Main circuit connection structure of low-voltage complete equipment, removable plug-in unit assembly and unit

Abstract

The application relates to a main circuit connection structure of a low-voltage complete equipment, a removable plug-in unit assembly and a unit. The main circuit connection structure comprises a main circuit connector, a circuit breaker and a mutual inductor. The phase-to-phase center of the wiring end of the main circuit connector of each phase on the incoming line side and the outgoing line side is arranged in correspondence with the phase-to-phase center of the corresponding phase of the circuit breaker. The mutual inductor of the B phase on the outgoing line side is sleeved on the main circuit connector of the corresponding phase. The wiring end of the main circuit connector of the B phase on the outgoing line side and the connecting point of the connecting conductive row are located in front of the mutual inductor. The beneficial effects are as follows: through the two innovative structures of the body reversing connection of the incoming line side main circuit connector and the lengthened sleeve mutual inductor of the outgoing line side B phase main circuit connector, the connection distance of the 630A and 400A circuit breakers is shortened to the limit of 88mm, the connection distance of the 250A and below is less than 88mm, the application of the mutual inductor arranged in the unit room with the depth of 300mm of the overall current unit is realized, 53.5% of copper is saved, and the depth of the cabinet is reduced by 200mm.

Description

Technical Field

[0001] This invention relates to the field of low-voltage complete sets of equipment, and in particular to a main circuit connection structure, a removable plug-in unit assembly and unit for low-voltage complete sets of equipment. Background Technology

[0002] Low-voltage complete sets of equipment have three main types of main circuit connection structures: fixed type, drawer type, and fixed plug-in type.

[0003] Fixed pluggable main circuit connection structure: The circuit breaker connector is fixed to the busbar via a drilled hole connection structure. This allows for troubleshooting and maintenance during power outages. Figure 17 and 18 As shown.

[0004] Drawer-type main circuit connection structure: Positioned in three positions (connection, testing, and separation); main circuit connectors plug into the busbars; maintenance without power interruption. Figure 16 As shown.

[0005] Fixed plug-in main circuit connection structure: The circuit breaker is plugged into the base, and the base is fixedly connected to the busbar by drilling holes. The spring plug of the base is prone to overheating and burning out. The base connection can only be removed for inspection and replacement after the power is cut off.

[0006] The drawer-type structure technology originated from ABB, Schneider Electric, and Siemens, while the fixed plug-in structure technology originated from foreign technologies introduced by ABB, Schneider Electric, and Siemens.

[0007] In the low-voltage equipment industry, fixed, drawer-type, and plug-in connection structures all have corresponding market share. In the past five years, the application of fixed and plug-in types has been gradually increasing, because 70% of the low-voltage equipment in the industry is power distribution equipment.

[0008] However, the fixed plug-in structure is only a main circuit connection structure and does not have a supporting structure for connection and disconnection operations. The circuit breaker is installed and connected to the base by fastening screws. When plugging or unplugging the circuit breaker, the incoming line is energized, which is unsafe and can easily cause personal injury accidents.

[0009] Furthermore, manufacturers and users have expressed significant concerns about the inconsistent quality of the rigid connection busbar structure and the base itself, resulting in poor operational reliability. While the fixed plug-in structure appears simpler and cheaper than the drawer-type structure, this is due to the lack of operational mechanisms, reduced sheet metal usage, and absence of functional accessories. The lower cost stems from a lack of functionalities. Moreover, the fixed plug-in type has an 80% probability of power outage and maintenance failure in the event of overheating, indicating an unreliable structural design.

[0010] The fixed pluggable base with a hard connection to the busbar requires a unit depth of 450mm to 500mm. Low-quality pluggable bases have a high overheating failure rate, but even high-priced brand-name bases manufactured by the original manufacturer experience a small number of overheating failures during operation. The cause of these failures stems from the structural principle of the fixed pluggable main circuit connection structure, as detailed below:

[0011] The structure of the fixed plug-in base is determined by the phase-to-phase center of the matching circuit breaker. The phase-to-phase center of the base is consistent with the phase-to-phase center of the circuit breaker. If the phase-to-phase center of the circuit breaker is small, the phase-to-phase center of the base is also small, and the center of the spring plug of the base is also small, resulting in insufficient current carrying capacity of the connection section, which can basically only reach 85% of the current of the matching circuit breaker. If the manufacturing process is slightly inferior, the temperature rise will exceed the standard during operation. In actual operation, the base overheating often occurs unless the derating factor is large.

[0012] The fixed plug-in base is rigidly connected to the busbar. The three phases A, B, and C of the busbar need to be drilled at different locations, which is time-consuming and labor-intensive. The installation of the connectors must be done on the cabinet. The placement of the current transformer behind the board brings labor-intensive and time-consuming manufacturing and installation.

[0013] Circuit breakers with a fixed plug-in structure require manual insertion of the base, which is physically demanding; installers must crawl on the ground to reach the lower unit. Replacing the base and removing the circuit breaker is also extremely difficult, typically requiring a power outage for replacement.

[0014] The drawer-type main circuit connection structure is used in power distribution circuits. It has a position interlock function and the operation and connection method is quick and convenient. However, the standard definition of power distribution circuits does not require a test position function, only a connection and isolation position function. Many industry users tend not to choose the drawer-type structure for power distribution equipment, mainly because the drawer-type is more expensive than the plug-in type.

[0015] According to the standard definition, a power distribution circuit requires uninterrupted maintenance when the main circuit connection fails. Mechanical positioning of the connection and isolation points is sufficient, and the operation should be convenient, safe, and fast with an openable control unit. However, fixed pluggable structures cannot fully achieve this goal of uninterrupted maintenance in practical applications.

[0016] In traditional drawer-type main circuit connection structures, the main circuit connectors require transition flip-outs to connect to the phase-to-phase center of the circuit breaker structure. Additionally, current transformers need to be installed, resulting in a large number of connecting conductors and a significant depth of the unit assembly. (See...) Figure 16 The distance between the rear end plate of the unit assembly frame and the rear end face of the circuit breaker must be at least 180mm to accommodate the current transformer. The copper usage for the connecting conductor of the 630A drawer unit is 5.88kg, for 400A it is 2.88kg, for 250A it is 1.85kg, and for 125A it is 1.0kg.

[0017] Our patent document CN211790382U discloses a main circuit body reversing plug and a main circuit connection structure. The main circuit connector can be connected to the circuit breaker without the need for flip-up. It also realizes quick and easy plugging and unplugging operations through a lever force-increasing propulsion mechanism.

[0018] In response to the aforementioned shortcomings of the fixed plug-in main circuit connection structure, relevant technical personnel in the industry, including operation and maintenance personnel from subway companies in Jiangsu Province, have been seeking a new main circuit connection structure technology that can be operated quickly and safely, while meeting the indoor layout requirements of the current transformer unit (the rear layout of the current transformer unit is not reasonable), and minimizing the amount of connecting conductors and the depth of the unit assembly, thereby reducing costs. Summary of the Invention

[0019] The technical problem to be solved by the present invention is to provide a main circuit connection structure, a removable plug-in unit assembly and unit for low-voltage complete equipment, which, while meeting the indoor layout requirements of the current transformer unit, minimizes the amount of connecting conductors and the depth of the unit assembly.

[0020] The technical solution adopted by this invention to solve its technical problem is: a main circuit connection structure for a low-voltage complete set of equipment, including main circuit connectors, circuit breakers, and instrument transformers. The three phases of the circuit breaker are specifically phase A, phase B, and phase C from top to bottom. The circuit breaker is connected to the main circuit connectors of each phase on the incoming and outgoing sides via connecting conductive bars. The phase-to-phase center of the wiring terminals of the main circuit connectors of each phase on the incoming and outgoing sides is aligned with the phase-to-phase center of the corresponding phase of the circuit breaker. Furthermore, the connecting conductive bars on the outgoing side are L-shaped, and the wiring terminals of the main circuit connectors of each phase on the outgoing side are positioned such that the main circuit connector of phase B is in the middle position. The terminals of the plug-in are staggered vertically from the terminals of the main circuit plugs of phases A and C, and are arranged in a triangular pattern on the inside. The L-shaped connecting conductor includes a horizontal section connecting the circuit breaker and a vertical section connecting the terminals of the main circuit plug-in. The current transformer of phase B on the outgoing side is mounted on the terminal of the corresponding phase's main circuit plug-in. The connection point between the terminal of the main circuit plug-in of phase B on the outgoing side and the connecting conductor is located in front of the current transformer of phase B. The current transformers of phases A and C on the outgoing side are mounted on the horizontal section of the connecting conductor of the corresponding phase and are located outside the connecting conductor of phase B.

[0021] Furthermore, the current transformer of phase B on the outgoing line side is installed using the current transformer mounting bracket on the unit frame.

[0022] Furthermore, the current transformer mounting bracket is an L-shaped bracket, with the vertical end plate of the L-shaped bracket mounted on the rear end plate of the frame, and the horizontal end plate of the L-shaped bracket serving as the mounting base for the current transformer.

[0023] Further specified, the terminals of the main circuit connectors of each phase on the incoming line side are arranged in a triangular pattern, with the terminals of the main circuit connector of phase B in the middle position staggered from the terminals of the main circuit connectors of phases A and C in the vertical direction.

[0024] Furthermore, the main circuit connectors for phases A, B, and C on the incoming line side are arranged in layers from top to bottom, and the horizontal phase spacing of the plug-in terminals of each phase's main circuit connector is consistent with the phase spacing of the busbar, for plug-in connection with the busbar. Considering the inconsistent external dimensions of the applied circuit breakers, the main circuit connectors for phases A and B are non-self-commutating main circuit connectors, while the main circuit connector for phase C is a self-commutating main circuit connector. The terminals of the main circuit connector for phase B are offset from the terminals of the main circuit connectors for phases A and C and located on the inner side; alternatively, the main circuit connector for phase A is a non-self-commutating main circuit connector, while the main circuit connectors for phases B and C are self-commutating main circuit connectors. The terminals of the main circuit connector for phase B are offset from the terminals of the main circuit connectors for phases A and C and located on the outer side. Both configurations achieve an L-shaped connection structure for the connecting conductor busbar.

[0025] Furthermore, the main circuit connectors on the incoming line side and the corresponding phases of the circuit breaker can be connected one-to-one through the connecting conductive bars arranged in layers from top to bottom, and the connecting conductive bars on the incoming line side are L-shaped.

[0026] Further specified, the circuit breaker is installed by a fixed bracket, which is L-shaped. The end of the vertical end plate of the fixed bracket is installed on the base plate of the unit frame, and the end of the horizontal end plate of the fixed bracket is installed on the rear end plate of the frame. The circuit breaker is installed on the vertical end plate of the fixed bracket.

[0027] A removable plug-in unit assembly, specifically a removable plug-in unit assembly for low-voltage switchgear, includes a unit frame and the main circuit connection structure of the aforementioned low-voltage switchgear. A handle is provided at the front of the unit frame for manually operating the unit assembly, and / or a lever-assisted upward propulsion mechanism is provided at the front of the unit frame for operating the unit assembly by lever amplification.

[0028] Further specified, the front of the unit frame has a position locking hole, which is a threaded hole or a through hole; the left and right sides of the bottom of the unit frame have sliding parts for the guide rail device; the bottom of the unit frame also has an upper hook plate; an additional mounting plate is installed on the top of the rear end plate of the unit frame, and auxiliary circuit connectors are installed on the additional mounting plate.

[0029] A removable plug-in unit, specifically a removable plug-in unit for low-voltage complete sets of equipment, includes a unit chamber and a unit assembly inside the unit chamber. The unit assembly is the aforementioned removable plug-in unit assembly. When the front part of the unit frame has a lever-assisted upward propulsion mechanism, a lever-assisted downward propulsion mechanism is provided on the unit chamber shelf of the unit chamber.

[0030] Further specified, the front of the unit frame and the unit compartment shelf of the unit compartment have matching position locking holes. When the unit assembly enters the connection position, the unit assembly is locked by locking bolts that pass through the position locking holes on both the unit frame and the unit compartment. The position locking holes on the unit frame or the unit compartment are threaded holes that are threaded to engage with the locking bolts.

[0031] Further specified, there is a guide rail device on each of the left and right sides of the unit assembly, which is used to guide the movement of the unit assembly in the unit chamber. The guide rail device includes a slide groove and at least two sliding members arranged front and rear embedded in the slide groove. The sliding members and the slide groove are located at the bottom of the unit frame and the unit chamber shelf of the unit chamber, respectively. The bottom of the unit frame and the unit chamber shelf have an upper hook plate and a lower hook plate that are mutually hooked and engaged. During the process of the unit assembly entering the connection position, the upper hook plate and the lower hook plate are in a hooked engagement state.

[0032] Furthermore, the slide is specifically provided by a guide rail, the sliding element is specifically a sliding column, and the upper surface of the guide rail has protruding ribs to reduce the frictional resistance of the unit assembly moving within the unit chamber.

[0033] Furthermore, the two ends of the slide are closed to cooperate with the sliding member to limit the travel of the unit assembly. When the unit assembly moves to the first end point of the travel, the upper hook plate and the lower hook plate are in a disengaged state.

[0034] The beneficial effects of this invention are as follows: Compared with the traditional main circuit connection structure, by applying the main circuit connector body reversing connection circuit breaker technology on the incoming side, the wiring terminals of the main circuit connectors for phases A, B, and C can all be positioned outside the incoming terminal of the circuit breaker. The connecting conductive busbar can achieve a 100% L-shaped structure, simplifying the manufacturing process and reducing assembly time, specifically saving 65% of labor. At the same time, the shortened length of the connecting conductive busbar results in lower temperature rise. A single unit with 6 connectors saves 53.5% of copper, and an average of 6.5-8 kg of copper is saved per unit.

[0035] The extended terminal arrangement of the B-phase main circuit connector on the outgoing side aims to fit the current transformer onto the terminal, with the connection hole of the terminal preceding the current transformer. The connection point of the connecting busbar to the terminal is located at the front end of the current transformer, creating an additional 32mm of clearance on the outgoing side. This allows the circuit breaker to be closer to the rear panel of the rack where the main circuit connector is installed. The connecting busbar on the outgoing side also features an L-shaped structure. The reduction of the unit depth to 300mm is the most innovative connection structure and a manufacturing and installation process structure that is extremely satisfactory to industry manufacturers.

[0036] This invention features two innovative structural arrangements: the incoming-side main circuit connector body reverses the connection of the circuit breaker, and the outgoing-side B-phase main circuit connector is extended and fitted with an instrument transformer. Compared with the traditional main circuit connection structure, the connection distance H of 630A and 400A circuit breakers can be shortened to a limit of 88mm, and the connection distance of 250A and below is less than 88mm. This achieves the application of instrument transformers in unit compartments with a unit depth of 300mm and a comprehensive structural technical goal of reducing cabinet depth by 200mm.

[0037] The main circuit connector for 250A and 125A circuit breakers only requires 78mm, and the unit depth can be 275mm. If all the equipment units are 250A and 125A circuit breakers, the cabinet depth only needs to be 600mm, which greatly reduces site space costs in environments with limited equipment installation space.

[0038] The guide rail device with grooves provides accurate positioning, ensuring that the displacement of the unit assembly is 100% accurately controlled within 0.5mm. Simultaneously, it ensures that the upper and lower hook plates are not squeezed, and that the unit assembly operation is unobstructed. Attached Figure Description

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0040] Figure 1 This is a schematic diagram of the removable plug-in unit assembly according to Embodiment 1 of the present invention;

[0041] Figure 2 This is a schematic diagram of the removable plug-in unit assembly from another perspective of Embodiment 1 of the present invention;

[0042] Figure 3 This is a top view structural diagram of the removable plug-in unit assembly of Embodiment 1 of the present invention;

[0043] Figure 4 This is a schematic diagram of the installation structure of the main circuit connector in Embodiment 1 of the present invention;

[0044] Figure 5 This is a schematic diagram of the mounting structure of the circuit breaker's fixing bracket and the current transformer according to Embodiment 1 of the present invention;

[0045] Figure 6 This is a schematic diagram of the unit assembly of Embodiment 1 of the present invention, omitting the L-shaped side plate and pull plate of the unit frame;

[0046] Figure 7 yes Figure 6 Another structural diagram from a different perspective;

[0047] Figure 8 This is a schematic diagram of the unit chamber structure of Embodiment 1 of the present invention;

[0048] Figure 9 This is a structural schematic diagram of the unit chamber of Embodiment 1 of the present invention from another perspective;

[0049] Figure 10 This is a schematic diagram of the removable plug-in unit of Embodiment 1 of the present invention;

[0050] Figure 11 This is a schematic diagram of the removable plug-in unit assembly according to Embodiment 2 of the present invention;

[0051] Figure 12 This is a schematic diagram of the unit chamber structure of Embodiment 2 of the present invention;

[0052] Figure 13 This is a schematic diagram of the installation structure of the main circuit connector in Embodiment 3 of the present invention;

[0053] Figure 14 This is a top view structural diagram of the removable plug-in unit assembly of Embodiment 3 of the present invention;

[0054] Figure 15 This is a schematic diagram of the structure of a low-voltage complete set of equipment using the removable plug-in unit of the present invention;

[0055] Figure 16 This is a structural schematic diagram of a drawer unit assembly in the prior art;

[0056] Figure 17 This is a front view structural diagram of a fixed pluggable unit in the prior art;

[0057] Figure 18 This is a schematic diagram of the rear view structure of a fixed pluggable unit in the prior art;

[0058] In the diagram, 1. Unit frame, 1-1. L-shaped rear plate, 1-1-1. Rear end plate of the frame, 1-2. L-shaped side plate, 1-3. Pull plate, 1-4. Additional mounting plate, 2. Main circuit connector, 2-1. Main circuit body reversing connector, 2-2. Terminal block, 3. Circuit breaker, 4. Current transformer, 5. Connecting conductor bar, 6. Spreader bar, 7. Support screw, 8. Current transformer mounting bracket, 9. Busbar, 10. Fixed bracket, 11-1. Lever 11-2. Lever-driven upward propulsion mechanism; 12. Handle; 13. Position locking hole; 14. Sliding component; 15. Guide rail; 15-1. Slide groove; 15-2. Protruding rib; 16-1. Upper hook plate; 16-2. Lower hook plate; 17. Outlet static socket; 18. Auxiliary circuit connector; 19-1. Unit compartment shelf; 19-2. Unit compartment back panel; 19-3. Unit door; 20. Locking bolt; 21. Protective isolation plate. Detailed Implementation

[0059] Example 1, such as Figures 1-10 As shown, a main circuit connection structure for a low-voltage complete set of equipment includes a main circuit connector 2, a circuit breaker 3, and a current transformer 4. The three phases of the circuit breaker 3 are specifically phase A, phase B, and phase C from top to bottom. The circuit breaker 3 is connected to the main circuit connector 2 of each phase on the incoming and outgoing sides via connecting conductive bars 5, for main circuit plug-in connection of incoming and outgoing lines. The current transformer 4 is mounted on the connecting conductive bars 5 on the outgoing side. The phase-to-phase center of the terminals of the main circuit connector 2 of each phase on the incoming and outgoing sides corresponds to the phase-to-phase center of the corresponding phase of the circuit breaker 3. Furthermore, the connecting conductive bars 5 on both the incoming and outgoing sides are L-shaped, and the terminals of the main circuit connector 2 of each phase on both the incoming and outgoing sides are in the middle position. The terminals of the main circuit connector 2 of phase B are staggered vertically from the terminals of the main circuit connectors 2 of phases A and C and located inside in a triangular arrangement. The L-shaped connecting conductor 5 includes a horizontal section connecting the circuit breaker 3 and a vertical section connecting the terminals of the main circuit connector 2. The current transformer 4 of phase B on the outgoing side is mounted on the terminal of the corresponding phase's main circuit connector 2. Specifically, the terminal is the connecting conductor 2-2. The connection point between the terminal of the main circuit connector 2 of phase B on the outgoing side and the connecting conductor 5 is located in front of the current transformer 4 of phase B. The current transformers 4 of phases A and C on the outgoing side are mounted on the horizontal section of the connecting conductor 5 of the corresponding phase and located outside the connecting conductor 5 of phase B.

[0060] A removable plug-in unit assembly includes a unit frame 1 and the aforementioned main circuit connection structure, with the main circuit connector 2 and circuit breaker 3 mounted on the unit frame 1.

[0061] like Figure 1 and 3As shown, the current transformers 4 for phases A and C on the outgoing side are mounted on the horizontal section of the corresponding phase connecting busbar 5 using a traditional installation method. Specifically, a spreader bar 6 is inserted into the central sensing hole of the current transformer 4, and support screws 7 are installed at both ends of the spreader bar 6. The support screws 7 support the connecting busbar 5, and the current transformer 4 is mounted on the connecting busbar 5 by the expansion support force of the spreader bar 6 and the support screws 7.

[0062] like Figure 5 As shown, the current transformer 4 of phase B on the outgoing side is mounted on the current transformer mounting bracket 8, which is mounted on the rear end plate 1-1-1 of the unit frame 1. The current transformer mounting bracket 8 is specifically an L-shaped bracket, with its vertical end plate mounted on the rear end plate 1-1-1 and its horizontal end plate serving as the mounting base for the current transformer 4.

[0063] On the incoming line side, the main circuit connectors 2 for phases A, B, and C are arranged in layers from top to bottom. The horizontal phase spacing of the plug-in terminals of each phase's main circuit connector 2 is consistent with the phase spacing of the busbar 9, for connection to the busbar 9. The main circuit connector 2 for phase A is a traditional non-self-commutating main circuit connector 2, with its plug-in terminal and wiring terminal on a straight line. The main circuit connectors 2 for phases B and C are main circuit self-commutating connectors 2-1, with the wiring terminal of phase B offset from that of phases A and C and located on the outside. On the outgoing line side, the main circuit connectors 2 for phases A, B, and C only need to use traditional non-self-commutating main circuit connectors 2 to achieve a main circuit connection structure where the phase center of the wiring terminal of the main circuit connector 2 corresponds to the phase center of the corresponding phase of the circuit breaker 3.

[0064] The circuit breaker 3 is installed by a fixed bracket 10, which is L-shaped. The end of the vertical end plate of the fixed bracket 10 is installed on the base plate of the unit frame 1, and the end of the horizontal end plate of the fixed bracket 10 is installed on the rear end plate 1-1-1 of the frame. The circuit breaker 3 is installed on the vertical end plate of the fixed bracket 10.

[0065] The unit frame 1 of the removable plug-in unit assembly in this embodiment 1 has a handle 12 at the front for manually operating the unit assembly. The front of the unit frame 1 has a position locking hole 13, which is a threaded hole or a through hole. The left and right sides of the bottom of the unit frame 1 have sliding parts 14 of the guide rail device. The bottom of the unit frame 1 also has an upper hook plate 16-1. An additional mounting plate 1-4 is installed on the top of the rear end plate 1-1-1 of the unit frame 1, and an auxiliary circuit connector 18 is installed on the additional mounting plate 1-4.

[0066] A removable plug-in unit for a low-voltage switchgear includes a unit compartment and a unit assembly within the unit compartment. The unit assembly is specifically the aforementioned removable plug-in unit assembly. The unit compartment shelf 19-1 also has a matching position locking hole 13. When the unit assembly enters the connection position, the unit assembly is locked by a locking bolt 20 that passes through both the unit frame 1 and the position locking hole 13 on the unit compartment. In the accompanying drawings of this embodiment 1, the position locking hole 13 on the unit compartment is shown as a threaded hole that engages with the locking bolt 20. This threaded hole is specifically provided by a nut fixed to the unit compartment shelf 19-1.

[0067] Each of the left and right sides of the unit assembly has a guide rail device for guiding the movement of the unit assembly within the unit chamber. The guide rail device includes a slide groove 15-1 and at least two sliding members 14 arranged front and rear, which are embedded in the slide groove 15-1. The sliding members 14 and the slide groove 15-1 are located at the bottom of the unit frame 1 and on the unit chamber shelf 19-1 of the unit chamber, respectively. The bottom of the unit frame 1 and the unit chamber shelf 19-1 have an upper hook plate 16-1 and a lower hook plate 16-2 that are engaged with each other. During the process of the unit assembly entering the connection position, the upper hook plate 16-1 and the lower hook plate 16-2 are in an engaged state of being engaged with each other.

[0068] The slide groove 15-1 is specifically provided by the guide rail 15, and the sliding member 14 is specifically a sliding column. The guide rail 15 is installed on the unit chamber shelf 19-1, and the sliding member 14 is installed at the bottom of the unit frame 1. The guide rail 15 has a protruding upper surface, and the slide groove 15-1 is formed on the upper surface of the guide rail 15. The upper surface also has a protruding rib 15-2 extending along the moving direction of the unit assembly, which is used to reduce the frictional resistance of the unit assembly moving in the unit chamber. The guide rail 15 supports the movement of the unit assembly through the rib 15-2. The two ends of the slide groove 15-1 are closed to cooperate with the sliding member 14 to limit the movement stroke of the unit assembly. When the unit assembly moves to the first end point of the movement stroke, the upper hook plate 16-1 and the lower hook plate 16-2 are in a disengaged state. The bottom of the unit assembly has three upper hook plates 16-1, two of which are located at the rear of the unit assembly and are arranged on the left and right sides, and the other upper hook plate 16-1 is located at the middle or near the middle of the front of the unit assembly.

[0069] The incoming line side uses the main circuit body reversing connector 2-1 to achieve the main circuit connection structure in which the phase-to-phase center of the wiring terminal of the main circuit connector 2 is aligned with the phase-to-phase center of the corresponding phase of the circuit breaker 3. This achieves the purpose of shortening the distance between the rear end plate 1-1-1 of the unit assembly frame and the rear end face of the circuit breaker 3, i.e., the circuit breaker connection distance H.

[0070] In existing technology, the installation method of the current transformer 4 of phase B on the outgoing side is the same as that of phase A and phase C, which also uses a flat bar 6 and support screws 7 for installation. This requires a specific installation depth. Furthermore, the length of the terminal block 2-2 of the main circuit connector 2 of phase B on the outgoing side is the same as the length of the terminal block 2-2 of the main circuit connector 2 of other phases. The current transformer 4 of phase B can only be installed in front of the connection point between the terminal of the main circuit connector 2 of phase B and the connection point of the connecting conductor 5, requiring an even greater installation depth. However, this embodiment 1, by innovating the installation structure of the current transformer 4 of phase B and lengthening the terminal block 2-2 of the main circuit connector 2 of phase B, can further shorten the circuit breaker connection distance H.

[0071] The removable plug-in unit of this embodiment 1 can reduce the distance between the rear end plate 1-1-1 of the unit assembly frame and the rear end face of the circuit breaker 3 to 85mm. The amount of copper used in the connecting conductive busbar 5 of the 630A drawer unit is only 2.19kg, the amount of copper used in the 400A unit is only 1.63kg, the amount of copper used in the 250A unit is only 0.83kg, and the amount of copper used in the 125A unit is only 0.49kg. The unit depth can be reduced by 100mm, which reduces the amount of copper used in the connecting conductive busbar 5 of the main circuit by 53.5% compared with the traditional fixed plug-in structure.

[0072] The unit frame 1 includes an L-shaped back plate 1-1, two L-shaped side plates 1-2, and a pull plate 1-3. The L-shaped side plates 1-2 are fixed to the left and right sides of the L-shaped back plate 1-1. The vertical plate of the L-shaped back plate 1-1 is the rear end plate 1-1-1 of the unit frame 1, and the horizontal plate of the L-shaped back plate 1-1 is part of the base plate of the unit frame 1. The pull plate 1-3 and the horizontal plate of the L-shaped back plate 1-1 are the front and rear parts of the base plate of the frame, respectively. The end of the vertical end plate of the fixed bracket 10 is installed on the horizontal plate of the L-shaped back plate 1-1. The pull plate 1-3 is fixed between the front parts of the L-shaped side plates 1-2. Two sliding parts 14 are arranged at the bottom of the L-shaped side plates 1-2. There are two handles 12 located on the left and right sides of the pull plate 1-3, respectively. The handles 12 are flat handles and are long and narrow. There is a handle groove at the top of the handle for easy pulling. Two upper hook plates 16-1 are arranged at the bottom of the horizontal part of the L-shaped back plate 1-1, and one upper hook plate 16-1 is arranged at the bottom of the pull plate 1-3. Two position locking holes 13 are arranged on the pull plate 1-3, located behind the handle 12.

[0073] Figure 15 This is a schematic diagram of the structure of a low-voltage switchgear using the removable plug-in unit of Embodiment 1.

[0074] The operational protection level of the removable plug-in unit in this embodiment 1 is as follows: a protective isolation plate 21 is arranged on the incoming side of the circuit breaker 3 to effectively isolate the human body for safe operation. The protection level is IP30 in the open state, while the standard only requires IP20.

[0075] The working process of this embodiment 1 is as follows:

[0076] Unit assembly insertion operation: The unit assembly enters the unit compartment, and the sliding member 14 is embedded in the groove 15-1 of the guide rail 15 on both sides of the unit compartment. Using both hands, push the open-type plug-in unit assembly into the connection position using the handle 12. The main circuit connector 2 on the inlet side is plugged into the busbar 9, and the main circuit connector 2 on the outlet side is plugged into the outlet static socket 17 on the unit compartment back panel 19-2. Use two locking bolts 20 to pass through the position locking holes 13 of the unit frame 1 and the unit compartment shelf 19-1 to position the unit assembly, thus completing the connection operation. Close the unit door 19-3 on the unit compartment and close the circuit breaker 3.

[0077] Unit assembly removal procedure: With circuit breaker 3 open, open unit door 19-3. First, loosen the two locking bolts 20 on unit frame 1, disengaging the locking bolts 20 from the position locking holes 13 on unit compartment shelf 19-1. Use both hands to pull out the unit assembly through handle 12. The front sliding member 14 contacts the front closed opening of the slide groove 15-1, limiting the front end point of the unit assembly's movement stroke. The upper hook plate 16-1 and lower hook plate 16-2 are disengaged. Lift the unit assembly to remove it.

[0078] The functions of the upper hook plate 16-1 and the lower hook plate 16-2 are as follows: After the sliding member 14 on the unit assembly is embedded in the sliding groove 15-1 of the unit chamber for effective left and right positioning, as long as the unit assembly moves backward by 1.0mm, the upper hook plate 16-1 and the lower hook plate 16-2 will start to engage with each other to effectively position the unit assembly vertically. Combined with the sliding member 14 and the sliding groove 15-1 for effective left and right positioning of the unit assembly, it ensures that the main circuit connector 2 is correctly aligned and plugged in within ±0.5mm during the operation of inserting the unit assembly.

[0079] The advantages of this embodiment 1 are as follows: the circuit breaker connection distance H is shortened to a limit of 88mm, achieving a structural technological breakthrough by saving 53.5% of copper in the conductive busbar used for circuit breaker connections. Furthermore, shortening the circuit breaker connection distance H as much as possible not only reduces the length of the conductive busbar, thus saving copper, but also results in lower resistance, lower temperature rise, lower operating energy consumption, and longer unit life. For the electrical industry, it is common knowledge that shorter connections result in lower temperature rise.

[0080] By shortening the circuit breaker connection distance H to 88mm, the unit depth can be reduced by 75mm, saving 10% of steel plates and 200mm of cabinet depth. On average, a single low-voltage switchgear unit can reduce steel consumption by 20kg and copper consumption by 6.5kg, resulting in significant economic benefits. Furthermore, the reduced space required for low-voltage switchgear units on offshore platforms, subways, and ships significantly lowers infrastructure costs.

[0081] Compared to traditional main circuit connectors that require transition flipping to connect to the phase-to-phase center of the circuit breaker structure, the main circuit connection structure of the present invention, which connects the phase-to-phase center in a consistent manner, can reduce manufacturing and installation labor costs. In terms of total manufacturing labor, each piece of equipment can save at least 1.5 person labor costs.

[0082] The improvement of installing the circuit breaker on the rear end plate of the rack means that the rack base plate of the unit rack is no longer the mounting base for the circuit breaker, and can be hollowed out in a large area. The structure of the unit rack of the present invention can reduce the amount of material used by 10%, simplify the manufacturing process, and reduce labor costs by 10%.

[0083] The functional units of this invention are all installed on the work platform, i.e., the unit compartment shelf, which saves labor, reduces workload, and has the function of uninterrupted power supply maintenance in case of faults. It creates a groundbreaking application technology route for the main circuit plug structure connection circuit breaker structure of functional units for low-voltage complete sets of equipment in China. This structural technology is not available in foreign brand companies, filling a gap in the industry and solving the long-standing shortcoming of insufficient application technology.

[0084] In high-current applications, the pull-out plug-in unit of this invention uses a lever-driven force-increasing mechanism for plugging and unplugging operations, while in low-current applications, it uses a manual plugging and unplugging operation. Both operations can be completed in about 20 seconds, making the operation fast and the application highly feasible.

[0085] The functional unit of this invention is material-saving, labor-saving, low-cost, and high-performance. It features a compact structure, small cabinet size, and minimal space occupation. Its manufacturing cost is 60% of foreign brands and 10% lower than domestic brands. Its application in various industries will undoubtedly generate significant economic benefits for the entire sector. It represents the most feasible technology for the main circuit connection structure of functional units in low-voltage complete sets of equipment, both domestically and internationally. Xinyuanxing auxiliary component performance testing indicators: Main circuit plug short-circuit withstand current 50KA / 1S for 630A, 40KA / 1S for 400A. Industry standards specify overload delay impact currents of 4536A / 30S for 630A, 2880A / 30S for 400A, and 1800A / 30S for 250A. Actual measured temperature rise is 32-36℃ for 630A, 40-44℃ for 400A, and 39-44℃ for 250A, with phase-to-phase temperature rise equilibrium within 5℃. These two testing indicators are the highest standards in the industry and have been verified by the Suzhou Electric Power Research Institute. The structural technology of this solution meets the application requirements of high-current equipment with a current of 2500A, fully meets the requirements of 5G equipment, and covers the standard requirements of equipment application technology in all industries.

[0086] Example 2, as Figure 11 and 12 As shown, this embodiment is basically the same as Embodiment 1, except that the removable plug-in unit of the low-voltage switchgear in Embodiment 2 does not have a handle 12 for manually operating the unit assembly. The front of the unit frame 1 has a lever-amplifying upward propulsion mechanism 11-1 for operating the unit assembly by lever amplification. Generally, handle 12 is not provided, but in application, a handle 12 can be provided on the left side of the lever-amplifying upward propulsion mechanism 11-1. The unit compartment shelf 19-1 of the unit compartment has a lever-amplifying downward propulsion mechanism 11-2. The lever-amplifying upward propulsion mechanism 11-1 and the lever-amplifying downward propulsion mechanism 11-2 constitute the lever-amplifying propulsion mechanism.

[0087] The working process of this embodiment 2 is as follows:

[0088] Unit assembly insertion operation: The unit assembly enters the unit compartment, and the sliding member 14 is embedded in the groove 15-1 of the guide rail 15 on both sides of the unit compartment. Insert the lever operating tool into the operating port of the lever force-increasing push mechanism and insert it all the way in. Pull up the lever operating tool to push the removable plug-in unit assembly into the connection position. The main circuit connector 2 on the incoming side is plugged into the busbar 9, and the main circuit connector 2 on the outgoing side is plugged into the outgoing static socket 17 on the back plate 19-2 of the unit compartment. Use two locking bolts 20 to pass through the position locking holes 13 of the unit frame 1 and the unit compartment shelf 19-1 to position the unit assembly, thus completing the connection operation. Close the unit door 19-3 on the unit compartment and close the circuit breaker 3.

[0089] Unit assembly removal operation: With circuit breaker 3 tripped, open unit door 19-3. First, loosen the two locking bolts 20 on unit frame 1 to disengage the locking bolts 20 from the position locking holes 13 on unit compartment shelf 19-1. Insert the lever operating tool into the operating port of the lever force-increasing mechanism and insert it all the way in. Pull down the lever operating tool to remove the removable plug-in unit assembly. The front sliding member 14 contacts the front closed opening of the slide groove 15-1, limiting the front end point of the unit assembly's movement stroke. The upper hook plate 16-1 and lower hook plate 16-2 are in a disengaged state. Lift the unit assembly to remove it.

[0090] Example 3, as Figure 13 and 14 As shown, it is basically the same as in Embodiment 1, except that: the main circuit connectors 2 of phase A and phase B on the incoming side of the unit assembly of the low-voltage switchgear in Embodiment 3 are traditional non-body commutation main circuit connectors 2, and only the main circuit connector 2 of phase C is the main circuit body commutation connector 2-1. The wiring terminals of the main circuit connector 2 of phase B are also offset from the wiring terminals of the main circuit connectors 2 of phase A and phase C, but are located on the inside.

[0091] Example 4 is essentially the same as Example 1, except that in Examples 1, 2, and 3, the main circuit connector 2 on the incoming side has a plug-in end that directly connects to the busbar 9. In Example 4, however, the main circuit connector 2 on the incoming side has a connector bar. A bidirectional connector is arranged on the unit compartment back panel 19-2. This bidirectional connector is a main circuit connector 2 that connects bidirectionally via a spring plug. The front end of the bidirectional connector connects to the busbar 9, and the connector bar of the main circuit connector 2 on the incoming side is inserted into the rear end of the bidirectional connector, connecting to the rear end of the spring plug. The main circuit connector 2 on the outgoing side remains unchanged, providing users with more options.

[0092] The technical solution of connecting the main circuit connector 2 on the incoming side of this embodiment 4 to the busbar via a bidirectional connector is disclosed in Chinese patent document CN202121053837.4, "Main Circuit Commutation Plug-in, Main Circuit Connection Structure and Functional Unit".

[0093] Example 5 is basically the same as Example 1, except that the unit assembly and functional unit in Example 5 are specifically a drawer unit assembly and a drawer unit. The main circuit connection structure and transformer 4 mounting structure of Examples 1, 2, 3, or 4 are applied to the drawer unit assembly and the drawer unit. Specifically, in the drawer unit assembly, the circuit breaker 3 is connected to the main circuit connector 2 of each phase on the incoming and outgoing sides through an L-shaped connecting conductive busbar 5. The phase-to-phase center of the wiring terminals of the main circuit connector 2 of each phase on the incoming and outgoing sides is set to correspond to the phase-to-phase center of the corresponding phase of the circuit breaker 3. The terminals of the main circuit connectors 2 of each phase on the outgoing side are arranged in a triangular pattern, with the terminals of the main circuit connectors 2 of phase B in the middle position being staggered from the terminals of the main circuit connectors 2 of phases A and C in the vertical direction and located inside. The current transformer 3 of phase B on the outgoing side is mounted on the terminal of the corresponding phase's main circuit connector 2. The connection point between the terminal of the main circuit connector 2 of phase B on the outgoing side and the connecting conductor 5 is located in front of the current transformer 4 of phase B. The current transformers 4 of phases A and C on the outgoing side are mounted on the horizontal section of the connecting conductor 5 of the corresponding phase and located outside the connecting conductor 5 of phase B.

[0094] In this invention, the phase-to-phase center of the wiring terminal of the main circuit connector 2 on the incoming line side is aligned with the phase-to-phase center of the corresponding phase of the circuit breaker 3. This allows the main circuit connector on the incoming line side and the corresponding phase of the circuit breaker to be connected one-to-one via connecting conductive bars arranged in layers from top to bottom. Preferably, the connecting conductive bars arranged in layers from top to bottom are L-shaped connecting conductive bars 5, which can better shorten the circuit breaker connection distance H. For example, in embodiments 1 to 5 above, the connecting conductive bars 5 on the incoming line side are all L-shaped. In embodiments 1, 2, and 4... The removable plug-in unit and the drawer unit of Example 5 are generally 400A and 630A units, and the removable plug-in unit of Example 3 is generally 250A and 125A units. However, due to the variety of circuit breaker models and specifications in this industry, the main circuit body commutation connector 2-1 sometimes only uses phase C, and sometimes both phase B and phase C are used. It is not ruled out that the connecting conductive busbar 5 on the incoming line side needs to be bent and is not L-shaped. However, all of them are set to correspond to the phase center of the wiring terminal of the main circuit connector 2 on the incoming line side and the phase center of the corresponding phase of the circuit breaker 3.

Claims

1. A main circuit connection structure of a low-voltage complete set of equipment, comprising a main circuit connector, a circuit breaker and a mutual inductor, the three phases of the circuit breaker are A phase, B phase and C phase from top to bottom, and the circuit breaker is connected with the main circuit connectors of each phase of the incoming line side and the outgoing line side through a connecting conductive row, characterized in that: The phase-to-phase center of the terminal of the main circuit connector of each phase of the incoming line side and the outgoing line side corresponds to and is arranged in accordance with the phase-to-phase center of the corresponding phase of the circuit breaker, the terminals of the main circuit connectors of each phase of the outgoing line side are arranged in a triangular shape with the terminal of the main circuit connector of the B phase in the middle position staggered in the vertical direction from the terminals of the main circuit connectors of the A and C phases in the upper and lower positions and located on the inner side, the transformer of the B phase of the outgoing line side is sleeved on the terminal of the main circuit connector of the corresponding phase, the terminal of the main circuit connector of the B phase of the outgoing line side and the connecting point of the connecting bus bar are located in front of the transformer of the B phase, and the transformers of the A and C phases of the outgoing line side are sleeved on the connecting bus bar of the corresponding phase and located on the outer side of the connecting bus bar of the B phase.

2. The main circuit connection structure of a low voltage complete set equipment according to claim 1, characterized in that: The connecting bus bar of the outgoing line side is in the shape of L, the connecting bus bar of the outgoing line side includes a horizontal segment connected to the circuit breaker and a vertical segment connected to the terminal of the main circuit connector, and the transformers of the A and C phases of the outgoing line side are sleeved on the horizontal segment of the connecting bus bar of the corresponding phase.

3. The main circuit connection structure of a low voltage complete set equipment according to claim 1, characterized in that: The transformer of the B phase of the outgoing line side is installed through the transformer mounting bracket on the unit rack.

4. The main circuit connection structure of a low voltage complete set equipment according to claim 3, characterized in that: The transformer mounting bracket is in the shape of L, the vertical end plate of the L-shaped bracket is installed on the rear end plate of the rack, and the horizontal end plate of the L-shaped bracket serves as the installation base of the transformer.

5. The main circuit connection structure of a low voltage complete set equipment according to claim 1, characterized in that: The terminals of the main circuit connectors of each phase of the incoming line side are arranged in a triangular shape with the terminal of the main circuit connector of the B phase in the middle position staggered in the vertical direction from the terminals of the main circuit connectors of the A and C phases in the upper and lower positions.

6. The main circuit connection structure of a low voltage complete set equipment according to claim 5, characterized in that: The main circuit connectors of the A, B and C phases of the incoming line side are arranged in layers from top to bottom, the horizontal phase-to-phase distance of the plug-in ends of the main circuit connectors of each phase is consistent with the phase-to-phase distance of the bus bar, and the main circuit connectors of each phase are used to be plugged into and connected to the bus bar, wherein the main circuit connectors of the A and B phases are non-body commutated main circuit connectors, the main circuit connector of the C phase is a main circuit body commutated connector, and the terminal of the main circuit connector of the B phase is staggered relative to the terminals of the main circuit connectors of the A and C phases and located on the inner side; or wherein the main circuit connector of the A phase is a non-body commutated main circuit connector, the main circuit connectors of the B and C phases are main circuit body commutated connectors, and the terminal of the main circuit connector of the B phase is staggered relative to the terminals of the main circuit connectors of the A and C phases and located on the outer side.

7. The main circuit connection structure of a low voltage complete set equipment according to claim 1 or 2, characterized in that: The main circuit connectors of the incoming line side are one-to-one connected to the corresponding phases of the circuit breaker through the connecting bus bar arranged in layers from top to bottom, and the connecting bus bar of the incoming line side is in the shape of L.

8. The main circuit connection structure of a low voltage complete set equipment according to claim 1, characterized in that: The circuit breaker is installed through the fixing bracket, the fixing bracket is in the shape of L, the end of the vertical end plate of the fixing bracket is installed on the rack bottom plate of the unit rack, the end of the horizontal end plate of the fixing bracket is installed on the rear end plate of the rack, and the circuit breaker is installed on the vertical end plate of the fixing bracket.

9. A draw-out plug-in unit assembly, in particular for a low voltage switchgear, characterized in that: The main circuit connection structure of the low-voltage complete equipment includes the unit rack and the main circuit connection structure of the low-voltage complete equipment according to claim 1, the unit rack is provided with a handle at the front part thereof for manually operating the unit assembly, and / or the front part of the unit rack is provided with a lever force amplification pushing mechanism for operating the unit assembly in a lever force amplification manner.

10. The pluggable unit assembly of claim 9, wherein: The front part of the unit rack has position locking holes which are threaded holes or through holes, the left and right sides of the bottom part of the unit rack have sliding members of the guide rail device, and the bottom part of the unit rack also has upper hook plates; An additional mounting plate is mounted on the top of the rear end plate of the unit rack, and an auxiliary circuit connector is mounted on the additional mounting plate.

11. A draw-out unit, in particular for a low voltage switchgear, comprising a unit chamber and a unit assembly within the unit chamber, characterized in that: The unit assembly of claim 9 has a lever force boosting push-in mechanism on the unit chamber layer plate of the unit chamber when the front part of the unit rack has a lever force boosting push-in mechanism.

12. The plug-in unit according to claim 11, characterized in that: The front part of the unit rack and the unit chamber layer plate of the unit chamber have matched position locking holes, and the unit assembly is locked by locking bolts which pass through the position locking holes on the unit rack and the unit chamber at the same time when the unit assembly enters the connecting position, the position locking holes on the unit rack or the unit chamber are threaded holes which are matched with the locking bolts.

13. The plug-in unit according to claim 11, characterized in that: The left and right sides of the unit assembly each have a guide rail device for guiding the movement of the unit assembly in the unit chamber, the guide rail device includes a sliding groove and at least two sliding members arranged in front and back in the sliding groove, the sliding members and the sliding groove are respectively located on the bottom part of the unit rack and the unit chamber layer plate of the unit chamber, and the bottom part of the unit rack and the unit chamber layer plate have upper hook plates and lower hook plates which are matched with each other, the upper hook plates and the lower hook plates are in the combined state of being matched with each other in the process of the unit assembly entering the connecting position.

14. The plug-in unit according to claim 13, characterized in that: The sliding groove is specifically provided by a guide rail, and the sliding member is specifically a sliding column, and the upper surface of the guide rail has protruding ribs for reducing the frictional resistance of the movement of the unit assembly in the unit chamber.

15. The plug-in unit according to claim 13, characterized by: The two ends of the sliding groove are closed for cooperating with the sliding members to limit the movement stroke of the unit assembly, and the upper hook plates and the lower hook plates are in the state of being separated from each other when the unit assembly moves to the front terminal point of the movement stroke.

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