Research On Structure Vibration And Identification Of Hydropower House

With the rapid development of hydroelectric engineering, the capacity and size of the modern hydrogenerator units are larger and the specific speed of the hydraulic turbine is enhanced markedly. The vibration of powerhouse structure has become an important and ubiquitous problem during its operation and design, and the phenomenon is serious especially in pumped-storage power plants which units are higher-water level, higher rotate speed and higher vibration frequency than the routine units. Therefore, to advanced treat the vibration of powerhouse structure is very important and indispensable. In this paper, combining the finite element analysis and field test of The Ming Tomb Pumped-storage Power Plant, the rational boundary conditions, the average elastic modulus and the dynamic loads are analyzed in turn by system identifying method. All of this fill in the blanks of research on structural vibration of pumped-storage power plant and hydropower house with large-sized generator unit, and reinforce the current design code for hydropower house. The analytical methods and procedures provide a reliable technical support for the structural dynamic calculation, identifying analysis and the establishing of a rational numerical model.In chapter one, the existed problems and current research works on vibration of hydropower house are introduced, and the system identifying methods and its applications is summarized.In chapter two, based on finite element analysis of power house for pumped-storage power plants, in-site vibration experiment and theoretical analysis, the vibration sources of hydro-generating unit supporting structure are studied systematically, and the internal mechanisms and properties of the vibration sources are discussed. At the same time, the boundary conditions, structural parameters and the lumped mass are analyzed. The study is directive to the design of hydropower station.In chapter three, by establishing a coupled finite element model of the machine hall and its auxiliary plant, the travel path of vibration and their behavior are studied, which supply references to vibration isolation and analysis.In chapter four, a dynamic identifying method based on immune operator is researched systemically, and is jointed to the ANSYS Code to establish an optimal immune identifying model.In chapter five, on the basis of the immune identifying model obtained in chapter four and from the aspect of structural vibration of powerhouse, some significant modal parameters (including damping, average elastic modulus, boundary parameters and dynamical loads) are identified and studied. The conclusions give a useful reference for the establishing of a precise numerical model.In chapter six, from the aspect of structural vibration of hydraulic turbine, the dynamical models of flexible rotor-bearing systems are constructed using FEM. A frequency method of identifying the dynamic characteristic parameters of journal bearing and loads on field condition and without artificial excitations is proposed by supposing the hydraulic pulsation on turbine as an equivalent spring force. Some numerical examples demonstrate the validness of the algorithms.