All-weather and all-seabed condition floating type fan stabilizing anchoring operation and maintenance system

Abstract

The present application relates to the field of suspended offshore wind power generation, aiming at the fact that the prior art cannot meet the anchoring of diatom mud seabed, the erection of suspended platform and the operation and maintenance in low temperature environment. On the one hand, the anchoring stress is reduced by using hard pipe rigid connection tower foundation to move down the anchoring center and reduce the anchoring point stress. For the diatom mud seabed without adhesion, the array anchoring method is proposed. For the diatom mud seabed, resistance plates are installed between anchor chains to form a continuous soil plug effect array. For the soft soil medium hardness seabed, a small amount of anchoring array such as 3*3 dragging anchoring point array is used to obtain horizontal load force. The traditional platform relies on huge gravity to maintain balance, transportation and material cost is high, the present application uses underwater hard pipe and wind turbine integrated structure to stabilize the platform, and the tower can be designed to rotate and lie down, which can realize batch loading transportation, cooperate with special maintenance ship and realize on-site maintenance in extremely low temperature. In summary, the present application reduces the cost of suspended wind turbine power generation from the aspects of shortening the operation and maintenance mileage, batch transportation and reducing the self weight.

Description

Technical Field

[0001] This invention relates to the field of offshore floating platform wind power generation technology, and in particular to a floating wind turbine foundation and anchoring stabilization system suitable for deep seas, employing multi-level lever constraints and dual-axis active counterweight coordination, especially suitable for extreme marine environments such as Antarctic interglacial lakes. Background Technology

[0002] As offshore wind power expands into deeper waters, floating wind turbine technology has become the industry mainstream. The core technical challenges facing floating wind turbines are threefold: first, how to maintain platform stability under the influence of wind, waves, and currents to ensure power generation efficiency; second, how to provide sufficiently reliable anchoring force in extreme soft soil and complex seabed conditions where conventional anchoring is not feasible; and third, how to reduce the cost of floating wind turbines.

[0003] Existing floating wind turbine stabilization technologies mainly fall into two categories: Passive mooring and anchoring: This method anchors the platform to the seabed using methods such as catenary mooring and tension leg mooring. Semi-submersible platforms are typically equipped with towed anchors, Spar structures with suction anchors, and TLP structures with gravity anchors. These passive methods face challenges such as insufficient anchoring force or construction difficulties on deep soft soil or hard rock seabeds.

[0004] Counterweight balance adjustment: Existing patents (such as CN104802949A) propose setting movable counterweights on the platform, adjusting the platform's center of gravity position by moving the counterweights to resist overturning moments. Another approach uses floating ballast tanks, adjusting the platform's attitude by pumping ballast media between different compartments.

[0005] However, existing technologies have significant drawbacks in the following aspects: Passive anchoring and active adjustment are disconnected: the anchor chain only serves as a passive connector and cannot participate in the platform's active attitude control.

[0006] Limited counterweight adjustment capability: The mass of the movable counterweight is relatively small, which can only provide a limited restoring torque and is insufficient to compensate for excessive overturning moments.

[0007] Single-axis counterweight mode: Existing mobile counterweights are arranged along a single straight line, making it difficult to accurately control multi-directional and complex tilting.

[0008] It is impossible to set anchor points in the extreme soft soil environment of Antarctic diatomaceous earth.

[0009] The maintenance costs are high in environments with temperatures as low as -65°C.

[0010] Wind turbines rely heavily on their own weight to stabilize the platform, resulting in high transportation and manufacturing costs.

[0011] Therefore, a novel platform erection method is urgently needed that can adapt to extremely soft seabeds while reducing the anchoring load requirements, enabling the erection of wind turbine platforms on such surfaces. Deeply coupling passive anchoring with active counterweights, combined with insulation and on-site indoor maintenance in low-temperature environments, can make it possible to erect suspended wind turbine platforms in previously impossible extreme environments such as Antarctic interglacial lakes. Furthermore, a series of cost-reduction and efficiency-enhancing design measures, such as lightweight platforms, bulk transportation, and low anchoring costs, can further reduce the cost of offshore suspended power generation and enhance market competitiveness. Summary of the Invention 3.1 Purpose of the Invention

[0012] The present invention aims to provide a low-cost wind turbine platform construction scheme applicable to all climates and seabed conditions.

[0013] For example, in seabeds with extremely soft soil and very low adhesion of diatomaceous earth (Antarctic interglacial lakes, -65°C, water depths of 1000-2000 meters), wind resources are abundant, but traditional anchoring systems cannot be used to install floating wind turbine platforms in these areas, or are prohibitively expensive, rendering wind power generation meaningless. This invention addresses these extreme natural conditions, focusing on cost reduction and efficiency improvement. Reduced anchoring stress: By using long, rigid pipes for rigid constraint and lever principles, the anchoring force requirement is significantly reduced, thereby improving platform stability. Experiments have verified that this solution effectively reduces the anchoring force requirement.

[0014] Matrix Anchoring Solution: For extreme soft mud surfaces (such as the Antarctic diatomaceous earth seabed), a matrix anchoring solution is implemented, using area to gain strength. The matrix structure consists of chains or chains plus stabilizing frames, using various planar or traditional anchors that generate resistance to form the matrix anchoring. This is combined with a floating wind turbine foundation system that organically integrates dual-axis counterweight active balancing, achieving ultra-high stability and full seabed adaptability for deep-sea floating wind turbines in extreme marine environments.

[0015] Adaptability to severe cold climates: Addressing the challenges posed by severe cold weather to electrical wiring and maintenance, the system utilizes an integrated design that combines a horizontally oriented fan with external insulation and internal temperature control. When used with a maintenance vessel, it enables temperature-controlled maintenance indoors, reducing maintenance difficulty and costs while improving accuracy and speed.

[0016] Convenience of transportation: The horizontally tiltable fan and lightweight design enable bulk transportation, reducing operating costs. 3.2 Technical Solution

[0017] To achieve the above objectives, the present invention adopts the following technical solution:

[0018] A floating platform; A wind turbine tower; A rigid tube is fixedly connected to the wind turbine tower or integrally formed therefrom; A rotating connection mechanism is disposed between the wind turbine tower or the rigid pipe and the floating platform, so that the wind turbine tower or the rigid pipe can rotate relative to the floating platform; The lower end of the rigid tube is connected to an anchoring foundation via a flexible anchor chain.

[0019] The rotating connection mechanism is, for example, a slewing bearing, which is installed at the center of the floating platform. After the wind turbine tower and the rigid pipe are fixed, they are installed as a whole on the slewing bearing, so that the wind turbine rotates from a vertical posture around the horizontal axis to a near-horizontal posture.

[0020] II. Anchoring Foundation The anchoring foundation is used to secure the system to the seabed. Depending on the seabed conditions, the anchoring foundation may take one or a combination of the following forms: Example 1 (Extremely soft seabed, such as Antarctic diatomaceous earth): Drag plate array, which consists of one or more main anchor chains and multiple drag plates connected in series and / or in parallel on the main anchor chains; each drag plate is provided with a stabilizing frame for maintaining its relative angle with the anchor chain; when used in parallel, there is a gap between adjacent drag plates, and a relative position holding frame can be added.

[0021] The working principle of the resistance plate array is as follows: under the restraint of the anchor chain, multiple resistance plates form a continuous bulldozing wall; the soft soil in front of each resistance plate is pushed and lifted, and some soil passes over the resistance plate and accumulates in the gap behind it, forming a dynamic soil plug, which provides the system with a passive anchoring force that continuously increases with the dragging distance.

[0022] Example 2 (soft to medium-hardness clay seabed): Drag plate anchor array (hybrid anchoring) (e.g.) Figure 2 The drag plate anchor array (as shown) consists of one or more main anchor chains connected in series or parallel with multiple drag plates, and simultaneously supports one or more conventional anchors (such as towed anchors, suction anchors, or gravity anchors). This design reduces the number of drag plates, while the drag plates provide auxiliary fixation for the conventional anchors.

[0023] Example 3 (hard seabed) describes an anchoring foundation that employs at least one of a single-point gravity anchor, a suction anchor, a towed anchor, or a pile anchor. For example, a towed anchor is embedded in the hard seabed and connected to the lower end of a rigid pipe via a flexible anchor chain, utilizing the anchoring force between the anchor claws and the seabed to provide the anchoring point.

[0024] Third, the anti-rotation independent anchor chain also includes an independent anchor chain, one end of which is connected to the anchor point directly in front of the floating platform in the windward direction, and the other end is connected to the seabed or anchor foundation, which is used to constrain the rotational freedom of the platform so that the platform always remains in the windward direction.

[0025] IV. The active control unit includes: multiple anchor chain tension sensors, each installed on a separate anchor chain; a wind direction and speed meter, installed at the top of the wind turbine tower; a controller (such as a PLC or industrial computer) that receives signals from the sensors and the wind direction meter; and multiple traction motors distributed around the platform, driven by the controller commands, used to adjust the orientation of the platform or wind turbine tower and the anchor chain preload.

[0026] The active control unit performs the following cooperative control method: Real-time monitoring of wind direction and platform tilt angle; When the platform tilt angle reaches a preset threshold (e.g., 15 degrees), the traction engines located around the platform are started to adjust the rotation angle of the platform or wind turbine tower so that the windward direction adapts to the new wind direction. The tension of each anchor chain is detected. When the tension is uneven, the anchor chain with excessive force is automatically loosened to achieve coordinated anchoring pre-tightening force. Due to the uneven local stress and creeping adaptation characteristics of soft mud, it gradually achieves small-angle adaptive deformation to adapt to new wind directions. When it is detected that the anchor chains are understressed, resulting in unstable anchoring, the platform engine is started to provide additional chain preload. When the wind speed exceeds the preset limit threshold (such as typhoon wind speed) or the wind direction changes drastically, the anchor chain is actively loosened and the positive buoyancy inside the rigid tube is used to make the wind turbine lie down from a vertical posture to a near-horizontal posture, completely avoiding wind load.

[0027] Structural relationship: The wind turbine tower is fixedly connected to the rigid pipe or integrally formed to form an inflexible integral structure.

[0028] Transportation attitude: When it is necessary to carry out sea towing, the active control unit actively relaxes the anchor chain and uses the positive buoyancy inside the rigid tube to rotate the wind turbine tower and the rigid tube as a whole from the vertical attitude around the horizontal axis to the transportation tilt attitude.

[0029] Typhoon protection posture: When the wind speed exceeds the preset limit threshold, the active control unit actively loosens the anchor chain and uses the positive buoyancy inside the rigid tube to rotate the wind turbine tower and the rigid tube from a vertical posture around the horizontal axis to a near-horizontal posture in order to avoid wind load.

[0030] VI. The insulation and temperature control system also includes an outer insulation layer and an inner temperature control system, which are used to ensure that the electrical equipment inside the fan can operate normally in an environment of -65°C. 3.3 Beneficial Effects

[0031] Compared with the prior art, the present invention has the following beneficial effects: A rigid-flexible anchoring system combines the rigid constraint of long, rigid pipes with distributed, flexible array anchoring. In hard rock areas, traditional pile anchoring methods can be used (due to the significantly reduced stress requirements on the anchor points from the rigid pipes, the force required for pile anchoring is greatly reduced). Reliable anchoring force can be obtained in soft soil areas, especially in extremely soft soil areas. The "soil plugging effect" between the array anchors generates passive earth pressure that continuously increases with displacement, giving the anchoring force positive feedback characteristics.

[0032] Full seabed adaptability: The array anchoring combined with rigid pipes is suitable for any soft soil seabed, and together with the traditional pile planting method for hard seabeds, it covers the vast majority of marine geological conditions worldwide.

[0033] Extreme maintainability: All active components of the system are located above the waterline or inside the platform, with no underwater precision equipment, facilitating maintenance. The turbine's tilt-over protection mechanism provides ultimate safety in extreme weather conditions. In extreme geographical locations (such as -65°C in the Antarctic Ocean), the turbine's external insulation and internal temperature control ensure that the electrical components operate at suitable temperatures. After the turbine is tilted, a dedicated maintenance vessel can connect to it, enabling offshore maintenance.

[0034] Transportation convenience: The weight of the wind turbine platform is significantly lower than that of traditional solutions, there are no counterweight cement blocks, and it can be laid down in a tilted position for transportation, thus enabling batch transportation. Attached Figure Description

[0035] Figure 1 : Schematic diagram of the lever arm principle of a rigid tube floating island. Figure 2 : Schematic diagram of drag plate and anchor claw array anchoring (drag plate + anchor hybrid, suitable for soft soil to medium hard clay seabed). Figure 3 Schematic diagram of resistance plate array anchoring (pure resistance plate array, suitable for extreme soft soil). Figure 4 : Array anchorage stress analysis diagram. Figure 5 Force and equilibrium diagram of the suspended platform in the windward direction. Figure 6 Automatic balancing analysis diagram of the suspended platform (including the role of the active control unit). Figure 7 Schematic diagram of the adaptive balance of the suspended platform's slight rotation and anchor chain assembly. Figure 8 : Schematic diagram of platform maintenance and reclining protection. Figure 9 : Diagram of bulk shipment. Detailed Implementation Example 1: Overall structural configuration (Antarctic interglacial lake, extreme soft soil)

[0036] This embodiment provides a 20MW floating wind turbine foundation anchoring and stabilization system for use in Antarctic interglacial lakes (water depth approximately 1000-2000 meters, seabed composed of diatomaceous mud).

[0037] The floating platform adopts a steel truss structure with a diameter of 400 square meters. A large slewing bearing (i.e., a rotating connection mechanism) is set in the center of the platform. After the wind turbine tower and rigid pipe are fixedly connected, the whole assembly is installed on the slewing bearing. The wind turbine hub height is 200 meters, and the length of the rigid pipe is 300 meters (i.e., 1.5 times the hub height), with a total height of 500 meters for the entire wind turbine and rigid pipe.

[0038] The anchoring foundation uses a resistance plate array: 1,000 resistance plates are deployed, each measuring 1 meter × 1 meter × 20 mm, and are connected in series at 5-meter intervals to 4 anchor chains with a diameter of 150 mm. Every 10 resistance plates, a vertical steel stabilizing frame with a height of 1 meter is welded on, with a total width of 50 meters and a total anchor chain length of approximately 10,000 meters.

[0039] Active control unit: includes anchor chain tension sensors (one per chain), wind direction and speed meters (top of the tower), PLC controller, and four traction motors (evenly distributed around the platform). When a change in wind direction causes the platform to tilt by more than 15°, the controller starts the traction motors, driving the slewing bearing to yaw the wind turbine tower to face the wind; at the same time, it adjusts the anchor chain preload. Example 2: Working Mechanism of the Resistance Plate Array (corresponding to) Figure 3 , Figure 4 )

[0040] As the anchor chain is dragged, the soft mud in front of each resistance plate is pushed and lifted, with some soil overflowing the 1-meter-high steel frame and accumulating in the 5-meter gap between the plates. This process produces the following effects: The accumulated soil forms a continuous "soil plug," which continues to grow as the dragging distance increases; Each resistance plate provides approximately 5-10 tons of passive earth pressure; The 1,000 resistance plates provide a total passive anchoring force of approximately 5,000 to 10,000 tons; As the material accumulates and becomes denser, the anchoring force continues to increase with the displacement (positive feedback). Example 3: Working mechanism of resistance plate anchor claw array (corresponding to) Figure 2 )

[0041] On soft to medium-hard clay seabeds (such as the North Sea clay), a drag plate anchor array is employed. Twenty drag plates (spaced 5 meters apart) are connected in series by a main anchor chain, with a towed anchor attached to every two drag plates. When the anchor chain is under tension, the drag plates generate bulldozing resistance, while the towed anchors embed themselves into the seabed to provide concentrated holding force. Compared to a pure drag plate array, the number of drag plates can be significantly reduced, lowering construction costs. This hybrid approach fully utilizes the "soil-plugging effect" of the drag plates and the instantaneous holding force of traditional anchors. Example 4: Anchoring Scheme for Hard Seabed

[0042] For hard seabeds (such as rock or dense sand), traditional anchoring methods are used. In this embodiment, the anchoring foundation consists of three towed anchors arranged in a triangle, each connected to the lower end of a rigid pipe via an independent flexible anchor chain. Once embedded in the seabed, the towed anchors provide approximately 150-200 tons of holding power. No drag plate array is required. Example 5: When to tilt the fan back (corresponding to) Figure 8 )

[0043] The wind turbine tower and the rigid tube are fixedly connected or integrally formed to create an inflexible whole. "Real-time wind speed monitoring: when the wind speed is between the rated wind speed and the limit threshold, the blade angle is first adjusted via the pitch system to limit the power captured by the rotor; when the wind speed exceeds the preset limit threshold (e.g., 25 m / s) or when offshore towing is required, the lying-down procedure is initiated. The controller issues a command: first, loosen the anchor chain, then utilize the positive buoyancy provided by the sealed cavity inside the rigid tube and / or the traction of the power cable. This causes the entire structure formed by the wind turbine tower and the rigid tube to rotate from a vertical position around the horizontal axis to a near-horizontal position (typhoon protection) or a transport tilted position (towing). After lying down, it facilitates direct docking and maintenance by the repair vessel." Example 6: Thermal Insulation and Temperature Control System (corresponding to) Figure 8 )

[0044] The wind turbine tower and nacelle are covered with a 100mm thick polyurethane insulation layer, and an internal electric heating temperature control system is installed with a temperature setting of 15℃±2℃. All electrical equipment, controllers, and sensors are placed in a constant temperature environment to ensure normal operation in an external environment of -65℃. Example 7: The specific working process of the active control unit (corresponding to...) Figure 6 , Figure 7 )

[0045] When the wind direction changes, the anemometer detects the change, the platform tilt sensor indicates that the platform is tilting, and the anchor chain tension sensor detects that some anchor chains have increased tension while others have decreased tension. The controller initiates a tension balancing program: actively loosening excessively tense anchor chains while tightening excessively tense ones, restoring tension balance to all anchor chains. After several creeping adjustments, the platform adapts to the new equilibrium position without needing to activate the high-power yaw motor. If the tilt angle exceeds a preset threshold (e.g., 15 degrees), the traction engine is activated to drive the slewing bearing, causing the wind turbine tower to quickly align with the wind.

Claims

1. A floating wind turbine foundation system, characterized in that, include: A floating platform; A wind turbine tower; A rigid tube is fixedly connected to the wind turbine tower or integrally formed therefrom; A rotating connection mechanism is disposed between the wind turbine tower or the rigid pipe and the floating platform, so that the wind turbine tower or the rigid pipe can rotate relative to the floating platform; An anchoring foundation; The lower end of the rigid tube is connected to the anchoring foundation via a flexible anchor chain, and the anchoring foundation is used to fix the system to the seabed. An active control unit is used to monitor the platform attitude and anchor chain tension, and adjust the preload of the anchor chain or adjust the orientation of the wind turbine tower accordingly.

2. The system according to claim 1, characterized in that, The length of the rigid tube is greater than half the height from the floating platform to the wind turbine hub.

3. The system according to claim 2, characterized in that, The length of the rigid tube is 1.5 times the height from the floating platform to the wind turbine hub.

4. The system according to claim 1, characterized in that, The anchoring foundation includes at least one of the following: single-point gravity anchor, suction anchor, resistance plate array, drag anchor, and pile anchor.

5. The system according to claim 4, characterized in that, The anchoring foundation includes a resistance plate array, which consists of one or more main anchor chains and multiple resistance plates connected in series and / or in parallel on the main anchor chains.

6. The system according to claim 4, characterized in that, The anchoring foundation includes a resistance plate anchor claw array, which consists of one or more main anchor chains connected in series or in parallel with multiple resistance plates, and simultaneously carrying one or more anchors.

7. The system according to claim 5 or 6, characterized in that, The spacing between the resistance plates is configured such that when the anchor chain is dragged, the soil in front of each resistance plate is pushed and lifted, and some soil passes over the resistance plate and accumulates in the gap behind it, forming a dynamic soil plug, thereby providing a passive anchoring force that continuously increases with the dragging distance.

8. The system according to claim 1, characterized in that, It also includes an independent anchor chain, one end of which is connected to the anchor point directly in front of the floating platform in the windward direction, and the other end is connected to the seabed or anchor foundation, to constrain the platform's rotational degrees of freedom.

9. The system according to claim 1, characterized in that, The wind turbine tower has a foldable structure; and the active control unit is also configured to: when the wind speed exceeds a preset limit threshold, actively loosen the anchor chain and use the positive buoyancy inside the rigid tube to make the wind turbine lie down from a vertical posture to a horizontal posture.

10. The system according to claim 1, characterized in that, It also includes an external insulation layer and an internal constant temperature environment control system, which are used to ensure that the electrical equipment inside the fan can work normally in an environment of -65°C.

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