mounting insulator, whereby the first mounting insulator is used to support and insulate the main blade stationary contact, and the second mounting insulator is used to support and insulate the moving contact, ensuring that key live components in different locations can obtain consistent insulation performance under the same design logic. Subsequently, using the first and second mounting insulators as core insulation support components, the installation method, relative position, and insulation relationship between the contacts in the load switch and the frame are designed holistically, ensuring that the surface creepage path and spatial separation distance of the load switch stably meet the corresponding insulation constraints under different operating conditions such as closing, opening, and grounding.

[0057] Furthermore, the step of determining the corresponding constraints based on the electrical insulation performance target and the environmental conditions includes: S101. Based on the electrical insulation performance target, determine the maximum permissible surface electric field strength and maximum spatial electric field strength of the insulating component under disconnection conditions. S102. Based on the maximum surface electric field strength, determine the minimum surface path length required to avoid creepage discharge along the surface of the insulating member, and define the minimum surface path length as the creepage distance constraint condition. S103. Based on the maximum spatial electric field strength and the relative geometric state between each contact under the disconnection condition, the minimum spatial gap that needs to be satisfied under the disconnection condition is deduced. According to the minimum spatial gap and the environmental conditions, the corresponding minimum spatial separation distance constraint condition is determined.

[0058] In this embodiment, both the maximum surface electric field strength and the maximum spatial electric field strength serve as intermediate quantities for converting the electrical insulation performance target into a geometric constraint. This transforms the target requirement of "no surface creepage discharge and spatial breakdown under disconnection conditions" into a verifiable threshold that can be used for structural design. The maximum surface electric field strength refers to the upper limit of the electric field strength that the surface of the insulating component can withstand under disconnection conditions, with units of kV / mm, and is used to characterize the maximum allowable potential gradient per unit distance on the surface of the insulating component. The maximum spatial electric field strength refers to the upper limit of the electric field strength that can be withstand within the spatial medium between components at different potentials under disconnection conditions, also with units of kV / mm, and is used to characterize the maximum allowable potential gradient for air or gaseous media to prevent spatial breakdown under these environmental conditions.

[0059] In determining the maximum surface electric field strength and the maximum spatial electric field strength, this embodiment adopts a three-stage determination logic of "target tolerance - environmental correction - safety margin": First, based on the tolerance requirements corresponding to the electrical insulation performance target, the representative voltage stress level to be considered under the disconnection condition is determined. This voltage stress level is preferably the voltage corresponding to the tolerance index most relevant to the disconnection condition (e.g., at least one of power frequency withstand voltage or lightning impulse withstand voltage), and this voltage stress level is used as the benchmark input for the subsequent electric field strength threshold; Second, a preset safety margin is introduced to adjust the corrected threshold in a conservative direction so that the obtained maximum surface electric field strength and maximum spatial electric field strength can cover the uncertainties introduced by manufacturing tolerances, assembly deviations and operational fluctuations.

[0060] After determining the maximum surface electric field strength, this embodiment uses it to generate creepage distance constraints. The working principle is as follows: Under disconnected conditions, the risk of creepage discharge on the surface of the insulating component is directly related to the surface potential gradient. When the voltage stress per unit distance on the insulating surface exceeds the maximum allowable surface electric field strength, a continuous leakage path is easily formed under contaminated or humid conditions, triggering surface discharge. Therefore, this embodiment uses the relationship between the representative voltage stress level under disconnected conditions and the maximum surface electric field strength as a basis to deduce the minimum surface path length required to ensure that the surface potential gradient does not exceed the threshold, and uses this minimum surface path length as the creepage distance constraint. In engineering implementation, this minimum surface path length corresponds to the cumulative path length after the outer surface of the insulating component folds back along the umbrella skirt structure. Subsequently, the actual surface path length is made to meet or exceed this constraint value through the design of the number of umbrella skirt sets and the spacing between the umbrella skirts, thereby ensuring that a sustainable creepage discharge path is not easily formed on the insulating surface under disconnected conditions.

[0061] After determining the maximum spatial electric field strength, this embodiment uses it to generate the minimum spatial separation distance constraint. Its working principle is as follows: Under disconnection conditions, the risk of spatial breakdown between contacts is mainly determined by the electric field concentration under the most unfavorable geometric state. When the minimum straight-line distance between contacts is insufficient, the potential gradient within the spatial medium increases and may exceed the maximum allowable spatial electric field strength, leading to breakdown. Therefore, this embodiment determines the equivalent straight-line gap in the most unfavorable direction based on the relative geometric state between each contact under disconnection conditions, and derives the minimum spatial gap to be satisfied based on the relationship between the representative voltage stress level and the maximum spatial electric field strength. In engineering implementation, the minimum spatial separation distance constraint corresponds to the lower limit of the minimum straight-line distance between the main cutter stationary contact and the moving contact, and between the grounding contact and the moving contact at the tripping termination position. Through spatial adaptation design of the moving contact swing angle, moving contact length, and grounding contact position, the minimum straight-line distance is made to meet or exceed this constraint value, thereby ensuring the stability of the spatial insulation distance under disconnection conditions.

[0062] For ease of understanding, this embodiment provides a set of non-limiting examples: Under the condition that the 24kV switch is placed in a sealed SF6 gas box with a relative positive pressure of 0.035MPa, the representative voltage stress level is determined based on the electrical insulation performance target. After safety margin processing, the maximum surface electric field strength threshold and the maximum spatial electric field strength threshold (in kV / mm) can be obtained for the design verification of this embodiment. Then, based on these thresholds, the minimum surface path length and the minimum spatial gap are derived respectively, and the creepage distance constraint and the minimum spatial separation distance constraint are determined accordingly. Then, through a structural design with 3-5 sets of umbrella skirts and a ratio of umbrella skirt spacing to insulating column diameter of 1 / 5-1 / 4, the actual surface path length meets the creepage distance constraint. At the same time, through a structural layout with a contact opening distance of not less than 60mm when the opening angle is about 45°, the actual spatial gap meets the minimum spatial separation distance constraint, thereby achieving a synergistic improvement of surface insulation and spatial insulation.

[0063] Through the above implementation methods, this embodiment not only clarifies the physical meaning, unit form, and acquisition logic of the maximum surface electric field strength and the maximum spatial electric field strength, but also provides the working principle of how they, as intermediate quantities, support the subsequent "backward calculation" steps, so that the generation of creepage distance constraints and minimum spatial separation distance constraints has an implementable basis, thereby ensuring that the overall design method has a clear engineering foundation and verifiability.

[0064] Specifically, regarding the supplementary explanation of the potential for air gaps in the sleeve structure leading to partial discharge: In this embodiment, the first mounting insulator 3a and the main blade stationary contact 2, the second mounting insulator 3b and the connecting post 51 mounted thereon, and the moving contact 5 hinged to the other end of the connecting post 51 are all assembled using a tight fit method to avoid the formation of open air gaps between the insulating and conductive components. Specifically, the internal mounting areas of the first mounting insulator 3a and the second mounting insulator 3b are respectively matched and machined according to the external dimensions of the main blade stationary contact 2 and the moving contact 5, so that after the main blade stationary contact 2 and the moving contact 5 are assembled into their corresponding mounting areas, a continuous and fitted interface is formed between them, thereby reducing the existence of local air layers. At the same time, the first mounting insulator 3a and the second mounting insulator 3b are also installed with a fixed connection to the frame 1, ensuring that the insulating components maintain a stable positional relationship when bearing mechanical support, and preventing gap changes at the connection interface due to operational vibration or thermal expansion and contraction. In this structure, a continuous insulating transition region is formed between the main stationary contact 2, the moving contact 5, and the corresponding insulating components. When the load switch is in high-voltage operation, the electric field can be continuously distributed along the surface of the insulating components without forming a significant electric field concentration in the local air gap region, thereby reducing the risk of corona discharge and partial discharge. Through the above structural design, the first mounting insulator 3a and the second mounting insulator 3b not only increase the creepage distance but also reduce local insulation weaknesses caused by interface air gaps, thereby improving the overall insulation stability of the load switch during operation.

[0065] Supplementary explanation for why only the disconnection condition is considered: In this embodiment, the disconnection condition is determined as a control condition in the insulation design of the load switch because when the load switch is in the disconnected state, the maximum potential difference is formed between the main stationary contact 2, the moving contact 5, and the grounding contact 4, and the components with different potentials are isolated only by air gaps and insulating components. At this time, both the spatial electric field strength and the surface electric field strength reach a relatively high state during operation. Therefore, the disconnection condition constitutes the most unfavorable condition in the insulation design. After determining the creepage distance constraint and the minimum spatial separation distance constraint based on the disconnection condition, it can be ensured that the load switch still meets the electrical insulation performance target under the most stringent insulation conditions. In contrast, when the load switch is in the closed state, the main stationary contact 2 and the moving contact 5 are in a conducting state, and their potentials tend to be consistent, no longer forming a cross-gap electric field. Therefore, it is not necessary to design according to the spatial insulation conditions under the disconnection condition. During the opening transition process, the moving contact 5 gradually moves from the conducting state to the disconnected state, and the spatial electric field strength formed at any time will not exceed the electric field strength in the final disconnected state. Therefore, this implementation method uses the disconnection condition as the basis for generating constraint conditions to achieve overall coverage of insulation requirements for other operating conditions. This ensures insulation reliability while avoiding the need to repeatedly establish independent insulation constraint models for all operating conditions, thereby improving the engineering implementation efficiency of the load switch insulation design process.

[0066] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A load switch with improved electrical insulation performance, characterized by, The aforementioned load switch with improved electrical insulation performance includes: Frame (1); The main blade stationary contact (2) is located at the top of the frame (1) and is fastened with a first mounting insulator (3a) by bolts. Grounding contact (4) is located at the bottom of the frame (1); The moving contact assembly (5) includes a connecting post (51) that is fastened to a second mounting insulator (3b) by bolts and located on the upper part of the second mounting insulator (3b), and a moving contact (52) that is hinged to the connecting post (51) at one end. The driving component (6) is rotatably connected to the frame (1) at one end and connected to the moving contact (52) at the other end through an arc-shaped push rod (63) to drive the other end of the moving contact (52) to swing, thereby dynamically connecting with the main blade stationary contact (2) or the grounding contact (4); The spacing between the sheds on the first mounting insulator (3a) and the second mounting insulator (3b) is arranged according to a preset spacing, and the number of shed groups on the first mounting insulator (3a) and the second mounting insulator (3b) is set as a preset number of groups.

2. A load break switch with improved electrical insulation properties according to claim 1, characterized in that, The driving component (6) includes a driving mechanism, a main shaft (61), a collar (62), and an arc-shaped push rod (63). The main shaft (61) is rotatably mounted on the frame (1) and connected to the driving end of the driving mechanism. One end of the collar (62) is sleeved with the main shaft (61), and the other end of the collar (62) is hinged with one end of the arc-shaped push rod (63). The other end of the arc-shaped push rod (63) is hinged with the moving contact. When the driving end of the driving mechanism drives the main shaft (61) to rotate relative to the frame (1), the collar (62) rotates with the rotation of the main shaft (61) and pushes and pulls the other end of the moving contact (52) through the arc-shaped push rod (63) so that the other end of the moving contact (52) swings.

3. A load break switch with enhanced electrical insulation properties according to claim 1, characterized in that, Both the first mounting insulator (3a) and the second mounting insulator (3b) include an integrally formed insulating column (31) and a plurality of skirt groups (32) arranged sequentially on the insulating column (31), wherein the preset number of skirt groups is 3-5.

4. A load break switch for improved electrical insulation performance according to claim 3, characterized in that The spacing between the umbrella skirts is the distance between two adjacent umbrella skirt groups (32), and the ratio between the preset spacing and the diameter of the insulating column (31) is 1 / 5 to 1 / 4.

5. A load switch for improving electrical insulation performance according to claim 1, characterized in that, The straight-line distance between the main blade stationary contact (2) and the moving contact (52), and the straight-line distance between the grounding contact (4) and the moving contact (52) are determined as the contact opening distance, and each of the contact opening distances is greater than 60mm.

6. A load switch for improving electrical insulation performance according to claim 1, characterized in that, The grounding contact (4) includes a first contact end (41) and a second contact end (42) formed by bending and integral molding. The first contact end (41) and the second contact end (42) are both placed vertically at the bottom of the frame (1). The second contact end (42) is connected to a baffle extending upward from the bottom of the frame (1). The first contact end (41) is dynamically attached to the other end of the moving contact (52).

7. A design method for a load switch to improve electrical insulation performance, characterized in that, The design method, applied to a load switch with improved electrical insulation performance as described in any one of claims 1-6, comprises: Based on the predetermined design requirements, the corresponding target voltage level and environmental conditions are obtained. Based on the target voltage level, the electrical insulation performance target that the load switch needs to meet under at least one disconnection condition is determined. According to the electrical insulation performance target and the environmental conditions, the corresponding constraints are determined. The constraints include at least creepage distance constraints and minimum spatial separation distance constraints. Based on the creepage distance constraint, the surface creepage path characteristics of the insulating component are determined; Based on the minimum spatial separation distance constraint and the surface creepage path characteristics, the separation spacing characteristics of the insulating components are determined. Based on the surface creepage path characteristics and the separation spacing characteristics, a corresponding target insulating component is designed, and a corresponding load switch is designed based on the target insulating component. The target insulating component includes at least a first mounting insulator and a second mounting insulator.

8. The design method for a load switch to improve electrical insulation performance according to claim 7, characterized in that, The step of determining the corresponding constraints based on the electrical insulation performance target and the environmental conditions includes: Based on the electrical insulation performance targets, determine the maximum permissible surface electric field strength and maximum spatial electric field strength of the insulating component under disconnection conditions; Based on the maximum surface electric field intensity, the minimum surface path length required to avoid creepage discharge along the surface of the insulating member is determined, and the minimum surface path length is determined as the creepage distance constraint condition. Based on the maximum spatial electric field strength and the relative geometric state between the contacts under the disconnection condition, the minimum spatial gap required under the disconnection condition is derived. Based on the minimum spatial gap and the environmental conditions, the corresponding minimum spatial separation distance constraint is determined.

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