基于有限元的汽轮发电机模型机设计研究

研究与300MW大型汽轮发电机同槽数的7.5kW模型机和300MW发电机的空载特性相似性。运用FEM(有限元)稳态计算程序计算模型机的空载特性,将计算数据与试验数据进行对比验证程序的可靠性。选定、转子铁心具有恒定高导磁率时所得空载线为反映气隙磁压降的实际气隙线,并以二者气隙线重合为基准对空载曲线作标么值处理,电压基值选各自电机额定端电压,电流基值选气隙线上各自达到额定电压时对应的励磁电流,从而在同一张图中对比两电机的实际饱和特性与气隙线的靠近程度。通过改变模型机转子导磁材料、气隙大小,得出结论:在允许范围内选用高导磁性材料、加大气隙可以改善模型机和300MW发电机的空载特性相似性。讨论了材料饱和程度与空载饱和特性相似性的关系。

Design and Study On Model Turbo-generator Based on FEM

The similarity of no-load characteristics of the 7.5kW model turbo-generator and 300MW turbine generator of the same slot number is studied.The no-load characteristics are calculated with FEM stable computing program.The calculated results are compared with the tested data to verify the validity of the FEM program.The no-load curves of constant-high permeability of stator and rotor iron cores are selected as air-gap line to reflect the declining of air-gap voltage.The fitting of two lines is used as reference to process the no-load curves using per-unit.The rated voltage is adopted as base value and the corresponding exciting current value is used as base value when its voltage reaches the rated value on each air-gap line.The two no-load characteristic curves are compared in one picture to see the approximation extent of actual saturated characteristic and their air-gap line of the two generators.By changing the magnetoconductivity and air-gap of rotor material,it is concluded that choosing high-magnetoconductivity and increasing air-gap in permitted range can improve their similarity.The relationship between the saturation of rotor material and no-load saturating characteristics is discussed.