Environment-friendly gas insulation ring main unit

Abstract

The invention relates to an environment-friendly gas insulation ring main unit which comprises a gas chamber and a vacuum arc-extinguishing chamber arranged in the gas chamber, the vacuum arc-extinguishing chamber comprises a shell and a moving contact arranged in the shell, the environment-friendly gas insulation ring main unit further comprises a static contact assembly, the static contact assembly comprises a static contact rod, a center hole is formed in the static contact rod, a guide hole is formed in the side of the center hole, and a sliding groove is formed in the static contact rod; the floating contact is movably arranged at the front end of the static contact rod, and an avoiding hole is formed in the axis of the floating contact in a penetrating manner; the guide rod is fixedly arranged at the rear end of the floating contact and is assembled in the guide hole in an anti-drop manner; the insulating feeler lever is slidably assembled in the center hole, and the front end of the insulating feeler lever penetrates through the avoiding hole; the elastic buffer assembly comprises a main spring and a reset spring; the damping matching structure is used for providing axial motion damping; the thrust matching structure comprises a first thrust block and a second thrust block, the first thrust block is located in front of the second thrust block, and the first thrust block and the second thrust block both slide along the sliding groove; and the floating contact is electrically connected with the static contact rod. Rigid impact is avoided, and closing bounce is eliminated.

Description

Technical Field

[0001] This invention relates to the field of ring main unit equipment, specifically to an environmentally friendly gas-insulated ring main unit. Background Technology

[0002] As global requirements for controlling the greenhouse effect become increasingly stringent, sulfur hexafluoride (SF6) gas, which has extremely high global warming potential, is being phased out in the medium-voltage power distribution sector. A new generation of environmentally friendly gas-insulated ring main units (typically using dry air or nitrogen) has emerged to meet this need.

[0003] In environmentally friendly gas-insulated ring main units, the vacuum interrupter is the core component for load interruption and short-circuit current cutoff. Because the insulation performance of environmentally friendly gases is typically slightly lower than that of SF6, and the arc-extinguishing capability mainly depends on the vacuum interrupter itself, the performance requirements for the interrupter are more stringent. These ring main units usually employ a fully sealed gas-filled structure, requiring the equipment to have extremely high maintenance-free operation and mechanical reliability.

[0004] Existing environmentally friendly gas-insulated ring main units generally suffer from the following technical bottlenecks in the configuration of vacuum interrupters: To ensure the compactness of the gas box structure and the stability of the insulation distance, the stationary contacts of traditional vacuum interrupters are usually rigidly fixed to the busbar side of the gas box, or fixed only by tiny adjusting shims. However, the spring operating mechanism of the ring main unit, in order to ensure rapid closing of short-circuit current, has a large closing output power, a fast closing speed of the moving contacts, and a large impact force.

[0005] When a high-speed moving contact strikes a rigid stationary contact, the enormous kinetic energy is instantly converted into impact force. This "hard-on-hard" rigid impact can have serious consequences: the contact rebounds at the moment of contact, causing closing bounce; a pre-breakdown arc is generated between the moving and stationary contacts, resulting in severe electro-erosion and welding on the contact surface, directly reducing the electrical life of the arc-extinguishing chamber. The impact vibration is transmitted to the bellows and ceramic shell sealing joint of the arc-extinguishing chamber. Long-term operation may lead to micro-cracks in the bellows or air leakage at the sealing joint, causing a decrease in vacuum and triggering insulation accidents. Summary of the Invention

[0006] The purpose of this invention is to provide an environmentally friendly gas-insulated ring main unit that can effectively absorb closing impacts and eliminate bounce, while also limiting opening follow-up to ensure the breaking speed.

[0007] The technical solution of the environmentally friendly gas-insulated ring main unit of the present invention is as follows: An environmentally friendly gas-insulated ring main unit includes a gas chamber and a vacuum interrupter disposed within the gas chamber. The vacuum interrupter includes a housing and a stationary contact assembly and a moving contact disposed within the housing. The stationary contact assembly includes: The stationary contact rod has a central hole along its central axis, at least one guide hole on the side of the central hole, and an axially extending groove inside the stationary contact rod that connects the guide hole and the central hole. A floating contact is movably disposed at the front end of the stationary contact rod, and a clearance hole is provided through the axis of the floating contact; The guide rod is fixedly installed at the rear end of the floating contact, and extends backward to be fitted into the guide hole of the stationary contact rod to prevent detachment. An insulating contact rod is slidably fitted axially in the center hole of a stationary contact rod, with its front end passing through the clearance hole and extending to the front of the floating contact. The elastic buffer assembly includes a main spring assembled between the guide rod and the stationary contact rod; and a return spring disposed in the central hole and exerting a forward moving force on the insulating contact rod. A damping mechanism is provided between the insulating contact rod and the central hole to provide axial motion damping; The thrust-stopping structure includes a first thrust block disposed on the side wall of the insulating contact rod and a second thrust block disposed on the side wall of the guide rod. The first thrust block is located in front of the second thrust block, and both extend into the groove and slide along the groove. The floating contact and the stationary contact rod maintain an electrical connection; During the opening process, the insulating contact rod moves with a lag due to damping, and the first thrust block on it blocks the movement of the second thrust block in the slide groove to limit the separation speed of the floating contact relative to the stationary contact rod.

[0008] Furthermore, two guide holes are symmetrically arranged around the central hole, and two corresponding guide rods are also provided. The sliding grooves are respectively connected to the central hole and the guide holes on both sides, forming a double-sided symmetrical balanced thrust structure.

[0009] Furthermore, the stationary contact rod includes a first inner insulating layer and a first metal conductive layer covering the outside of the first inner insulating layer, and the central hole and the guide hole are both arranged in the first inner insulating layer; the floating contact includes a second inner insulating layer and a second metal conductive layer covering the outside of the second inner insulating layer; the clearance hole is formed in the second inner insulating layer.

[0010] Furthermore, the first metal conductive layer of the stationary contact rod bends inward at the front end to form a shielding end plate covering the front end face of the first inner insulating layer. The shielding end plate has a central through hole for the insulating contact rod to pass through and a side through hole for the guide rod and the main spring to pass through. The edges of the central through hole and the side through hole are provided with smooth chamfers or inwardly folded shielding ring lips.

[0011] Furthermore, the front end of the first metal conductive layer is provided with an axially extending annular conductive groove, and the rear end of the second metal conductive layer is provided with a protruding annular conductive sleeve. Within the floating stroke range of the floating contact, the annular conductive sleeve is always located within the annular conductive groove and maintains a sliding electrical connection.

[0012] Furthermore, the damping fit structure is provided with a high friction coefficient coating or surface roughening treatment on the outer wall of the insulating contact rod and / or the inner wall of the central hole, and the damping is provided by the static friction force generated by the interference fit.

[0013] Furthermore, an annular groove is formed on the inner wall of the central hole or the outer wall of the insulating contact rod, and the damping fit structure includes an elastic damping ring disposed in the annular groove.

[0014] Furthermore, a buffer spring is provided between the first thrust block and the second thrust block.

[0015] Furthermore, an anti-detachment block is provided on the side wall of the guide rod. The anti-detachment block extends into the slide groove and engages with the slide groove for limiting. The anti-detachment block is located in front of the second thrust block and the first thrust block.

[0016] The beneficial effects of this technical solution are as follows: The environmentally friendly gas-insulated ring main unit involved in this invention adopts a logic structure of "damping hysteresis + sliding groove thrust". At the moment of opening, the insulating contact rod, which is limited by high damping, is used as a brake. The first thrust block blocks the second thrust block, forcibly restricting the following movement of the floating contact. This makes the stationary contact almost stationary when the moving contact is quickly withdrawn, thereby maximizing the relative separation speed of the moving and stationary contacts and significantly improving the opening success rate of the vacuum interrupter in an environmentally friendly gas-insulated environment.

[0017] During closing, the moving contact first contacts the insulating contact rod, achieving primary buffering through a combination of a return spring and damping structure. Then, it contacts the floating contact, achieving secondary buffering through the main spring. The enormous kinetic energy is absorbed in stages. At the same time, the flexible connection between the floating contact and the stationary contact rod avoids rigid impact, effectively eliminating closing bounce and protecting the service life of the contact surface and bellows.

[0018] Meanwhile, during the stroke, the floating contact and the stationary contact rod remain electrically connected, completely eliminating the risk of internal parasitic arcing caused by instantaneous separation in traditional end-face contact. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a specific embodiment of the environmentally friendly gas-insulated ring main unit of the present invention; Figure 2 for Figure 1 Side view; Figure 3 forFigure 2 Cross-sectional view of a medium vacuum interrupter; Figure 4 for Figure 3 A magnified view of part A; Figure 5 for Figure 3 Mid-break switch status diagram; Figure 6 for Figure 5 Enlarged view of section B in the middle.

[0020] In the diagram: 1-cabinet; 11-gas chamber; 12-operation panel; 13-circuit breaker; 14-vacuum interrupter; 2-Stationary contact rod; 21-First inner insulation layer; 211-Center hole; 212-Guide hole; 213-Groove; 22-First conductive metal layer; 221-Annular conductive groove; 222-Shielding end plate; 223-Shielding lip; 224-Side through hole; 225-Central through hole; 3-Floating contact; 31-Second inner insulation layer; 311-Allowing hole; 32-Second metal conductive layer; 321-Circumferential conductive sleeve; 33-Guide rod; 331-Second thrust block; 4-Insulating contact rod; 41-First thrust block; 5-Main spring; 6-Return spring; 7-Buffer spring; 8-Friction surface; 9-Moving contact; 10-Bellwall. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0024] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0025] A specific embodiment of the environmentally friendly gas-insulated ring main unit of the present invention: as follows Figures 1 to 6 As shown, the structure of the environmentally friendly gas-insulated ring main unit is as follows: Figure 1 and Figure 2 As shown, it includes a cabinet 1, with an operation panel 12 on the front side of the cabinet 1, and an air chamber 11 on one side of the cabinet 1. The air chamber 11 contains a circuit breaker 13, a disconnect switch, etc. (For...) Figure 2 The structure of the vacuum interrupter 14 in the circuit breaker 13 is as follows: Figure 3 As shown, it includes a housing, a stationary contact assembly, a moving contact 9, a bellows 10, and other structures. The lower part of the arc-extinguishing chamber is the moving end, which includes a moving contact rod that achieves vacuum sealing by means of the bellows 10, and its top end is provided with a flat or finger-shaped moving contact 9.

[0026] The stationary contact assembly mainly includes a stationary contact rod 2, a floating contact 3, a guide rod assembly, an insulating contact rod 4, and corresponding buffer, damping, and conductive structures.

[0027] The structure of the stationary contact rod 2 is as follows Figure 3 As shown, the base rod adopts a composite material structure, including a first inner insulating layer 21 located in the core (the material can be alumina ceramic or high-strength insulating engineering plastic, without specific limitation) and a first metal conductive layer 22 tightly covering the outside, wherein the first metal conductive layer 22 covers the front end of the first inner insulating layer 21. At the axial position of the first inner insulating layer 21, a rearwardly extending central hole 211 is precisely machined, and two guide holes 212 are symmetrically and parallelly opened on both sides of the central hole 211. In addition, a groove 213 is formed in the first inner insulating layer 21, which radially penetrates the central hole 211 and the guide holes 212 on both sides. The groove 213 has a predetermined length along the axial direction, forming a mating window between the central hole 211 and the guide holes 212.

[0028] The floating contact 3 is located at the front end of the stationary contact rod 2 and also adopts a composite structure, including a second inner insulating layer 31 and a second metal conductive layer 32 covering the outside of the second inner insulating layer 31. The center of the second inner insulating layer 31 has a clearance hole 311 for the insulating contact rod 4 to pass through. There are two guide rods 33, which are fixed to the rear end face of the floating contact 3 and extend rearward to be inserted into the two guide holes 212 of the stationary contact rod 2. The guide rod 33 is provided with an anti-disengagement limiting structure to prevent it from sliding out completely. In this embodiment, the anti-disengagement limiting structure is an anti-disengagement block set on the side wall of the guide rod 33, which slides and is fitted in the slide groove 213 and cooperates with the front end limiting of the slide groove 213 to achieve anti-disengagement. A main spring 5 is sleeved on the guide rod 33, which is located on the front side of the first insulating layer. One end of the main spring 5 abuts against the rear end of the floating contact 3, and the other end abuts against the front end face of the first inner insulating layer 21, providing the forward reset spring force for the floating contact 3.

[0029] The insulating contact rod 4 is slidably fitted into the central hole 211, with its front end passing through the clearance hole 311 and extending forward. It can be made of high-temperature resistant ceramic material. A damping fit structure is provided between the insulating contact rod 4 and the central hole 211. In this embodiment, the damping fit structure can be formed by providing a high coefficient of friction coating on the outer wall of the insulating contact rod 4 and / or the inner wall of the central hole 211, or by forming a friction surface 8 through surface roughening treatment. The static friction force generated by the interference fit provides damping, that is, the two achieve a large inelastic static friction resistance buffer through the surface contact of the high coefficient of friction.

[0030] Additionally, a first thrust block 41 is radially extended and fixed to the side wall of the insulating contact rod 4, and correspondingly, a second thrust block 331 is radially extended and fixed to the side walls of the two guide rods 33. Both the first thrust block 41 and the second thrust block 331 extend into the slide groove 213. Spatially, the first thrust block 41 is located in front of the second thrust block 331 to reduce the tendency of the floating contact 3 to move forward. Furthermore, to reduce rigid collisions, a miniature buffer spring 7 is preferably provided between the first thrust block 41 and the second thrust block 331.

[0031] Preferably, the axial length of the groove 213 is limited to the forming range of the thrust block, and the groove 213 does not penetrate to the front end face of the stationary contact rod 2, ensuring that the groove 213 is always in a closed or semi-closed environment inside the stationary contact rod 2, preventing the metal vapor generated by the electric arc from entering the groove 213 and causing an electrical short circuit between the insulating contact rod 4 and the guide rod 33.

[0032] A return spring 6 is provided at the bottom of the central hole 211, which abuts against the tail of the insulating contact rod 4, giving it a tendency to return to its original position.

[0033] To achieve flexible buffering during closing and forced lag during opening, the damping mechanism is designed to provide a sliding damping force approximately half that of the main spring 5. Furthermore, after closing, the buffer spring 7 between the first thrust block 41 and the second thrust block 331 is subjected to extreme compression, approaching its compression limit. In actual testing, approximately 5mm-8mm of compression remains before reaching the compression limit. This ensures that during opening, the guide rod 33 can move forward a certain distance due to the force of the main spring 5, without affecting the rapid opening operation between the moving contact 9 and the floating contact 3.

[0034] In addition, to ensure reliable conductivity during the floating process and to prevent metal vapor contamination, the front end of the first conductive metal layer is machined with an axially recessed annular conductive groove 221, which can be provided with a contact finger or a tight-fitting surface. The rear end of the second conductive metal layer 32 is machined into a protruding annular conductive sleeve 321. The annular conductive sleeve 321 is inserted into the groove, and the insertion depth can cover the entire stroke of the floating contact 3. This constitutes a piston-type sliding electrical connection.

[0035] The front edge of the first metal conductive layer 22 is bent inward to form a shielding end plate 222, which completely covers the front end face of the first inner insulating layer 21. A central through hole 225 and a side through hole 224 are formed on the shielding end plate 222 at the positions corresponding to the central hole 211 and the guide hole 212. The edges of the holes are all made into shielding ring lips 223 that are folded inward. These lips not only eliminate tip discharge, but also block metal particles that may fall into the holes.

[0036] Work process: When the circuit is closed, the moving contact 9 moves toward the stationary contact assembly and first contacts the front end of the insulating contact rod 4. The insulating contact rod 4 overcomes the damping force generated by the friction surface 8 on the inner wall of the central hole 211 and the elastic force of the return spring 6 and begins to retract. At this time, the first thrust block 41 in the slide groove 213 retracts accordingly.

[0037] Next, the moving contact 9 contacts the floating contact 3, and the moving contact 9 pushes the floating contact 3 and the guide rod 33 backward together, compressing the main spring 5. At this time, the second thrust block 331 on the guide rod 33 moves backward in the slide groove 213. Since the insulating contact has been pushed in, the two thrust blocks remain separated or move backward synchronously, without interfering with each other. Finally, the circumferential conductive sleeve 321 slides into a deeper position in the circumferential groove, and the circuit is reliably connected. The whole process avoids risks such as rigid collision, closing bounce and vibration.

[0038] When the circuit breaker is opened, the moving contact 9 retracts rapidly under the action of the operating mechanism. At this time, the main spring 5 releases energy and pushes the floating contact 3 to try to follow the moving contact 9 forward and accelerate.

[0039] However, the slight displacement of the floating contact 3 drives the guide rod 33 forward, causing the second thrust block 331 to quickly strike the first thrust block 41 within the slide groove 213. At this time, the action of the buffer spring 7 greatly reduces the impact force, causing the buffer spring 7 to be compressed.

[0040] The insulating contact rod 4 connected to the first thrust block 41 is subjected to huge resistance generated by static friction, and its movement speed is extremely slow, exhibiting a great motion lag. Therefore, the first thrust block 41 blocks the forward movement path of the second thrust block 331.

[0041] The floating contact 3 is thus restricted and cannot extend quickly, while the moving contact 9 leaves at full speed, thus creating a huge speed difference. The moving and stationary contacts instantly create enough insulation distance to ensure that the arc is extinguished.

[0042] After the arc is extinguished, the insulating contact rod 4 will extend under the continuous action of the reset spring 6, and the floating contact 3 will be reset to the initial state to prepare for the next closing.

[0043] This solution perfectly resolves the contradiction between the mechanical impact and the breaking speed faced by the vacuum interrupter 14 in the environmentally friendly gas-insulated ring main unit.

[0044] In other embodiments, the damping fit structure may also be designed to have an annular groove on the inner wall of the central hole 211 or the outer wall of the insulating contact rod 4, wherein the damping fit structure includes an elastic damping ring disposed in the annular groove.

[0045] In other embodiments, the electrical connection between the floating contact 3 and the stationary contact 2 can be achieved using a soft conductive strip.

[0046] In other embodiments, a semi-conductive shielding layer may be added between the inner insulating layer and the outer metal conductive layer of the stationary contact rod 2, and vacuum integral casting may be used to eliminate the potential for air gap discharge at the interface of dissimilar materials.

[0047] In other embodiments, the guide rod 33 may be designed as one or more, without specific limitation.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. An environmentally friendly gas-insulated ring main unit, comprising a gas chamber and a vacuum interrupter disposed within the gas chamber, the vacuum interrupter comprising a shell and a moving contact disposed within the shell, characterized in that, Also includes: The stationary contact assembly includes: The stationary contact rod has a central hole along its central axis, and at least one guide hole is provided on the side of the central hole. The stationary contact rod has an axially extending groove that connects the guide hole and the central hole. A floating contact is movably disposed at the front end of the stationary contact rod, and a clearance hole is provided through the axis of the floating contact; The guide rod is fixedly installed at the rear end of the floating contact, and extends backward to be fitted into the guide hole of the stationary contact rod to prevent detachment. An insulating contact rod is slidably fitted into the center hole of the stationary contact rod along the axial direction, with its front end passing through the clearance hole and extending to the front of the floating contact. The elastic buffer assembly includes a main spring assembled between the guide rod and the stationary contact rod; and a return spring disposed in the central hole and exerting a forward moving force on the insulating contact rod. A damping mechanism is provided between the insulating contact rod and the central hole to provide axial motion damping; The thrust-stopping structure includes a first thrust block disposed on the side wall of the insulating contact rod and a second thrust block disposed on the side wall of the guide rod. The first thrust block is located in front of the second thrust block, and both extend into the groove and slide along the groove. The floating contact and the stationary contact rod maintain an electrical connection; During the opening process, the insulating contact rod moves with a lag due to damping, and the first thrust block on it blocks the movement of the second thrust block in the slide groove to limit the separation speed of the floating contact relative to the stationary contact rod.

2. The environmentally friendly gas-insulated ring main unit according to claim 1, characterized in that, Two guide holes are symmetrically arranged around the central hole, and two corresponding guide rods are also provided. The sliding grooves are respectively connected to the central hole and the guide holes on both sides, forming a double-sided symmetrical balanced thrust structure.

3. The environmentally friendly gas-insulated ring main unit according to claim 1, characterized in that, The stationary contact rod includes a first inner insulating layer and a first metal conductive layer covering the outside of the first inner insulating layer. The central hole and the guide hole are both arranged in the first inner insulating layer. The floating contact includes a second inner insulating layer and a second metal conductive layer covering the outside of the second inner insulating layer. The clearance hole is formed in the second inner insulating layer.

4. The environmentally friendly gas-insulated ring main unit according to claim 3, characterized in that, The first metal conductive layer of the stationary contact rod bends inward at the front end to form a shielding end plate covering the front end face of the first inner insulating layer. The shielding end plate has a central through hole for the insulating contact rod to pass through and a side through hole for the guide rod and the main spring to pass through. The edges of the central through hole and the side through hole are provided with smooth chamfers or inwardly folded shielding ring lips.

5. The environmentally friendly gas-insulated ring main unit according to claim 3, characterized in that, The first metal conductive layer has an axially extending annular conductive groove at its front end, and the second metal conductive layer has a protruding annular conductive sleeve at its rear end. Within the floating stroke range of the floating contact, the annular conductive sleeve is always located within the annular conductive groove and maintains a sliding electrical connection.

6. The environmentally friendly gas-insulated ring main unit according to claim 1, characterized in that, The damping fit structure is provided by applying a high friction coefficient coating or surface roughening treatment to the outer wall of the insulating contact rod and / or the inner wall of the central hole, and by using the static friction force generated by the interference fit to provide damping.

7. The environmentally friendly gas-insulated ring main unit according to claim 1, characterized in that, An annular groove is formed on the inner wall of the central hole or the outer wall of the insulating contact rod, and the damping fit structure includes an elastic damping ring disposed in the annular groove.

8. The environmentally friendly gas-insulated ring main unit according to claim 1, characterized in that, A buffer spring is provided between the first thrust block and the second thrust block.

9. The environmentally friendly gas-insulated ring main unit according to claim 1, characterized in that, The guide rod has an anti-detachment block on its side wall. The anti-detachment block extends into the slide groove and is matched with the slide groove for limiting. The anti-detachment block is located in front of the second thrust block and the first thrust block.

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