發(fā)布時間：2018-06-08 08:01

  本文選題：大容量火電機(jī)組 + 軸系振動特性��； 參考：《華北電力大學(xué)》2014年博士論文

【摘要】：隨著我國經(jīng)濟(jì)的快速發(fā)展,用電負(fù)荷的峰谷差逐漸增大。近些年來,針對越來越高的節(jié)能環(huán)保要求,我國火力發(fā)電設(shè)備經(jīng)過了上大壓小的產(chǎn)業(yè)結(jié)構(gòu)調(diào)整,投運(yùn)了大量600MW及以上的大容量火電機(jī)組。我國新能源發(fā)電的快速發(fā)展,也對電網(wǎng)的負(fù)荷變化產(chǎn)生新影響。在這種背景下,參與調(diào)峰運(yùn)行的火電機(jī)組容量不斷增加,許多大容量火電機(jī)組也投入到調(diào)峰運(yùn)行的行列,根據(jù)電網(wǎng)的負(fù)荷需求在較大范圍內(nèi)進(jìn)行負(fù)荷調(diào)節(jié)�；痣姍C(jī)組參與寬負(fù)荷范圍調(diào)峰運(yùn)行的關(guān)鍵問題是對電網(wǎng)負(fù)荷快速變化的適應(yīng)性和低負(fù)荷下運(yùn)行的穩(wěn)定性。我國大容量火電機(jī)組通常以承擔(dān)中問負(fù)荷為主進(jìn)行設(shè)計,這類機(jī)組參與調(diào)峰運(yùn)行,由于運(yùn)行工況條件發(fā)生變化,出現(xiàn)較多極端運(yùn)行工況,可能帶來軸系結(jié)構(gòu)熱應(yīng)力、變形、軸系振動和穩(wěn)定性等方面的新問題,導(dǎo)致設(shè)備存在重大安全隱患。提高大容量火電機(jī)組在寬范圍負(fù)荷快速變動條件下的運(yùn)行安全性是發(fā)電行業(yè)急需解決的關(guān)鍵技術(shù)問題。 大容量火電機(jī)組參與調(diào)峰所帶來的運(yùn)行安全穩(wěn)定性問題在我國更加突出,原因是我國在機(jī)網(wǎng)兩側(cè)的條件與西方國家存在差異,而這方面尚缺少深入的研究。本文針對大容量火電機(jī)組的特殊性,以600MW汽輪發(fā)電機(jī)組為對象,在國家和企業(yè)科技項目的支持下,深入開展大范圍變負(fù)荷運(yùn)行條件下的機(jī)組軸系動態(tài)特性與穩(wěn)定性、故障狀態(tài)下的振動特性及故障特征提取方法等方面的研究,對于提高機(jī)組參與調(diào)峰運(yùn)行的安全可靠性具有重要的科學(xué)和工程實際意義。 論文的主要研究內(nèi)容及成果如下： (1)600MW機(jī)組結(jié)構(gòu)及運(yùn)行特點(diǎn)分析。結(jié)合兩個細(xì)則,分析了AGC運(yùn)行方‘式對汽輪機(jī)壽命、材料及軸系振動特性的影響,對大容量火電機(jī)組振動監(jiān)測保護(hù)系統(tǒng)(TSI系統(tǒng)和TDM系統(tǒng))的技術(shù)現(xiàn)狀進(jìn)行綜述；針對某600MW亞臨界火電機(jī)組,利用實際運(yùn)行數(shù)據(jù)分析了自動發(fā)電控制(AGC)運(yùn)行方式下,機(jī)組負(fù)荷、主汽壓力、主汽流量變化對于汽輪機(jī)軸系振動的擾動。從運(yùn)行數(shù)據(jù)反映的長期趨勢看,機(jī)組快速變化負(fù)荷對高中壓缸兩端軸承振動產(chǎn)生一定影響。從瞬態(tài)振動數(shù)據(jù)分析來看,負(fù)荷變化對振動信號波形、頻譜構(gòu)成影響不明顯,沒有改變高中壓轉(zhuǎn)子的振動狀態(tài)。 (2)軸系振動特性的計算分析。以國產(chǎn)典型600MW火電機(jī)組為對象,分別用傳遞矩陣法和有限元法對軸系彎振和扭振固有特性、快速變負(fù)荷狀態(tài)下的軸系扭振響應(yīng)特性、發(fā)電機(jī)兩相短路故障下的軸系扭振響應(yīng)特性進(jìn)行了仿真計算和比較研究。分析結(jié)果表明,600MW機(jī)組的軸系扭振危險軸段均位于各轉(zhuǎn)子之間的連接部位：在快速升降負(fù)荷時,軸系扭矩響應(yīng)呈現(xiàn)衰減振蕩特性,表明機(jī)組在快速升負(fù)荷時軸系處于穩(wěn)定狀態(tài)；兩相短路故障的扭矩響應(yīng)中,一、二階扭振固有頻率處的峰值最突出,工頻及其二次諧波也比較明顯,存在共振風(fēng)險。因此兩相短路故障對軸系安全性影響較大。 (3)汽輪機(jī)瞬態(tài)過程的軸系異常振動分析。通過實際案例,對大容量火電機(jī)組出現(xiàn)的異常振動現(xiàn)象進(jìn)行分析,探討異常振動的響應(yīng)特性,研究提取故障特征的信號分析方法,為進(jìn)行軸系故障診斷提供依據(jù)。研究了某600MW機(jī)組高中壓轉(zhuǎn)子發(fā)生的緩慢熱變形現(xiàn)象的振動特征,確定了導(dǎo)致轉(zhuǎn)子熱變形的原因,。提出了一種基于Gabor變換時頻域濾波的提取振動信號中特殊頻率成分,進(jìn)行軸系穩(wěn)定性分析和故障判斷的方法。通過對升降速過程的振動信號、氣流激振導(dǎo)致的不穩(wěn)定振動信號的分析,證明了該方法的效果。 (4)汽輪機(jī)碰磨故障監(jiān)測診斷方法研究。汽輪發(fā)電機(jī)組發(fā)生輕微動靜部件碰磨故障時,相對軸振響應(yīng)信號中的故障信息非常微弱。針對這一特點(diǎn),提出采用結(jié)構(gòu)振動檢測和信號分析處理相結(jié)合的碰磨故障監(jiān)測診斷新方法,該方法利用碰磨引起的較高頻率的沖擊振動能量信息,適用于碰磨這類具有瞬時沖擊特征的異常振動。由于相對軸振監(jiān)測對碰磨引起的沖擊振動響應(yīng)不敏感,提出一種采用小波奇異值檢測碰磨沖擊故障的方法,用小波多分辨率分析獲取在特定尺度上的碰磨瞬時沖擊信號,提取該瞬時沖擊信號的幅值包絡(luò),然后采用小波奇異值檢測方法對碰磨引起的突變信息進(jìn)行檢測,可以明顯改善微弱碰磨故障特征的提取效果。 (5)汽輪機(jī)振動源的盲分離方法研究。采用頻域ICA分析方法對多臺大容量汽輪機(jī)組進(jìn)行了多通道軸振信號振源分離,結(jié)果表明頻域ICA能夠更清楚地給出源信號的描述,分離結(jié)果更符合汽輪機(jī)轉(zhuǎn)子系統(tǒng)振動源的實際情況。頻域ICA可以分離出軸振測量信號中包含的可能很微弱的故障信息,分離結(jié)果的物理意義比較清晰明確。研究了利用單通道振動實測信號的ICA特征提取方法,結(jié)果表明,僅僅依靠單通道ICA分離出的基函數(shù)不足以反映機(jī)組運(yùn)行狀態(tài)的變化,需要進(jìn)一步對各個基函數(shù)進(jìn)行處理,驗證其作為特征信息的有效性。
[Abstract]:With the rapid development of China's economy, the peak and valley difference of electric load has gradually increased. In recent years, in view of the increasing demand for energy saving and environmental protection, China's thermal power generation equipment has been adjusted to the large pressure and small industrial structure, and a large number of large capacity thermal power units have been transported to 600MW and above. Load change has a new effect. Under this background, the capacity of thermal power units involved in peak load regulation is increasing, and many large capacity thermal power units are also put into the ranks of peak load regulation. Load regulation is carried out in a large range according to the load demand of power grid. The key problem of the power generating unit to participate in the wide negative load range regulation is the negative power grid. The capacity of large capacity thermal power units in China is usually designed by the medium load, which is involved in peak load regulation. Because of the change of operating conditions, many extreme operating conditions may occur, which may bring about the thermal stress, deformation, shafting vibration and stability of the shaft system. It is a key technical problem to improve the operation safety of large capacity thermal power unit under the condition of wide range load rapid change.
The problem of operation safety and stability caused by the participation of large capacity thermal power unit in peak regulation is more prominent in our country. The reason is that the conditions on both sides of the machine network are different from the western countries, but this aspect is still lacking in deep research. In this paper, the 600MW Turbo generator set is the object of the large capacity thermal power unit, and the state and enterprise are in the state and enterprise. Under the support of scientific and technological projects, it is of great importance to study the dynamic characteristics and stability of the shaft system under the condition of large variable load operation, the vibration characteristics and the method of fault feature extraction under the condition of failure. It is of great importance to improve the safety and reliability of the unit to participate in the operation of peak regulation.
The main contents and achievements of this paper are as follows:
(1) analysis of the structure and operation characteristics of 600MW unit. Combined with two detailed rules, this paper analyzes the influence of AGC running formula on the life of steam turbine, the vibration characteristics of materials and shafting, and describes the technical status of the vibration monitoring and protection system of large capacity thermal power unit (TSI system and TDM system), and the actual operation of a 600MW subcritical thermal power unit. The data analyzed the disturbance of turbine shafting vibration under the operating mode of automatic generation control (AGC), unit load, main steam pressure, and main steam flow change. From the long-term trend of operation data, the rapid change load of the unit has a definite influence on the vibration of the bearing at both ends of the high and high pressure cylinder. It has no obvious effect on vibration signal waveform and spectrum structure, and does not change the vibration state of high and medium pressure rotor.
(2) the calculation and analysis of the vibration characteristics of the shaft system. Taking the domestic typical 600MW thermal power unit as the object, the natural characteristics of the bending vibration and torsional vibration of the shaft system, the torsional vibration response characteristic of the shaft system under the fast load condition and the response characteristic of the axial torsional vibration under the two phase short circuit fault of the generator are simulated and compared. The analysis results show that the torsional vibration hazard axis of the shaft system of the 600MW unit is located in the connection position between the rotors. In the fast lifting and lifting load, the torque response of the shaft system presents a attenuation oscillation characteristic, which indicates that the shaft is in a stable state at the rapid load rise, and the first and two natural frequencies of the torsional vibration in the two phase short circuit fault are in the torque response. The peak value is the most prominent, the power frequency and its two harmonics are also obvious, and there is a resonance risk. Therefore, the two phase short circuit fault has great influence on the safety of shafting.
(3) the abnormal vibration analysis of the shaft system in the transient process of the steam turbine. Through the actual case, the abnormal vibration phenomenon of the large capacity thermal power unit is analyzed, the response characteristic of the abnormal vibration is discussed, the signal analysis method of extracting the characteristics of the fault is studied to provide the basis for the fault diagnosis of the shaft system. The high school pressure rotor of a 600MW unit is studied. The cause of the thermal deformation of the rotor is determined by the vibration characteristics of the slow thermal deformation. A method based on the Gabor transform time frequency domain filtering is proposed to extract the special frequency components of the vibration signals and carry out the analysis of the stability of the shafting and the fault judgment. The analysis of the signal proves the effect of the method.
(4) study on the fault monitoring and diagnosis method of the Turbine rubbing fault. The fault information in the relative axis vibration response signal is very weak when the turbine generator unit occurs a slight moving and static part rubbing fault. A new method of monitoring and diagnosis of the rubbing fault is proposed by combining the structural vibration detection with the signal analysis and processing. The high frequency shock vibration energy information is applied to the abnormal vibration with instantaneous impact characteristics of the rubbing. Due to the insensitivity of the relative axial vibration monitoring to the impact vibration response caused by the rubbing, a method of wavelet singular value detection for the impact failure of the rubbing is proposed, and the wavelet multi-resolution analysis is used to obtain the specific scale on the specific scale. The instantaneous impact signal of the rubbing is extracted and the amplitude envelope of the instantaneous shock signal is extracted. Then the wavelet singular value detection method is used to detect the mutation information caused by the rubbing, which can obviously improve the extraction effect of the characteristics of the weak rubbing fault.
(5) the blind separation method of the steam turbine vibration source. The frequency domain ICA analysis method is used to separate the multi channel vibration signal source of the multi channel shaft vibration signal. The result shows that the frequency domain ICA can give the description of the source signal more clearly. The separation result is more consistent with the actual situation of the vibration source of the turbine rotor system. The frequency domain ICA can be separated. The physical meaning of the separation results is clear and clear. The ICA feature extraction method using the single channel vibration measured signal is studied. The results show that the base function separated by only single channel ICA is not enough to reflect the change of the operating state of the unit. A base function is processed to verify its effectiveness as feature information.
【學(xué)位授予單位】：華北電力大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TM311

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本文編號：1995243