WIND TURBINE AND METHOD FOR DETECTING LOW-FREQUENCY OSCILLATIONS IN AN ELECTRICAL SUPPLY GRID

A method for detecting low-frequency oscillations, in particular subsynchronous resonances, in a grid is provided. The method includes recording a series of measurements, having measurement points, of a grid variable over a measurement time period, for performing a frequency analysis and multiplying the series a time-dependent sinusoidal test function for the same measurement time period. The test function is characterized by a test frequency and a test angle as phase angle. The series for each measurement point is multiplied by the test function in order to obtain a test product for each measurement point. The method includes adding the test products taking into consideration the mathematical sign thereof to give a product sum, and evaluating, depending on the product sum, whether the series of measurements has a low-frequency oscillation having a frequency in the region of the test frequency and a phase angle in the region of the test angle.