Research On Coupled Dynamic Characteristics And Vibration Transfer Path Of Generator Set And Hydropower House

The coupled dynamic characteristics between generator set and hydropower house is complicated,which consits linear and nonlinear relation,and the vibration of generator set and hydropower house is related to hydraulic,mechanical,electromagnetic and other factors.Based on the prototype observation data of underground powerhouse in a large domestic hydropower station,the paper sdudied the coupled dynamic characteristics and vibration transfer path of generator set and hydropower house.The main research contents and conclusions of the paper are as follows:(1)The analysis of main vibration source.The measured source of vibration is classified according to the theoretical frequencies of various vibration sources.The paper analyse the primary and secondary frequency from statistic point of view and the energy proportion of different vibration components in generator set and hydropower house.The main source of generator set and hydropower house is confirmed,which consists low frequency fluctuation of tail water,generator running,non-uniform flow field in the volute.(2)The research on coupled dynamic characteristics between generator set and hydropower house.The complicated coupled dynamic characteristics between generator set and hydropower house is studied in these three aspects: the characteristics of horizontal and vertical vibration varying with the loads of generator set,the correlation coefficient of horizontal and vertical vibration under different loads of generator set,the correlation in time and frequency domain of horizontal and vertical vibration.The conclusions are as follws: the synchronicity and correlation of vertical vibration is stronger,the vertical vibration correlation with frequency range in low frequency fluctuation of tail water is stronger than other frequency range,the vertical coupling relation between generator set and hydropower house is establish by low frequency fluctuation of tail water;the synchronicity and correlation of horizontal vibration is weaker,the horizontal vibration correlation with frequency range in rotating frequency and low frequency fluctuation of tail water is stronger than other frequency range,the horizontal coupling relation between generator set and hydropower house is establish by low frequency fluctuation of tail water and generator running.(3)The research on vibration transfer path of rotating frequency and vortex belt.The signal of vortex belt and rotating frequency is obtained by wavelet decomposition and reconstruction.The paper combine the adaptive wavelet threshold de-noising method based on EMD and the transfer entropy method,which can identify the vibration transmission path of powerhouse in hydropower station.The conclusions are as follws:(a)The main transmission path of vertical vibration caused by the vortex belt is as follows: the head cover of turbine→turbine pier →generator floor slab,39.8% of vortex belt information transmit from head cover of turbine to the foudation of stator,58.2% of vortex belt information transmit from head cover of turbine to the foudation of lower bracket,23.5% of vortex belt information transmit from the foudation of stator to the generator floor slab,16.1% of vortex belt information transmit from the foudation of lower bracket to the generator floor slab;(b)The main transmission path of the horizontal vibration of the lower bracket is as follows: the lower bracket→turbine pier→the pillars in electrical floor slab.75.9% of rotating frequency information transmit from the lower bracket to the foudation of lower bracket,18.4% of rotating frequency information transmit from the lower bracket to the foudation of stator,19.5% of vrotating frequency information transmit from the foudation of stator to the pillars in electrical floor slab,8.6% of rotating frequency information transmit from the foudation of lower bracket to the pillars in electrical floor slab.