WIND TURBINE AND METHOD FOR DETECTING LOW-FREQUENCY VIBRATIONS IN AN ELECTRIC SUPPLY NETWORK

摘要

The invention relates to a method for detecting low-frequency vibrations, in particular sub- synchronous resonance, in an electric supply network. The electric supply network has a network voltage with a network nominal frequency. The method has the steps of receiving a first and a second measurement series, in each case for carrying out a frequency analysis, in particular FFT, carrying out a lower frequency analysis for the first measurement series for a lower frequency range, a lower amplitude spectrum being formed for the lower frequency range, carrying out an upper frequency analysis for the second measurement series for an upper frequency range, an upper amplitude spectrum being formed for the upper frequency range, and checking whether a low-frequency vibration component can be identified in the lower amplitude spectrum and checking whether a low-frequency vibration component can be identified in the upper amplitude spectrum. The presence of a low-frequency vibration is reported if a low-frequency vibration component is identified in at least one of the amplitude spectrums.