【摘要】：同步發(fā)電機(jī)在擾動后的動態(tài)運(yùn)行能力對于系統(tǒng)安全穩(wěn)定運(yùn)行具有重要意義。本文建立了用于研究擾動條件下發(fā)電機(jī)運(yùn)行能力的時步有限元模型,研究了汽輪發(fā)電機(jī)轉(zhuǎn)子復(fù)雜阻尼結(jié)構(gòu)及其材料特性對系統(tǒng)穩(wěn)定性的影響,并與電力系統(tǒng)仿真分析所用的發(fā)電機(jī)三種實用模型的計算結(jié)果進(jìn)行了對比研究。在此基礎(chǔ)上,以時步有限元結(jié)果作為標(biāo)準(zhǔn)響應(yīng),辨識了發(fā)電機(jī)大擾動過程中的電機(jī)參數(shù)。主要成果如下： 1.建立了用于分析汽輪發(fā)電機(jī)轉(zhuǎn)子三部分阻尼結(jié)構(gòu)和阻尼材料特性對其動態(tài)運(yùn)行能力影響的時步有限元模型,對該模型的時空離散策略進(jìn)行了優(yōu)化和改進(jìn),使其能夠更加準(zhǔn)確的計及多因素非線性條件下轉(zhuǎn)子阻尼結(jié)構(gòu)中的渦流集膚效應(yīng),并通過模型機(jī)試驗驗證了該模型的準(zhǔn)確性。 2.以一臺300MW汽輪發(fā)電機(jī)為例,通過詳細(xì)的時步有限元計算分析,揭示了汽輪發(fā)電機(jī)轉(zhuǎn)子大齒導(dǎo)條、轉(zhuǎn)子鐵心和轉(zhuǎn)子導(dǎo)電槽楔等阻尼結(jié)構(gòu)與發(fā)電機(jī)第一擺穩(wěn)定性之間的關(guān)系,發(fā)現(xiàn)轉(zhuǎn)子阻尼結(jié)構(gòu)對第一擺穩(wěn)定極限的影響主要取決于其等效電阻；進(jìn)一步對轉(zhuǎn)子槽楔采用不同材料時發(fā)電機(jī)的第一擺穩(wěn)定性進(jìn)行研究,揭示了第一擺穩(wěn)定極限隨轉(zhuǎn)子槽楔電導(dǎo)率的變化規(guī)律。 3.揭示了實用模型兩種假設(shè)條件的物理本質(zhì),假設(shè)A模型計及了勵磁繞組和阻尼繞組的互漏磁鏈,忽略了阻尼繞組自漏磁鏈；假設(shè)B模型反之；在假設(shè)B模型的基礎(chǔ)上進(jìn)一步對阻尼相關(guān)項進(jìn)行簡化得到了假設(shè)B-1模型。在此基礎(chǔ)上,對比分析了時步有限元模型與三種實用模型所計算的大擾動和小擾動結(jié)果,得出不同模型仿真結(jié)果之問的差異。 4.將解析法和數(shù)值仿真相結(jié)合研究了實用模型中定子繞組電磁暫態(tài)對發(fā)電機(jī)機(jī)電暫態(tài)過程的影響,發(fā)現(xiàn)忽略定子繞組暫態(tài)后,發(fā)電機(jī)三相突然短路過程中的交變電磁轉(zhuǎn)矩分量和定子非周期電流產(chǎn)生的單向電磁轉(zhuǎn)矩分量均被忽略,而后者屬于制動性質(zhì)的轉(zhuǎn)矩,被忽略后會影響功角第一擺穩(wěn)定性的仿真精度。 5.以時步有限元結(jié)果作為目標(biāo)曲線,采用最小二乘法辨識了發(fā)電機(jī)大擾動過程中的電機(jī)參數(shù),揭示了這些參數(shù)隨發(fā)電機(jī)功角的變化規(guī)律,得出辨識參數(shù)計算結(jié)果的精度明顯高于廠家參數(shù)。同時,對轉(zhuǎn)子導(dǎo)電槽楔采用不同材料時的發(fā)電機(jī)參數(shù)進(jìn)行辨識,得出轉(zhuǎn)子槽楔電導(dǎo)率對發(fā)電機(jī)各參數(shù)的影響。研究結(jié)果為實用模型的進(jìn)一步改進(jìn)提供了理論支撐。
[Abstract]:The dynamic operation ability of synchronous generator after disturbance is of great significance to the safe and stable operation of the system. In this paper, a time-step finite element model is established for the study of generator operating capacity under disturbance conditions. The influence of complex damping structure and material characteristics of turbogenerator rotor on the stability of the system is studied. The results are compared with the results of three practical models used in power system simulation. On this basis, the parameters of the generator in the process of large disturbance are identified by using the time-step finite element results as the standard response. The main results are as follows: 1. A time-step finite element model is established to analyze the influence of three-part damping structure and damping material characteristics on the dynamic performance of turbogenerator rotor. The spatio-temporal discretization strategy of the model is optimized and improved. The skin effect of eddy current in rotor damping structure can be taken into account more accurately, and the veracity of the model is verified by the model machine test. 2. Taking a 300MW turbogenerator as an example, through detailed time-step finite element calculation and analysis, the relationship between the damping structure of the turbine generator rotor, such as the large tooth guide bar, the rotor core and the rotor conductive slot wedge, and the first pendulum stability of the generator is revealed. It is found that the influence of rotor damping structure on the stability limit of the first pendulum mainly depends on its equivalent resistance. It is revealed that the stability limit of the first pendulum varies with the conductivity of the rotor slot wedge. The physical nature of the two hypothetical conditions of the practical model is revealed. Model A assumes the mutual flux leakage between the excitation winding and the damping winding and neglects the self-leakage flux chain of the damping winding. On the basis of hypothesis B model, the damping correlation term is further simplified and the hypothesis B-1 model is obtained. On this basis, the results of large and small disturbances calculated by time step finite element model and three practical models are compared and analyzed, and the differences between the simulation results of different models are obtained. 4. The influence of electromagnetic transient of stator winding on electromechanical transient process of generator is studied by combining analytical method and numerical simulation. It is found that the transient state of stator winding is ignored. The alternating electromagnetic torque component and the one-way electromagnetic torque component produced by the aperiodic current of the stator are ignored in the process of three-phase short circuit of the generator, and the latter belongs to the braking torque. The simulation accuracy of the stability of the first pendulum at the power angle will be affected by neglecting it. 5. 5. Taking the time-step finite element results as the target curve, the parameters of the generator in the process of large disturbance are identified by the least square method, and the variation of these parameters with the power angle of the generator is revealed. The accuracy of the calculation results of identification parameters is obviously higher than that of factory parameters. At the same time, the generator parameters are identified when different materials are used in the rotor slot wedge, and the influence of rotor slot wedge conductivity on the generator parameters is obtained. The results provide theoretical support for further improvement of the practical model.
【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】：TM31

【參考文獻(xiàn)】

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本文編號：2191839