Vibration Performance Evaluation Research Of Underground Power Plant

With the rapid development of hydropower construction, the capacity and dimensions ofthe units is larger and the specific speed of the hydraulic turbine is increased markedly, thevibration of units and powerhouse structure has become a important issues for its design andoperation. In particular, a large number of higher-water level and higher-capacitypumped-storage power stations have been built for the regulation of large power, because ofthe characteristics of its higher-water level, higher rotate speed and two-way operation, thevibration phenomenon is more prominent. Therefore, the vibration problems of supportingplant structure can not be ignored. In this paper, combining field test and the finite elementanalysis of one Pumped-storage Power Station, the rational model for the boundary conditionsof powerhouse structure is revised based on the method of modal parameter sensitivityanalysis, and the vibration performance of underground plant structure are evaluatedaccording to structural response of the revised model calculated and field test. Results of thispaper have a positive significance to improve the level of understanding and prediction ofvibration characteristics pumped-storage power station and large conventional power plant,the analysis methods and ideas in this paper can server as technical support and reference forfuture similar vibration calculation, model updating analysis and reasonable construction ofplant model. Specifically, the main contents include:1,In the introduction section, the vibration problems and research survey of pumpedstorage power plant are described, and the method and the research status of vibrationperformance evaluation about the hydropower plant structure is briefly summarizes.2,Based on the achievements of the Pumped-storage power plant structural vibrationresearch, One Pumped-storage Power Station underground plant has been studied, And thefinite element analysis of plant structure is done through ANSYS, the model construction andvibration characteristics of underground plant are studied by numerical calculations, and theboundary conditions that greatly influence the plant numerical model were analyzed,providing a reference and basis for model updating of the underground powerhouse.3,The actual structure of the underground plant is tested on field; based on the prototypeobservation data the vibration source is studied; and the natural features of plant structure isexplored. Vibration source test is conducted under the unit running; the vibration signal isanalyzed to determine its frequency components. Ambient excitation modal testing is adoptedto study the scene mode testing of the complex structure in vibration characteristics test. Field test dates are analyzed to identify the modal parameters of underground plant structures.4,Firstly, the modal parameters of finite element analysis and identified by field testingare contrastively analyzed to determine the model boundary condition stiffness parameters ofthe model updating. Then, the boundary restraint stiffness is determine d based on modalparameter sensitivity analytical method, so as to revise the initial finite element model, and tomake the modified finite element model more realistic and more accurate.5,The response of damage parts in underground plant is calculated by using revisedfinite element model. Combined with the structural response of the field test results, accordingto the current relevant methods and standards for vibration performance evaluating, areasonable vibration performance evaluation is given, which provides a useful reference andideas for the vibration performance evaluation of the similar structure...