The invention presents a method for operating a horizontal axis wind turbine, the wind turbine comprising a tower and a rotor with at least one rotor blade, the rotor being connected to the tower, and being adapted to drive a generator connected to a utility grid, wherein a pitch angle of each rotor blade is adjustable, the method comprising detecting, when the wind turbine is in an idling power producing situation in relation to the utility grid, a tower oscillation, and controlling, when the wind turbine is in the idling power producing situation, the pitch angle of the at least one rotor blade so as to produce aerodynamic forces counteracting the detected tower oscillation.

A wind installation comprising a wind turbine (1) and an airborne wind energy system (12, 13), e.g. in the form of a kite (12) or a glider (13) is disclosed. The wind turbine (1) is electrically connected to the power grid via a power transmission line (27). The wind installation further comprises an airborne wind energy system (12, 13), e.g. in the form of a kite (12) or a glider (13), for generating electrical energy. The airborne wind energy system (12, 13) comprising a separate generator is coupled to the wind turbine (1) via a cable (6) and the separate generator is electrically connected to the power transmission line (27).

A system and method for protecting a wind turbine from extreme wind gusts includes monitoring a wind speed and a wind direction at the wind turbine. The method also includes determining a wind gust threshold, wherein wind speeds and wind directions exceeding the wind gust threshold, respectively, are indicative of an extreme wind gust occurring at the wind turbine. In addition, the method includes comparing, via a controller, the monitored wind speed or a function thereof and the wind direction or function thereof to the wind gust threshold, respectively. Thus, the method includes implementing, via a controller, a corrective action when the monitored wind speed and the monitored wind direction exceed the wind gust threshold, respectively.

A method for operating a wind turbine, and the wind turbine has an aerodynamic rotor with a rotor hub and with rotor blades of which the blade angle can be adjusted, and the aerodynamic rotor can be adjusted in respect of its azimuth direction, and the method comprises the steps of detecting a storm situation in which the prevailing wind is so strong that the wind turbine is moved to a coasting mode for self-protection purposes, orienting the rotor in respect of its azimuth position into a low-loading orientation in relation to the wind, in which orientation the wind turbine is subjected to as little loading as possible by the wind from a main wind direction, detecting at least one loading (L.sub.M) which is caused by a gust of wind and acts on the rotor, and adjusting at least one of the rotor blades in respect of its blade angle such that the at least one rotor blade is subjected to as little loading as possible by the causative gust of wind.

A method for setting a fully or partially built wind power installation having a rotor having a plurality of rotor blades whose blade angle can be adjusted, wherein the wind power installation can take on variable operating situations, and each operating situation is characterized by a combination of settable installation settings of the wind power installation and environmental conditions that can be captured, with the result that an operating situation can be set for given environmental conditions by setting the installation settings, and operating situations that should be avoided and/or suitable operating situations are stored in a memory by storing a combination of environmental conditions and installation settings as a combination to be avoided for an operating situation that should be avoided in each case, and/or storing a combination of environmental conditions and installation settings as a suitable combination for a suitable operating situation in each case, and, to avoid operating situations that should be avoided, environmental conditions are captured and, depending on the captured environmental conditions and the stored combinations to be avoided and/or suitable combinations, installation settings of the wind power installation are selected and set such that installation settings of stored combinations to be avoided are avoided, and/or installation settings are selected from stored suitable combinations.

Rotor restraining and rotating apparatus and methods for a wind turbine (1) are described. An apparatus (200) has a rotatable control element (204) associated with a rotor (8, 203) of the wind turbine, the control element being at least part-circular in form, the control element comprising a plurality of engagement formations (205) disposed on a periphery thereof. The apparatus also has a control member (206), comprising a plurality of engagement formations (207). The control member is movable (208) in a first degree of freedom between: (a) a non-restraining position; and (b) a restraining position in which the control member engagement formations are able to engage the control element engagement formations to restrain rotation of the control element. The control member is also movable (209) in a second degree of freedom. In the restraining position, on movement of the control member in the second degree of freedom, the control member engagement formations are operable to move the control element engagement formations thereby to cause rotation of the control element.

A method of handling a wind turbine is provided including a nacelle coupled via a yawing system to a tower for protection against high wind load, the method including: supplying a control signal to a yawing actuator of the yawing system, while the nacelle is in a first orientation; exerting, by the yawing actuator, a torque to the nacelle relative to the tower, thereby turning the nacelle to a second orientation being a downwind orientation.

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.

A locking unit (24) for a rotor lock system (20) of a wind turbine (1), the locking unit (24) comprising: a locking shaft (34) that is slidably movable within a barrel (30) under the influence of an actuator (32); and an angular drive arrangement (48, 50) which is configured to enable angular movement of the locking shaft (34) about a longitudinal axis as the locking shaft (34) is moved linearly within the barrel (30) by the actuator (32).

The invention relates to wind power and allows effectively convert the kinetic energy of the wind, after its (wind) accelerating, to electrical power. The multi-stage wind turbine, which allows multiple accelerate directed air flow (wind), even of most minimal speed, up to strong wind and convert it's energy into electrical power, is proposed. It is achieved due to modularity of installation, where the wind is accelerated within each module due to the processes of capturing the initial wind flow, injection-ejection and aerodynamic Coanda effect as well, by virtual necks and conical confusors nested one into another. The system of truncated cones and virtual necks with optimum aerodynamic sizes provides the capture of the airflow not only perpendicular to the base of these cones, but also from lateral sides of these cones. Moreover, the area of wind flow capturing by lateral surface of this system, depending on the number of stages, several times exceeds the area of wind flow capturing by base of first confusor from side of wind flow. In proposed installation for increase of output power, three parameters are used at relatively small sizes of airscrew. In this case, the wind flow, which is captured by working part of the wind turbine, is compressed by all sides, increasing the speed of the directed airflow, acting on the airscrew. All turbine stages, except the last stage, represent the not full Venturi tubes consisting of a confusors and virtual necks. The last stage represents the classical Venturi tube, consisting of confusor, neck and diffusers. The airscrew is located within the neck of the Venturi tube. Turbine is equipped with a weather vane and means of protection from destruction during hurricane wind.