Offshore floating type overhead transmission tower system

Abstract

The invention relates to the technical field of offshore overhead power transmission, in particular to an offshore floating type overhead power transmission tower system which comprises a four-stand-column semi-submersible type optimization platform and an overhead power transmission tower installed on the four-stand-column semi-submersible type optimization platform. The four-stand-column semi-submersible optimization platform comprises an upper deck, four surrounding stand columns and a lower heaving plate. The upper deck is of a centrosymmetric cross structure, and arms of the cross structure are connected through arc-shaped transition sections. The lower heaving plate adopts a square frame structure with a hollow center; the lower heaving plate is used for increasing vertical damping so as to at least partially counteract heaving displacement generated by the four-stand-column semi-submersible optimization platform under the action of waves. Compared with the prior art, the system has the advantages that the overhead transmission tower and the four-stand-column semi-submersible optimization platform are stably combined, and the structure of the four-stand-column semi-submersible optimization platform is optimized, so that the stability and the reliability of an offshore overhead transmission device are improved, and reliable support is provided for offshore power transmission.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore overhead power transmission, and particularly to an offshore floating overhead power transmission tower system. Background Art

[0002] In the context of the increasing energy transformation and environmental awareness, green energy, especially wind energy, is regarded as an important pillar of future energy supply due to its clean and renewable characteristics. Offshore wind power has become a new focus of wind energy development with its abundant wind resources and geographical advantages close to the power demand centers. However, with the continuous progress of wind power technology and the gradual depletion of shallow sea resources, the development of offshore wind power is gradually advancing towards deep and far seas.

[0003] Currently, the power transmission of offshore wind power mainly relies on submarine cable transmission technology. However, this method faces many challenges in long-distance power transmission. Traditional submarine cable transmission technology has high costs and reduced reliability in long-distance power transmission due to requirements such as large cross-sections, high-voltage loads, and insulation aging. Especially in deep and far seas, the laying and power transmission costs of submarine cables increase exponentially, making it difficult to meet the needs of large-scale development. To overcome these challenges, overhead power transmission technology shows certain advantages in the offshore environment, but its implementation depends on a stable support structure. On land, power transmission towers are connected to the foundation through anchor bolts and can effectively support overhead lines. However, in the offshore environment, traditional fixed foundations are not applicable, and floating platform technology must be combined. However, existing floating platform technologies also show certain limitations when applied to offshore wind power transmission systems. For example, although the single-column floating platform (Spar Platform) has good heaving stability, its rolling and pitching motions are relatively large, affecting the stability of the power transmission tower. The tension leg platform (Tension Leg Platform, TLP) has good heaving and swaying motion characteristics, but its mooring system is complex, with high construction and installation costs, and is vulnerable to ocean currents. The damping plate design in the semi-submersible platform (Semi-submersible Platform) does not achieve the best damping effect, and its overall stability effect is still poor.

[0004] In addition, dynamic loads such as wind waves and ocean currents in the marine environment pose higher requirements for the stability of floating power transmission towers. Therefore, how to achieve a stable connection between the power transmission tower and the floating platform in deep and far seas and ensure its reliability in a complex marine environment has become a key problem that needs to be solved urgently by current technologies. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides an offshore floating overhead transmission tower system, comprising: a four-column semi-submersible optimized platform and an overhead transmission tower installed on the four-column semi-submersible optimized platform; wherein, the overhead transmission tower includes a transmission tower head, a transmission tower body, and a transmission tower foot, and the four-column semi-submersible optimized platform includes an upper deck, four surrounding columns, and a lower heaving plate arranged in sequence from top to bottom; The upper deck adopts a centrally symmetric cross-shaped structure, and the arms of the cross-shaped structure are connected by arc transition sections; the cross-shaped structure is used to provide buoyancy support, and the load generated by the overhead transmission tower and the cable system is dispersed to the lower heaving plate through the four surrounding columns to offset the dynamic disturbance moment generated by the four-column semi-submersible optimized platform under uneven load; The lower heaving plate adopts a square frame structure with a hollow center; the lower heaving plate is used to increase the vertical damping, and an additional damping moment is generated in the vertical heaving direction during the interaction between the four-column semi-submersible optimized platform and the waves through the increased vertical damping, and the heaving motion inertia moment generated by the waves on the four-column semi-submersible optimized platform is absorbed through the damping moment, thereby at least partially offsetting the heaving displacement of the four-column semi-submersible optimized platform under the action of the waves.

[0006] In a further embodiment, the overhead transmission tower is used to support and transmit electricity; The axis of the transmission tower body coincides with the geometric center of the cross-shaped structure, and the transmission tower body extends vertically downward and locks the transmission tower foot to the four ends of the upper deck through a connecting mechanism.

[0007] In a further embodiment, the connecting mechanism includes bolts, washers, and nuts; The bolts protrude upward from the upper deck and are screwed to the transmission tower foot, the bolts and the nuts are arranged opposite to each other, and washers are arranged between the bolts and the nuts; wherein, the washers are used to disperse the pressure of the nuts on the transmission tower foot and provide frictional resistance for the nuts.

[0008] In a further embodiment, the four ends of the cross-shaped structure are respectively fixedly connected to the top ends of the four surrounding columns, and the bottom ends of the four surrounding columns are installed and fixed at the four corners of the lower heaving plate.

[0009] In a further embodiment, the four-column semi-submersible optimized platform further includes an anchoring assembly, and the anchoring assembly includes a catenary mooring cable, a seabed anchor, and an anchor winch; The anchoring assembly is used to provide an anchoring force through the fixing effect of the subsea anchor and the tension control of the catenary mooring cable by the anchor winch, so as to at least partially offset the unbalanced horizontal displacement force generated by the marine environmental load on the four-column semi-submersible optimized platform.

[0010] In a further embodiment, fairlead holes are provided in the middle of the four surrounding columns, and guiding grooves are arranged in the fairlead holes; The catenary mooring cable is installed and fixed on the anchor winches in the middle sections of the four surrounding columns through the guiding grooves of the fairlead holes, and the subsea anchor is connected to the four-column semi-submersible optimized platform through the catenary mooring cable.

[0011] In a further embodiment, the bottoms of the four surrounding columns are respectively connected with hanging weights through suspension lines; The hanging weights are used to provide an additional downward pulling force, make the center of gravity of the four-column semi-submersible optimized platform shift downward and be located below the center of buoyancy, and inhibit the inclination of the four-column semi-submersible optimized platform under the action of external forces by generating a reverse inertial force.

[0012] In a further embodiment, the four surrounding columns have an aspect ratio of 0.5 to 0.9, and the aspect ratio is the ratio of the height of the four surrounding columns to their maximum width on the plane of the four-column semi-submersible optimized platform.

[0013] In a further embodiment, the pontoons of the four-column semi-submersible optimized platform are located below the water surface, and the pontoons are connected to the upper deck through the four surrounding columns; The pontoons are used to provide buoyancy to suspend the upper deck of the four-column semi-submersible optimized platform above the water surface.

[0014] In a further embodiment, the hollowed-out part in the center of the lower heaving plate is in a square shape; The side length of the square shape is 1 / 3 - 1 / 2 of the distance between the four surrounding columns.

[0015] The present invention provides an offshore floating overhead transmission tower system, which includes a four-column semi-submersible optimized platform and an overhead transmission tower installed on the four-column semi-submersible optimized platform. The four-column semi-submersible optimized platform includes an upper deck, four surrounding columns, and a lower heaving plate arranged in sequence from top to bottom. The upper deck adopts a central-symmetric cross-shaped structure, and the arms of the cross-shaped structure are connected by arc transition sections. The cross-shaped structure is used to provide buoyancy support and disperse the loads generated by the overhead transmission tower and the cable system to the lower heaving plate through the four surrounding columns, so as to offset the dynamic disturbing torque generated by the four-column semi-submersible optimized platform under uneven loads. The lower heaving plate adopts a square frame structure with a hollow center. The lower heaving plate is used to increase the vertical damping, generate an additional damping torque in the heaving direction during the interaction between the four-column semi-submersible optimized platform and the waves through the increased vertical damping, and absorb the heaving motion inertia torque generated by the waves on the four-column semi-submersible optimized platform through the damping torque, thereby at least partially offsetting the heaving displacement of the four-column semi-submersible optimized platform under the action of the waves. Compared with the prior art, this system firmly combines the overhead transmission tower and the four-column semi-submersible optimized platform, and optimizes the structures such as the upper deck and the lower heaving plate of the four-column semi-submersible optimized platform, enhancing the stability of the four-column semi-submersible optimized platform under uneven loads, improving the stability and reliability of the offshore overhead transmission device, and being able to meet the requirements of large-scale power transmission for offshore wind power. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of the offshore floating overhead transmission tower system provided by an embodiment of the present invention; Figure 2 is a front view of the offshore floating overhead transmission tower system provided by an embodiment of the present invention; Figure 3 is a partial schematic diagram of the connecting mechanism provided by an embodiment of the present invention; Figure 4 is a partial schematic diagram of the four-column semi-submersible optimized platform provided by an embodiment of the present invention; Figure 5 is a top view of the offshore floating overhead transmission tower system provided by an embodiment of the present invention; Figure 6 is a partial top view of the fairlead provided by an embodiment of the present invention; Figure 7 is an axonometric view of the fairlead provided by an embodiment of the present invention; Figure 8 is a schematic diagram for comparing the stability curves of the square-shaped lower heaving plate provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The following specifically illustrates the implementation mode of the present invention in conjunction with the accompanying drawings. The embodiments are provided for illustrative purposes only and cannot be understood as limiting the present invention. The accompanying drawings are provided for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0018] refer to Figure 1 , Figure 2 The embodiment of the present invention provides an offshore floating overhead transmission tower system, such as Figure 1 , Figure 2 As shown, the system includes a four-column semi-submersible optimization platform and an overhead transmission tower installed on the four-column semi-submersible optimization platform, wherein the overhead transmission tower includes a transmission tower head 1, a transmission tower body 2 and a transmission tower foot 3, and the four-column semi-submersible optimization platform includes an upper deck 4, four surrounding columns 5, a fairlead hole 6, a lower heave plate 7, a catenary mooring cable 8, a seabed anchor 9, a suspension line 10, a suspended weight 11, a guide groove 12 and an anchor machine 13.

[0019] In some embodiments, the overhead transmission tower is used as the main structure for power transmission, which is used to support and transmit power, and the cable is overhead for large-scale offshore power transmission. The overhead transmission tower of this embodiment adopts an overhead method to replace the traditional submarine cable transmission, and is fixed to the upper deck of the four-column semi-submersible optimization platform by bolts, so as to achieve a stable combination of the transmission tower and the platform, and provide a reliable support structure for offshore overhead transmission, thereby realizing the combination of the transmission tower and the floating platform into a set of floating overhead transmission devices, breaking through the limitations of traditional submarine cable transmission, and improving the reliability of large-scale offshore wind power transmission. At the same time, the platform structure is optimized to enhance its stability in complex sea conditions. In this embodiment, the lower part of the transmission tower head 1 is fixedly connected to the transmission tower body 2, and the lower part of the transmission tower body 2 is fixedly connected to the transmission tower foot 3. The transmission tower body 2 extends vertically downward and locks the transmission tower foot 3 to the four ends of the upper deck through a connecting mechanism. Figure 3 As shown, the connection mechanism includes bolts, washers and nuts. When installing the overhead transmission tower, this embodiment uses bolts pre-buried in the upper deck and fastened with washers and nuts. The washers are used to disperse the pressure of the nuts on the tower foot of the transmission tower and provide friction resistance for the nuts. Specifically, the bolts extend upward from the upper deck and are screwed to the tower foot of the transmission tower. The bolts and the nuts are arranged opposite to each other and a washer is arranged between the bolts and the nuts. When installing the embodiment, the tower foot of the transmission tower is firstly put on the bolts welded firmly at the corresponding positions on the upper deck, the washers are placed, and then the nuts are screwed on to ensure the stable connection between the transmission tower and the platform.

[0020] In this embodiment, the upper deck 4, the four surrounding columns 5, and the lower heaving plate 7 are arranged in sequence from top to bottom. As Figure 4 shown, the four ends of the cross-shaped structure are respectively fixedly connected to the top ends of the four surrounding columns, and the bottom ends of the four surrounding columns are fixedly installed at the four corners of the lower heaving plate.

[0021] In some embodiments, as Figure 5 shown, the upper deck adopts a centrally symmetric cross-shaped structure, and the arms of the cross-shaped structure are connected by arc transition sections. The axis of the transmission tower body coincides with the geometric center of the cross-shaped structure; the cross-shaped structure is used to provide buoyancy support, and the loads generated by the overhead transmission tower and the cable system are dispersed to the lower heaving plate through the four surrounding columns to offset the dynamic disturbing torque generated by the four-column semi-submersible optimized platform under uneven loads. Specifically, in this embodiment, the upper deck adopts a centrally symmetric cross-shaped structure, and the arms are connected by arc transition sections. This design forms a stable connection interface between the four-column semi-submersible optimized platform and the transmission tower, not only increasing the rigidity and stability of the structure, enabling the deck to distribute stress more evenly when stressed, thereby improving its load-bearing capacity, but also dispersing the loads generated by the overhead transmission tower and the cable system to the lower heaving plate through the four surrounding columns, being able to adapt to electric towers with different foundation spreads, reducing the impact of uneven loads on the platform stability, and achieving stable suspension and efficient load dispersion under uneven loads.

[0022] In summary, the upper deck in this embodiment adopts a centrally symmetric cross design, and its function is to generate additional stability torque through the specific structural design to offset the overturning torque generated by the platform under uneven loads, thereby reducing the inclination and sway amplitude of the four-column semi-submersible platform under various sea conditions, enhancing the overall stability of the four-column semi-submersible platform after carrying the transmission tower. The upper deck can form a stable connection interface between the four-column semi-submersible platform and the transmission tower, evenly dispersing the loads generated by the transmission tower and the cable system to each part of the platform, thereby offsetting the overturning torque encountered by the platform under complex sea conditions, and ensuring the continuous reliable and stable transmission of the entire floating overhead transmission device during offshore operations.

[0023] In some embodiments, the lower heaving plate adopts a square frame structure with a hollow center; the lower heaving plate is used to increase the vertical damping. During the interaction between the four-column semi-submersible optimized platform and the waves, an additional damping moment is generated in the heaving direction through the increased vertical damping, and the damping moment is used to absorb the heaving motion inertia moment generated by the waves on the four-column semi-submersible optimized platform, thereby at least partially offsetting the heaving displacement of the four-column semi-submersible optimized platform under the action of the waves, enhancing the overall dynamic stability of the four-column semi-submersible platform after carrying the transmission tower. The lower heaving plate in this embodiment generates an additional resistance effect in the wave action area through the design of a square frame structure with a hollow center, effectively absorbing and dispersing wave energy. This design reduces the direct impact of the waves on the platform, thereby reducing the amplitude of the heaving motion of the platform. Specifically, the lower heaving plate generates a dynamic resistance response under the action of the waves through its frame shape and position layout, and this response interacts with the heaving motion of the platform, thus offsetting the vertical displacement of the platform caused by the waves. In this embodiment, the function of the lower heaving plate is to act as a dynamic damping element, optimizing the dynamic performance of the platform through its structural characteristics and enhancing the stability and reliability of the entire offshore floating overhead transmission device in the face of complex sea conditions.

[0024] Specifically, in the offshore floating overhead transmission tower system provided in this embodiment, the lower heaving plate adopts a square frame with a hollow center, and four surrounding columns are located around the lower heaving plate. Through the optimization of the shape and position, the vertical damping effect is enhanced. This characteristic effectively reduces the heaving motion of the four-column semi-submersible optimized platform, thereby being able to absorb wave energy, reduce the direct impact of the wave height on the four-column semi-submersible optimized platform, and further enhancing the dynamic stability of the four-column semi-submersible optimized platform. At the same time, the upper deck adopts a centrally symmetric cross design. This design forms a sharp contrast with the lower heaving plate. This design not only ensures that the buoyancy center is above the center of gravity, improving the stability of the four-column semi-submersible optimized platform, but also takes into account the economic cost of consumables. Through the centrally symmetric cross design of the upper deck, the offshore floating overhead transmission tower system can reduce the impact of uneven loads on the platform stability and achieve a more balanced load distribution.

[0025] In this embodiment, the four surrounding columns serve as the key structures connecting the upper deck and the lower heaving plate, providing a solid support for the overall structure. They evenly distribute the weight and load of the upper deck to the lower heaving plate, ensuring the balance and stability of the platform structure. In addition, by adjusting the amount of ballast water filled inside the columns, the system can flexibly adjust the buoyancy and inclination of the platform, thereby maintaining the horizontal state and stability of the platform. It should be noted that compared with the traditional three-column structure, the design of the four surrounding columns in this embodiment can further optimize the anti-tilting ability of the platform. This optimization improvement enables the platform to exhibit higher stability and anti-overturning ability when facing complex environmental loads such as wind, waves, and currents.

[0026] Based on the above embodiments, in some implementation manners, the four-column semi-submersible optimized platform further includes an anchoring assembly. The anchoring assembly includes a catenary mooring cable, a seabed anchor, and an anchor winch. The anchor winch is installed in the middle section of the surrounding columns; the anchoring assembly is used to provide an anchoring force through the fixing action of the seabed anchor and the tension control of the catenary mooring cable by the anchor winch, so as to at least partially offset the unbalanced horizontal displacement force generated by the marine environmental load on the four-column semi-submersible optimized platform. Specifically, the combination of the catenary mooring cable, the anchor, and the anchor winch is used to provide the anchoring force, and the floating platform is firmly moored in the designated sea area through the anchoring force, realizing the stable mooring of the floating overhead transmission device. The catenary mooring cable forms a catenary shape by its own weight, effectively absorbing the dynamic influence of environmental loads such as waves and wind on the platform, reducing the displacement and swaying of the platform; the seabed anchor penetrates deep into the seabed to provide a strong fixing force to prevent the platform from drifting; the anchor winch is responsible for controlling and adjusting the tension and length of the catenary mooring cable to ensure that the platform can maintain a stable position under different sea conditions. These three work together. Through the catenary mooring cable connecting the platform and the anchor, combined with the fixing action of the anchor on the seabed and the winch control of the cable, the horizontal displacement force generated by the marine wind, waves, currents and other environmental loads on the platform is offset, enhancing the stability and reliability of the floating platform in the complex marine environment, and thus ensuring the safe operation of the offshore overhead transmission device.

[0027] Based on the above embodiments, in some implementation manners, as Figure 6 , Figure 7 shown, a fairlead hole 6 is provided in the middle of the four surrounding columns 5, and a guiding groove 12 is provided in the fairlead hole 6; the catenary mooring cable 8 is installed and fixed on the anchor winch 13 in the middle section of the four surrounding columns 5 through the guiding groove 12 of the fairlead hole 6, and the seabed anchor 9 is connected to the four-column semi-submersible optimized platform through the catenary mooring cable 8.

[0028] Based on the above embodiments, in some embodiments, the bottoms of the four surrounding columns 5 are respectively connected to hanging weights 11 through suspension lines 10; the hanging weights 11 are used to provide an additional downward pulling force, shift the center of gravity of the four-column semi-submersible optimized platform downward and below the center of buoyancy, and suppress the inclination of the four-column semi-submersible optimized platform under the action of external forces by generating a reverse inertial force. On the basis of the optimization and improvement of the upper deck and the lower heaving plate, in this embodiment, the center of gravity position of the platform is reduced by hanging weights under the four surrounding columns, the inclination and sway response of the platform are reduced, the inertial force of the platform is increased, and the damping effect is improved. This measure effectively improves the stability of the platform under extreme conditions and ensures the long-term, safe and reliable operation of the offshore floating overhead transmission tower system.

[0029] Specifically, the hanging weights are connected to the bottoms of the four surrounding columns through suspension lines, and their main function is to increase the stability of the entire floating platform. These weights provide an additional downward pulling force, which reduces the center of gravity of the entire offshore floating transmission device. Thus, when the platform has a tendency to tilt or sway under the action of external environmental loads such as wind, waves, and currents, the hanging weights generate a reverse inertial force, reducing the inclination and sway response of the platform under the action of waves. When the platform is subjected to external forces, the hanging weights can generate a reverse inertial force, which helps to offset the displacement caused by the external forces, thereby reducing the movement amplitude of the platform and improving the overall stability and hydrodynamic performance of the platform.

[0030] Based on the above embodiments, in some embodiments, the four surrounding columns have an aspect ratio of 0.5 to 0.9, and the aspect ratio is the ratio of the height of the four surrounding columns to their maximum width in the plane of the four-column semi-submersible optimized platform.

[0031] Based on the above embodiments, in some embodiments, the pontoons of the four-column semi-submersible optimized platform are located below the water surface, and the pontoons are connected to the upper deck through the four surrounding columns; the pontoons are used to provide buoyancy to suspend the upper deck of the four-column semi-submersible optimized platform above the water surface. Specifically, in this embodiment, the transmission tower is connected to the optimized four-column semi-submersible platform by bolts fixed on the platform deck. The pontoons of the optimized four-column semi-submersible platform are located below the water surface, and the columns connect the pontoons and the upper deck of the platform, effectively reducing the impact of waves on the platform. The center of gravity can be controlled to be lower than the center of buoyancy by adjusting the configuration of the pontoons and the ballast water system, realizing the stability of the four-column semi-submersible optimized platform, having the ability to operate at sea for a long time, and providing continuous and reliable support. When designing this embodiment, the platform response under various sea conditions is considered, and the shape and structure of the platform are optimized through hydrodynamic simulation to minimize vibration and movement, making the hydrodynamic performance of this offshore floating overhead transmission device better, more stable and reliable.

[0032] In this embodiment, the pontoons, as the key buoyancy components of the four-column semi-submersible optimized platform, provide the necessary buoyancy to support the weight of the entire offshore floating overhead transmission device, enabling the device to float stably on the water surface. The design of the pontoons located below the water surface effectively reduces the direct impact of waves on the platform. At the same time, through the synergistic effect with the ballast water system, the pontoons can adjust the buoyancy and inclination of the platform to ensure that the platform remains horizontal and stable under various sea conditions, providing a reliable support foundation for the transmission tower and ensuring the reliability and safety of offshore overhead power transmission.

[0033] Based on the above embodiments, in other embodiments, the hollowed-out part in the center of the lower heaving plate is in a square shape, and the side length of the square is 1 / 3 - 1 / 2 of the spacing between the four surrounding columns, as Figure 8As shown, in this embodiment, the restoring moment magnitudes corresponding to the platform inclination angles of two different design shapes, namely the cross shape and the square shape, are evaluated based on the same dimensions. The results show that under the same inclination angle condition, the restoring moment generated by the square-shaped hollow part in the center of the lower heaving plate is significantly greater than that of the cross-shaped scheme. Among them, the restoring moment refers to the couple formed by buoyancy and gravity when the platform or ship tilts, and its direction is opposite to the tilting moment, which can prompt the platform to return to its original equilibrium position. Since the magnitude of the restoring moment is directly related to the stability of the platform, therefore, from the perspective of ensuring the stability of the platform after carrying the transmission tower, the square-shaped hollow part in the center of the lower heaving plate demonstrates more excellent performance. Specifically, the center of gravity of the square-shaped scheme is 1.84 m below the water plane, deeper than the 1.34 m below the water plane of the cross-shaped scheme, and at the same time, the draft depth is also greater. This indicates that the square-shaped scheme makes more effective use of the distribution of buoyancy and the center of gravity in the overall structural design, thus showing better stability in actual use and being more suitable for carrying transmission towers for large-scale offshore power transmission.

[0034] In summary, there are various problems with the traditional submarine cable power transmission method, such as large cross-sections, high-voltage loads, insulation aging, etc. These problems not only increase the maintenance cost but also reduce the reliability of power transmission. In addition, the erosion of seawater on cable materials also seriously affects the service life of the cables. To overcome these drawbacks, the offshore floating overhead transmission tower system proposed in this embodiment combines an overhead transmission tower with a floating platform and uses the method of overhead cables for large-scale offshore power transmission instead of the traditional submarine cable power transmission method, breaking through various problems existing in traditional submarine cable power transmission, such as insulation aging caused by large cross-sections and high-voltage loads, and the erosion of seawater on cable materials. Thus, the reliability of large-scale offshore wind power transmission is significantly enhanced, and the economic benefits are improved. In terms of the design optimization of the four-column semi-submersible platform, the present invention optimizes the original four-column platform. By reducing the overall size of the platform and the height-width ratio of the four surrounding columns, the center of gravity position of the entire system is lowered. This design improvement significantly enhances the stability of the system under complex environmental loads such as wind, waves, and currents.

[0035] In addition, the design of the lower heaving plate and the surrounding columns in this embodiment has also been optimized, rather than the consistent design of the upper and lower structures of the original platform. The lower heaving plate adopts a square frame design with a hollow center, optimizing the shape of the lower heaving plate and the positions of the surrounding columns. This design reduces the position of the center of buoyancy, increases the effective moment of vertical damping, thereby effectively reducing the amplitude of the heaving motion of the platform, reducing the direct impact of waves on the platform, enhancing the dynamic stability of the platform. This improvement makes the system more suitable for the situation where there is a lateral tension in the upper transmission tower, improving the stability of the entire system after carrying the transmission tower, and facilitating large-scale power transmission after offshore wind power generation. At the same time, the upper deck adopts a central symmetric cross design, and an arc transition is set between the cross structures to adapt to electric towers with different foundation spreads. This design ensures that the center of buoyancy is above the center of gravity, while considering the economic cost of consumables, effectively reducing the impact of uneven loads on the stability of the platform. In addition, the central symmetric cross structure can generate structural stability, and through this stability, an additional resistance balance is generated between the acting points of the environmental loads, offsetting the dynamic disturbing moment at the acting points of the loads, reducing the impact of uneven loads on the stability of the platform, and further enhancing the overall stability and anti-overturning ability of the entire floating overhead transmission device under environmental loads such as wind, waves, and currents, as well as the ability to cope with the ultimate tension of the upper transmission tower.

[0036] To further improve the stability of the platform, this embodiment also adopts a scheme of hanging heavy objects under each of the four columns of the semi-submersible platform. This design effectively reduces the center of gravity position of the entire platform, reduces the inclination and sway response of the platform, and increases the inertial force of the platform. When the platform is affected by external forces, the hanging heavy objects will generate reverse inertial forces to offset the displacement caused by the external forces, thereby reducing the movement amplitude of the platform and further improving the stability of the platform. The offshore floating overhead transmission tower system combining the transmission tower and the floating platform in this embodiment has higher stability and reliability under different sea conditions and is suitable for large-scale power transmission of offshore wind power.

[0037] An embodiment of the present invention provides an offshore floating overhead transmission tower system, which includes a four-column semi-submersible optimized platform and an overhead transmission tower installed on the four-column semi-submersible optimized platform; the four-column semi-submersible optimized platform includes an upper deck, four surrounding columns and a lower heaving plate arranged in sequence from top to bottom; the upper deck adopts a centrally symmetric cross-shaped structure, and the arms of the cross-shaped structure are connected by arc transition sections; the cross-shaped structure is used to provide buoyancy support, and the loads generated by the overhead transmission tower and the cable system are dispersed to the lower heaving plate through the four surrounding columns to offset the dynamic disturbing moment generated by the four-column semi-submersible optimized platform under uneven loads; the lower heaving plate adopts a square frame structure with a hollow center; the lower heaving plate is used to increase the vertical damping, and an additional damping moment is generated in the heaving direction during the interaction between the four-column semi-submersible optimized platform and the waves through the increased vertical damping, and the heaving motion inertia moment generated by the waves on the four-column semi-submersible optimized platform is absorbed through the damping moment, thereby at least partially offsetting the heaving displacement of the four-column semi-submersible optimized platform under the action of waves. Compared with the prior art, this system effectively reduces the heaving motion by firmly combining the overhead transmission tower and the four-column semi-submersible optimized platform and optimizing the structures such as the upper deck and the lower heaving plate, enhances the stability of the four-column semi-submersible optimized platform under uneven loads, improves the stability and reliability of the offshore overhead transmission device, ensures the safe operation of the overhead transmission tower and the cable system, and provides reliable support for offshore power transmission.

[0038] The above embodiments only represent several preferred embodiments of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the protection scope of the claims.

Claims

1. A marine floating overhead transmission tower system, characterized in that, Comprising: A four-column semi-submersible optimized platform and an overhead transmission tower installed on the four-column semi-submersible optimized platform; wherein, the overhead transmission tower includes a transmission tower head, a transmission tower body, and a transmission tower foot, and the four-column semi-submersible optimized platform includes an upper deck, four surrounding columns, and a lower heaving plate arranged in sequence from top to bottom; The upper deck adopts a central symmetric cross-shaped structure, and the arms of the cross-shaped structure are connected by arc transition sections; the cross-shaped structure is used to provide buoyancy support, and the load generated by the overhead transmission tower and the cable system is dispersed to the lower heaving plate through the four surrounding columns to offset the dynamic disturbing moment generated by the four-column semi-submersible optimized platform under uneven load; The lower heaving plate adopts a square frame structure with a hollow center; the lower heaving plate is used to increase the vertical damping, and an additional damping moment is generated in the heaving direction during the interaction between the four-column semi-submersible optimized platform and the waves through the increased vertical damping, and the heaving motion inertia moment generated by the waves on the four-column semi-submersible optimized platform is absorbed through the damping moment, thereby at least partially offsetting the heaving displacement of the four-column semi-submersible optimized platform under the action of the waves.

2. The marine floating overhead transmission tower system according to claim 1, characterized in that: The overhead transmission tower is used to support and transmit electricity; The axis of the transmission tower body coincides with the geometric center of the cross-shaped structure, and the transmission tower body extends vertically downward and locks the transmission tower foot to the four ends of the upper deck through a connecting mechanism.

3. The marine floating overhead transmission tower system according to claim 2, characterized in that: The connecting mechanism includes bolts, gaskets, and nuts; The bolts protrude upward from the upper deck and are screwed to the transmission tower foot, the bolts and the nuts are arranged oppositely, and gaskets are arranged between the bolts and the nuts; wherein, the gaskets are used to disperse the pressure of the nuts on the transmission tower foot and provide frictional resistance for the nuts.

4. The marine floating overhead transmission tower system according to claim 1, characterized in that: The four ends of the cross-shaped structure are respectively fixedly connected to the top ends of the four surrounding columns, and the bottom ends of the four surrounding columns are installed and fixed at the four corners of the lower heaving plate.

5. The marine floating overhead transmission tower system according to claim 1, characterized in that: The four-column semi-submersible optimized platform further includes an anchoring assembly, and the anchoring assembly includes a catenary mooring cable, a seabed anchor, and an anchor winch; The anchoring assembly is used to provide an anchoring force through the fixing action of the seabed anchor and the tension control of the catenary mooring cable by the anchor winch to at least partially offset the unbalanced horizontal displacement force generated by the marine environmental load on the four-column semi-submersible optimized platform.

6. The marine floating overhead transmission tower system according to claim 5, characterized in that: Guide holes are provided in the middle of the four surrounding columns, and guide grooves are provided in the guide holes; The catenary mooring cable is installed and fixed on the anchor winches in the middle sections of the four surrounding columns through the guide grooves of the guide holes, and the seabed anchor is connected to the four-column semi-submersible optimized platform through the catenary mooring cable.

7. The marine floating overhead transmission tower system according to claim 1, characterized in that: The bottoms of the four surrounding columns are respectively connected to hanging weights through suspension lines; The suspended heavy object is used to provide additional downward pulling force, shift the center of gravity of the four-column semi-submersible optimized platform downward and locate it below the center of buoyancy, and suppress the inclination of the four-column semi-submersible optimized platform under the action of external forces by generating reverse inertial force.

8. The marine floating overhead transmission tower system according to claim 1, characterized in that: The four surrounding columns have an aspect ratio of 0.5 to 0.9, and the aspect ratio is the ratio of the height of the four surrounding columns to their maximum width on the plane of the four-column semi-submersible optimized platform.

9. The marine floating overhead transmission tower system according to claim 1, characterized in that: The pontoon of the four-column semi-submersible optimized platform is located below the water surface, and the pontoon is connected to the upper deck through the four surrounding columns; The pontoon is used to provide buoyancy to suspend the upper deck of the four-column semi-submersible optimized platform above the water surface.

10. The marine floating overhead transmission tower system according to claim 1, characterized in that: The hollowed-out part in the center of the lower heaving plate is in a square shape with a hollow in the middle; The side length of the square shape with a hollow in the middle is 1 / 3 - 1 / 2 of the spacing between the four surrounding columns.

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