Lower hanging cable layer structure suitable for deepwater offshore converter station

Abstract

The invention provides a lower hanging cable layer structure suitable for a deepwater offshore converter station. The lower hanging cable layer structure comprises a main gallery and a secondary gallery which are arranged below a deck layer of an upper module of the converter station. The elevation of the main gallery is lower than that of the bottom of the secondary gallery; the secondary gallery is arranged below the bottom elevation of the first deck layer; the main corridor comprises a first platform structure, the first platform structure is provided with a grating wave dissipation area and a planking protection area, the planking protection area is located on the inner side of the grating wave dissipation area, and a submarine cable anchoring device and a first support are arranged at the position, on the planking protection area, of the first platform structure. A water retaining structure is arranged around the submarine cable anchoring device and the first bracket; a wave dissipation structure is arranged on the periphery of the grid wave dissipation area; the secondary corridor comprises a second platform structure and a second support, and the second support is arranged on the second platform structure. The overall gravity center height of the upper module is remarkably reduced by adopting a lower hanging type arrangement design, and the problem that the loading capacity of a ship is insufficient during high-position floating support installation is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of offshore wind power technology, specifically to a cable layer structure suitable for deep-water offshore converter stations. Background Technology

[0002] In recent years, my country's deep-sea wind power development has entered a stage of rapid growth, with coastal provinces such as Zhejiang, Guangdong, Shandong, and Fujian planning and deploying multiple deep-sea wind farm sites. Compared with near-shore wind power, deep-sea wind power projects are characterized by large single-unit capacity, complex water depth conditions, and harsh marine environments. These characteristics pose unprecedented technical requirements for the design and construction of the core hub of the wind farm—the offshore converter station. The upper module of the offshore converter station (or simply the offshore converter module) integrates numerous complex and important sets of equipment and facilities. Due to the limitations of the offshore operating environment, the overall weight control of the module is crucial to ensuring the safety and economy of the project construction. This means that "based on process requirements and structural characteristics, the layout should be compact, space-saving, and weight-reducing, while ensuring reliable operation and ease of maintenance" (NB / T 11599, Design Specification for Offshore Converter Stations in Wind Farm Projects).

[0003] The traditional design methods used in the Three Gorges Rudong offshore converter module, a benchmark project in shallow waters in China, face significant challenges in deep-sea scenarios, mainly in three aspects: First, there is the elevation issue. Increased water depth necessitates raising the design elevation of the first deck to nearly 30 meters (relative to average sea level), requiring the module to adopt high-level floating installation technology or configure a huge temporary deck support frame (DSF). Second, there are contradictions in cable layout. Deep-sea projects generally use 66kV submarine cables as power collection lines, with more than 30 cable loops per station, requiring a dedicated cable layer (approximately 6 meters high) to meet turning radius and wiring requirements. Most importantly, there is the center of gravity effect. When the total weight of the module exceeds 20,000 tons, experience shows that every 0.5-meter increase in center of gravity height will result in a loss of approximately 500 tons of load-bearing capacity for the floating installation vessel, creating a vicious cycle of "increased elevation → raised center of gravity → exponential increase in installation costs."

[0004] Due to the complexity of multi-condition design limit states and the constraints of multi-disciplinary design boundary conditions, existing technologies often fall short in controlling the overall weight of modules. CN114386243A explicitly points out that "structural designers often conduct structural design after receiving the electrical layout plan. However, the results of the electrical design in the aforementioned technologies may not be the optimal solution for the structural design. This could lead to an unoptimal design strategy for the offshore converter platform, meaning that the size and weight of the offshore converter platform could be unreasonable, and the cost could be very high." This problem is also reflected in CN112510745A (large area occupied by cable overhead layer) and CN217307269U (discontinuous core axis grid frame of structure), and both are inferior to the overall solution of CN110042819B (i.e., the already completed Rudong Station solution) in terms of overall weight and eccentricity control. The technical solution adopted by CN112510745A (i.e., the Qingzhou Station solution under construction) is to raise the valve hall and set up a cable and auxiliary equipment room below the valve hall. Although this solution solves the problem of convenient access for the entire field collection lines after they are connected to the offshore converter station from all directions, it is better than CN110042819B. However, the center of gravity is significantly raised, which increases the lateral load on the components under inertial conditions such as offshore transportation, installation and in-situ earthquakes. In addition, the cancellation of the auxiliary plant on one side of the module reduces the design flexibility of the auxiliary rooms. Under the control of the structural axis grid, the density of each room and the load-bearing capacity of the structural materials are different, and the overall weight index is still not ideal.

[0005] Currently, conventional technical approaches have obvious inherent defects: simply increasing the height of the deck layer causes the structural center of gravity to shift upward, significantly increasing the risk factor of float-over installation; the built-in cable layer design will cause the total height of the upper module to exceed 50m, which will greatly challenge the operational capabilities of most float-over installation vessels, requiring ship modification or even making the solution unfeasible; and there is a lack of effective measures to ensure the long-term reliability of armored cables after stripping the armor.

[0006] To address the aforementioned technical challenges, there is an urgent need to develop an innovative cable underlay structure solution. This solution must simultaneously meet multiple technical requirements, including maintaining the optimal center of gravity height of the upper module, ensuring the flexibility of arranging more than 30 high-voltage cables, achieving mechanical protection and electrical insulation reliability of the stripped-armored cable throughout its entire life cycle, and being compatible with the economic requirements of existing floating installation processes. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a sub-cable layer structure suitable for deep-water offshore converter stations. Compared with traditional built-in cable layers, the sub-mounted arrangement design of this invention significantly lowers the overall center of gravity of the upper module, effectively solving the problem of insufficient ship carrying capacity during high-level floating installation, making the floating installation of 20,000-ton upper modules more feasible and economical.

[0008] This invention provides a cable layer structure suitable for deep-water offshore converter stations, including a main corridor and a secondary corridor located below the first deck layer of the upper module of the converter station. Both the main corridor and the secondary corridor are semi-enclosed spaces with partial water permeability. The main corridor and the secondary corridor are arranged in an "II" shape. The elevation of the main corridor is lower than the bottom elevation of the secondary corridor to meet the first turning requirement of the cable after armor stripping. The secondary corridor is lower than the bottom elevation of the first deck layer to meet the second turning requirement of the cable after armor stripping. The main corridor includes a first platform structure formed by connecting multiple circular tube beams. The first platform structure is provided with a grating wave-dissipating area and a paving protection area. The paving protection area is located inside the grating wave-dissipating area. On the first platform structure, a submarine cable anchoring device and a first support are provided at the location of the paving protection area. Water-blocking structures are provided around the submarine cable anchoring device and the first support. The grating wave-dissipating area is provided with a wave-dissipating structure. The secondary corridor includes a second platform structure and a second support. The second platform structure is composed of multiple circular tube beams connected together, and the second support is installed on the second platform structure.

[0009] As a preferred embodiment of the present invention: the submarine cable anchoring device includes a first flange, a stiffening plate, a node pipe, a protective pipe, and a reinforcing diagonal brace; the first flange is provided on the top of the node pipe and is connected to the first support through the first flange; the stiffening plate is connected between the bottom of the first flange and the first platform structure; the node pipe is connected to the first platform structure; the bottom of the node pipe has a protective pipe extending downwards from the first platform structure; the bottom end of the protective pipe adopts an outwardly flared trumpet shape; and the reinforcing diagonal brace is connected between the protective pipe and the first platform structure.

[0010] As a preferred embodiment of the present invention: multiple second supports are arranged at intervals along the direction of the second platform structure on the second platform structure. The second support includes a portal frame and a slot box. The slot box is fixed to the second platform structure by the portal frame and is used for laying cables.

[0011] As a preferred technical solution of the present invention: the water-blocking structure includes a folded plate and structural square steel. The folded plate is vertically arranged around the submarine cable anchoring device and the first support. The structural square steel is arranged horizontally on the top of the folded plate along the arrangement direction of the folded plate. The structural square steel is vertically spaced on the folded plate for separation and reinforcement.

[0012] As a preferred technical solution of the present invention: the wave-dissipating structure includes a steel grating and a reinforced railing, the reinforced railing is provided on the periphery of the wave-dissipating area of ​​the grating on the first platform structure, and the steel grating is laid on the top surface of the first platform structure in the wave-dissipating area of ​​the grating.

[0013] As a preferred technical solution of the present invention: the first platform structure is provided with a boarding ramp, a gangway boarding area, a secondary corridor ladder and a jacket boarding area; the first platform structure is connected to the first deck level through the boarding ramp; the gangway boarding area is provided with a boarding gangway for connecting with a professional maintenance vessel; the first platform structure is connected to the second platform structure through the secondary corridor ladder.

[0014] As a preferred technical solution of the present invention: the under-hanging cable layer structure has a maintenance channel system, the maintenance channel system includes maintenance channels disposed on the first platform structure and the second platform structure, the maintenance channels are arranged inside the first platform structure or the second platform structure, and the water-blocking structure is arranged outside the maintenance channel of the first platform structure. The maintenance passage connects the boarding ramp, the gangway boarding area, the secondary corridor elevator, and the jacket platform boarding area.

[0015] As a preferred embodiment of the present invention: the secondary corridor includes a safety railing, which is located on the periphery of the second platform structure; both the first platform structure and the second platform structure are composed of multiple circular tube beams connected together.

[0016] As a preferred technical solution of the present invention: the first platform structure of the main corridor is provided with a water supply and drainage pipe anchoring device, and the water supply and drainage pipe anchoring device is provided with a through hole for the water supply and drainage sleeve of the upper module of the converter station to pass through. The water supply and drainage sleeve extends downward from the upper module of the converter station, passes through the main corridor, and is fixedly connected to the water supply and drainage pipe anchoring device.

[0017] As a preferred technical solution of the present invention: the water supply and drainage pipe anchoring device includes a node ring plate, a node sleeve, and a reinforcing rib; the node sleeve is connected to the first platform structure, and its interior is used for the water supply and drainage pipe to pass through; the node ring plate is disposed at the top of the node sleeve and is used to fix it to the second flange on the water supply and drainage pipe; the reinforcing rib connects the node ring plate, the node sleeve, and the first platform structure.

[0018] The beneficial effects provided by this invention are as follows: The proposed under-mounted cable layer structure solves a key technical challenge faced by deep-sea converter stations in deep-water environments. Compared with traditional built-in cable layers, this under-mounted structure has multiple technical advantages: 1. Regarding structural center of gravity optimization, the under-mounted arrangement design adopted in this invention significantly reduces the overall center of gravity height of the superstructure and improves the rigidity of the large-span structure of the main plant. Under the same water depth conditions, this structure can reduce the height of the superstructure by 5-6 meters. This improvement effectively solves the problem of insufficient ship carrying capacity during high-level floating installation, making the floating installation of the 20,000-ton superstructure more feasible and economical.

[0019] 2. In terms of innovative multi-functional integrated design, this invention adopts an open steel structure design, with structures at the bottom and around the perimeter that combine safety protection and wave dissipation functions. Through optimized spatial layout, this invention can meet the turning and laying requirements of more than 30 66kV cables. The wave dissipation structure can effectively reduce the impact load of waves on the main structure. Compared with traditional fully enclosed cable layers, this design eliminates the need for ventilation and air conditioning equipment, reduces the amount of steel structure used, and significantly saves on overall costs.

[0020] 3. In terms of support and protection functions, this invention integrates the support functions of submarine cable protection pipe and water supply and drainage sleeve, solving the problem of unsupported sections above 12m in traditional solutions; the cable layer of this invention can ensure the reliability of key processes such as submarine cable traction, offshore welding installation, and in-situ maintenance, thereby significantly improving the structural strength of tubular components under extreme working conditions.

[0021] 4. In response to the special requirements of the marine environment, this invention adopts several innovative designs to improve hydrodynamic performance—all beam systems use tubular components with excellent hydrodynamic performance; the sides and bottom are equipped with reinforced railings and steel grating wave-dissipating structures; the wave-dissipating structure can effectively disrupt the complete wave surface and reduce wave forces; the structural reliability of various types of casings during in-situ is significantly improved compared with traditional solutions.

[0022] 5. In terms of safety protection, the water-blocking structure of the present invention can effectively prevent waves from directly impacting the stripped cable, further protecting the cable after stripping; the maintenance channel is set inside the water-blocking structure, which significantly improves the safety and comfort of operation.

[0023] 6. Regarding offshore installation, the water supply and drainage anchoring device of this invention adopts an adjustable flange matching structure, which has the ability to adapt to a floating installation error of 100mm on one side. Through on-site error measurement, the flange of the water supply and drainage sleeve is finely adjusted and fixed to the node ring plate of this invention on-site. The success rate of offshore installation is high, the overall structure is more reliable, and the efficiency and quality of offshore construction are greatly improved.

[0024] In summary, this invention can solve the problems of wave risk, structural load-bearing capacity, cable layout, cable bends, and operation and maintenance in the cable underlayment of deep-sea offshore converter stations. It achieves cable protection while fully considering operation and maintenance, reliability throughout the entire life cycle, reducing offshore floating installation costs, and improving the economic efficiency of the project. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 An elevation view of the under-cable layer structure provided in an embodiment of the present invention; Figure 2 This is a plan view of the under-cable layer structure provided in an embodiment of the present invention; Figure 3 This is a plan view of the maintenance access system provided in an embodiment of the present invention; Figure 4 This is a top view of the submarine cable anchoring device provided in an embodiment of the present invention; Figure 5 This is a front view of the submarine cable anchoring device provided in an embodiment of the present invention; Figure 6 This is a front view of the water supply and drainage pipe anchoring device provided in an embodiment of the present invention; Figure 7 This is a top view of the water-blocking structure provided in an embodiment of the present invention; Figure 8 This is a front view of the water-blocking structure provided in an embodiment of the present invention; Figure 9 This is a schematic diagram of the structure of the encrypted railing provided in an embodiment of the present invention; Figure 10 A schematic diagram of the structure of a safety railing provided in an embodiment of the present invention; Figure 11 A schematic diagram of the area where the floating support mounting slot is located, as provided in this embodiment of the invention.

[0027] Figure label: 1a-West main corridor; 1b-East main corridor; 11-Dense railing; 12-Grate wave-dissipating area; 13-Panel protection area; 14-Water-retaining structure; 141-Folded plate; 142-Structural square steel; 15-Circular tube beam; 2a - North secondary corridor; 2b - South secondary corridor; 21 - Safety railing; 22 - Secondary corridor hanging column 22; Submarine cable anchoring device; 31-First flange; 32-Flange bolt hole; 33-Reinforcing plate; 34-Node pipe; 35-Protective pipe; 36-Reinforcing diagonal brace; 37-Flare shape; Water supply and drainage pipe anchoring device; 41-water supply and drainage sleeve; 411-second flange; 42-node ring plate; 43-node sleeve; 44-reinforcing rib; Cable; 51-First bracket; 52-Second bracket; 53-Equipment wiring hole; Maintenance access system; 61-Maintenance access; 62-Secondary corridor elevator; 63-Entry ramp; 64-Aircraft bridge entry area; 65-Jacket platform entry area Upper module of converter station. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples. However, it should be understood that the accompanying drawings are for illustrative purposes only and should not be construed as limiting the present invention. For better illustration of this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable that some well-known structures and their descriptions may be omitted in the drawings for those skilled in the art. The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting the present invention.

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0030] like Figure 1 , Figure 2 as well as Figure 11 As shown, a cable layer structure suitable for deep-water offshore converter stations includes a main corridor and a secondary corridor located below the first deck layer of the upper module 7 of the converter station. Both the main corridor and the secondary corridor are semi-enclosed spaces with partial water permeability. The main corridor is located on both sides of the float-over installation slot, and the secondary corridor is located above the float-over installation slot and connects to the main corridors on both sides. There are two main corridors and two secondary corridors, arranged in a "II" shape rotated 90°. The elevation of the main corridor is 2.5m to 3m lower than the bottom elevation of the secondary corridor to meet the first turning requirement of the cable 5 after stripping the armor. The secondary corridor is also arranged 2.5m to 3m lower than the bottom elevation of the first deck layer to meet the second turning requirement of the cable 5 after stripping the armor. Specifically, an east main corridor 1b is set on the east side below the upper block 7 of the offshore converter station, and a west main corridor 1a is set on the west side below it. A north secondary corridor 2a and a south secondary corridor 2b are set in the middle of the column legs of the upper block 7 of the converter station.

[0031] The main corridor includes a first platform structure formed by multiple circular tube beams. The first platform structure is equipped with a grating wave-dissipating area 12 and a plank protection area 13. The plank protection area 13 is located inside the grating wave-dissipating area 12. On the first platform structure, a submarine cable anchoring device 3 and a first support 51 are installed at the position of the plank protection area 13. After the submarine cable is pulled through and anchored in the submarine cable anchoring device 3, it extends to the first support 51 and is stripped of its armor to become a cable 5. The first support 51 is arranged near the submarine cable anchoring device 3 and mainly serves to support the submarine cable and facilitate the stripping of the submarine cable. Water-blocking structures 14 are set around the submarine cable anchoring device 3 and the first support 51, and do not interfere with the maintenance passage 61. A wave-dissipating structure is set around the periphery of the grating wave-dissipating area 12. In this embodiment, the two main corridors are located on the east and west sides below the first deck level. One of the main corridors below the auxiliary building also includes the water supply and drainage pipe anchoring device 4 required for the offshore converter station cooling system. The four corners of the main corridor are the gangway boarding area 64. The secondary corridor includes a second platform structure and a second support 52. The second platform structure is composed of multiple circular pipe beams connected together. The second support 52 is installed on the second platform structure and mainly serves to neatly lay out the cables 5.

[0032] In this embodiment, the two secondary corridors are located in the middle of the north and south sides of the main plant below the first deck level. The facades of the secondary corridors and the ground floor components of the main plant connected to the top form two truss beams to support the large span space of the main plant above.

[0033] The final elevations of the first and second platform structures were determined based on wave climb effect and wave load analysis on the jacket structure. The top elevation of the first platform structure in the main corridor should meet the requirement that, after fully considering the wave climb effect, only breaking waves impact the first platform structure of the main corridor. The top elevation of the second platform structure in the secondary corridor meets the minimum requirement of being unaffected by waves. The first and second platform structures are composed of multiple circular tube beams 15 welded together to minimize the hydrodynamic load under the most dangerous conditions. The beam grid composed of the circular tube beams 15 is generally no larger than 2m × 2m to ensure the load-bearing capacity of the steel grating in the wave-damping structure and the maintenance passage system 6 components.

[0034] Based on the location of the submarine cable anchoring wells, the east main corridor 1b and the west main corridor 1a are divided into a grating wave-dissipating area 12 and a paving protection area 13. Water-blocking structures 14 are installed between the grating wave-dissipating area 12 and the paving protection area 13 and near the submarine cable anchoring device 3 area to further protect against unpredictable extreme sea conditions. At the same time, reinforced railings 11 are installed around the east main corridor 1b and the west main corridor 1a, which can further play a role in wave dissipation and load reduction.

[0035] According to the requirements of cable 5 laying, the north secondary corridor 2a and the south secondary corridor 2b are set in the middle area of ​​the slot. In this embodiment, after the first rise and turn, the cable 5 on the east main corridor 1b side is laid horizontally to the second support 52 in the north secondary corridor 2a and the south secondary corridor 2b. After passing through the north secondary corridor 2a and the south secondary corridor 2b, the cable 5 turns for the second time and is connected to the bottom equipment wiring hole 53 on the first floor.

[0036] like Figure 4 and Figure 5 As shown, the submarine cable anchoring device 3 includes a first flange 31, a stiffening plate 33, a node pipe 34, a protective pipe 35, and a reinforcing diagonal brace 36. The top of the node pipe 34 is welded to the first flange 31 and connected to the first support 51 through the first flange 34. Specifically, the first flange 31 has flange bolt holes 32 for connection with the first support 51. The bottom of the first flange 31 is reinforced by the stiffening plate 33 connected to the first platform structure. The top elevation of the node pipe 34 is higher than the top elevation of the circular tube beam 15 of the first platform structure. The pipe body of the node pipe 34 is welded to the circular tube beam 15 of the first platform structure. The bottom of the node pipe 34 has a protective pipe 35 extending downwards from the first platform structure, so that the bottom of the submarine cable anchoring device 3 is about 1m away from the top of the submarine cable protective pipe 35 of the guide frame. On the one hand, this can effectively protect the cable 5 from the influence of external sunlight and seawater. On the other hand, it can significantly improve the structural rigidity of the submarine cable protective pipe 35 of the guide frame (reducing the cantilever section) and meet the process requirements during floating installation and docking. The bottom end of the protective tube 35 adopts an outwardly flared horn shape 37, and the protective tube 35 is connected to the first platform structure by the reinforcing diagonal brace 36.

[0037] Multiple second brackets 52 are arranged at intervals along the direction of the second platform structure. Each second bracket 52 includes a portal bracket and a trough box. The trough box is fixed to the circular tube beam of the second platform structure by the portal bracket. The trough box is used to lay cables 5.

[0038] like Figure 7 and Figure 8 As shown, the water-blocking structure 14 includes a folded plate 141 and structural square steel 142. The folded plate 141 is vertically arranged around the submarine cable anchoring device 3 and the first support 51. The structural square steel 142 is arranged horizontally on the top of the folded plate 141 along the arrangement direction of the folded plate 141. The structural square steel 142 is vertically spaced on the folded plate 141 for separation and reinforcement.

[0039] The height of the water-blocking structure 14 is determined based on the wave climb effect and is usually not less than 1m. A structural square steel 142 is installed on the top of the folded plate 141 to enhance the water-blocking plate's resistance to slamming. When the span of the folded plate 141 exceeds 6m, a vertically installed structural square steel 142 is used for separation and reinforcement. Its function is to prevent wave impact in the cable 5 anchorage area under extreme harsh conditions and to further protect the stripped cable 5.

[0040] The wave-damping structure includes a steel grating and reinforced railings 11. The reinforced railings 11 are installed around the perimeter of the grating wave-damping area 12 on the first platform structure. The steel grating is laid on the top surface of the first platform structure within the grating wave-damping area 12, meaning the steel grating is located in the area outside the submarine cable anchoring device 3. Compared to traditional railings, the reinforced railings 11 not only meet the personnel safety protection requirements of traditional railings, but also further reduce waves caused by lateral wave rise, thus reducing the overall wave load on the platform structure and further improving the overall structural reliability.

[0041] The first platform structure is provided with a boarding ramp 63, a gangway boarding area 64, a secondary corridor ladder 62, and a jacket platform boarding area 65; the first platform structure is connected to the first deck level via the boarding ramp 63; the gangway boarding area 64 is provided with a boarding ramp for connecting with a professional maintenance vessel; the first platform structure is connected to the second platform structure via the secondary corridor ladder 62.

[0042] like Figure 3 As shown, the under-hanging cable layer structure has a maintenance channel system 6, which includes a maintenance channel 61 disposed on the first platform structure and the second platform structure. The maintenance channel 61 is arranged inside the first platform structure or the second platform structure, and the water-blocking structure 14 is arranged outside the maintenance channel 61 of the first platform structure. The maintenance passage 61 connects the boarding ramp 63, the gangway boarding area 64, the secondary corridor elevator 62, and the jacket boarding area 65.

[0043] The maintenance passage 61 of the main corridor is connected along the length of the main corridor and is also connected to the maintenance passage 61 of the secondary corridor. A straight ladder 62 of the secondary corridor is set at the connection point with the secondary corridor, and the location of the ladder avoids the location of the large main beam on the first floor. The maintenance passage 61 uses steel plate as the floor to avoid the wave effect in the maintenance area and to ensure the convenience and comfort of maintenance personnel.

[0044] Maintenance passage 61 runs north-south through the east main corridor 1b and the west main corridor 1a, and is located within the paved protection area 13 to improve the comfort of operation and maintenance. Maintenance passage 61 also connects to the access corridor platform, where an access elevator 63 is installed to cross a 2.5m elevation. Jacket access areas 65 are set at the northwest corner of the west main corridor 1a and the southeast corner of the east main corridor 1b, and maintenance passage 61 also connects to these areas to ensure accessibility for escape and rescue from all locations.

[0045] The secondary corridor includes safety railings 21, which are installed around the perimeter of the second platform structure. The safety railings 21 are only installed around the perimeter of the secondary corridor, and their main function is the same as traditional railings, serving only a safety protection purpose.

[0046] like Figure 9 and Figure 10 As shown, the reinforced railing 11 and the safety railing 21 are respectively installed around the platform structures of the east main corridor 1b, the west main corridor 1a, the north secondary corridor 2a, and the south secondary corridor 2b. Compared to the safety railing 21, the height of the reinforced railing 11 is determined based on wave rise calculations and is not less than 1.2m; at the same time, the maximum spacing between the horizontal tie rods on the reinforced railing 11 is 300mm, and the maximum spacing between the vertical posts is 600mm, making its structural strength higher than that of the safety railing 21, thus meeting the personnel safety protection requirements of traditional railings.

[0047] like Figure 6 As shown, the first platform structure of the main corridor is provided with a water supply and drainage pipe anchoring device 4, and the water supply and drainage pipe anchoring device 4 has a through hole for the water supply and drainage sleeve 41 of the upper module 7 of the converter station to pass through. The water supply and drainage sleeve 41 extends downward from the upper block 7 of the converter station, passes through the main corridor, and is fixedly connected to the water supply and drainage pipe anchoring device 4.

[0048] The water supply and drainage anchoring device 4 can be divided into a water intake pipe anchoring device and a drainage pipe anchoring device. The two anchoring devices are constructed in the same way, and only need to be adjusted according to the diameter of the water intake pipe and the drainage pipe.

[0049] The water supply and drainage pipe anchoring device 4 includes a node ring plate 42, a node sleeve 43, and a reinforcing rib 44. The node sleeve 43 is connected to the circular pipe beam 15 of the first platform structure, and its interior is used for the water supply and drainage sleeve 41 to pass through. The node ring plate 42 is located on top of the node sleeve 43 and is used to fix it to the second flange 411 on the water supply and drainage sleeve 41 after the floating support installation is completed. The diameter of the node sleeve 43 is larger than the diameter of the water supply and drainage sleeve 41, and the installation space on one side can be controlled by 100mm based on the floating support installation experience error. The reinforcing rib 44 connects the node ring plate 42, the node sleeve 43, and the first platform structure. The reinforcing rib 44 is used to strengthen the support strength of the node ring plate 42 and the node sleeve 43 to the circular pipe beam 15. Through the water supply and drainage anchoring device, the cantilever length of the water supply and drainage sleeve 41 hanging from the first floor can be significantly reduced, further increasing the support strength of the water supply and drainage sleeve 41 under extreme working conditions and ensuring the reliability of the pipeline throughout its entire life cycle.

[0050] The upper module 7 of the deep-sea converter station has eight deck levels. The east and west sides of the platform house auxiliary powerhouses, typically with a span of 12-13 meters. The main powerhouse is located in the middle of the east and west sides, with a width adapted to the floating installation barge. A 66kV GIS room is located on the west side of the first-floor platform; this side is a key facility connecting the upper module to the lower cable layer. Cable 5 is fixed via submarine cable anchoring device 3 and then connected to the 66kV GIS through equipment wiring hole 53. A seawater lifting room is located on the east side of the first-floor platform for reliable connection to the water supply and drainage sleeve 41 of the lower cable layer. Positive and negative valve halls are located on the north and south sides of the central part of the platform, with a full height typically exceeding 20 meters. Auxiliary powerhouses on both sides, at other heights above the valve halls, house freshwater circulation equipment rooms, secondary equipment rooms, battery rooms, station transformer rooms, station power rooms, fresh air machine rooms, HVAC machine rooms, and other auxiliary rooms. The main powerhouse on the fifth floor of the upper module houses the cable 5 mezzanine and DC field. Above the cable mezzanine is a connecting transformer and a 500kV... The GIS room, DC field and connecting transformer, and GIS room extend to the top of the 8th deck. Auxiliary rooms such as the central control room, fresh air machine room and HVAC machine room are set up in the auxiliary plant above the 5th floor. The roof is equipped with conventional offshore converter station functional components such as lifting equipment and maintenance hoists.

[0051] The secondary corridor is located directly below the valve tower in the valve hall. Its truss structure forms an integral whole with the valve tower equipment foundation beam and is reinforced by the secondary corridor hanging columns 22. A safety railing 21 is installed in the middle of the secondary corridor hanging columns 22, forming a spatial frame system of valve hall ground beam - hanging column - railing - corridor ground beam. This makes the bottom of the valve tower more rigid and further improves the valve tower's seaworthiness and seismic performance, ensuring the safe and reliable operation of the converter valve, the most critical equipment in the offshore converter station. This is also a major advantage of this embodiment.

[0052] The construction process of the under-cable layer structure, the submarine cable traction and laying process, and the water supply and drainage sleeve laying process of this invention are as follows: 1. All structures of the lower layer of this invention are manufactured and integrated together with the upper module at the land dock to form a whole, without interfering with the floating installation slot. Except for the second flange 411, there are no components that need to be installed at sea. 2. After the buoy installation is completed, the submarine cable is pulled to the anchoring position of cable 5 through the lower conduit J pipe. After anchoring, it is raised to the first support 51 and stripped of armor. The inner cable 5 is laid into the corresponding cable trays and finally connected to the first-floor 66kV GIS equipment. 3. The water supply and drainage sleeve 41 is installed below the pipeline through the first-floor seawater lifting equipment room. Based on the final construction error of the floating installation, the size of the docking flange is slightly adjusted on site and matched with the lower hanging layer node ring plate 42. The water supply and drainage sleeve 41 is fixed by on-site welding. 4. Grind, repair, and spray the welded areas on site to complete the installation of the upper module.

[0053] Based on the description and accompanying drawings of this invention, those skilled in the art can readily manufacture or use the under-cable layer structure of this invention suitable for deep-water offshore converter stations, and can achieve the positive effects described in this invention.

[0054] Unless otherwise specified, in this invention, terms such as "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe orientation or positional relationships in this invention are for illustrative purposes only and should not be construed as limiting this invention. For those skilled in the art, the specific meaning of the above terms can be understood in conjunction with the accompanying drawings and according to the specific circumstances.

[0055] Unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" in this invention should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A cable layer structure suitable for deep-water offshore converter stations, characterized in that: It includes a main corridor and a secondary corridor located below the first deck layer of the upper module of the converter station, and both the main corridor and the secondary corridor are semi-enclosed spaces with partial water permeability; the main corridor and the secondary corridor are arranged in an "II" shape; the elevation of the main corridor is lower than the bottom elevation of the secondary corridor to meet the first turning requirement of the cable after stripping the armor; the secondary corridor is lower than the bottom elevation of the first deck layer to meet the second turning requirement of the cable after stripping the armor. The main corridor includes a first platform structure formed by connecting multiple circular tube beams. The first platform structure is provided with a grating wave-dissipating area and a paving protection area. The paving protection area is located inside the grating wave-dissipating area. On the first platform structure, a submarine cable anchoring device and a first support are provided at the location of the paving protection area. Water-blocking structures are provided around the submarine cable anchoring device and the first support. The grating wave-dissipating area is provided with a wave-dissipating structure. The secondary corridor includes a second platform structure and a second support. The second platform structure is composed of multiple circular tube beams connected together, and the second support is installed on the second platform structure.

2. The under-cable layer structure for deep-water offshore converter stations according to claim 1, characterized in that: The submarine cable anchoring device includes a first flange, a stiffening plate, a node pipe, a protective pipe, and a reinforcing diagonal brace. The first flange is installed on the top of the node pipe and is connected to the first support through the first flange. The stiffening plate is connected between the bottom of the first flange and the first platform structure. The node pipe is connected to the first platform structure. The bottom of the node pipe has a protective pipe extending downwards from the first platform structure. The bottom end of the protective pipe adopts an outwardly flared trumpet shape. The reinforcing diagonal brace is connected between the protective pipe and the first platform structure.

3. The under-cable layer structure for deep-water offshore converter stations according to claim 1, characterized in that: Multiple second supports are arranged at intervals along the direction of the second platform structure. Each second support includes a portal frame and a cable tray. The cable tray is fixed to the second platform structure by the portal frame and is used for laying cables.

4. The under-cable layer structure for deep-water offshore converter stations according to claim 1, characterized in that: The water-blocking structure includes a folded plate and structural square steel. The folded plate is vertically arranged around the submarine cable anchoring device and the first support. The structural square steel is arranged horizontally on the top of the folded plate along the arrangement direction of the folded plate. The structural square steel is vertically spaced on the folded plate for separation and reinforcement.

5. The under-cable layer structure for deep-water offshore converter stations according to claim 1, characterized in that: The wave-dissipating structure includes a steel grating and a reinforced railing. The reinforced railing is installed on the outer perimeter of the wave-dissipating area of ​​the grating on the first platform structure, and the steel grating is laid on the top surface of the first platform structure in the wave-dissipating area of ​​the grating.

6. The under-cable layer structure for deep-water offshore converter stations according to claim 1, characterized in that: The first platform structure is equipped with a boarding ramp, a gangway boarding area, a secondary corridor ladder, and a jacket platform boarding area; the first platform structure is connected to the first deck level via the boarding ramp; the gangway boarding area is equipped with a boarding ramp for connecting with a specialized maintenance and repair vessel; The first platform structure is connected to the second platform structure via a secondary corridor and a straight elevator.

7. The under-cable layer structure for deep-water offshore converter stations according to claim 6, characterized in that: The under-cable layer structure has a maintenance access system, which includes maintenance access channels set on the first platform structure and the second platform structure. The maintenance access channels are arranged inside the first platform structure or the second platform structure, and the water-blocking structure is arranged outside the maintenance access channel of the first platform structure. The maintenance passage connects the boarding ramp, the gangway boarding area, the secondary corridor elevator, and the jacket platform boarding area.

8. The under-cable layer structure for deep-water offshore converter stations according to claim 1, characterized in that: The secondary corridor includes safety railings, which are located on the periphery of the second platform structure.

9. The under-cable layer structure for deep-water offshore converter stations according to claim 1, characterized in that: The first platform structure of the main corridor is equipped with a water supply and drainage pipe anchoring device, and the water supply and drainage pipe anchoring device has a through hole for the water supply and drainage sleeve of the upper module of the converter station to pass through. The water supply and drainage sleeve extends downward from the upper module of the converter station, passes through the main corridor, and is fixedly connected to the water supply and drainage pipe anchoring device.

10. The under-cable layer structure for deep-water offshore converter stations according to claim 9, characterized in that: The water supply and drainage pipe anchoring device includes a node ring plate, a node sleeve, and a reinforcing rib; the node sleeve is connected to the first platform structure, and its interior is used for the water supply and drainage pipe to pass through; the node ring plate is located at the top of the node sleeve and is used to fix it to the second flange on the water supply and drainage pipe; the reinforcing rib connects the node ring plate, the node sleeve, and the first platform structure.

Images