Abstract: A vibration mitigating device for engagement with a wind turbine blade includes an air flow modifying element that is configurable between a retracted configuration and an extended configuration. A frame is attachable to and has a fixed length in a span-wise direction of the wind turbine blade. The air flow modifying element is movable along the frame between the retracted configuration and the extended configuration. In the retracted configuration, the modifying element extends between the blade tip and the blade root with a first spanwise length, and in the extended configuration the modifying element extends between the blade tip and the blade root with a second, greater spanwise length.

Abstract: The present disclosure relates to wind turbine blades, devices and methods for reducing vibrations in wind turbines, particularly during installation. In an aspect, a device for mitigating vibrations of a blade of a wind turbine during standstill is provided. The device comprises a flexible base having a first connection area and a second connection area, the first connection area being configured to be attached to the second connection area to form a removable attachment. The device further comprises one or more airflow modifying elements attached to the flexible base. The flexible base is configured to fit around a portion of the rotor blade such that the removable attachment is positioned substantially at a leading edge of the blade. The present disclosure further relates to methods for mitigating vibrations in a parked wind turbine blade and to sleeves for wrapping around a portion of a wind turbine blade.

Abstract: The present disclosure relates to devices (300) for wind turbine blades (22) and methods (400) for reducing vibrations in wind turbines (10). More particularly, the present disclosure relates to devices (300) for mitigating vortex induced vibrations and stall induced vibrations, wind turbine blades (22) comprising such devices (300), and methods (400) for reducing wind turbine vibrations when the wind turbine (10) is parked, especially during wind turbine installation and/or maintenance. A device (300) is configured to be arranged around a wind turbine blade (22) and comprises three or more air flow modifying elements (305) comprising a concave outer surface (323) configured to face away from a wind turbine blade (22). The device further comprises a supporting structure (310) configured to support the plurality of air flow modifying elements (305). An angular distance (307) between adjacent air flow modifying elements (305) in cross-section is substantially constant.

Abstract: A wind turbine blade includes a leading edge protection element attached to the leading edge of the wind turbine blade. The leading edge protection element extends in a longitudinal direction between an outboard end and an inboard end and includes an attachment surface mounted to an exterior surface of the blade, an exterior surface opposite the attachment surface, a first section extending from the leading edge and along a part of the pressure side of the wind turbine blade to a first transverse end at a first position on the pressure side of the blade, and a second section extending from the leading edge and along a part of the suction side of the wind turbine blade to a second transverse end at a second position on the suction side of the blade.

Abstract: The present disclosure relates to methods (100, 200) for controlling and operating wind turbines (10). More particularly, the present disclosure relates to methods and systems for determining a surface condition of one or more wind turbine blades (22) of a wind turbine (10). a method comprises rotating the wind turbine rotor (18) under the influence of a wind in predetermined rotation conditions, wherein the predetermined rotation conditions include at least a predetermined pitch angle (252) of the additional wind turbine blades (222, 223). The method further comprises determining a current value of one or more parameters of the wind turbine (10) when rotating in the predetermined rotation conditions and comparing the current value of the one or more parameters of the wind turbine with one or more reference values (37) to determine the surface condition of the wind turbine blades (22).

Abstract: The present disclosure relates to devices (300) for wind turbine blades (22) and methods for reducing vibrations in wind turbines (10). More particularly, the present disclosure relates to devices (300) for mitigating vortex induced vibrations and stall induced vibrations, wind turbine blades (22) comprising such devices (300), and methods for reducing wind turbine vibrations when the wind turbine (10) is parked, especially during wind turbine installation and/or maintenance. A device (300) comprises a proximal support (310) configured to be arranged around a first portion (221) of a wind turbine blade (22), a distal support (320) configured to be arranged around a second portion (222) of the wind turbine blade (22), and a barrier (330) extending between the proximal support (310) and the distal support (320). The first portion (221) of the wind turbine blade (22) is at a different longitudinal position along the blade (22) than the second portion (222).

Abstract: The present disclosure relates to devices (350) for reducing vibrations in wind turbines (10) and to methods (450) for using the devices (350) and mitigating wind turbine vibrations. More particularly, the present disclosure relates to devices (350) for reducing vortex induced vibrations and stall induced vibrations when the wind turbine (10) is parked, especially during wind turbine installation and/or maintenance, and to ways in which the devices (350) can be used, e.g. for installing them on wind turbine blades (22) or once they are already installed thereon. A vibration mitigating device (350) for mitigating vibrations of a parked wind turbine (10) is provided. The device (350) is configured to be arranged with a wind turbine blade (22). The device (350) comprises one or more air flow modifying elements (330). At least one of the air flow modifying elements (330) is configured to change between a retracted configuration (370) and an extended configuration (375).

Abstract: The present disclosure relates to devices (300) for wind turbine blades (22) and methods (400) for reducing vibrations in wind turbines (10). More particularly, the present disclosure relates to devices (300) for mitigating vortex induced vibrations and stall induced vibrations, wind turbine blades (22) comprising such devices (300), and methods (400) for reducing wind turbine vibrations when the wind turbine (10) is parked, especially during wind turbine installation and/or maintenance. A device (300) is configured to be arranged around a wind turbine blade (22) and comprises three or more air flow modifying elements (305) comprising a concave outer surface (323) configured to face away from a wind turbine blade (22). The device further comprises a supporting structure (310) configured to support the plurality of air flow modifying elements (305). An angular distance (307) between adjacent air flow modifying elements (305) in cross-section is substantially constant.

Abstract: The present disclosure relates to methods and systems for measuring deflection of blades of a wind turbine. Examples include a light emitting and collection device mounted to the nacelle and configured to emit light in a direction within a substantially vertical plane. Examples include a method for operating a wind turbine including emitting light above a hub, receiving the light when reflected by a blade of the wind turbine, and, if the level of blade deflection is above a threshold, reducing blade loading of the blade before the blade reaches a vertically downward position. Examples include a method for monitoring deflection of a rotor blade of a wind turbine comprising emitting a light sheet, collecting reflections of the emitted light, and determining deflection of the rotor blade by determining a time during which the blade reflects the emitted light sheet.

Abstract: Methods (200) for reducing vibrations in one or more rotor blades (120) of a wind turbine (160), when the wind turbine is in standstill conditions are provided. The method comprises measuring (201) one or more deformation parameters indicative of deformation of one or more blades (120), determining (202), at a dedicated controller (190) for an auxiliary drive system (20, 107), a vibration of one or more of the blades (120) based on the deformation parameters, wherein the dedicated controller (190) for the auxiliary drive system is separate from the wind turbine controller (180), and generating (203), at the dedicated controller (190), an output signal to operate the auxiliary drive system to reduce the vibration. Also disclosed are wind turbines (160) which comprise a dedicated controller (190) configured to determine a vibration and generating an output signal to reduce the vibration, when the wind turbine is in standstill conditions.

Abstract: The present disclosure relates to methods and systems for measuring deflection of blades of a wind turbine. Examples include a light emitting and collection device mounted to the nacelle and configured to emit light in a direction within a substantially vertical plane. Examples include a method for operating a wind turbine including emitting light above a hub, receiving the light when reflected by a blade of the wind turbine, and, if the level of blade deflection is above a threshold, reducing blade loading of the blade before the blade reaches a vertically downward position. Examples include a method for monitoring deflection of a rotor blade of a wind turbine comprising emitting a light sheet, collecting reflections of the emitted light, and determining deflection of the rotor blade by determining a time during which the blade reflects the emitted light sheet.

Abstract: Methods of operating a variable speed wind turbine as a function of wind speed are described. The wind turbine has a rotor with a plurality of blades and a generator. The generator has a design rotor speed which varies so as to follow a theoretical generator rotor rotational speed curve describing the rotational speed of the rotor as a function of wind speed. The method comprises determining an erosion risk condition of the blades, determining erosion damage of one or more of the blades accumulated over time and changing the rotor rotational speed from the design rotor speed as a function of the determined erosion risk condition and the determined accumulated erosion damage. Wind turbines configured to carry out such methods are also described.

Abstract: Methods (200) for reducing vibrations in one or more rotor blades (120) of a wind turbine (160), when the wind turbine is in standstill conditions are provided. The method comprises measuring (201) one or more deformation parameters indicative of deformation of one or more blades (120), determining (202), at a dedicated controller (190) for an auxiliary drive system (20, 107), a vibration of one or more of the blades (120) based on the deformation parameters, wherein the dedicated controller (190) for the auxiliary drive system is separate from the wind turbine controller (180), and generating (203), at the dedicated controller (190), an output signal to operate the auxiliary drive system to reduce the vibration. Also disclosed are wind turbines (160) which comprise a dedicated controller (190) configured to determine a vibration and generating an output signal to reduce the vibration, when the wind turbine is in standstill conditions.

Abstract: Methods of operating a variable speed wind turbine as a function of wind speed are described. The wind turbine has a rotor with a plurality of blades and a generator. The generator has a design rotor speed which varies so as to follow a theoretical generator rotor rotational speed curve describing the rotational speed of the rotor as a function of wind speed. The method comprises determining an erosion risk condition of the blades, determining erosion damage of one or more of the blades accumulated over time and changing the rotor rotational speed from the design rotor speed as a function of the determined erosion risk condition and the determined accumulated erosion damage. Wind turbines configured to carry out such methods are also described.

Abstract: Leading edge protectors for a wind turbine blade are disclosed. The leading edge protectors are configured to at least partially cover a blade leading edge section. The leading edge protectors comprise a main body having a substantially constant thickness and having a trailing end. The leading edge protectors further comprise a plurality of irregularities arranged on an outer surface of the main body upstream from the trailing end and configured to energize a boundary layer. Wind turbines comprising such leading edge protectors are also disclosed.

Abstract: A wind turbine including a rotor, a nacelle, a support structure for the nacelle and at least one wind sensing apparatus mounted on the support structure.

Abstract: Method of operating a wind turbine having a tower, a rotor with a plurality of blades arranged on the tower, one or more pitch systems for pitching the blades, a system for determining an instantaneous representative wind speed, and a system for determining a distance between a blade and the tower. The method comprises determining the instantaneous representative wind speed, and determining the distance between the tower and one of the blades when said blade is in the shadow of the tower. The method further comprises determining a tower distance pitch adjustment depending on the determined distance between the tower and the blade in the shadow of the tower and on the determined instantaneous representative wind speed. The method still further comprises the one or more pitch systems applying the determined tower distance pitch adjustment to at least the next blade to be in the shadow of the tower.

Abstract: Wind turbine blade comprising a spar, a plurality of ribs rotatably mounted on said spar, and a rotating means adapted to rotate at least two consecutive ribs independently of each other. The blade can thus be operated so as to rotate at least two consecutive ribs independently of each other, although it is also possible to jointly rotate all the ribs.

Abstract: Wind turbine blade comprising a spar, a plurality of ribs rotatably mounted on said spar, and a rotating means adapted to rotate at least two consecutive ribs independently of each other. The blade can thus be operated so as to rotate at least two consecutive ribs independently of each other, although it is also possible to jointly rotate all the ribs.

Abstract: A wind turbine including a rotor, a nacelle, a support structure for the nacelle and at least one wind sensing apparatus mounted on the support structure.