【作者】 张新丽；

【导师】 罗应立；

【作者基本信息】 华北电力大学（北京） ， 电机与电器， 2007， 博士

【摘要】 本文系统研究了汽轮发电机在正常及非正常运行条件下的复杂非线性问题。提出了汽轮发电机的非线性特征曲线族包含四种类型,揭示了这四种类型各自出现的条件。对导致上述非线性特征曲线族相互之间及其与空载特性之间出现显著差异的三个本质因素（主磁通饱和效应、励磁电流漏磁通饱和效应及磁场畸变非线性）进行了定量分析,揭示了这三个因素与运行条件及稳态非线性参数之间的关系。进而对非线性模型机进行了设计研究。本文工作主要包括以下几个方面:1)通过对发电机在多种不同运行条件下非线性特征曲线族的系统分析,提出了汽轮发电机气隙电势与合成磁势之间的非线性关系具有四种类型。在不同运行条件下它们之间及与空载特性之间存在着偏斜、相交及交错等复杂关系。某些运行条件下差异显著,为产生同一气隙电势,所需磁势与传统按空载特性确定的数值差异可达100%以上。2)对导致上述非线性特征曲线族相互之间呈现复杂关系的三个内在因素（主磁通饱和效应、励磁电流漏磁通饱和效应及磁场畸变非线性）进行了定量分析。揭示了电机这三种内在非线性因素是导致外在负载非线性特征曲线族相互之间出现显著差异的本质原因。3)首次提出上述三个内在非线性因素与外部运行条件具有如下关系:主磁通饱和效应不仅受到端电压大小的影响还受到功角的影响;励磁电流漏磁通导致的转子轭部附加饱和除了受到励磁电流的影响还受到了功角的影响;磁场畸变程度不仅与功角有关,还与励磁电流及q轴电流的大小有关,在某些运行条件下,等效气隙长度可达电机实际气隙长度的3倍以上。4)本文对已有的7.5kW模型机进行数值分析及实验研究。发现该模型机无法有效模拟大型汽轮发电机的非线性特性。在此基础上,提出模型机的结构特点及材料选择是成功模拟大型汽轮发电机非线性特性的关键。进而设计了一种新型的30kW非线性模型机。5)将最小二乘法参数辨识与非线性参数的数值计算相结合,得到了不同运行条件下的非线性参数x_ad和x_aq。并利用发电机内部的非线性机理对非线性参数变化趋势的合理性进行了说明。更多还原

【Abstract】 The complex nonlinear characteristics of turbo-generator operating under variousconditions are studied in this thesis. The thesis proposes that nonlinear characteristics curvesof large generators include four typies. Three inner factors inducing the difference ofnonlinear characteristics curves are analyzed quantitatively including the main magnetic fluxcausedsaturation,excitedcurrent causedsaturationandmagneticfielddistortionnonlinearity.The relationship between these factors and operating conditions are discovered. Finally, thenonlinear model machine is further studied and designed. The work and attribute of the thesisisshownbelow:1)Load characteristics of turbo-generator under different operating conditions arestudied. The analysis shows that these curves include four types. Load characteristics of thefour cases are compared and it finds that most of them have great discrepancies from no-loadcurves and there are also discrepancies among these curves. In some cases, the discrepancymayreachto100%.2)Thesolutionandtheexpressionofmagneticdensityandmagneticpotentialaregivenin this thesis. Theyare used to quantitativelydescribe the inner nonlinear degree. Three innerfactors causing the difference of outer load characteristics are introduced. It shows that thethree inner nonlinear factors are the essential reasons resulting in the complex loadcharacteristics.3)Through extensive study it discovers that: The main flux saturation is influenced bythe terminal voltage and the power angle; the excited flux leakage caused iron saturation isnot only affected by the excited current but also affected by the power angle; while themagnetic field distortion is influenced bythe power angle, the excited currents and the q-axiscurrent.Undersomeconditions,theeffectiveair-gapmaybethreetimesofmachineair-gap.4)Through the numerical calculation and test research on a 7.5kW model machine, itshows that this model machine could not model the characteristics of the 300MW generatorexactly due to the structure difference. Through the analysis on the typical operatingconditions of the load and no-load characteristics of the 7.5kW and 300MW, the thesisdiscovers that a proper structure is the key problem of a good model machine. According tothe above conclusions, a 30kW model machine with novel structure is designed. The resultsshow that load characteristics of 30kW machine are ideal and can model the 300MWgeneratorwell.5)Theleastsquaremethodisusedtoestimatethelinearparametersof300MWgenerator.The saturated parameters xa dand x aqare calculated with the outside conditions changing.The analysis shows that the inner nonlinear factors are the essential cause making theparameterschanging.更多还原