【作者】 陈伟梁；

【导师】 徐博侯；

【作者基本信息】 浙江大学 ， 固体力学， 2008， 硕士

【摘要】 在正常工作状态下,大型汽轮发电机定子绕组端部会受到电磁力的作用,其中对端部绕组起主要作用的是二倍工频(即100Hz)的电磁力。如果汽轮发电机定子绕组端部等构件的固有频率与这个电磁力的频率相同或者接近时,就会产生共振或较大幅度的振动,影响汽轮发电机的正常运行,甚至造成重大事故。目前,汽轮发电机厂设计和维护人员用实验法来测试定子绕组端部的振动特性,但此法只能对生产后的成品进行检测,不能在产品生产前提供相关的特性。后来提出的锥壳－梁等效模型,经过复杂的动态设计优化,虽然可以从整体进行相关的等效,然而由于简化的细节过多,不能得出一些关键部位的受力分析情况。基于上述方法的局限性,本文的方法则从实际定子绕组三维模型入手,简化一些不太影响结果的细节,根据等效的原则,获得简化的有限元模型；利用结构的循环对称特性和矩阵的摄动方法,推导出多重循环结构的摄动法。根据现有的影响循环对称特性的非循环部件或者约束,选取适当的步骤,对循环结构逐步摄动求解,就可以在这一过程中判断模态的走向,识别并确定最后所得的感兴趣的模态,将分析结果与试验数据对比,设定可调节参数的合理值。以此为基础,进一步分析定子绕组端部在单相、双相以及三相短路时,受电磁力作用下各部件结构的动态响应,还可以根据需要分析某些部件约束处受力情况。如果相关部件有受力标准,对比标准,可以进一步改进定子绕组端部结果,这对汽轮发电机设计和维护有积极的参考作用。更多还原

【Abstract】 Large turbo-generator’s stator winding end will undergo electromagnetic force in the normal working status, among them the dominated force is correspond to double base frequency(100Hz). If the natural frequency of the stator winding end is the same as or near that of dominated electromagnetic force, then the stator winding end will result in resonance or large amplitude vibration and this will affect the normal operation of Large turbo-generator, even result in worse accident.As for now, people are using test instrument to test vibration performance of stator winding ends, but this kind of method can only know the vibration performance after the production of stator winding ends. Later on, another method called shell-beam equivalent model is suggested, but we can’t get enough results as we like because its equivalent is global. For these reasons, this article makes use of 3D model of stator winding ends, simplifies unnecessary details and finally creates the corresponding 2D finite modal; compare the model result with the test data, we then can get the proper parameters for the model; based on model and its parameters, we can get stator winding’s dynamic response under electromagnetic force or even certain place’s load conditions. If we know the criteria of load conditions, we then can further improve the result and make it more accurate. It will be surely a great reference to the design and maintenance of turbo-generator.更多还原