Impact-rub fault feature extraction for generation unit using improved second generation wavelet algorithm

To extract impact-rub fault feature of generation unit, an improved second generation wavelet algorithm is presented to extract fault feature in time domain. This algorithm is based on second generation wavelet, and the equivalent filters are constructed to analyze frequency band aliasing causes. Using data-based optimization algorithm, the prediction operator and update operator which lock on to the dominant signal structure at every level are designed. Applying Fourier transform method, the high-order polynomial signal structure in approximation signal is eliminated and leaving only the low-order signal structure, the low-order polynomial signal structure in detail signal is removed and preserving only the high-order polynomial signal structure, and the signal characteristics in time domain at the corresponding frequency band are well revealed. Simulative and engineering results confirm the advantage of improved second generation wavelet algorithm over second generation wavelet for feature extraction, and the typical features of impact-rub of turbo-generation unit in time domain are desirably extracted by improved second generation wavelet algorithm.