Search results for "vindturbiner"
showing 2 items of 2 documents
Numerical study of a concept for major repair and replacement of offshore wind turbine blades
2020
Repair and replacement of offshore wind turbine blades are necessary for current and future offshore wind turbines. To date, repair activities are often conducted using huge jack-up crane vessels and by applying a reverse installation procedure. Because of the high costs associated with installation and removal of offshore wind turbine components and the low profit margin of the offshore wind industry, alternative methods forinstallation and removal are needed. This paper introduces a novel concept for replacement or installation of offshore windturbine blades. The concept involves a medium-sized jack-up crane vessel and a tower climbing mechanism. This mechanism provides a stable platform …
Load mitigation method for wind turbines during emergency shutdowns
2021
Wind turbines experience countless shutdowns during their lifetimes. A shutdown is a transient process characterised by a pitch-to-feather manoeuvre of three blades. Such a pitch manoeuvre is often collective, open-loop, and can substantially slow the rotor speed within several seconds. However, undesirable structural responses may arise because of the imbalanced aerodynamic loads acting on the rotor. To address this issue, this paper proposes a method that actively adjusts the individual pitch rate of each blade during an emergency shutdown. This method is founded on a minimal intervention principle and uses the blade-root bending moment measurements as the only inputs. The control objecti…