A method is described for the early identification of material fatigue in drive train components of a wind turbine installation. In particular, a signal, representing revolutions per minute of a wind turbine shaft, is obtained and modulated by the azimuth angle measurement of the turbine blade. This signal is band passed at twice the frequency of rotation and Fourier transformed to extract amplitude values. An alert response can then be triggered when it is determined that there has been a change in a characteristic of the amplitude values such as the amplitude values increasing beyond a multiple of a determined baseline amplitude value.

Wind turbine cable connector monitoring method and device for monitoring a connector (1) attached to cable (4). A temperature sensor (6) is provided for sensing a measured temperature at a position a known distance along the cable (4) from the connector (1). A controller (8,19) records the measured temperature from the temperature sensor (6) while the connector (4) is in use, and identifies a potential fault condition in the connector (4) based on the measured temperature and the position the known distance along the cable (4) from the connector (1).

Prestressing device designed to be inserted into a hole in a component to suppress an ovalization of the hole when the component is loaded is provided. The device includes a sleeve and a tensioning mechanism, wherein the device is designed to be inserted into the hole along an insertion axis and the tensioning mechanism is designed to deform the sleeve in such a way, that the diameter of the outer surface of the sleeve in the radial direction with respect to the insertion axis can be increased from a first diameter to a second diameter in at least one axial section of the sleeve.

A method is for testing a functionality of a system of a wind turbine. The system includes an electro-mechanical actuator, an energy storage unit, and an energy dissipating element connectable to the energy storage unit for selectively transferring energy from the energy storage unit to the energy dissipating element. The method includes: providing first information representative of an operating mode of the system, and, if the operating mode is a test mode: causing a discharging of energy from the energy storage unit and a supply of at least a portion of the discharged energy to the energy dissipating element; receiving measurements being representative of a state of at least one of the energy storage unit and the energy dissipating element during the discharging and the supply; and determining a functionality of at least one of the energy storage unit and the energy dissipating element based on the measurements.