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 method includes receiving, via one or more turbine-level controllers, an indication of at least one of a communication loss between the one or more turbine-level controllers and a farm-level controller, a detection of an absence of reactive power regulation by the farm-level controller, or a reactive power command of the farm-level controller being equal to or above a saturation threshold during transitioning between a baseline operational mode and reactive power mode, the reactive power mode being characterized in that only reactive power is generate. Upon receipt of the indication, the method includes adjusting a reactive power response of one or more reactive power regulators of the one or more turbine-level controllers so as to avoid an overshoot reactive power event or an undershoot reactive power event at the point of interconnection.

A method of operating a wind turbine generator comprising a plurality of blades, the method comprising iterating the following steps: comparing an indicated rotor speed with a rotor speed target to determine a rotor speed error; generating a modified rotor speed error by applying a control factor to the rotor speed error; controlling the pitch angle of the blades via a pitch control system in accordance with the modified speed error; and altering the control factor in dependence on a size of the indicated rotor speed.

A pitch energy module comprising one or more ultracapacitors storing electrical energy for a wind turbine emergency pitch energy event. The pitch energy module replaces at least one battery within a battery housing of a wind turbine and interfaces with the existing battery wiring harness to communicate with a control system of the wind turbine. The pitch energy module is installed without further modification to the battery housing or the battery wiring harness.

The invention provides a wind turbine method that includes receiving alarm state data indicating that the wind turbine has entered an alarm state in which operation of the wind turbine has stopped, and receiving sensor data from a plurality of sensors of the wind turbine indicative of operating conditions associated with the wind turbine. When the alarm state data is received, the method includes executing a trained machine learning model based on the received sensor data and the alarm state to obtain an output, where the machine learning model is trained based on historical data associated with a plurality of wind turbines, the historical data being indicative of the plurality of wind turbines previously being in the alarm state. The method includes providing, based on the obtained output, an action to be performed to allow the wind turbine to resume operation.

A control arrangement of a wind turbine includes a watchdog including a reset module and a trigger module, wherein the watchdog reset module is configured to perform an internal reset when a sign-of-life signal is received from a remote communication system within a predetermined time limit, and wherein the watchdog trigger module is configured to issue a watchdog trigger when the predetermined time limit is exceeded; a sensor arrangement including a number of sensors configured to observe local parameters and to report local sensor data; and a wind turbine controller that initiates a local control sequence in response to the watchdog trigger, which local control sequence is configured to switch between a first mode of operation and a second mode of operation on the basis of the local sensor data. A method of operating a wind turbine is further provided.

A system and method are provided for controlling a wind farm during low wind speeds. Accordingly, the farm controller designates at least one of the plurality of wind turbines of the wind farm as a designated turbine. The designated turbine is operating in a full auxiliary mode when the speed of the wind acting on the wind farm is below a wind speed threshold. The remaining wind turbines are operated in a reduced auxiliary mode. The reduced auxiliary mode includes the disabling of at least one of pitching and yawing of the remaining wind turbines. When a power output for the designated wind turbine exceeds a power threshold, the farm controller directs at least one group of the remaining wind turbines to transition from the reduced auxiliary mode to the full auxiliary mode. During certain grid conditions, the transition between auxiliary modes may be delayed.

A method of monitoring a split wind-turbine-converter system with at least one generator-side converter and at least one grid-side converter arranged at distant locations, and a DC-link in the form of an elongated conductor arrangement with at least one positive and at least one negative conductor. The impedance of the DC-link conductor arrangement is determined by means of DC-voltage sensors. The voltages between the positive and the negative conductors are determined at the generator-side converter and at the grid-side converter, and the difference between the voltages is determined. The impedance of the DC-link conductor arrangement is determined by putting the determined voltage difference in relation to the DC current flowing through the DC-link conductor arrangement. If the impedance exceeds a given impedance threshold a fault state is recognized.

A method is provided for controlling the operation of a wind turbine, the wind turbine including a generator, a converter, a converter control unit, a wind turbine controller and a connection device to an external electrical power grid, wherein electrical power generated by the generator is input into the power grid via the converter, wherein the wind turbine controller is configured to determine a fault condition according to a fault condition signal and to active a safe operating mode in response to the fault condition signal indicating a fault condition, wherein the fault condition signal is determined by evaluating changes in an available output power signal generated by the converter control unit, the available output power signal describing the active output power available from the converter.

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.