Horizontal Rotor Blade Synchronization for Offshore Hub Installation
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Solution Overview
Problem
The installation of large rotor blades in offshore wind turbines is challenging due to increasing dimensions and mass, exacerbated by sea state and wind-induced motions, leading to potential damage from relative motion between the blade root and mounting structure during the mating process.
Innovation Solution
A blade motion synchronization and positioning device with a wind turbine coupler, blade coupler, and controllable motion arm actuator assembly is used to synchronize and stabilize the rotor blade with tower top motion, allowing controlled engagement and alignment with the mounting structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a crane is used to lift the rotor blade in horizontal orientation, then the blade can be positioned at the mounting structure, but relative motion between the blade root and mounting structure causes difficulty in mating bolts with bolt holes
Solution Approach 1:
The blade is pre-positioned in a receiving position where the blade root is aligned with the mounting structure before the actual fastening operation. This preliminary positioning allows the bolts to be introduced into the bolt holes without dealing with tower top motions during the critical mating process, thereby resolving the alignment difficulty while maintaining ease of operation
Solution Approach 2:
A motion arm is introduced as an intermediary component between the crane and the blade root. This motion arm absorbs and compensates for tower top motions, isolating the blade root and mounting structure from relative motion during the fastening operation, thereby enabling precise bolt alignment while maintaining operational flexibility
2Reliability
If the blade is held in position during fastening, then secure attachment is achieved, but tower top motions cause relative motion leading to potential damage from impact or collision
Solution Approach 1:
The blade root is positioned in advance in a receiving position where it is already aligned with the mounting structure. This preliminary alignment ensures that when the blade is held in position during fastening, there is no relative motion between the blade root and mounting structure, thereby preventing impact damage while maintaining attachment security
Solution Approach 2:
The motion arm serves as a mediator that compensates for tower top motions during the fastening operation. By absorbing these motions, the motion arm prevents relative motion between the blade root and mounting structure, eliminating the risk of impact or collision damage while allowing the blade to be securely attached
3Productivity
If the blade root is brought close to the mounting structure, then fastening can proceed, but wind and sea state induced motions make the process difficult and time-consuming
Solution Approach 1:
The motion arm acts as an intermediary that actively compensates for wind and sea state induced motions during the blade installation process. This motion compensation capability allows the blade root to be brought close to the mounting structure and held in the receiving position despite environmental disturbances, thereby maintaining installation speed without excessive complexity
Solution Approach 2:
The motion arm system incorporates feedback control to continuously monitor and compensate for tower top motions induced by wind and sea states. This feedback mechanism allows the system to automatically adjust and maintain proper alignment between the blade root and mounting structure, improving installation productivity while keeping the control system manageable
Data Source
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AI summary
In the installation of a rotor blade in horizontal orientation to the hub of a horizontal axis offshore wind turbine use is made of a blade motion synchronization and positioning device, which comprises a wind turbine coupler, a blade coupler, a motion arm between the wind turbine coupler and the blade coupler, and a controllable motion arm actuator assembly. The method comprises bringing and maintaining the blade coupler in a motion compensated receiving position, wherein the arm is operated to compensate for sea state and/or wind induced tower top motion. In receiving position the coupler is coupled to the blade that is suspended from a crane. The actuator assembly is then operated to gradually bring, and then maintain, the coupled blade in a horizontal motion that is synchronized with tower top motion, and to displace the coupled blade root into a pre-mounting position. Then a mounting motion is performed wherein the blade root is moved into a mounting position and the blade root is fastened to mounting structure by fasteners.