A method for controlling a wind turbine system connected to a power grid. The method comprises generating a wind turbine control signal based on a power control reference for controlling a power output of a wind turbine; monitoring an electrical frequency of the power grid; in response to detecting a change in the frequency in the power grid, activating a fast frequency support method comprising the steps of; adjusting the power control reference to cause an overproduction of power by the wind turbine; the overproduction of power causing a transfer of inertial kinetic energy from the wind turbine to electrical power; wherein the power control reference is determined by applying an adaptive gain function to a measurement of a difference in grid frequency from a nominal level.

Provided is a method of controlling a wind turbine during damping a mechanical oscillation of the wind turbine having a generator system coupled to a rotor at which plural rotor blades are mounted, the method including: generating a damping control signal in dependence of an indication of the oscillation; performing damping control of the generator system based on the damping control signal causing damping related power output variation at an output terminal of the generator system; and controlling an energy storage device connected to the output terminal of the generator system and connected to an output terminal of the wind turbine based on the damping control signal.

A method for controlling a power output of a power generating unit includes receiving at least two measurement data sets from a location of integration of a power generating unit to an electrical grid. Each measurement data set includes a plurality of electrical parameters. The method further includes generating a grid model of the electrical grid based on the at least two measurement data sets. The grid model is characterized by an equivalent grid voltage and an equivalent grid impedance. The method further includes computing a strength value of the electrical grid based on the grid model, using the at least two measurement data sets. The method also includes controlling the power output of a power generating unit based on the strength value of the electrical grid.

A method for controlling a wind power installation or a wind farm is provided. The method includes establishing that there is a grid fault within an electrical power supply grid operated by a grid operator and to which the wind power installation or the wind farm is electrically connected via a point of common coupling; switching electrical switches of the wind power installation or the wind farm using a control unit of the wind power installation or the wind farm which is operated by a low-voltage power supply, so that the wind power installation or the wind farm is voltage-free; testing an electrical store for ensuring the low-voltage power supply once the grid fault has been established; and switching further electrical switches of the wind power installation or the wind farm to a predefined switching state in which start-up of the wind power installation or the wind farm is possible.

It is provided a wind turbine and methods of operating a wind turbine as described herein.

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 of operating at least one wind turbine including: receiving a first signal which is indicative of a level of a remuneration for electrical energy, which is fed currently and/or in the future into a grid to which the wind turbine is connected, producing a control signal dependent on the first signal, and controlling the wind turbine with the control signal for generating power of the wind turbine, that is dependent on the control signal. A wind turbine and a central control for carrying out such a method and a system comprising a central control and a plurality of wind turbines.

A method of generating power. An airborne power generating craft is connected to an anchor using a tether line. The anchor is secured to an underwater floor. Power is generated based on movement of the airborne power generating craft in response to a wind force. The tether line is maintained at a constant length between the airborne power generating craft and the anchor as the airborne power generating craft moves in response to the wind force. The airborne power generating craft is connected to an electrical transmission system through at least part of the tether line. The generated power is transmitted to the electrical transmission system. A condition is sensed in which transmitting power to the electrical transmission system is not desired. The airborne power generating craft is electrically isolated to prevent power from being transmitted from the airborne power generating craft to the electrical transmission system.

A wind farm comprises a plurality of wind turbines connected to a network internal to the wind farm, a network feed-in point in the network internal to the wind farm for feeding electrical power into a supply network, a control device associated with the network feed-in point designed to control the wind turbines feeding power into the supply network by the network feed-in point on the basis of measured values recorded at the network feed-in point, and at least one additional network feed-in point having an additional control device designed to control the wind turbines feeding power into the supply network by the additional network feed-in point on the basis of measured values recorded at the additional network feed-in point, wherein the network internal to the wind farm is designed to variably connect at least one wind turbine to one of the plurality of network feed-in points.