Study On The Vibration Feedback Of The Underground Powerhouse In A Large-scale Hydropower Station

In recent years, in the case of global economic growth, climate change and waterresources increasingly tense, the hydropower as a regenerated energy source, isincreasingly regarded. Over the past over half a century, water conservancy andhydropower business has been rapid development and achieved fruitful results. Butwith the completion and operation of a large number of large-scale, high head, largecapacity western hydropower development project,vibration problems of Turbinegenerator unit and concrete structure induced by hydraulic pulsation are becomingmore prominent, and even endanger the safety of buildings in and around the station.Based on the practical engineering of one underground powerhouse, this paper studiesfield test data and numerical simulation analysis, the main research contents include:(1)Based on the vibration measured data of variable load, start-stop, loadshedding and generator step-up operational test, the amplitude and frequencycharacteristics, the vibration displacement or pulsating pressure changes underdifferent conditions and the vibration status assessment of power house is analyzed.(2)Since powerhouse structure is a complex nonlinear coupled system, thevibration problems are complex dynamic problems. In this paper, the vibration sourceidentification, water-electrical-structure coupled vibration characteristics and thetravel path of unit vibration and current pulse is analyzed by the correlation analysistheory. On this basis, the vibration response of hydropower station can be predictedusing the relevance vector machine regression algorithm.(3)It is so hard to measure excitation sources of powerhouse structural vibr-ation that makes structural mode parameters identification difficult.So this paperpresents an important method(EEMD+RDT+STD) based on environmental excitationthat can effectively alleviate the problem of modal confusion, it is specially fit for thefirst mode parameters of a powerhouse structure.(4)This paper establishes three-dimensional finite element model of undergroundpowerhouse structure and analyzes inherent vibration characteristics and resonancechecking.Basing on the measured vibration displacement data, the feedback analysisof the vertical dynamic load on the unit pier was done. Form the numerical simulation,the response of the powerhouse structure can be known. And the resonance frequency,dynamic responses and stress of underground powerhouse structure under thehydraulic excitation is also analyzed.