A ring main unit equipped with a bushing assembly with a load-bearing support structure

Abstract

This utility model belongs to the field of ring main unit technology and discloses a ring main unit with a bushing assembly equipped with a load-bearing support structure. The ring main unit consists of a cable working compartment, a switch compartment, a mechanism compartment, a control box compartment, a control box panel, a mechanism compartment panel, and a cable compartment door, all fixedly connected together. The switch compartment, from top to bottom, is equipped with a gas box unit, a circuit breaker mechanism, an isolation mechanism, a bushing assembly, and a current transformer, all fixedly assembled together. The bushing assembly includes a pressure plate support, a bushing, a welded bushing pressure plate, a pressure plate nut, and a tapered rubber sleeve, all fixedly assembled together. This utility model creatively integrates support and fixing functions. It directly improves the existing "bushing pressure plate" (a standard component) by integrating or fixing a stainless steel cylindrical support component directly below the corresponding bushing.

Description

Technical Field

[0001] This utility model belongs to the field of ring main unit technology, and in particular relates to a ring main unit with a sleeve assembly with a load-bearing support structure. Background Technology

[0002] In 10kV distribution networks, ring main units (RMMs) are crucial electrical equipment. Their internal current transformers (CTs) typically employ a three-phase integrated structure, combining protection and measurement windings. To meet the measurement accuracy and protection sensitivity requirements under different operating conditions, current transformers need to be designed with different transformation ratios. When the transformer's transformation ratio is small and the accuracy requirement is high, its core cross-section needs to be increased, and the number of winding turns needs to be increased, directly leading to a significant increase in the overall size, thickness, and weight of the transformer. The weight of a current transformer (CT) can sometimes reach tens of kilograms, directly pressing onto the epoxy resin insulation of the bushing, forming a huge static load.

[0003] In existing technologies, these heavy three-phase integrated current transformers are typically fixed directly to their mounting bases, relying on bushings on the ring main unit's gas box as the primary electrical connection and mechanical support points. The bushings themselves are cast from insulating materials such as epoxy resin, and their mechanical strength, especially their resistance to bending and shearing, is limited.

[0004] Based on the above analysis, the problems and shortcomings of the existing technology are as follows: Excessive mechanical load can damage the bushing: The heavy transformer body applies a continuous downward static load to the bushing. During the transportation of the ring main unit, bumps and vibrations will generate additional dynamic loads and bending moments, which can easily exceed the mechanical strength limit of the bushing, leading to breakage at the bushing root.

[0005] High risk of gas box seal failure: Bushings are typically connected to the ring main unit's gas box (SF6 gas / environmentally friendly gas insulated enclosure) via sealing rings. The weight of the transformer can cause slight deformation of the bushing, which, over time, may compromise the integrity of the sealing structure. This problem is amplified, especially during transport vibrations or cable installation, leading to gas box leakage, decreased insulation performance, and potentially serious operational accidents.

[0006] Superimposed stress during cable installation: When installing incoming and outgoing cables on site, the cables themselves are under stress (such as bending stress and tensile force), which is transmitted to the bushing through the cable head. Under the existing structure, the bushing must simultaneously bear the weight of the transformer and the cable stress, forming a combined stress state, which further exacerbates the risk of bushing breakage and gas box leakage.

[0007] High maintenance costs and reduced power supply reliability: If a bushing breaks or the gas box leaks, it cannot be repaired on-site. The entire ring main unit must be returned to the factory or replaced. The maintenance cycle is long and the cost is high, which leads to longer power outage time for users and seriously affects the reliability of power supply. Utility Model Content

[0008] To overcome the problems existing in related technologies, this utility model discloses a ring main unit with a bushing assembly equipped with a load-bearing support structure. Specifically, it relates to a pressure plate assembly for the bushing of a ring main unit and the ring main unit itself.

[0009] The technical solution is as follows: A ring main unit with a bushing assembly having a load-bearing support structure is assembled together by a cable working compartment, a switch compartment, a mechanism compartment, a control box compartment, a control box panel, a mechanism compartment panel, and a cable compartment door through a fixed connection; the switch compartment is assembled together by a gas box unit, a circuit breaker mechanism, an isolation mechanism, a bushing assembly, and a current transformer in sequence from top to bottom; The sleeve assembly includes: pressure plate support, sleeve, sleeve pressure plate welding, pressure plate nut, and tapered rubber sleeve fixed together.

[0010] Furthermore, the cable compartment door is connected to the interlocking device of the isolation mechanism.

[0011] Furthermore, the gas box unit is equipped with a main busbar, circuit breaker switch, and conductive components of a three-position isolating / grounding switch; the gas box unit is equipped with a circuit breaker mechanism and an isolation mechanism for controlling the closing, opening, and grounding of the circuit breaker switch, three-position isolating / grounding switch, and the gas box unit itself.

[0012] The sleeve assembly for electrical connection between the conductive components inside the gas box unit and the external flexible cable is installed at the lower end of the gas box unit.

[0013] A current transformer used to proportionally convert a large primary current into a standard small current is mounted on a bushing assembly. The sleeve pressure plate is fixed together with the sleeve pressure plate and the cylindrical support by welding. Bushing clamps are used to fix and fasten bushings, and cylindrical supports are used to support current transformers. The pressure plate support is a cylindrical support component used to support the sleeve pressure plate on the sleeve pressure plate during welding.

[0014] The conical rubber sleeve is embedded between the cylindrical support member welded to the sleeve and the sleeve pressure plate, and is used to fix, protect and buffer the sleeve.

[0015] The pressure plate support is mounted on the sheet metal gas box unit on the switch chamber, corresponding to the energy storage welding screw.

[0016] Combining all the above technical solutions, the beneficial effects of this utility model are as follows: This invention aims to solve the problem of excessive mechanical stress on the bushings of ring main unit caused by the excessive weight of three-phase integrated current transformers. It provides a simple and easy-to-install support device that effectively distributes the load applied to the bushings by the transformer, significantly reducing the risk of bushing breakage and gas box seal failure, and improving the mechanical reliability and sealing stability of the ring main unit during transportation, installation, and operation.

[0017] This utility model creatively integrates the supporting and fixing functions into one. Instead of adding support elsewhere, it directly improves the existing "sleeve pressure plate" (a standard part) by designing or fixing a stainless steel cylindrical support component directly below the corresponding sleeve. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure; Figure 1 This is a schematic diagram of a ring main unit with a sleeve assembly having a load-bearing support structure provided in this embodiment of the utility model; Figure 2 This is a schematic diagram of the structure of each component of the switch chamber provided in this embodiment of the utility model; Figure 3 This is a schematic diagram of the structure of each component of the sleeve assembly provided in this embodiment of the utility model; Figure 4 This is a schematic diagram of the conical rubber sleeve provided in an embodiment of the present utility model; Figure 5 This is a schematic diagram of the welding components of the sleeve pressure plate provided in this embodiment of the utility model; Figure 6 This is a three-dimensional rendering of the welding components of the sleeve pressure plate provided in this embodiment of the utility model; In the diagram: 1. Cable working compartment; 2. Switch room; 210. Gas box unit; 220. Circuit breaker mechanism; 230. Isolation mechanism; 240. Bushing assembly; 2401, pressure plate support; 2402, sleeve; 2403, sleeve pressure plate welding; 2403-1, Sleeve clamping plate; 2403-2, Cylindrical support component; 2404, pressure plate nut; 2405, tapered rubber sleeve; 250. Current transformer; 3. Mechanism room; 4. Control box room; 5. Control box panel; 6. Mechanism room panel; 7. Cable room door. Detailed Implementation

[0019] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0020] Example 1, such as Figures 1-6 As shown, the ring main unit equipped with a bushing assembly with a load-bearing support structure is assembled together by a fixed connection of the cable working compartment 1, switch compartment 2, mechanism compartment 3, control box compartment 4, control box panel 5, mechanism compartment panel 6, and cable compartment door 7.

[0021] A switch chamber 2 is installed above the rear of the cable working compartment 1, and a mechanism chamber 3 is installed above the front of the cable working compartment 1. The mechanism chamber 3 and the switch chamber 2 are fixedly connected together.

[0022] The control box 4 is installed on top of the mechanism room 3. Inside the control box 4 are various secondary components that monitor the various states of the ring main unit.

[0023] The control panel 5 is installed at the front of the control box 4, protecting the secondary components inside the control box 4.

[0024] The mechanism chamber panel 6 is installed directly in front of the mechanism chamber 3 and the two are fixed together by screws (not shown in the figure).

[0025] The cable compartment door 7 is installed directly in front of the cable working compartment 1; like Figure 2 As shown, the switch compartment 2 is equipped with a gas box unit 210, a circuit breaker mechanism 220, an isolation mechanism 230, a bushing assembly 240, and a current transformer 250, which are fixedly assembled together from top to bottom. like Figure 3 As shown, the sleeve assembly 240 includes: a pressure plate support 2401, a sleeve 2402, a sleeve pressure plate weld 2403, a pressure plate nut 2404, and a tapered rubber sleeve 2405 (e.g., Figure 4 They are fixedly combined together; For example, the cable compartment door 7 is connected to and interlocked with the isolation mechanism 230 to prevent accidental entry into the energized compartment.

[0026] The gas box unit 210 contains conductive components such as a main busbar, circuit breaker switch, and three-position isolating / grounding switch. The gas box unit 210 is equipped with a circuit breaker mechanism 220 and an isolating mechanism 230, which control the closing, opening, and grounding of the circuit breaker switch and the three-position isolating / grounding switch inside the gas box unit 210.

[0027] The sleeve assembly 240 is installed at the lower end of the air box unit 210 to realize the electrical connection between the conductive components inside the air box unit 210 and the external flexible cable.

[0028] The current transformer 250 is mounted on the bushing assembly 240. Its function is to convert the large current on the primary side (e.g., 630A current on the 10kV side) into a standard small current (usually 5A or 1A) proportionally, and provide it to measuring instruments, energy meters, relay protection devices and other equipment.

[0029] like Figure 3 The sleeve pressure plate welding 2403 is a key structural and functional component in the assembly of the ring main unit's gas box. Its core function is to achieve a reliable connection and integration between the sleeve 2402 and the sealing components on the sleeve and the gas box sheet metal through bolt fastening, using fasteners such as the pressure plate support 2401 and pressure plate nut 2404. It plays a role in mechanical fixing and support.

[0030] like Figure 5 , Figure 6 As shown, the bushing clamping plate welding 2403 is formed by fixing the bushing clamping plate 2403-1 and the cylindrical support member 2403-2 together by welding. The bushing clamping plate 2403-1 secures the bushing 2402, while the cylindrical support member 2403-2 supports the current transformer 250, fundamentally dispersing and offsetting the weight of the transformer and external stress, thereby improving the mechanical stability and overall reliability of the bushing.

[0031] like Figure 4 The conical rubber sleeve 2405 is embedded between the cylindrical support 2403-2 on the sleeve 2402 and the sleeve pressure plate weld 2403, and plays a role in fixing, protecting and buffering the sleeve 2402.

[0032] The cylindrical support component 2403-2 is made of stainless steel, ensuring sufficient mechanical strength, rigidity, and resistance to environmental corrosion. The cylindrical design simplifies manufacturing, provides structural stability, and facilitates precise height adjustment, ensuring effective and reliable rigid contact between the support component and the load-bearing base.

[0033] Working principle.

[0034] Assembly steps for ring main units with bushing assemblies featuring load-bearing support structures: Step 1: Install sleeve 2402. Install sleeve 2402 into the corresponding hole on the sheet metal air box of air box unit 210 on switch chamber 2. Step 2: Install the pressure plate support 2401. Install the pressure plate support 2401 on the energy storage welding screw corresponding to the sheet metal air box on the air box unit 210 on the switch chamber 2. The pressure plate support 2401 is a cylindrical support 2403-2, which is mainly used to support the bushing pressure plate 2403-1 on the bushing pressure plate welding 2403. Step 3: Install bushing pressure plate welding 2403. Install bushing pressure plate welding 2403 on the air box unit 210 on the installation switch chamber 2 of 2401 according to the corresponding bushing hole positions. Note that there are 3 claws in the 3 holes of bushing pressure plate 2403-1, which correspond to the 3 grooves on bushing 2402 respectively. They fix bushing 2402, prevent bushing 2402 from rotating, and ensure airtightness. Step 4: Install pressure plate nut 2404. Install pressure plate nut 2404 on the sheet metal gas box corresponding to the energy storage welding screw on the gas box unit 210 on the switch chamber 2. Note that you should first pre-tighten by hand, and then use a torque wrench to tighten it diagonally in sequence. After tightening, the bushing pressure plate welding 2403 will press the bushing 2402 to ensure airtightness. Step 5: Place the conical rubber sleeve 2405. Insert the conical rubber sleeve 2405 between the sleeve 2402 and the cylindrical support 2403-2 on the sleeve pressure plate welding 2403. The conical rubber sleeve 2405 can fix, protect and buffer the sleeve 2402.

[0035] Working principle (1) During transportation or on-site installation, there is a mounting bracket under the current transformer 250. The mounting bracket ensures that the three-phase bushing hole of the current transformer 250 is coaxial with the cylindrical support 2403-2 on the bushing pressure plate 2403-1. In this way, the current transformer 250 will not put pressure on the bushing 2402 due to its own weight.

[0036] The inner surface of the three-phase bushing hole of the current transformer 250 is in contact with the outer surface of the cylindrical support 2403-2, so the current transformer 250 will not directly press down on the bushing 2402, thus overcoming the force of the weight of the current transformer 250 itself on the bushing 2402.

[0037] (2) When installing incoming and outgoing cables on site, the sleeve 2402 is supported by the cylindrical support 2403-2 and the conical rubber sleeve 2405 on the sleeve pressure plate 2403-1. The weight of the cable and cable accessories (hereinafter referred to as: cable assembly) or the stress of the cable itself will not be directly pressed on the sleeve 2402. Under the support of the cylindrical support 2403-2 and the conical rubber sleeve 2405, the weight of the cable assembly and its own stress cannot cause the sleeve 2402 to move in any direction, thus preventing air leakage or breakage at the installation point of the sleeve 2402. This fundamentally solves the pain points and difficulties in the industry.

[0038] The cable accessories of the cable assembly extend into the cylindrical support 2403-2. The outer surface of the cable accessories is in contact with the inner surface of the cylindrical support 2403-2. Under the action of the cylindrical support 2403-2, the weight and stress of the cable assembly itself will not directly act on the sleeve 2402, thus solving the problem of the superimposed force of the cable on the sleeve 2402.

[0039] It can be seen that the technical solution of this utility model is novel, the structure is simple, and the solution takes into account both low cost and high reliability, and is flexible and convenient to install. This utility model achieves fundamental optimization of the force path through a clever and simple structural supplement, directly addressing the long-standing pain point of mechanical damage to the 2402 bushing in the industry, and effectively improving the overall reliability of ring main unit products. It is a practical innovation with great market application value.

[0040] This utility model does not require major modifications to the main structure of the ring main unit, the transformer, or the gas box. It only requires adding a standard component (bushing assembly 240) to the existing pressure plate. The modification cost is extremely low, the production and installation process is simple, and it is easy to promote and implement. It has significant economic benefits and practicality.

[0041] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0042] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any modifications, equivalent substitutions and improvements made by those skilled in the art within the scope of the technology disclosed in the present utility model, within the spirit and principles of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A ring main unit equipped with a bushing assembly with a load-bearing support structure, comprising a switch compartment (2), a mechanism compartment (3), a control box compartment (4), a control box panel (5), a mechanism compartment panel (6), and a cable compartment door (7) assembled together by a fixed connection; characterized in that, The switch room (2) is equipped with, from top to bottom, a gas box unit (210), a circuit breaker mechanism (220), an isolation mechanism (230), a bushing assembly (240), and a current transformer (250); the gas box unit (210) is equipped with a main busbar, a circuit breaker switch, and conductive components of a three-position isolating / grounding switch. The gas box unit (210) is equipped with a circuit breaker mechanism (220) and an isolation mechanism (230) for controlling the closing, opening and grounding of the internal circuit breaker switch, three-position isolating / grounding switch and the gas box unit (210). The sleeve assembly (240) includes: a fixedly installed pressure plate support (2401), a sleeve (2402), a sleeve pressure plate weld (2403), a pressure plate nut (2404), and a conical rubber sleeve (2405); the sleeve pressure plate weld (2403) is fixed together by welding the sleeve pressure plate (2403-1) and the cylindrical support (2403-2); the sleeve pressure plate (2403-1) is used to fix and tighten the sleeve (2402), and the cylindrical support... The support member (2403-2) is used to support the current transformer (250); the pressure plate support (2401) is a cylindrical support member (2403-2) used to support the bushing pressure plate (2403-1) on the bushing pressure plate weld (2403); the conical rubber sleeve (2405) is embedded between the cylindrical support member (2403-2) on the bushing (2402) and the bushing pressure plate weld (2403) and is used to fix, protect and buffer the bushing (2402).

2. The ring main unit with a bushing assembly having a load-bearing support structure as described in claim 1, characterized in that, The cable compartment door (7) is connected to the interlocking device on the isolation mechanism (230).

3. The ring main unit with a bushing assembly having a load-bearing support structure as described in claim 1, characterized in that, A sleeve assembly (240) for electrical connection between the conductive components inside the gas box unit (210) and the external flexible cable is installed at the lower end of the gas box unit (210).

4. The ring main unit with a bushing assembly having a load-bearing support structure as described in claim 1, characterized in that, A current transformer (250) for proportionally converting a large primary current into a standard small current is mounted on a bushing assembly (240).

5. The ring main unit with a bushing assembly having a load-bearing support structure as described in claim 1, characterized in that, The pressure plate support (2401) is installed on the sheet metal gas box corresponding to the energy storage welding screw on the gas box unit (210) on the switch chamber (2).

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