A Novel Multidimensional Frequency Band Energy Ratio Analysis Method for the Pressure Fluctuation of Francis Turbine
A Novel Multidimensional Frequency Band Energy Ratio Analysis Method for the Pressure Fluctuation of Francis Turbine
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DOI：
10.1155/2018/3494785
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发表时间：
2018-01
影响因子：
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通讯作者：
W. Weiyu;Qijuan Chen;Xining Liang;Xuhui Yue;Jinzhou Dou
中科院分区：
文献类型：
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作者：
W. Weiyu;Qijuan Chen;Xining Liang;Xuhui Yue;Jinzhou Dou
压力波动对混流式水轮机的稳定运行有多方面的影响，其影响程度随运行条件的不同而不同。针对混流式水轮机压力波动的分析，提出了一种基于希尔伯特-黄变换的多维频带能量比特征提取方法。首先，利用EEMD将压力波动信号分解为固有模式函数。其次，利用希尔伯特边际谱分析了基函数的频率特性。然后，根据混流式水轮机压力脉动的频率特性，将其划分为高、中、低三个频段。然后计算各频段与原始信号的能量比，实现多维频段能量比的特征提取。实际应用证明，该方法不仅能提取压力波动的时频特征，而且能对压力波动的状态特征进行分析。这是一种提取混流式水轮机压力波动特征的新方法。
The pressure fluctuation has multiple influence on the steady operation of Francis turbine, and the impact degree varies with the operation condition. In this paper, for the analysis of pressure fluctuation in the Francis turbine, a novel feature extraction method of multidimensional frequency bands energy ratio is proposed based on Hilbert Huang Transform (HHT). Firstly, the pressure fluctuation signal is decomposed into intrinsic mode functions (IMFs) by EEMD. Secondly, the Hilbert marginal spectrum is utilized to analyze the frequency characteristics of IMFs. Then, according to the inner frequency of IMFs, each of them is divided into high, medium, or low frequency band which are constructed based on the frequency characteristic of the pressure fluctuations in the Francis turbine. Afterward, the energy ratio of each frequency band to the original signal is calculated, which is to realize the feature extraction of multidimensional frequency band energy ratio. Actual applications verify that this method not only can extract the time-frequency characteristics but also can analyze the condition feature of the pressure fluctuation. It is a novel method for extracting the feature of pressure fluctuation in the Francis turbine.