Mooring Systems Optimization for Offshore Wind Turbines

A method to reduce fatigue damage in the moorings of a floating wind turbine by controlling the turbine based on pitch motion and wind direction. When the wind predominantly impacts one mooring, curtailing the turbine reduces the loads and fatigue on that mooring. This is achieved by offsetting the blade pitch to reduce rotor thrust. Since wind loading on a single mooring applies higher loads than distributed loading, the turbine controller monitors pitch motion and wind direction, applying pitch offset to reduce the strain on the affected mooring.

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A tethered wind turbine tower offers a cost-effective solution for building taller wind turbines. The tower is stabilized by cables attached to it and anchored in the ground. These cables are pre-tensioned to minimize oscillations. The attachment points for the cables are optimized to converge within the tower wall thickness, allowing the use of standard tower sections and cables while effectively stabilizing the taller structure.

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A floating wind turbine with enhanced stability, moored using angled lines instead of vertical lines. The mooring lines intersect above the nacelle to counteract overturning moments and stabilize the platform. This design allows the platform to partially submerge, reducing motions that could strain the turbine. The mooring lines are equipped with a tensioning system to adjust the platform's draft for optimal stability. Additionally, the platform has buoyancy tanks that can be submerged when the lines are tensioned.

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A wind turbine tower design that allows for taller towers without excessive weight and cost. The tower is stabilized by cables attached at intervals around its circumference. These pre-tensioned cables reduce tower sway and converge within the tower wall thickness at precise attachment points. The cables are anchored to a separate, thicker tower section and attached to ground anchor points. The tower sections are joined sequentially, with the cables already in place.

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An offshore wind turbine mounted on a floating platform with enhanced stability to maintain the turbine blades in an optimal position for power generation. The platform is designed to minimize pitch and roll motions, keeping the turbine upright and avoiding excessive nacelle accelerations. This stability is achieved through several features, including a low center of gravity, pitch stiffness provided by the mooring system, and a pitch eigenperiod that matches the wave frequency.

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A method for erecting tall towers, particularly wind turbine towers, stabilized by multiple tensioned cables. This method employs a motorized winch to quickly attach and tension the cables. Tower sections are assembled one by one on the ground, with some cables pre-attached to minimize work at height. The winch pulls the remaining cable ends into position and attaches them to anchor blocks. The cables are then pre-tensioned to ensure tower stability.

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A method for mooring offshore structures, such as wind turbines, to prevent collisions and drifting if mooring lines break. Each structure is secured using 3-8 mooring lines attached to separate bases, with each base anchoring lines from 3-8 structures. The mooring lines are arranged asymmetrically, ensuring that if one line breaks, the remaining lines prevent the structure from colliding with others. This method allows for effective mooring without the need for excessively strong lines, using the asymmetric arrangement to enhance safety and stability.

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An airborne wind turbine system that reduces the cost and complexity of harnessing wind energy by using an aerial vehicle connected via a tether to an adjustable buoyant underwater body. The tether may be routed through an undersea mooring and then back up to an underwater buoyant body, such as an inflatable bladder, with adjustable buoyancy. In another embodiment, the tether passes through a floating landing platform to the underwater buoyant body. The buoyancy of the body can be adjusted based on the flight mode of the aerial vehicle.

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A floating offshore wind power generation system designed for reduced mooring costs and improved stability. The system features a floating body that supports the wind turbine tower and nacelle above the water surface. A single mooring member connects the floating body to a seabed anchor point, attaching above the floating body's center of gravity. This configuration allows the floating body to rotate around the mooring connection, aligning with wind and waves for increased stability. It also lowers construction costs compared to systems with multiple moorings.

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Wind turbine systems featuring floating offshore turbines that can track wind direction, use rotors with counter-rotating blade sets to reduce gyroscopic forces, and employ an innovative remote anchoring system. The system floats on the water's surface, with a main anchor line connecting it to an anchor buoy. A sliding trolley on the anchor line allows for lateral movement. A secondary anchor line connects the trolley to a submerged secondary anchor. A drop line can lower the secondary anchor toward the main anchor. When the secondary anchor is set, the trolley being pulled outward tensions the main anchor line. This setup provides a stable pivot point for the floating turbines to rotate around, enabling them to track wind direction without rotating the entire system.

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A method of erecting a wind turbine tower that is tethered by cables extending between attachment elements on the tower and anchoring elements on an anchor block. The method involves using a motorized winch to pull the cable ends into position at the anchor blocks and attach them, and pre-tensioning the cables to support the tower before lifting subsequent tower sections. Using the winch instead of cranes for cable positioning speeds up erection and reduces costs. The winch can guide the cable ends into anchors and pre-tension them.

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A method of maintaining offshore floating wind turbines by swapping them out for maintenance, allowing work in a stable environment regardless of wind and wave conditions at the mooring site. The method involves transferring the turbine needing maintenance to a calmer location for servicing while replacing it at the mooring with another turbine. This enables extensive maintenance away from the harsh conditions and ensures continuous generation.

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A floating wind turbine assembly with improved stability. The assembly comprises a floating platform moored to the seabed with tensioned mooring lines. The mooring lines are attached at an angle instead of vertically, which helps stabilize the platform and turbine against overturning forces when the turbine is producing power. Tensioning the lines lowers the platform to submerge the buoyancy tanks, further stabilizing it.

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A floating support for offshore wind turbines that can be ballasted and deballasted to adjust its draft. The support has a cross-section that increases in area towards the surface as depth decreases. This ensures stability with a shallow draft mainly from shape, and stability with a deeper draft from both shape and mass.

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Wind turbine tower configuration that allows for taller towers without increasing shell thickness. The tower is tethered by cables from anchors in the ground. The cables attach to the tower at locations where their projection lines converge inside the tower wall. This reduces the number of cables needed and allows thinner tower sections. The cables are tensioned to prevent oscillations.

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