Study On Natural Vibration Characteristics And Dynamic Response Of Hydropower Station

Hydropower development in southwest China accounts for 70 to 75 percent of the country’s total.In the southwestern basin,a large number of large-scale hydropower plants are being planned or built.Among them,the single installed capacity of baihetan reaches 1000MW.The increase of single machine capacity will ineviTablely bring new problems to the organization design of each department of the plant.The structure and function of the hydropower station building vibrates during operation,but the unit capacity and size increase and the hydropower station floor board also vibrates.The unit size is relatively large,the pulsating energy of water fl,ow increases,the stiffness of structural support decreases,and the pulsating water flow easily causes the vibration of the structure,which increases the resonance risk.The hydropower station that will be built in the future is bound to develop in the direction of large capacity,large structure size and high head height.Taking the plant of sanhekou project as an example,the source and frequency of vibration caused by structural vibration are studied.Study on the vibration characteristics of the whole structure and the local structure of the plant.The dynamic response analysis of the structure of the plant under the vibration load of the unit is carried out.It is found that under the action of vibration load of the unit,the vertical dynamic displacement of each structure of the plant is larger near the pier,especially near the stator foundation.The deformation concentration is obvious near the vertical dynamic load area.Carry out dynamic analysis of each part of the plant under the influence of pu’lsating pressure.It is found that the dynamic stress caused by pulsating pressure is mainly concentrated in the area of the flow channel under the direct action of pulsating pressure,and the dynamic stress value is not large.Under the combined action of unit vibration and pulsating pressure,the stress mainly appeared in the vicinity of stator foundation and undercarriage foundation in the piers wind shield structure,while the stress level of the steel lining such as the volute and tail pipe was improved when the pulsating pressure acted alone.