A method of mitigating a vibration of a wind turbine not receiving power from to a utility grid includes: receiving power from an energy storage system of the wind turbine; utilizing the power received from the energy storage system: to detect a wind direction and to adjust an orientation of the rotor axis of a rotor shaft, if a criterion is satisfied taking into account at least the relative orientation of the rotor axis and the detected wind direction and/or taking into account a level of the vibration.

A lock for preventing rotation of a rotor of a wind turbine has a rotatable lock pin, a pin support supportable in a nacelle of the wind turbine and a mechanism for rotating the lock pin. The pin support has a hub-facing face proximate a rotor hub. The rotatable lock pin is rotatably mounted on the pin support. The lock pin has a cammed portion extending away from the hub-facing face toward the hub. The lock pin inserted into a complementary rotor lock aperture on the rotor hub when the pin support is supported in the nacelle. Rotation of the lock pin causes engagement of an exterior surface of the cammed portion with an interior surface of the rotor lock aperture to immobilize the lock pin against the interior surface to prevent relative motion between the lock pin and the aperture to prevent rotation of the rotor.

A wind turbine (1) comprising a tower (2), a nacelle (3) and a hub (7) is disclosed. The hub (7) comprises a blade canying structure (4) with one or more wind turbine blades (5) connected thereto. Each of the wind turbine blades (5) is connected to the blade canying structure (4) via a hinge (6) at a hinge position of the wind turbine blade (5), each wind turbine blade (5) thereby being arranged to perform pivot movements relative to the blade carrying structure (4) between a minimum pivot angle and a maximum pivot angle. The wind turbine (1) further comprises a stop mechanism arranged to move the wind turbine blades (5) to a safe pivot angle in the case of an emergency, the stop mechanism comprising a release mechanism (8, 12, 14) and at least one wire (9, 10) interconnecting the release mechanism (8, 12, 14) and each of the wind turbine blades (5). Activation of the release mechanism (8, 12, 14) causes an abrupt change in a pulling force applied to the wind turbine blades (5) by the wire(s) (9, 10), the change in pulling force causes the wind turbine blades (5) to move immediately to the safe pivot angle.

A wind turbine is provided. The wind turbine includes a wind rotor and a generator, mechanically coupled to the wind rotor. The wind turbine is configured to operate in a first mode of operation and in a second mode of operation, wherein, in the second mode of operation, the wind rotor is oriented in an opposite direction relative to a wind direction compared with the first mode of operation. The generator of the wind turbine is configured to generate power both in the first mode of operation and in the second mode of operation. Furthermore, a corresponding method of operating a wind turbine is provided.

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).

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). The proximal (310) and distal (320) supports are configured to provide a gap (350) between the barrier (330) and a wind turbine blade surface.

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.

A method for operating a plurality of wind energy installations configured for supplying electric power to an electrical supply system, that each have an aerodynamic rotor with rotor blades and an electrical generator and also operating equipment, is disclosed. The wind energy installations are operated while they are not connected to the electrical supply system, where at least one of the wind energy installations produces electric power and inputs the electric power into a local DC voltage system that connects the wind energy installations if the at least one of the wind energy installations currently produces more power than needed for supplying its own operating equipment. Additionally or alternatively, the operating equipment is supplied totally or in part with power from the local DC voltage system if the at least one of the wind energy installations currently produces less power than needed for supplying its operating equipment.

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.

A wind turbine has a Lidar device to sense wind conditions upstream of the wind turbine. Signals from the wind turbine are processed to detect an extreme change in wind direction. The detection is performed by differentiating the rate of change of wind direction and filtering for a period of time. On detection of extreme change the system controller takes the necessary evasive action which may include shutting down the turbine, commencing an immediate yawing action, and de-rating the turbine until the yawing action is complete.