Abstract: A method for monitoring a wind turbine is provided. The method includes defining at least one subsystem of the wind turbine and providing a simulation model for the at least one subsystem. During normal operation of the wind turbine at least an input parameter of the at least one subsystem is determined a behavior of the at least one subsystem is simulated using the at least one input parameter as an input of the simulation model. Based on the simulated behavior, it is determined, if the at least one subsystem operates within a given specification.

Abstract: A method for monitoring a wind turbine is provided. The method includes defining at least one subsystem of the wind turbine and providing a simulation model for the at least one subsystem. During normal operation of the wind turbine at least an input parameter of the at least one subsystem is determined A behavior of the at least one subsystem is simulated using the at least one input parameter as an input of the simulation model. Based on the simulated behavior, it is determined, if the at least one subsystem operates within a given specification.

Abstract: A method for the operation of a wind energy plant with a rotor, which transfers a driving moment to a generator via a drive train, wherein the generator provides a pre-settable generator moment acting opposite to the driving moment and is connectable to a grid, characterised in that after a sudden voltage change in the grid, the generator moment is controlled depending from the phase position of a torsional vibration of the drive train.

Abstract: A method for the operation of a wind energy plant with a rotor, which transfers a driving moment to a generator via a drive train, wherein the generator provides a pre-settable generator moment acting opposite to the driving moment and is connectable to a grid, characterised in that after a sudden voltage change in the grid, the generator moment is controlled depending from the phase position of a torsional vibration of the drive train.

Abstract: A method for temperature calibration of a strain sensor for a rotor blade of a wind turbine is provided, the method including operating the wind turbine in a mode in which substantially no bending of the rotor blade due to wind occurs, repeatedly measuring gravitationally induced bending moments of the rotor blade for a plurality of temperatures measured at the place of the strain sensor, determining a temperature dependency of the strain sensor on the temperature, calibrating the strain sensor based on the determined temperature dependency of the strain sensor such that the temperature dependency of the strain sensor is compensated.

Abstract: A method for the determination of a strain of a wind energy plant (30), with the following steps: presetting an assignment code, which assigns a characteristic value (K) for the strain of the wind energy plant to each pair of variates of a value for a wind velocity and a value for an acceleration of a component of the wind energy plant, determining a value (v?), which represents a measured wind velocity v, determining a value (a?), which represents a measured acceleration a of a component of the wind energy plant, applying the assignment code to the pair, of variates of the value (v?) for the measured wind velocity v and the value (a?) for the measured acceleration a in order to determine the characteristic value (K) for the strain.