Single blade installation using active control of three tugger lines

Abstract

Single blade installation using jack-up vessels is a commonly used blade installation setup for offshore wind turbines. During this operation, each blade is lifted by the main crane from the deck, moved, and then bolted to the rotor hub at the top of the turbine tower. Tugger lines from the crane boom are connected to the suspended blade to reduce the blade’s pendulum motions. Lately, much research has been conducted to reduce the blade motion by actively controlling the tension force in the tugger lines. Since the tugger lines can only provide positive tension, pretension is needed before the mating process. In this paper, an active PID control strategy with a three-tugger-line configuration is proposed to reduce the blade motion by controlling the tugger line forces acting on the blade . The placement of the additional 3rd line is discussed. The control allocation is achieved by convex programming with an auto-generation solver using CVXGEN. Simulations under turbulent wind conditions are conducted to verify the active control scheme in HAWC2. The results shows that the active control scheme effectively reduces the translational motion of the blade root relative to the hub in the mean wind direction.