1000WM Hydroelectric Generator Sets’ Vibration Analysis And Stiffness And Strength Research

With the vigorous development of China’s hydropower construction, installedcapacity of hydropower generating units increase gradually, the structure ofhydroelectric generator also increases in size. Whether the stiffness and strength ofthe generator sets meet the requirements of a variety of running conditions, andwhether the vibration of power generator sets while running avoids its naturalfrequency, so as to achieve the state standards. These have become our concern andproblems to be solved. The thesis is based on the needs of the project of HarbinElectrical Machinery Plant, and hope that through the powerful modeling andanalysis capabilities of business finite analysis software achieve a comprehensivetesting of hydro sets.Through the finite element models’ establishment of hydroelectric generatorsets’ stator, stator frame,upper bracket, rotor, rotor bracket and lower bracket,analyzing their stiffness and strength under different running conditions of thevarious components of the generator sets by using ANSYS software in order to getcomponents of stress and strain distribution, and check it according to stressassessment criteria given by the Harbin Electrical Machinery Plant. The calculationshows that the design could ensure hydropower generating units operating normallyand safely in level of stiffness and strength.The trials and research of BaihetanHydropower units provide an important reference for its structural design.After the stator and upper bracket joint finite element model are established,andresearch structural dynamics analysis of components, in order to get their vibrationsituation and see whether they have the resonance happens. If the components of thevibration frequency avoid the exciting frequency effectively, and then thecomponents meet the vibration requirements. Separately considering the vibration ofthe lower bracket, which is mainly affected by the axial vibration,so calculate itsaxial natural frequency by ANSYS, and observe whether it can avoid theinterference frequency within a certain range in order to determine whether it meetthe design requirements or not.In addition to separately considering the various components of vibration,the paper also do the whole hydroelectric generating set dynamic characteristicsresearch which is taking into account the hydropower units-foundation interactionThis is less involved in part of studies of hydropower units. the dynamic interactionproblems of structure and foundation has been an important research topic in theactual project.There are basically two methods: one is the direct finite elementmethod, and the other is the substructure method. Direct finite element method is toestablish the structural finite element model, and to take into account the foundationof a certain size or to consider using the boundary element to simulate thefoundation. The substructure method is that structure and foundation are treated astwo different substructure,after foundation of the complex frequency influencecoefficient is resolved and solving its dynamic response which is coupled withstructure.The structure and foundation interaction is equal to increase additionalstiffness matrix and the additional damping matrix in motion equation of thestructure. To establish the structure’s dynamic calculation model,using direct finiteelement method by considering the structure and foundation interaction. Consideringthe range of the foundation,the size is taken as one, two, three, five times thestructure height in turn.The larger the foundation’s size,the smaller the naturalfrequency of structure, but the magnitude of the natural vibration frequencydecreases with the foundation’s size increases to gentle.The foundation calculateddynamic characteristics has larger difference in considering the foundation or not.