Modular assembled smart substation

Abstract

The present invention relates to the technical field of substations, and discloses a modular assembled intelligent substation, including a plurality of prefabricated cabin modules, each of which has its own power equipment installed inside, and each prefabricated cabin module is a hexahedral steel structure frame, on which mounting holes are arranged, a cable interlayer is arranged at the bottom of each prefabricated cabin module, a cable well is arranged at the side, and the connection cables of each prefabricated cabin module are collected from the cable interlayer to the cable well, and a plurality of prefabricated cabin modules are assembled in a flat or stacked manner, and the assembly position is connected to the mounting hole of the steel structure frame by fasteners. The present invention performs modular disassembly and transportation according to different transportation conditions, and then performs flat or stacked assembly and construction according to specific land occupation requirements, and the assembly and construction are convenient, the construction period is short, the disassembly is convenient, and the modules can be reused.

Description

Technical Field

[0001] The present invention relates to the technical field of substations, and in particular to a modular assembled intelligent substation. Background Art

[0002] With the development of society, my country's land resources are becoming increasingly scarce. How can the construction of substations save more space, how can they have more flexible and convenient construction forms, and how can they adapt to various complex geographical transportation environments and conditions? These problems are constantly testing enterprises. The traditional concrete structure substation construction method and steel structure substation construction plan can no longer solve the above problems well.

[0003] The existing substation construction method not only has a long construction period, but also requires a large investment. Especially for substations that are used for a short period of time, the initial site selection, construction, and later dismantling and leaving the site are all time-consuming and laborious investments. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned problem and to provide a modular assembled intelligent substation, which can be modularly disassembled and transported according to different transportation conditions, and then assembled and constructed in a flat or stacked manner according to specific land requirements. The substation has convenient assembly and construction, short construction period, easy disassembly and can be reused.

[0005] The technical solution adopted by the present invention is:

[0006] A modular assembled intelligent substation, characterized in that it comprises a plurality of prefabricated cabin modules, each of which has its own power equipment installed inside, and each prefabricated cabin module is a hexahedral steel structure frame, on which mounting holes are arranged, a cable interlayer is arranged at the bottom of each prefabricated cabin module, and a cable well is arranged at the side, and the connecting cables of each prefabricated cabin module are collected from the cable interlayer to the cable well, and a plurality of prefabricated cabin modules are assembled in a flat or stacked manner, and the assembly position is connected to the mounting holes of the steel structure frame by fasteners, and the cables between the assembled prefabricated cabin modules are connected at the cable well, and the plurality of prefabricated cabin modules at least include a main control prefabricated cabin module and a distribution unit prefabricated cabin module.

[0007] Furthermore, the steel structure frames are arranged at the top and bottom of the prefabricated cabin module, a slope structure is arranged on the top steel structure frame, the bottom of the prefabricated cabin module is hollowed out, and the size of the bottom steel structure frame is larger than the size of the top steel structure frame.

[0008] Furthermore, when the two pre-cabin modules are assembled up and down, a first auxiliary component is arranged at the staggered contact point of the two cabin bodies, and the first auxiliary component includes an angle steel and a channel steel arranged on the upper cabin body, one side of the angle steel is horizontal and the other side is vertical, and the channel steel is buckled on the vertical side of the angle steel and the edge of one side of the lower cabin body; a second auxiliary component is arranged at the docking position of the upper and lower cabin bodies, and the second auxiliary component is an angle steel, one side of the angle steel is fastened to the side of the lower cabin body, and the other side is horizontally located on the lower surface of the upper cabin body.

[0009] Furthermore, the assembled substation also includes a secondary wiring prefabricated cabin module, a communication prefabricated cabin module, a battery prefabricated cabin module, and a fan prefabricated cabin module. The fan prefabricated cabin module and the distribution unit prefabricated cabin module are installed on the ground, and the main control prefabricated cabin module, the secondary wiring prefabricated cabin module, the communication prefabricated cabin module, and the battery prefabricated cabin module are installed above the fan prefabricated cabin module and the distribution unit prefabricated cabin module.

[0010] Furthermore, when the prefabricated cabin modules are assembled in stacked form, vertical reinforcing channel steels are arranged on the steel structure frames of the prefabricated cabin modules located in the middle and lower layers, and the number of reinforcing channel steels on the prefabricated cabin modules located at the lower layers is greater than the number of reinforcing channel steels on the prefabricated cabin modules located at the upper layers.

[0011] Furthermore, when the prefabricated cabin modules are assembled in stacked form, cage ladders are provided at multiple side positions of the prefabricated cabin.

[0012] Furthermore, the layer where the main control prefabricated cabin module is located and the lower layer form a spare platform, and the spare platform includes a toothed frame, which is fixed on the top of the lower cabin by bolts. A passage is set between the main control prefabricated cabin module and the spare platform, and guardrails are set around the spare platform and the passage.

[0013] Furthermore, the ground frame of the spare platform is a mesh plane.

[0014] Furthermore, an escalator is provided between the spare platform and the ground.

[0015] Furthermore, each door of the prefabricated cabin module is equipped with an emergency escape lock.

[0016] Furthermore, the cable shaft includes two longitudinal columns of shafts, one column is a control cable shaft, and the other column is a power cable shaft. Each column of shafts is provided with a number of levels, each level is divided into a number of sub-columns, and the number of sub-columns of each level of the same shaft is the same. A wire binding rack is provided on each level, and the wire binding racks on each level are at the same horizontal height, and the positions of the wire binding racks on every two levels are staggered.

[0017] Furthermore, the cable shaft is a steel structure, and a number of safety doors are arranged in front of each shaft from top to bottom, and the steel structure is a detachable frame structure.

[0018] Furthermore, when the two prefabricated cabin modules are assembled up and down, triangular upper connecting plates are respectively provided on the four corners of the bottom of the upper prefabricated cabin, and triangular lower connecting plates are respectively provided on the four corners of the top of the lower prefabricated cabin. The triangular sides of the upper connecting plate and the lower connecting plate are welded to the corner steel beams of the prefabricated cabin. An upper elliptical hole is provided on the upper connecting plate, and the angle between the length direction of the upper elliptical hole and the side direction of the prefabricated cabin is 45 degrees. A lower elliptical hole is provided on the lower connecting plate, and the length direction of the lower elliptical hole is perpendicular to the length direction of the upper elliptical hole. The upper and lower elliptical holes have the same size. When the upper and lower layers of the prefabricated cabin are docked, the positions of the upper connecting plate and the lower connecting plate correspond, and the positions of the upper and lower elliptical holes of the upper and lower connecting plates correspond, and fasteners are installed in the upper and lower elliptical holes to fix the upper and lower layers of the prefabricated cabin.

[0019] Furthermore, there are two upper elliptical holes on the upper connecting plate, and the two upper elliptical holes are arranged in parallel, and there are two lower elliptical holes on the lower connecting plate, and the two lower elliptical holes are arranged in parallel.

[0020] Furthermore, there are two upper elliptical holes on the upper connecting plate, and the two upper elliptical holes are arranged on the same straight line. There are two lower elliptical holes on the lower connecting plate, and the two lower elliptical holes are arranged in parallel.

[0021] The beneficial effects of the present invention are:

[0022] (1) Modular assembly type, which enables substations to be assembled according to needs and has strong flexibility;

[0023] (2) Modular disassembly and transportation are carried out according to different transportation conditions, and then flat-laying or stacked assembly and construction are carried out according to specific land requirements. The assembly and construction are convenient, the construction period is short, the disassembly is convenient, and the structure can be reused. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Attached Figure 1 It is a schematic diagram of the structure of a modular assembled intelligent substation of the present invention;

[0025] Attached Figure 2 Yes Figure 1 Back view of ;

[0026] Attached Figure 3 Yes Figure 1 Side view of;

[0027] Attached Figure 4 Yes Figure 2 A partial enlarged view of middle A;

[0028] Attached Figure 5 Yes Figure 2 A partial enlarged view of B in the middle;

[0029] Attached Figure 6 Yes Figure 1 The upper view of the Figure 7 The upper level top view;

[0030] Attached Figure 7 It is a schematic diagram of the structure of a substation example;

[0031] Attached Figure 8 Yes Figure 7 Side view of;

[0032] Attached Fig. 9 Yes Figure 7 A top view of the lower level;

[0033] Attached Fig.10 It is a schematic diagram of the three-dimensional structure of the cable well;

[0034] Attached Fig.11 This is a schematic diagram of the structure of the upper connecting plate on one corner of the upper prefabricated cabin of the substation;

[0035] Attached Fig.12 It is a schematic diagram of the structure of the lower connecting plate on the opposite corner of the lower prefabricated cabin of the substation;

[0036] Attached Fig.13 It is a schematic diagram of the matching structure of the connecting plates of the upper and lower prefabricated cabins of the substation.

[0037] The reference numerals in the accompanying drawings are:

[0038] 1. Prefabricated cabin module; 2. Steel structure frame;

[0039] 3. Main control prefabricated cabin module; 4. Power distribution unit prefabricated cabin module;

[0040] 5. Slope structure; 6. First auxiliary component;

[0041] 7. Second auxiliary component; 8. Secondary wiring prefabricated cabin module;

[0042] 9. Communication prefabricated cabin module; 10. Battery prefabricated cabin module;

[0043] 11. Prefabricated wind turbine cabin module; 12. Cage ladder;

[0044] 13. Spare platform; 14. Toothed frame;

[0045] 15. Guardrail; 16. Escalator;

[0046] 17. Escape slide; 21. Control cable shaft;

[0047] 22. Power cable shaft; 23. Safety door;

[0048] 24. Layer frame; 31. Upper connecting plate;

[0049] 32. Upper elliptical hole; 33. Lower connecting plate;

[0050] 34. Lower oval hole. DETAILED DESCRIPTION

[0051] The specific implementation of the modular assembled smart substation of the present invention is described in detail below with reference to the accompanying drawings.

[0052] See attached Figures 1 to 6 The modular assembled intelligent substation includes multiple prefabricated cabin modules 1, at least two. Each prefabricated cabin module 1 has its own power equipment installed inside. Each prefabricated cabin module is a hexahedral steel structure frame 2, and mounting holes are set on the steel structure frame 2. A cable interlayer is set at the bottom of each prefabricated cabin module 1, and a cable well is set on the side. The connecting cables of each prefabricated cabin module 1 are collected from the cable interlayer to the cable well. When multiple prefabricated cabin modules 1 are assembled in a flat or stacked manner, the assembly position is connected to the mounting holes of the steel structure frame 2 by fasteners, and the cables between the assembled prefabricated cabin modules 1 are connected at the cable well.

[0053] The substation at least comprises a main control prefabricated cabin module 3 and a power distribution unit prefabricated cabin module 4, which are combined to form the simplest substation.

[0054] The top and bottom of the prefabricated cabin module 1 are provided with steel structure frames 2, a slope structure 5 is provided on the top steel structure frame 2, the bottom of the prefabricated cabin module 1 is hollowed out, and the size of the bottom steel structure frame 2 is larger than the size of the top steel structure frame 2. When the prefabricated cabin modules 1 are assembled in an up-and-down stacking manner, the bottom steel structure frame 2 of the upper prefabricated cabin module 1 is fixed together with the top steel structure frame 2 of the lower prefabricated cabin module 1, and the slope structure 5 of the lower prefabricated cabin module 1 falls into the hollow structure of the upper prefabricated cabin module 1 without causing interference.

[0055] See attached Figure 4 , 5 When two prefabricated cabin modules are assembled up and down, a first auxiliary component 6 is set at the staggered contact point of the two cabins. The first auxiliary component 6 includes an angle steel and a channel steel set on the upper cabin. One side of the angle steel is horizontal and the other side is vertical. The channel steel is buckled on the vertical side of the angle steel and the edge of one side of the lower cabin. A second auxiliary component 7 is set at the docking position of the upper and lower cabins. The second auxiliary component 7 is an angle steel. One side of the angle steel is fastened to the side of the lower cabin, and the other side is horizontally located on the lower surface of the upper cabin. The two auxiliary components make the upper and lower prefabricated cabin modules 1 assembled firmly connected to reduce safety hazards.

[0056] See attached Figures 6 to 9The modular assembly type intelligent substation can be installed in a flat or two-layer, three-layer or more-layer stacked assembly, and the modules are fixed by bolts. Let's take the double-layer stacked assembly construction as an example. The prefabricated cabin modules of the assembled substation include the main control prefabricated cabin module 3, the distribution unit prefabricated cabin module 4, the secondary wiring prefabricated cabin module 8, the communication prefabricated cabin module 9, the battery prefabricated cabin module 10, the fan prefabricated cabin module 11, and so on. According to the conventional installation method shown in the figure, the fan prefabricated cabin module 11 and the distribution unit prefabricated cabin module 4 are installed on the ground, and the main control prefabricated cabin module 3, the secondary wiring prefabricated cabin module 8, the communication prefabricated cabin module 9, and the battery prefabricated cabin module 10 are installed above the fan prefabricated cabin module 11 and the distribution unit prefabricated cabin module 4. The number of each prefabricated cabin module can be reasonably allocated according to the actual project needs to meet the construction of projects with different power consumption. Each door of the prefabricated cabin module is equipped with an emergency escape lock, so that the staff can respond to emergencies during operation.

[0057] When the prefabricated cabin modules 1 are stacked, vertical reinforcement channels are set on the steel structure frames 2 of the prefabricated cabin modules 1 located in the middle and lower layers, and the number of reinforcement channels on the prefabricated cabin modules 1 located at the bottom is greater than the number of reinforcement channels on the prefabricated cabin modules 1 located above. For example, in a three-layer stacked substation, the number of reinforcement channels of the prefabricated cabin modules 1 at the bottom is three to four, and the number of reinforcement channels of the middle layer is one to two. The number of channels can be adjusted according to the actual bearing capacity of the steel structure, so that the assembled substation structure is firm and meets relevant national standards. In addition, cage ladders 12 are set at multiple side positions of the assembled prefabricated cabin modules 1 to facilitate operation and maintenance.

[0058] See attached Figure 6 , 7 8. In order to cooperate with the actual production use of the staff, a spare platform 13 is formed on the top of some layers of the assembled substation. For example, the layer where the main control prefabricated cabin module 3 is located and the lower layer form a spare platform 13. The spare platform 13 is to provide a movable space for the staff, and can also be used as a viewing platform. The working cabin of the substation is relatively narrow, and the space available for the staff to rest and move is limited. The viewing platform is designed so that the staff can have space to rest and move when they are tired from work. The spare platform 13 includes a toothed frame 14, which is fixed on the top of the lower cabin by bolts. Since the roof of the lower cabin is a slope structure 5, the teeth of the toothed frame 14 are erected on the slope, and the spare platform 13 is above the toothed frame 14. The ground frame of the spare platform 13 is a mesh plane. A passage is set between the main control prefabricated cabin module 3 and the spare platform 13, and guardrails 15 are set around the spare platform 13 and the passage. The guardrail 15 is detachable and installable, which is convenient for maintenance and reuse. An escalator 16 is provided between the spare platform 13 and the ground. In addition, an escape slide 17 is provided on one side of the spare platform 13 or the upper main control prefabricated cabin module 3, extending from the upper layer to the ground.

[0059] See attached Fig.10 The side cable well of each prefabricated cabin module 1 includes two longitudinal columns of wells, one column is a control cable well 21, and one column is a power cable well 22. Each column of wells is provided with four levels. The number of levels of each column of wells can be adjusted according to the actual height of the cable well, and generally 3 to 8 are selected. Each level is divided into four columns, and the number of columns of each layer can also be adjusted according to the actual cable type. Generally, 3 to 6 are selected. The cable well is a steel structure, and the steel structure is a detachable frame structure, which is convenient for the use of prefabricated substations using cable wells. Three safety doors 23 are set from top to bottom in front of each well, and the safety doors 23 are set according to the height of the cable well to protect the cables and reduce safety accidents. The number of columns of each level of the two wells is the same, and each level is provided with a wire binding rack. The wire binding racks on each level are at the same horizontal height. The positions of the wire binding racks on every two levels are staggered. In this way, the classification effect of double cable types can be achieved. The wire binding frame is directly used as the hierarchical frame 24 of the cable well, and a plurality of wire binding holes are provided on the wire binding frame to facilitate the bundling of the cables.

[0060] This structure of the cable well allows the control cable and power cable to be separated, reducing signal interference and eliminating the original anti-electromagnetic interference materials. The cables can be divided into multiple columns, and the arrangement is flat and beautiful. The wire binding racks on each layer are at the same level, and the wire binding racks on every two layers are staggered, which can achieve a double classification effect of cable types; the detachable frame is suitable for prefabricated substations assembled on site, and can be modularly disassembled and transported according to different transportation conditions. It is easy to assemble and construct, with a short construction period, easy to disassemble, and reusable.

[0061] See attached Fig.11 When the two prefabricated cabin modules are assembled up and down, triangular upper connecting plates 31 are respectively provided on the four corners of the bottom of the upper prefabricated cabin, and triangular lower connecting plates 33 are respectively provided on the four corners of the top of the lower prefabricated cabin. An upper elliptical hole 32 is provided on the upper connecting plate 31, and the angle between the length direction of the upper elliptical hole 32 and the side direction of the prefabricated cabin is 45 degrees. A lower elliptical hole 34 is provided on the lower connecting plate 33, and the length direction of the lower elliptical hole 34 is perpendicular to the length direction of the upper elliptical hole 32, and the upper and lower elliptical holes 34 have the same size.

[0062] See attached Fig.12 The two sides of the triangular upper and lower connecting plates are welded to the corner steel beams of the prefabricated cabin. There are two upper elliptical holes 32 on the upper connecting plate 31, and the two upper elliptical holes 32 are arranged in parallel. There are two lower elliptical holes 34 on the lower connecting plate 33, and the two lower elliptical holes 34 are arranged in parallel.

[0063] See attached Fig.13When the upper and lower layers of the prefabricated cabin are butted, the positions of the upper connecting plate 31 and the lower connecting plate 33 correspond, the positions of the upper and lower elliptical holes 34 of the upper and lower connecting plates 33 correspond, and the hole positions of the upper and lower elliptical holes 34 when they intersect match the bolt diameter. Fasteners are installed on the intersecting hole positions of the upper and lower elliptical holes 34 to fix the upper and lower layers of the prefabricated cabin. When a slight displacement occurs during the assembly of the upper and lower prefabricated cabins, it does not affect the vertical overlapping position of the upper and lower elliptical holes 34, reducing the time and effort of precise positioning of the hoisting.

[0064] On the connection plate, elliptical holes of different positions and numbers can be set according to the structure of the prefabricated cabin, which is suitable for the upper and lower connection plates to match during installation. As shown in the figure, the two elliptical holes are designed on the same horizontal line, and each elliptical hole matches an elliptical hole on the connection plate of another layer.

[0065] The elliptical holes arranged vertically up and down can be fastened by bolts at the overlapping position even with a small deviation when docking. When assembling the upper and lower prefabricated cabins, the connection plates on the four corners can be fastened and installed by simply lifting and adjusting.

[0066] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A modular assembled smart substation, characterized by: The invention comprises a plurality of prefabricated cabin modules, each of which has its own power equipment installed inside, and each prefabricated cabin module is a hexahedral steel structure frame, and mounting holes are arranged on the steel structure frame, and a cable interlayer is arranged at the bottom of each prefabricated cabin module, and a cable well is arranged at the side, and the connecting cables of each prefabricated cabin module are collected from the cable interlayer to the cable well, and the plurality of prefabricated cabin modules are assembled in a flat or stacked manner, and the assembly position is connected to the mounting holes of the steel structure frame by fasteners, and the cables between the assembled prefabricated cabin modules are connected at the cable well, and the plurality of prefabricated cabin modules at least include a main control prefabricated cabin module and a distribution unit prefabricated cabin module, and the prefabricated cabin modules are provided with a plurality of prefabricated cabin modules ... The steel structure frames are arranged at the top and bottom of the cabin module, and a slope structure is arranged on the top steel structure frame. The bottom of the prefabricated cabin module is hollowed out, and the size of the bottom steel structure frame is larger than that of the top steel structure frame. When two prefabricated cabin modules are assembled up and down, a first auxiliary part is arranged at the staggered contact point of the two layers of cabin bodies, and the first auxiliary part includes an angle steel and a channel steel arranged on the upper cabin body, one side of the angle steel is horizontal and the other side is vertical, and the channel steel is buckled on the vertical side of the angle steel and the edge of one side of the lower cabin body; a second auxiliary part is arranged at the docking position of the upper and lower cabin bodies, and the second auxiliary part is an angle steel, one side of the angle steel is fastened to the side of the lower cabin body, and the other side is horizontally located on the lower surface of the upper cabin body.

2. The modular assembled smart substation according to claim 1 is characterized in that: The modular assembled intelligent substation also includes a secondary wiring prefabricated cabin module, a communication prefabricated cabin module, a battery prefabricated cabin module, and a fan prefabricated cabin module. The fan prefabricated cabin module and the distribution unit prefabricated cabin module are installed on the ground, and the main control prefabricated cabin module, the secondary wiring prefabricated cabin module, the communication prefabricated cabin module, and the battery prefabricated cabin module are installed above the fan prefabricated cabin module and the distribution unit prefabricated cabin module.

3. The modular assembled smart substation according to claim 1 is characterized in that: When the prefabricated cabin modules are stacked and assembled, vertical reinforcing channel steels are arranged on the steel structure frames of the prefabricated cabin modules located in the middle and lower layers, and the number of reinforcing channel steels on the prefabricated cabin modules located at the lower layers is greater than the number of reinforcing channel steels on the prefabricated cabin modules located at the upper layers.

4. The modular assembled smart substation according to claim 1 is characterized in that: When the prefabricated cabin modules are assembled in stacked form, cage ladders are provided at multiple side positions of the prefabricated cabin.

5. The modular assembled smart substation according to claim 2 is characterized in that: The layer where the main control prefabricated cabin module is located and the lower layer form an empty platform. The empty platform includes a toothed frame, which is fixed on the top of the lower cabin by bolts. A passage is set between the main control prefabricated cabin module and the empty platform, and guardrails are set around the empty platform and the passage.

6. The modular assembled smart substation according to claim 5 is characterized in that: The ground frame of the spare platform is a mesh plane.

7. The modular assembled smart substation according to claim 5 is characterized by: An escalator is arranged between the spare platform and the ground.

8. The modular assembled smart substation according to claim 1 is characterized by: Each door of the prefabricated cabin module is equipped with an emergency escape lock.

9. The modular assembled smart substation according to claim 1, characterized in that: The cable shaft includes two longitudinal columns of shafts, one column is a control cable shaft, and the other column is a power cable shaft. Each column of shafts is provided with a number of levels, and each level is divided into a number of sub-columns. The number of sub-columns of each level of the same shaft is the same. A wire binding rack is provided on each level. The wire binding racks on each level are at the same horizontal height, and the positions of the wire binding racks on every two levels are staggered.

10. The modular assembled smart substation according to claim 9, characterized in that: The cable well is a steel structure, and a plurality of safety doors are arranged in front of each well from top to bottom. The steel structure is a detachable frame structure.

11. The modular assembled smart substation according to claim 1, characterized in that: When the two prefabricated cabin modules are assembled up and down, triangular upper connecting plates are respectively provided on the four corners of the bottom of the upper prefabricated cabin, and triangular lower connecting plates are respectively provided on the four corners of the top of the lower prefabricated cabin. The triangular sides of the upper connecting plate and the lower connecting plate are welded to the corner steel beams of the prefabricated cabin. An upper elliptical hole is provided on the upper connecting plate, and the angle between the length direction of the upper elliptical hole and the side direction of the prefabricated cabin is 45 degrees. A lower elliptical hole is provided on the lower connecting plate, and the length direction of the lower elliptical hole is perpendicular to the length direction of the upper elliptical hole. The sizes of the upper and lower elliptical holes are the same. When the upper and lower layers of the prefabricated cabin are docked, the positions of the upper connecting plate and the lower connecting plate correspond, and the positions of the upper and lower elliptical holes of the upper and lower connecting plates correspond, and fasteners are installed in the upper and lower elliptical holes to fix the upper and lower layers of the prefabricated cabin.

12. The modular assembled smart substation according to claim 11, characterized in that: There are two upper elliptical holes on the upper connecting plate, and the two upper elliptical holes are arranged in parallel. There are two lower elliptical holes on the lower connecting plate, and the two lower elliptical holes are arranged in parallel.

13. The modular assembled smart substation according to claim 11, characterized in that: There are two upper elliptical holes on the upper connecting plate, and the two upper elliptical holes are arranged on the same straight line. There are two lower elliptical holes on the lower connecting plate, and the two lower elliptical holes are arranged in parallel.

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