The Research Of Wavelet Transform Technique Application To Turbine Generator Fault Diagnosis

Turbo-generator is a kind of typical rotation machine. The vibration signature of rotating machinery can be classified to stationary and non-stationary signature. Both of the signatures contain important information that can reflect the working station of rotating machinery. It is valuable to make good use the information on supervising machine working station. In this dissertation, wavelet transform technique (an advanced technique in signature processing) was deeply researched and explored. Turbo-generator fault diagnosis based on wavelet transform technique was implemented. 1. With the study of a great deal of literatures, the methods and theory of rotating machinery fault diagnosis were reviewed orderly. The disadvantage and problem existing in the signature processing methods are pointed out. 2. The latest development of wavelet transform technique is researched. The key technique problems that wavelet transform technique applied to turbine generator fault diagnosis are discussed in depth. 3. In this dissertation, we study the problem of wavelet packet basis (BWPB) and denosing threshold in depth. A new method based on BWPB is presented to denoise vibration signature; What about the selection of denoising threshold, we present a new denoising algorithm which is aimed to reduce the mean square error (MSE) between the reconstructed signal and the original signal. The detection results show that signal denoising applying BWPB method is in favor of enhancing the detection accuracy of turbine faults. 4. In this dissertation, we put forward a new method based on wavelet packet transform (WPT) for vibration monitoring and fault diagnosis of turbo-generator. The WPT is introduced as an alternative means of extracting time-frequency information from vibration signature. The results of WPT coefficients provide one with arbitrary time-frequency resolution of vibration signal. Extensive experiments on rotor laboratorial platform show that the implementation meets the requirement of vibration signals analysis. It is feasible and effective. 5. After the above-mentioned theoretic research organized together, a set of fault diagnosis system is implemented. For the complicated WPT algorithm, we design an effective method based on DSP to meet the real-time requirement of vibration signals analysis. Extensive experiments show that the DSP based application and it is a feasible and effective solution. The system not only can diagnose the turbo-generator fault presented by stationary signature, but also can diagnose the break fault. It can efficiently reduce the fault failed to report and the fault missed to report.