Circuit breaker core unit

Abstract

This utility model discloses a core unit of a circuit breaker. The gas chamber contains a switch unit, an upper busbar connection unit, and a lower busbar connection unit. The upper and lower busbar connection units are connected to the switch unit via connecting busbars. The upper busbar connection unit has three-phase bushings, each phase of which is connected to the upper connecting busbar via a flexible connection. Each phase is connected to a surge arrester assembly via a connecting component. The connecting component and surge arrester assembly are housed within the gas chamber. The surge arrester of the surge arrester assembly is sealed to the sleeve via a connecting shaft. The lower busbar connection unit has electronic bushings corresponding to the three phases, each electronic bushing connected to the switch unit via the lower connecting busbar. This utility model integrates the surge arrester assembly inside the gas chamber, allowing the gas chamber to directly protect the surge arrester assembly, avoiding exposure and saving the need for a protective box. This simplifies the circuit breaker structure, making the overall circuit breaker simpler and cleaner.

Description

Technical Field

[0001] This utility model relates to the field of power technology, and in particular to a core unit of a circuit breaker. Background Technology

[0002] A circuit breaker is a switching device capable of closing, carrying, and interrupting current under normal circuit conditions, and closing, carrying, and interrupting current under abnormal circuit conditions within a specified time. The core functions of a circuit breaker include distributing electrical energy and protecting circuits from damage caused by overload, short circuit, undervoltage, and other faults. It is widely used in power distribution systems.

[0003] Circuit breakers typically include surge arresters connected in parallel to protect electrical equipment from damage caused by lightning or switching overvoltages, ensuring the safe and stable operation of the power system. Currently, surge arresters in existing circuit breakers are usually located at the inlet end of the busbar bushing, outside the gas box. To avoid exposing the surge arrester, an additional protective enclosure is required, resulting in more components, a bulkier circuit breaker, and a larger footprint, making flexible placement in the application environment inconvenient.

[0004] The bushings of the three phases of the existing circuit breaker are usually set independently. After each bushing is connected to the sealing plate of the box, a sealing structure needs to be set separately for sealing. Not only is the structure more complex and there are more parts, but there are also more leakage points. If a leakage point is not sealed well, it is easy to cause gas leakage in the gas box, affecting the reliability of the seal. Utility Model Content

[0005] To address the aforementioned shortcomings of existing circuit breaker core units, the applicant provides a circuit breaker core unit with a reasonable structure, integrating the surge arrester into the gas box, making the overall circuit breaker simpler and cleaner; the three-phase bushings are integrated into one unit, simplifying the structure, reducing leakage points, and improving sealing reliability.

[0006] The technical solution adopted in this utility model is as follows: A circuit breaker core unit includes a switch unit, an upper busbar connection unit, and a lower busbar connection unit housed within a gas-filled box. The upper and lower busbar connection units are connected to the switch unit via connecting busbars. The upper busbar connection unit is equipped with three-phase bushings, each with a corresponding busbar bushing. Each phase busbar bushing is connected to the upper connecting busbar via a flexible connection. Each phase busbar bushing is connected to a surge arrester assembly via a connecting component. The connecting component and surge arrester assembly are housed within the gas-filled box. The surge arrester assembly includes a sleeve and a surge arrester inserted within the sleeve. The surge arrester is connected to the connecting component via a connecting shaft, which is sealed to the sleeve. The lower busbar connection unit is equipped with electronic bushings corresponding to each of the three phases, and each electronic bushing is connected to the switch unit via the lower connecting busbar.

[0007] As a further improvement to the above technical solution: The three-phase bushing is integrally formed on the connecting housing, and the connecting housing is sealed to the sealing plate of the gas box through the connecting assembly.

[0008] The connecting assembly includes an outer flange plate, a sealing plate, and an inner flange plate arranged sequentially. The outer flange plate is sleeved on the outside of the connecting housing of the three-phase bushing and fixedly connected to the seal of the gas box, pressing the sealing plate against the sealing plate of the gas box. The busbar bushing passes through the sealing plate and the inner flange plate. The connecting housing, the sealing plate, and the inner flange plate are locked and fixed by several fasteners. The inner flange plate and the busbar bushing of the three-phase bushing extend into the gas box from the mounting hole of the gas box.

[0009] A raised ring is provided on the sealing plate facing the inner cavity of the air box. The raised ring surrounds the outer side of the inner flange plate. The contact area between the housing and the sealing plate is located inside the annular area surrounded by the raised ring. The raised ring extends into the air box from the mounting hole and surrounds the outer periphery of the inner flange plate and the wall of the mounting hole.

[0010] The connection components between the busbar bushing and the lightning protection assembly include a connecting rod and a connecting bar. The connecting rod is connected to the connection point between the flexible connection and the upper connecting busbar, and the connecting rod is connected to the lightning protection assembly through the connecting bar.

[0011] The upper busbar connection unit is equipped with an insulated support plate, an insulated fixing plate, and several insulated partitions. The support plate and the fixing plate are arranged at intervals along the axial direction of the busbar bushing. The three-phase busbar bushings are installed on the support plate, and the three-phase connecting rods are installed on the fixing plate. Partitions are installed between the support plate and the fixing plate, between the busbar bushings of adjacent two phases, and on the outer sides of the front and rear busbar bushings.

[0012] One end of the partition is fixed to the support plate, and the other end passes through the fixed plate and extends towards the lightning protection component. The extension length covers at least the connection part between the lightning protection component and the connecting busbar. The support plate and the fixed plate are perpendicular to the busbar bushing, and the partition is orthogonal to the support plate and the fixed plate.

[0013] The sleeve of the surge arrester assembly is fixedly connected to the gas box sealing plate, and a sealing structure is provided between the sleeve and the gas box sealing plate; the end of the sleeve connected to the bus bushing is provided with a tapered part, and the connecting shaft is sealed and connected to the tapered part; the end of the sleeve facing the gas box sealing plate is an open surface, and the gas box sealing plate is provided with an insertion hole corresponding to the sleeve, so that the surge arrester can be inserted into the sleeve from the insertion hole of the gas box and the open surface of the sleeve; the surge arrester is connected to the grounding busbar through the connecting shaft.

[0014] A power transformer is connected between the electronic bushings of two phases of the lower busbar connection unit. A current transformer is integrated on the electronic bushing. The electronic bushing is provided with a primary output terminal and a secondary output terminal. The current output of the secondary output terminal is less than the current output of the primary output terminal. The electronic bushing passes through the sealing plate of the gas box, and the power transformer is located inside the gas box.

[0015] The switch unit includes a disconnector assembly and a circuit breaker assembly, which are arranged vertically. One assembly is located on top and connected to the upper busbar connection unit via an upper connecting busbar, while the other assembly is located on the bottom and connected to the lower busbar connection unit via a lower connecting busbar. The gas box is equipped with a disconnector operating mechanism and a circuit breaker operating mechanism corresponding to the switch unit. The disconnector operating mechanism corresponds to the disconnector assembly, and the circuit breaker operating mechanism corresponds to the circuit breaker assembly.

[0016] The beneficial effects of this utility model are as follows: This utility model places the lightning protection component on one side of the connection between the flexible connection and the upper connecting busbar near each phase busbar bushing. The lightning protection component is integrated into the gas box, and the gas box directly provides protection for the lightning protection component, avoiding the lightning protection component being exposed to the outside, saving the use of the protective box, simplifying the structure of the circuit breaker, and making the circuit breaker simpler and neater overall.

[0017] This invention utilizes a novel three-phase bushing that integrates the three-phase busbar bushings into one unit. It connects to the gas box sealing plate via an integrally molded connecting shell, which not only simplifies the structure but also reduces leakage points and improves sealing reliability. Attached Figure Description

[0018] Figure 1 This is a three-dimensional schematic diagram of the present invention.

[0019] Figure 2 This is a front view schematic diagram of the present utility model.

[0020] Figure 3 This is a three-dimensional schematic diagram of the upper busbar connection unit.

[0021] Figure 4 This is a sectional view of the upper busbar connection unit.

[0022] Figure 5 for Figure 4 Enlarged view of point A in the middle.

[0023] Figure 6 This is a partial structural cross-sectional view of the three-phase bushing after it has been installed into the gas box.

[0024] Figure 7 This is a three-dimensional schematic diagram of a three-phase bushing.

[0025] Figure 8 This is a three-dimensional schematic diagram of the lower busbar connection unit.

[0026] In the picture: 1. Air box; 11. Insertion hole; 12. Mounting hole; 2. Switching unit; 21. Disconnecting switch assembly; 22. Circuit breaker assembly; 3. Upper busbar connection unit; 31. Three-phase bushing; 311. Connecting shell; 312. Busbar bushing; 32. Flexible connection; 33. Connecting rod; 34. Connecting busbar; 35. Lightning arrester assembly; 351. Sleeve; 3511. Taper; 3512. Connecting flange; 352. Lightning arrester; 353. Connecting shaft one; 354. Connecting shaft two; 36. Support plate; 37. Fixing plate; 38. Partition plate; 39. Connecting assembly; 391. Outer flange plate; 392. Inner flange plate; 393. Sealing plate; 3931. Raised ring; 4. Lower busbar connection unit; 41. Electronic bushing; 411. Primary output terminal; 412. Secondary output terminal; 42. Power transformer; 5. Upper busbar connection; 6. Lower busbar connection; 7. Grounding busbar; 8. Isolation operating mechanism; 9. Circuit breaker operating mechanism. Detailed Implementation

[0027] The specific embodiments of this utility model are described below with reference to the accompanying drawings.

[0028] like Figure 1 , Figure 2 As shown, the core unit of the circuit breaker described in this utility model is a gas-filled switchgear. Its gas box 1 contains a switch unit 2, an upper busbar connection unit 3, and a lower busbar connection unit 4. The upper busbar connection unit 3 is located above the switch unit 2, and the lower busbar connection unit 4 is located below the switch unit 2. The switch unit 2 includes a disconnector assembly 21 and a circuit breaker assembly 22, arranged vertically. One assembly is located above and connected to the upper busbar connection unit 3 via an upper connecting busbar 5, while the other is located below and connected to the lower busbar connection unit 4 via a lower connecting busbar 6. In this embodiment, the disconnector assembly 21 is located above, and the circuit breaker assembly 22 is located below. The upper busbar connection unit 3 is connected to a grounding busbar 7, which is located outside the gas box 1. On the outside of the gas box 1, corresponding to the switch unit 2, there is an isolation operation mechanism 8 and a circuit breaker operation mechanism 9. The isolation operation mechanism 8 corresponds to the disconnect switch assembly 21. The disconnect switch assembly 21 can be opened, closed, and grounded through the isolation operation mechanism 8. The circuit breaker operation mechanism 9 corresponds to the circuit breaker assembly 22. The circuit breaker operation mechanism 9 can be opened, closed, and grounded through the circuit breaker operation mechanism 9.

[0029] like Figures 3 to 6As shown, the busbar connection bushing of the upper busbar connection unit 3 adopts an integrated three-phase bushing 31, including busbar bushings 312 corresponding to phases A, B, and C respectively. The three busbar bushings 312 are integrally formed on the connection housing 311, and the connection housing 311 is sealed to the sealing plate of the gas box 1 through the connection assembly 39. Figure 3 , Figure 4 As shown, each phase of the three-phase bushing 31's busbar bushing 312 is connected to the upper connecting busbar 5 via a flexible connector 32. A connecting rod 33 is connected at the connection point between the flexible connector 32 and the upper connecting busbar 5. The connecting rod 33 is connected to the surge arrester assembly 35 via a connecting busbar 34. The surge arrester assembly 35 is connected to the grounding busbar 7. The flexible connector 32, connecting rod 33, connecting busbar 34, and surge arrester assembly 35 are all housed inside the gas box 1. The upper busbar connection unit 3 places the surge arrester assembly 35 on one side near the connection point between the flexible connector 32 and the upper connecting busbar 5 of each phase busbar bushing 312. The surge arrester assembly 35 is integrated into the gas box 1, and the gas box 1 directly provides protection to the surge arrester assembly 35, preventing the surge arrester assembly 35 from being exposed. This saves on the use of a protective box, simplifies the circuit breaker structure, and makes the overall circuit breaker simpler and cleaner. The three-phase bushing 31 integrates the three-phase busbar bushings 312 into one unit and is connected to the gas box 1 sealing plate through the integrally formed connecting housing 311. This not only simplifies the structure but also reduces leakage points and improves sealing reliability.

[0030] like Figure 3 As shown, the upper busbar connection unit 3 is equipped with an insulating support plate 36, an insulating fixing plate 37, and several insulating partitions 38. The support plate 36 and the fixing plate 37 are perpendicular to the busbar bushing 312 and arranged at intervals along the axial direction of the busbar bushing 312. The three-phase busbar bushing 312 passes through the support plate 36, which provides support for the busbar bushing 312. The three-phase connecting rod 33 passes through the fixing plate 37, which provides support for the connecting rod 33 and the upper connecting busbar 5. Between the support plate 36 and the fixing plate 37, partition plates 38 are respectively provided between the bus bushings 312 of adjacent two phases and on the outside of the front and rear bus bushings 312. The partition plates 38 are orthogonal to the support plate 36 and the fixing plate 37. One end of the partition plate 38 is fixed on the support plate 36, and the other end passes through the fixing plate 37 and extends towards the lightning protection assembly 35. The extension length covers at least the connection part between the lightning protection assembly 35 and the connecting bar 34. The partition plate 38 insulates between phases to prevent discharge between phases.

[0031] like Figure 3 , Figure 4 As shown, the surge arrester assembly 35 includes a sleeve 351 and a surge arrester 352 inserted into the sleeve 351. One end of the surge arrester 352 is connected to the connecting busbar 34 via a connecting shaft 353, and the other end is connected to the grounding busbar 7 via a connecting shaft 354. Figure 4As shown, the sleeve 351 has a tapered portion 3511 at the end facing the connecting bar 34, and the connecting shaft 353 is sealed to the tapered portion 3511 to ensure a tight seal. The sleeve 351 has a connecting flange 3512 at the end facing the gas box 1 sealing plate. The connecting flange 3512 is fixedly connected to the gas box 1 sealing plate by fasteners, and a sealing structure is provided between the mating surfaces of the connecting flange 3512 and the gas box 1 sealing plate to ensure a tight seal. The end of the sleeve 351 facing the gas box 1 sealing plate is an open surface, such as... Figure 1 As shown, the sealing plate of the gas box 1 has an insertion hole 11 corresponding to the sleeve 351. The surge arrester 352 can be inserted into the sleeve 351 through the insertion hole 11 of the gas box 1 and the open surface of the sleeve 351. It is connected to the connecting shaft 353 by fasteners. Since the end of the sleeve 351 facing the connecting row 34 is sealed by the connecting shaft 353, the removal and installation of the surge arrester 352 will not affect the sealing performance inside the gas box 1, thus improving the sealing reliability.

[0032] like Figure 4 , Figure 5 As shown, the connecting assembly 39 includes an outer flange plate 391, a sealing plate 393, and an inner flange plate 392, stacked sequentially from the outside of the gas box 1 towards the inside. A raised ring 3931 protrudes from the sealing plate 393 towards the inner cavity of the gas box 1, surrounding the outer side of the inner flange plate 392. The outer flange plate 391 is fitted onto the outside of the connecting housing 311 of the three-phase bushing 31. The busbar bushing 312 passes through the sealing plate 393 and the inner flange plate 392. The connecting housing 311, the sealing plate 393, and the inner flange plate 392 are locked and fixed by several fasteners, so that the connecting housing 311 abuts against the sealing surface of the sealing plate 393. The contact area between the connecting housing 311 and the sealing plate 393 is located inside the annular area enclosed by the raised ring 3931, ensuring that the entire sealing surface of the connecting housing 311 is in contact with the sealing plate 393, resulting in a more reliable seal. Figure 6 As shown, the sealing plate of the gas box 1 has a mounting hole 12 corresponding to the connecting component 39. During installation, the outer flange plate 391 and the sealing plate 393 of the connecting component 39 are locked and fixed to the sealing plate of the gas box 1 by several fasteners. The sealing surface of the sealing plate 393 is close to the sealing plate of the gas box 1. The convex ring 3931 of the sealing plate 393, the inner flange plate 392, and the busbar sleeve 312 of the three-phase bushing 31 extend into the gas box 1 from the mounting hole 12. The convex ring 3931 surrounds the outer periphery of the inner flange plate 392 and the hole wall of the mounting hole 12. The convex ring 3931 can seal the gap between the inner flange plate 392 and the hole wall of the mounting hole 12 on the one hand, and on the other hand, it can make the three-phase bushing 31 and the sealing plate of the gas box 1 adjustable, which is convenient for adjusting the three-phase bushing 31 during installation.

[0033] like Figure 2 , Figure 8As shown, the lower busbar connection unit 4 includes three independent electronic bushings 41 corresponding to phases A, B, and C, respectively. Each electronic bushing 41 is connected to the switch unit 2 via the lower connecting busbar 6. A power transformer 42 is connected between the electronic bushings 41 of two phases (phase A and phase C in this embodiment). A current transformer is integrated on the electronic bushing 41, which has a primary output terminal 411 and a secondary output terminal 412. The current output from the secondary output terminal 412 is less than the current from the primary output terminal 411. The electronic bushings 41 are mounted on the sealing plate of the gas box 1. The power transformer 42 is housed inside the gas box 1 and protected by the gas box 1, preventing the power transformer 42 from being exposed, simplifying the circuit breaker structure, and making the overall circuit breaker simpler and cleaner.

[0034] The above description is an explanation of the present utility model and not a limitation thereof. The present utility model can be modified in any form without departing from its spirit.

Claims

1. A circuit breaker core unit, wherein a switch unit (2), an upper busbar connection unit (3), and a lower busbar connection unit (4) are provided in a gas box (1), the upper busbar connection unit (3) and the lower busbar connection unit (4) being connected to the switch unit (2) respectively via connecting busbars; characterized in that: The upper busbar connection unit (3) is provided with a three-phase bushing (31), and the three-phase bushing (31) is provided with a busbar bushing (312) corresponding to each phase. The busbar bushing (312) of each phase is connected to the upper connecting busbar (5) through a flexible connection (32). The busbar bushing (312) of each phase is connected to a lightning protection assembly (35) through a connecting component. The connecting component and the lightning protection assembly (35) are located in the gas box (1). The lightning protection assembly (35) includes a sleeve (351) and a surge arrester (352) inserted in the sleeve (351). The surge arrester (352) is connected to the connecting component through a connecting shaft (353). The connecting shaft (353) is sealed and connected to the sleeve (351). The lower busbar connection unit (4) is equipped with an electronic bushing (41) corresponding to the three phases. Each electronic bushing (41) is connected to the switch unit (2) through the lower connection busbar (6).

2. The circuit breaker core unit according to claim 1, characterized in that: The bus bushing (312) of the three-phase bushing (31) is integrally formed on the connecting housing (311), and the connecting housing (311) is sealed to the sealing plate of the gas box (1) through the connecting assembly (39).

3. The circuit breaker core unit according to claim 2, characterized in that: The connecting assembly (39) includes an outer flange plate (391), a sealing plate (393), and an inner flange plate (392) arranged in sequence. The outer flange plate (391) is sleeved on the outside of the connecting housing (311) of the three-phase bushing (31) and fixedly connected to the seal of the gas box (1), pressing the sealing plate (393) against the sealing plate of the gas box (1). The bus bushing (312) passes through the sealing plate (393) and the inner flange plate (392). The connecting housing (311), the sealing plate (393), and the inner flange plate (392) are locked and fixed by several fasteners. The inner flange plate (392) and the bus bushing (312) of the three-phase bushing (31) extend into the gas box (1) from the mounting hole (12).

4. The circuit breaker core unit according to claim 3, characterized in that: A raised ring (3931) is provided on the sealing plate (393) facing the inner cavity of the gas box (1). The raised ring (3931) surrounds the outer side of the inner flange plate (392). The contact area between the connecting housing (311) and the sealing plate (393) is located inside the annular area surrounded by the raised ring (3931). The raised ring (3931) extends into the gas box (1) from the mounting hole (12) of the gas box (1). The raised ring (3931) surrounds the outer periphery of the inner flange plate (392) and the hole wall of the mounting hole (12).

5. The circuit breaker core unit according to claim 1, characterized in that: The connection components between the bus bushing (312) and the lightning protection assembly (35) include a connecting rod (33) and a connecting bar (34). The connecting rod (33) is connected at the connection point between the flexible connection (32) and the upper connecting bus (5). The connecting rod (33) is connected to the lightning protection assembly (35) through the connecting bar (34).

6. The circuit breaker core unit according to claim 1, characterized in that: An insulating support plate (36), an insulating fixing plate (37), and several insulating partitions (38) are provided on the upper busbar connection unit (3). The support plate (36) and the fixing plate (37) are arranged at intervals along the axial direction of the busbar bushing (312). The three-phase busbar bushing (312) passes through the support plate (36), and the three-phase connecting rod (33) passes through the fixing plate (37). Partitions (38) are provided between the support plate (36) and the fixing plate (37), between the adjacent two-phase busbar bushings (312), and on the outside of the front and rear busbar bushings (312).

7. The circuit breaker core unit according to claim 6, characterized in that: One end of the partition (38) is fixed to the support plate (36), and the other end passes through the fixed plate (37) and extends towards the lightning protection assembly (35). The length of the extension covers at least the connection between the lightning protection assembly (35) and the connecting bar (34). The support plate (36) and the fixed plate (37) are perpendicular to the bus bushing (312), and the partition (38) is orthogonal to the support plate (36) and the fixed plate (37).

8. The circuit breaker core unit according to claim 1, characterized in that: The sleeve (351) of the lightning arrester assembly (35) is fixedly connected to the sealing plate of the gas box (1), and a sealing structure is provided between the sleeve (351) and the sealing plate of the gas box (1); a cone (3511) is provided at one end of the sleeve (351) connected to the bus bushing (312), and a connecting shaft (353) is sealed and connected to the cone (3511); the end of the sleeve (351) facing the sealing plate of the gas box (1) is an open surface, and an insertion hole (11) is provided on the sealing plate of the gas box (1) corresponding to the sleeve (351), and the lightning arrester (352) can be inserted into the sleeve (351) from the insertion hole (11) of the gas box (1) and the open surface of the sleeve (351); the lightning arrester (352) is connected to the grounding bus (7) through the connecting shaft (354).

9. The circuit breaker core unit according to claim 1, characterized in that: A power transformer (42) is connected between two phases of the electronic bushing (41) of the lower busbar connection unit (4). The electronic bushing (41) integrates a current transformer. The electronic bushing (41) is provided with a primary output terminal (411) and a secondary output terminal (412). The current output by the secondary output terminal (412) is less than the current of the primary output terminal (411). The electronic bushing (41) is installed on the sealing plate of the gas box (1), and the power transformer (42) is installed inside the gas box (1).

10. The circuit breaker core unit according to claim 1, characterized in that: The switch unit (2) includes a disconnector assembly (21) and a circuit breaker assembly (22). The disconnector assembly (21) and the circuit breaker assembly (22) are arranged vertically, with one on top and connected to the upper busbar connection unit (3) via the upper connecting busbar (5), and the other on the bottom and connected to the lower busbar connection unit (4) via the lower connecting busbar (6). The gas box (1) is provided with a disconnector operating mechanism (8) and a circuit breaker operating mechanism (9) corresponding to the switch unit (2). The disconnector operating mechanism (8) corresponds to the disconnector assembly (21), and the circuit breaker operating mechanism (9) corresponds to the circuit breaker assembly (22).

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