本文選題：水電機(jī)組 + 過渡過程��； 參考：《工程科學(xué)與技術(shù)》2017年02期

【摘要】：隨著中國水電機(jī)組數(shù)量及裝機(jī)容量的不斷增加,水電機(jī)組啟動過渡過程故障問題也日趨明顯,利用信號分析法對機(jī)組故障診斷得到廣泛的應(yīng)用。利用一種處理非線性非平穩(wěn)信號自適應(yīng)方法——變分模態(tài)分解(Variational Mode Decompostion,VMD),對葛洲壩某臺機(jī)組啟動過渡過程振動信號分析。首先,利用VMD方法對啟動過渡過程仿真振動信號進(jìn)行分析,驗(yàn)證VMD方法處理非線性非穩(wěn)態(tài)信號的有效性。然后,利用該方法對機(jī)組啟動過渡過程實(shí)測振動信號進(jìn)行固有模態(tài)函數(shù)(IMF)的有效分離,通過Hilbert-Huang(HHT)變換對各IMF進(jìn)行瞬時(shí)頻率計(jì)算,得出相應(yīng)的Hilbert譜,并將結(jié)果與經(jīng)驗(yàn)?zāi)B(tài)分解(EMD)方法進(jìn)行對比。從最終的振動信號分析中可以看出,通過VMD分解后的IMF可劃分為3部分:第1部分主要為信號的發(fā)展趨勢;第2部分主要為信號的基礎(chǔ)分解,出現(xiàn)較強(qiáng)的規(guī)律性的"紡錘形"信號,且能夠反映機(jī)組開機(jī)過程的振動變化規(guī)律;第3部分主要為干擾噪音或機(jī)組故障導(dǎo)致的高頻特征信號,信號波形圖無明顯規(guī)律性,對應(yīng)的Hilbert譜也明顯具有主頻波動小,幅值穩(wěn)定等優(yōu)勢。結(jié)果表明:經(jīng)VMD分解后,機(jī)組啟動過渡過程振動信號各分量頻率變化與機(jī)組轉(zhuǎn)速時(shí)變規(guī)律吻合良好,能夠有效提取特征頻率,較EMD具有更好的自適應(yīng)性,分析結(jié)果更加準(zhǔn)確有效,能夠更好地揭示水電機(jī)組過渡過程信號中的振動規(guī)律。
[Abstract]:With the increasing of the number and installed capacity of hydropower units in China, the problem of transient faults in the start-up process of hydropower units is becoming more and more obvious. Signal analysis method is widely used in fault diagnosis of hydropower units. The vibration signal of a unit in Gezhouba during start-up transition is analyzed by means of the variational Mode decomposition (VMD), an adaptive method to deal with nonlinear and non-stationary signals. Firstly, the VMD method is used to analyze the simulated vibration signals in the start-up transition process, and the effectiveness of the VMD method in dealing with nonlinear unsteady signals is verified. Then, the method is used to effectively separate the vibration signals measured during the start-up transition of the unit from the inherent mode function (IMF). The instantaneous frequency of each IMF is calculated by Hilbert-Huang (HHT) transform, and the corresponding Hilbert spectrum is obtained. The results are compared with the empirical mode decomposition (EMD) method. From the final vibration signal analysis, we can see that the IMF after VMD decomposition can be divided into three parts: the first part is the development trend of the signal, the second part is the basic decomposition of the signal. A strong regular "spindle" signal appears and can reflect the vibration variation law of the unit during start-up. Part 3 mainly deals with the high frequency characteristic signal caused by the interference noise or the fault of the unit, and the signal waveform diagram has no obvious regularity. The corresponding Hilbert spectrum also has the advantages of small main frequency fluctuation and stable amplitude. The results show that after VMD decomposition, the frequency variation of vibration signal in the start-up transition process is in good agreement with the time-varying rule of unit rotational speed, and the characteristic frequency can be extracted effectively, which is more adaptive than EMD. The analysis results are more accurate and effective, and can better reveal the vibration law in the transient process of hydropower units.
【作者單位】： 四川大學(xué)水力學(xué)與山區(qū)河流開發(fā)保護(hù)國家重點(diǎn)實(shí)驗(yàn)室水利水電學(xué)院;西華大學(xué)流體及動力機(jī)械省部共建教育部重點(diǎn)實(shí)驗(yàn)室;
【基金】：國家自然科學(xué)基金資助項(xiàng)目(51309172) 西華大學(xué)教育部重點(diǎn)實(shí)驗(yàn)室開放基金資助項(xiàng)目(szjj2013-008) 重慶大學(xué)國家重點(diǎn)實(shí)驗(yàn)室開放基金資助項(xiàng)目(2007DA10512712405)
【分類號】：TV734

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