Time-frequency analysis method for non-stationary signals in starting process of hydroelectric generating set

The invention discloses a time-frequency analysis method for a non-stationary signal in a starting process of a hydroelectric generating set, which comprises the following steps of: properly reducing sampling frequency, adopting synchronous compression wavelet transform, and analyzing time-frequency characteristics of vibration of the set when the set is started, so as to quantitatively describe a relationship between time and frequency of a vibration time-varying signal and accurately evaluate instantaneous characteristics of the set. Compared with short-time Fourier transform, the method has better frequency domain focusing capacity and can be well suitable for extracting the vibration characteristic frequency in the starting process of the hydroelectric generating set, an analysis result shows that rotating frequencies and obvious frequency multiplication components of all orders exist in a set throw measuring point in the speed increasing process of the set, the frequencies are correspondingly increased a