Three-position switch and ring main unit

Abstract

Provided in the present disclosure are a three-position switch (100) and a ring main unit (400). The three-position switch (100) comprises a first fixed base (1) and a plurality of grounding contacts (2), wherein each grounding contact (2) corresponds to one phase in the power supply of the ring main unit (400), and the plurality of grounding contacts (2) are all arranged on the first fixed base (1); a grounding shielding base (3) is provided on the first fixed base (1), the grounding shielding base (3) is configured as an integrally formed metal part, the grounding shielding base (3) is provided with a plurality of openings (301), and each grounding contact (2) is exposed from a corresponding opening (301); an isolated stationary contact (5) is correspondingly provided on each second fixed base (4); and a plurality of movable contacts (7) are provided at intervals on a third fixed base (6), and the movable contacts (7) can rotate relative to the third fixed base (6), so as to be selectively electrically connected to the grounding contacts (2) or isolated stationary contacts (5). By means of optimizing the electric field of the three-position switch (100), the three-position switch (100) can have a higher level of insulation, and the overall size of the three-position switch (100) can be reduced. Furthermore, the three-position switch (100) can also be applied to the small-size ring main unit (400) having space limitations and higher insulation requirements.

Description

Three-position switch and ring main unit

[0001] This application claims priority to Chinese patent application No. 2024212218035, filed on May 30, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to the field of ring main unit technology, and mainly to a three-position switch and a ring main unit. Background Technology

[0003] In switchgear, SF6 gas is commonly used for insulation due to its excellent insulating and arc-extinguishing properties. However, as a greenhouse gas, SF6 is detrimental to environmental protection. Currently, some manufacturers use dry air directly as the insulating gas, which is more economical and environmentally friendly. However, this often requires a larger insulation space in the switchgear, resulting in larger switchgear units. For smaller switchgear, especially medium- and high-voltage switchgear, using air as the insulating gas is still insufficient to meet the insulation requirements. Summary of the Invention

[0004] This disclosure provides a three-position switch and a ring main unit with good insulation performance, and also enables the three-position switch to be used in small-sized ring main units with space constraints.

[0005] According to one aspect of this application, a three-position switch is proposed, comprising: a first fixed base and a plurality of grounding contacts, each grounding contact corresponding to a phase in the power supply of a ring main unit, the plurality of grounding contacts being disposed on the first fixed base; a grounding shield, disposed on the first fixed base, the grounding shield being configured as an integrally formed metal part, the grounding shield having a plurality of openings, each grounding contact being exposed from a corresponding opening; a plurality of second fixed bases and a plurality of isolating stationary contacts, each second fixed base correspondingly disposed with one isolating stationary contact; a third fixed base and a plurality of moving contacts, the third fixed base having a plurality of moving contacts spaced apart, the moving contacts being rotatable relative to the third fixed base to selectively connect electrically with the grounding contacts or the isolating stationary contacts.

[0006] According to another aspect of this application, a ring main unit is proposed, including a cabinet and at least one three-position switch and a three-position operating mechanism as described in any of the above embodiments are disposed in the cabinet. The three-position operating mechanism is connected to the moving contact of the three-position switch and can drive the moving contact of the three-position switch to rotate.

[0007] This application discloses a three-position switch and a ring main unit. The three-position switch includes a first fixed base and multiple grounding contacts mounted on the first fixed base. The grounding shield is configured as an integrally formed metal component, uniformly enclosing the multiple grounding contacts together. Each grounding contact is exposed through a corresponding opening, allowing the moving contact to connect with the grounding contact. In this way, the grounding shield can optimize the electric field distribution of the grounding contacts and enhance insulation performance. Furthermore, the metal material of the grounding shield can provide good electromagnetic shielding for the grounding contacts. Compared to single-phase individually shielded grounding contacts, this reduces the risk of electrical faults at assembly or connection points. Simultaneously, it makes the structure on the grounding contact side more compact, reducing the overall size of the three-position switch. Moreover, it allows the three-position switch to be used in small-sized ring main units with space constraints, while also meeting the higher insulation requirements of small-sized ring main units. Attached Figure Description

[0008] The above and / or additional aspects and features of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0009] Figure 1 is a schematic diagram of a ring main unit according to some embodiments of this application;

[0010] Figure 2 is a perspective view of a three-position switch according to some embodiments of this application;

[0011] Figure 3 is a left view of a three-position switch according to some embodiments of this application;

[0012] Figure 4 is a schematic diagram showing the connection of the first fixed base, the grounding contact, and the grounding shield base according to some embodiments of this application;

[0013] Figure 5 is a schematic diagram of the second fixing base according to some embodiments of this application.

[0014] Implementation of this disclosure

[0015] The embodiments of this application are described in detail below, and the embodiments described with reference to the accompanying drawings are exemplary.

[0016] Traditional ring main units typically use SF6 gas insulation. While SF6 gas has excellent insulation and arc-quenching properties, it is a greenhouse gas and detrimental to environmental development. Therefore, using air insulation in existing ring main units aligns better with the concept of green and environmentally friendly development.

[0017] The smaller the size of a ring main unit, the weaker its insulation. In particular, when designing miniaturized ring main units that use dry air as the insulating gas, it is necessary to maintain the insulation performance of the unit while reducing its size.

[0018] Therefore, for small-sized ring main units, especially medium- and high-voltage ring main units, it is necessary to further improve the insulation performance within the cabinet. Among these components, the three-position switch is a critical element. The operation of a three-position switch involves three states: on, off, and grounded. Due to its diverse functions and operational complexity, the three-position switch may face high voltage and electric field strength during operation. However, current three-position switches, due to insufficient optimization of the electric field design, are unable to meet the insulation requirements of switchgear using dry air as the insulating gas.

[0019] Please refer to Figure 1. This application discloses a ring main unit 400, including a cabinet, a three-position switch 100 and a three-position operating mechanism 200 disposed in the cabinet. The three-position operating mechanism 200 is connected to the moving contact 7 of the three-position switch 100. Under the drive of the three-position operating mechanism 200, the moving contact 7 of the three-position switch 100 can be selectively electrically connected to the isolating stationary contact 5 or the grounding contact 2 by rotation.

[0020] The three-position switch 100 has three different operating states. It integrates the functions of both a disconnector and a grounding switch, with the same moving contact 7 performing both functions. This allows for mechanical interlocking, preventing the grounding switch from being closed while the main circuit is energized. The three operating states of the three-position switch 100 include: the closed position where the moving contact 7 is connected to the disconnector, i.e., the moving contact 7 is electrically connected to the isolating stationary contact 5; the grounding position where the moving contact 7 is electrically connected to the grounding stationary contact; and the isolated position where the main contacts are separated, i.e., the moving contact 7 is not connected to either the isolating stationary contact 5 or the grounding stationary contact.

[0021] Please refer to Figures 2 to 5. The three-position switch 100 includes a first fixed base 1, a grounding contact 2, a grounding shield base 3, a second fixed base 4, an isolating stationary contact 5, a third fixed base 6, and a moving contact 7.

[0022] The grounding contact 2 includes multiple grounding contacts, each grounding contact 2 corresponding to one phase of the power supply of the ring main unit 400, and the multiple grounding contacts 2 are all set on the first fixed base 1.

[0023] The first mounting base 1 is installed on the cabinet of the ring main unit 400. As shown in Figures 2 and 3, three grounding contacts 2 are arranged on the first mounting base 1, and the three grounding contacts 2 correspond to the three phases of the power supply in the ring main unit 400.

[0024] In some embodiments, the first fixing base 1 may be made of a conductive metal part, so that the first fixing base 1 can ground the grounding static contacts of multiple phases through the same path.

[0025] Please refer to Figure 3. The grounding shield 3 is disposed on the first fixed base 1. The grounding shield 3 is configured as an integrally formed metal part. The grounding shield 3 has multiple openings 301, and each grounding contact 2 is exposed from the corresponding opening 301.

[0026] Among them, the grounding shield 3 can be made of sheet metal in one piece, and the three-phase grounding contact 2 can be uniformly wrapped by the same metal part, which can evenly distribute the electric field of the grounding contact 2 and reduce the risk of excessive local electric field. Moreover, the metal material of the grounding shield 3 can provide good electromagnetic shielding for the grounding contact 2, reduce the risk of electric field diffusion during the electrical connection between the moving contact 7 and the grounding contact 2, and is conducive to the electrical stability of the three-position switch 100.

[0027] Furthermore, compared with the separate shielding of the single-phase grounding contact 2 in the prior art, the grounding shield base 3 is integrally formed with metal parts, which can reduce manufacturing and installation costs and reduce assembly and welding processes. Traditional single-phase separate shielding may easily increase the risk of electrical faults due to assembly or connection problems. The integrated design of the grounding shield base 3 reduces this risk and improves the insulation performance and reliability of the three-position switch 100.

[0028] Considering the overall size of the three-position switch 100, the grounding shield 3 is integrally molded, which can more compactly wrap the grounding contact 2. This helps to reduce the overall size of the three-position switch 100, making the structure more compact and suitable for small-sized switch cabinets.

[0029] Please refer to Figures 3 and 4. The grounding shield 3 is an arched plate formed by bending a metal part. The arched plate and the first fixed base 1 enclose the first shielding space 302. Each grounding contact 2 is distributed at intervals in the first shielding space 302, and each grounding contact 2 is exposed through the opening 301 of the arched plate.

[0030] Among them, the arched plate is made of bent metal parts, and the manufacturing process of the grounding shield 3 is relatively simple and the cost is low.

[0031] As shown in Figure 4, the two sides of the arched plate along the length direction are connected to the first fixed base 1, forming a first shielding space 302 with the first fixed base 1, which can achieve the effect of uniform electric field for the three-phase grounding contacts 2.

[0032] Please refer to Figure 2. The three-position switch 100 includes multiple second fixed bases 4 and multiple isolating stationary contacts 5, with each second fixed base 4 corresponding to an isolating stationary contact 5.

[0033] Each of the second fixed bases 4 is connected to the circuit breaker 300, and the isolating stationary contact 5 is connected to the circuit breaker 300 through the second fixed base 4. Specifically, the three poles of the circuit breaker 300 correspond to the three phases in the power supply of the ring main unit 400, and the isolating stationary contact 5 provided on the second fixed base 4 is electrically connected to the stationary end of the corresponding pole.

[0034] Please refer to Figure 5. The second fixing base 4 is a one-piece metal. The second fixing base 4 encloses and forms the second shielding space 401. The isolating stationary contact 5 is located inside the second shielding space 401. The isolating stationary contact 5 is electrically connected to the circuit breaker 300 through the second fixing base 4.

[0035] The second fixing base 4 includes a connecting part 41 and bent side parts 42 located on both sides of the connecting part 41. The bent side parts 42 are arranged opposite to each other, and the connecting part 41 and the bent side parts 42 enclose a second shielding space 401. The connecting part 41 is used to fix it on the corresponding circuit breaker 300.

[0036] As shown in Figure 5, the two bent sides 42 are provided on opposite sides of the isolating stationary contact 5, which can provide electrical isolation for the isolating stationary contact 5, thereby isolating the electric field between the three phases of the circuit breaker 300 and improving the insulation performance.

[0037] An opening 402 is formed between the ends of the two bent sides 42 away from the connecting part 41. The opening 402 is oriented downwards and allows the moving contact 7 to extend into the second shielding space 401. Thus, when the moving contact 7 is connected to the isolating stationary contact 5 and is in the closed position of the disconnecting switch, the electric field can be evenly distributed in the second shielding space 401 formed by the bent sides 42 and the connecting part 41, thereby improving the electric field distribution at the electrical connection between the moving contact 7 and the isolating stationary contact 5.

[0038] The connection between the connecting portion 41 and the bent side portion 42 is a rounded transition. Thus, the transition surface 801 at the connection between the connecting portion 41 and the bent side portion 42 that forms the second shielding space 401 can reduce the abrupt change in electric field at the connection between the connecting portion 41 and the bent side portion 42, and further optimize the electric field distribution within the second shielding space 401.

[0039] The end apex of the bent side 42 away from the connecting part 41 is configured as a rounded chamfer 43. In this way, the risk of electric field accumulation due to the formation of a sharp point on the second fixing seat 4 can be reduced, and the electric field of the isolating stationary contact 5 can be better optimized.

[0040] As shown in Figure 2, a plurality of moving contacts 7 are spaced apart on the third fixed base 6. The moving contacts 7 can rotate relative to the third fixed base 6 to selectively connect to the grounding contact 2 or the isolating stationary contact 5.

[0041] The moving contact 7 includes a middle part 71 and a first end 72 and a second end 73 located at both ends of the middle part 71. The second end 73 is rotatably mounted on the third fixed base 6. The middle part 71 is used for transmission connection with the three-station operating mechanism 200. The first end 72 can rotate around the second end 73 under the drive of the three-station operating mechanism 200.

[0042] As shown in Figure 2, three moving contacts 7 are arranged at intervals on the third fixed base 6. The middle part 71 of the moving contact 7 is driven to rotate both ends of the moving contact 7 by a transmission connection with the three-position operating mechanism 200. Among them, the first end 72 of the moving contact 7 is a fixed end and is rotatably connected to the third fixed base 6, and the second end 73 of the moving contact 7 is a free end that rotates around the rotational connection point between the moving contact 7 and the third fixed base 6.

[0043] The second end 73 of the moving contact 7 can rotate clockwise to the grounding shield 3 and extend into the first shielding space 302 through the opening 301 of the grounding shield 3, connecting with the grounding contact 2 located in the first shielding space 302. The second end 73 of the moving contact 7 can rotate counterclockwise to the second fixed seat 4 and extend into the second shielding space 401 through the opening 402 of the second fixed seat 4, connecting with the isolating stationary contact 5 located in the second shielding space 401. Thus, the three-position switch 100 disclosed in this application can optimize the electric field at the electrical connection positions of the moving contact 7 with the grounding contact 2 and the isolating stationary contact 5, reducing the risk of electric field interference between multiple phases or other externally generated electromagnetic field interference, thereby improving the insulation level of the three-position switch 100.

[0044] As shown in Figures 2 and 3, the first end 72 is provided with a first shield 8, which is used to uniformly distribute the electric field of the first end 72, and the first shield 8 can extend into the second fixed seat 4 or the grounding shield 3 as the first end 72 rotates.

[0045] The first shielding cover 8 includes two shielding plates arranged opposite each other. The shielding plates are located on opposite sides of the first end 72 of the moving contact 7, so that the connection between the first end 72 of the moving contact 7 and the second fixed base 4 is located within the space enclosed by the shielding plates arranged opposite each other, thereby providing a uniform electric field to the first end 72 of the moving contact 7.

[0046] The outer surface of the first shielding plate 81 is an arc surface 801. As shown in Figure 3, the first shielding plate 81 can be designed as a hemispherical shape. In this way, the outer surface of the first shielding plate 81 is an arc surface 801, which can reduce the risk of high-intensity electric field regions being easily formed due to the presence of sharp edges or right-angle areas, and achieve the purpose of a uniform electric field.

[0047] Multiple moving contacts 7 are arranged at intervals along the same row, and a second shielding cover 9 is provided at the connection between the second end 73 of each moving contact 7 and the third fixed base 6.

[0048] The second shield 9 includes two opposing second shield plates 91, which are located on opposite sides of the second end 73 of the moving contact 7, so that the second end 73 of the moving contact 7 is located within the space enclosed by the opposing shield plates, thereby improving the electric field distribution of the second end 73 of the moving contact 7.

[0049] Furthermore, the outer surface of the second shielding plate 91 of the second shielding cover 9 is an arc surface, which further improves the uniformity of the electric field of the second shielding cover 9 on the second end 73 of the moving contact 7.

[0050] In summary, the three-position switch 100 disclosed in this application, by setting an integrally formed grounding shield 3, uniformly encloses the grounding contacts 2 of multiple phases within the first shielding space 302 formed by the grounding shield 3 and the first fixed seat 1, which can uniformly distribute the electric field of the grounding contacts 2. Compared with single-phase individual shielding, it has the advantages of compact structure and better electric field optimization effect, and reduces the size and space occupied by the three-position switch 100. A second fixed seat 4 is provided at the isolating stationary contact 5, and the second shielding space 401 formed by the second fixed seat 4 can play a role in uniformly distributing the electric field of the isolating stationary contact 5. Furthermore, a first shield 8 is provided at the first end 72 of the moving contact 7, and a second shield 9 is provided at the second end 73 of the moving contact 7. The first shield 8 and the second shield 9 can respectively play a role in optimizing the electric field at both ends of the moving contact 7.

[0051] It is understood that the three-position switch 100 technical solution of this application optimizes the electric field of the grounding contact, the isolating stationary contact and the moving contact, so that the electric field of the three-position switch 100 can be evenly distributed in each position in the states of being connected, isolated and grounded, reducing the risk of breakdown caused by electric field concentration, thereby effectively improving the insulation level of the three-position switch 100, so that it can be used in the smaller ring main unit 400 to meet higher insulation requirements.

[0052] It is understood that those skilled in the art can make equivalent substitutions or changes based on the technical solutions and inventive concepts of this disclosure, and all such changes or substitutions should fall within the protection scope of this disclosure.

Claims

1. A three-position switch, comprising: A first fixed base and multiple grounding contacts, each of the grounding contacts corresponding to one phase of the ring main unit power supply, and all the multiple grounding contacts are set on the first fixed base; A grounding shield is disposed on the first fixed base. The grounding shield is configured as an integrally formed metal part. The grounding shield has multiple openings, and each grounding contact is exposed from the corresponding opening. Multiple second fixed seats and multiple isolating stationary contacts, with one isolating stationary contact correspondingly provided on each of the second fixed seats; A third fixed base and a plurality of movable contacts are provided on the third fixed base at intervals. The movable contacts are rotatable relative to the third fixed base to selectively connect to the grounding contact or the isolating stationary contact.

2. The three-position switch according to claim 1, characterized in that, The grounding shield is an arched plate formed by bending a metal part. The arched plate and the first fixed base enclose a first shielding space. The grounding contacts are spaced apart in the first shielding space, and each grounding contact is exposed through an opening in the arched plate.

3. The three-position switch according to claim 1 or 2, wherein, Each of the second fixing bases is connected to the circuit breaker. The second fixing base is an integrally formed metal. The second fixing bases enclose a second shielding space. The isolating stationary contact is located within the second shielding space. The isolating stationary contact is electrically connected to the circuit breaker through the second fixing base.

4. The three-position switch according to claim 3, wherein, The second fixing base includes a connecting part and bent sides located on both sides of the connecting part. The bent sides are arranged opposite to each other, and the connecting part and the bent sides enclose the second shielding space. An opening is formed between the ends of the two bent sides away from the connecting part. The opening is oriented downwards and allows the moving contact to extend into the second shielding space. The connecting part is used to fix it to the corresponding circuit breaker.

5. The three-position switch according to claim 4, wherein, The connection between the connecting part and the bent side is a rounded transition.

6. The three-position switch according to claim 4, wherein, The end apex of the bent side away from the connecting part is configured as a rounded chamfer.

7. The three-position switch according to claim 1 or 2, wherein, The moving contact includes a middle part and a first end and a second end located at both ends of the middle part. The second end is rotatably mounted on the third fixed base. The middle part is used for transmission connection with the three-position operating mechanism. The first end can rotate around the second end under the drive of the three-position operating mechanism. The first end is provided with a first shield, which is used to uniform the electric field of the first end, and the first shield can extend into the second fixed base or the grounding shield as the first end rotates.

8. The three-position switch according to claim 7, wherein, The first shielding cover includes two opposing first shielding plates, which are located on opposite sides of the first end of the moving contact; The outer surface of the first shielding plate is an arc surface.

9. The three-position switch according to claim 7, wherein, Multiple moving contacts are arranged at intervals, and a second shield is provided at the connection between the second end of each moving contact and the third fixed base.

10. A ring main unit, comprising: Cabinet; The cabinet includes a three-position switch and a three-position operating mechanism as described in any one of claims 1 to 9, wherein the three-position operating mechanism is connected to the moving contact of the three-position switch and the three-position operating mechanism can drive the moving contact of the three-position switch to rotate.

Images