Abstract: Provided is a method for controlling a wind power system, that is to say a wind power installation or a wind farm comprising a plurality of installations, for feeding electrical power from wind into an electrical supply grid, and for damping low-frequency oscillations, in particular subsynchronous resonances, in the grid, wherein the grid has a line voltage with a nominal line frequency, wherein a damping control with a closed control circuit is used for damping the low-frequency oscillations, and the damping control for damping the low-frequency oscillations controls a feed-in of electrical power into the grid using a wind system control, the damping control is designed for a controlled system comprising the grid, the wind power system, and the wind system control, or parts thereof, wherein the damping control is designed such that it prevents and/or damps weakly damped modes in the closed control circuit.

Abstract: Provided is a method for identifying low-frequency oscillations, in particular subsynchronous resonances, in an electrical supply network, wherein the electrical supply network has a line voltage with a nominal line frequency, comprising the steps: detecting at least one electrical signal of the electrical supply network as at least one test signal and filtering and/or transforming the at least one detected test signal into at least one check signal, temporal derivation of the at least one check signal or difference formation of temporally separated values of the check signal, in order to obtain a gradient signal in each case, identifying the presence of a low-frequency oscillation if the gradient signal or at least one of the gradient signals meets a predetermined check criterion, in particular at least one predetermined check limit is exceeded.

Abstract: A method for controlling a wind farm to damp low-frequency electrical oscillations, in particular subsynchronous resonances, in an electrical supply grid having a grid voltage with a nominal grid frequency is provided. The wind farm comprises at least one wind turbine connected to the electrical supply grid.

Abstract: Provided is a method for controlling a wind power system, that is to say a wind power installation or a wind farm comprising a plurality of installations, for feeding electrical power from wind into an electrical supply grid, and for damping low-frequency oscillations, in particular subsynchronous resonances, in the grid, wherein the grid has a line voltage with a nominal line frequency, wherein a damping control with a closed control circuit is used for damping the low-frequency oscillations, and the damping control for damping the low-frequency oscillations controls a feed-in of electrical power into the grid using a wind system control, the damping control is designed for a controlled system comprising the grid, the wind power system, and the wind system control, or parts thereof, wherein the damping control is designed such that it prevents and/or damps weakly damped modes in the closed control circuit.

Abstract: Provided is a method for identifying low-frequency oscillations, in particular subsynchronous resonances, in an electrical supply network, wherein the electrical supply network has a line voltage with a nominal line frequency, comprising the steps: detecting at least one electrical signal of the electrical supply network as at least one test signal and filtering and/or transforming the at least one detected test signal into at least one check signal, temporal derivation of the at least one check signal or difference formation of temporally separated values of the check signal, in order to obtain a gradient signal in each case, identifying the presence of a low-frequency oscillation if the gradient signal or at least one of the gradient signals meets a predetermined check criterion, in particular at least one predetermined check limit is exceeded.

Abstract: A method for controlling a wind farm to damp low-frequency electrical oscillations, in particular subsynchronous resonances, in an electrical supply grid having a grid voltage with a nominal grid frequency is provided. The wind farm comprises at least one wind turbine connected to the electrical supply grid.

Abstract: A method for operating a wind turbine (WEA), which has a generator for supplying electric power to an electric supply grid, is provided. After being operated in a first operating state with a first power output and a first rotational speed, the wind turbine is set to a second operating state with a second power output and a second rotational speed. In order to set the wind turbine to the second operating state, an aerodynamic power output which is available for supply is determined, a target rotational speed is determined from the available output, and a target output to be set for the generator is specified from the target rotational speed.

Abstract: A method for operating a wind turbine (WEA), which has a generator for supplying electric power to an electric supply grid, is provided. After being operated in a first operating state with a first power output and a first rotational speed, the wind turbine is set to a second operating state with a second power output and a second rotational speed. In order to set the wind turbine to the second operating state, an aerodynamic power output which is available for supply is determined, a target rotational speed is determined from the available output, and a target output to be set for the generator is specified from the target rotational speed.