Transient Hydraulic Pressure Fluctuation Analysis of a Hydroturbine via Ensemble Empirical Mode Decomposition
Hydroturbines are the key asset in hydroelectric power stations,and their monitoring and diagnosis play an important role in the asset management and maintenance.Hydraulic pressure fluctuation is inevitable during the operation of hydroturbines.It has nonstationarity during transient processes.The hydraulic pressure fluctuation signal measured in the draft tube of an axial-flow hydroturbine during a start-up transient process is analyzed based on ensemble empirical mode decomposition and Hilbert spectrum.The frequency components and their time evolution with the operating conditions are identified.A dominant low frequency component waxing and waning around a constant smaller than the rated rotating frequency exists throughout the transient process,indicating the possible occurrence of vortex core.Both the amplitude and the frequency are time varying,and are closely related to the operating conditions,especially the guide vane opening and switch,but they are not dominated by the speed.The closure and opening of guide vane and the on-off switching ofhydroturbine can result in large amplitude pressure fluctuation,even the pressure surges or impulses in draft tube,which may excite the resonance of some parts and destroy the operating stability.The Hilbert spectrum based on ensemble empirical mode decomposition is suitable to analyze the nonstationary hydraulic pressure fluctuation signals of low frequency.
Hilbert-Huang Transform Ensemble Empirical Mode Decomposition Time-frequency Analysis Nonstationary Signal Hydroturbine Transient Process Pressure Fluctuation Draft Tube
Canxun Du Weihua Gui Zhikun Hu
School of Information Science and Engineering,Central South University,No.932 Lushannan Road,Changsh School of Physics and Electronics,Central South University,No.932 Lushannan Road,Changsha410083,Huna
国际会议
沈阳
英文
1755-1760
2012-09-26（万方平台首次上网日期，不代表论文的发表时间）