摘要
为解决大型二极汽轮发电机定子端部绕组常出现的振动问题,建立了端部绕组的简化模型,采用有限元法计算了该结构的低阶模态,给出了端部绕组主振型的近似表达式;基于磁拉力的空间分布,通过振型叠加法推导出了端部绕组强迫振动响应的计算公式。研究发现,大型发电机端部绕组只有同时满足2个条件——磁拉力频率等于或接近端部绕组固有频率,主振型的周向行波数等于发电机的极数,才可能发生共振,简称为端部绕组共振的二重点理论。根据二重点理论,当额定工作转速为3 000r/min的二极发电机定子端部绕组发生共振时,可以调整端部绕组的固有频率使其避开100Hz,也可以选择修改端部绕组的结构使其主振型中不再出现椭圆振型。
To avoid usual vibration accidents of stator end winding in a large two-pole turbogenerator,a simplified model is established for the end wing,lower order modes of the structure are evaluated with finite element method,and approximate expressions of the main vibration modes are obtained.A formula for forced vibration response of the end winding to electric-magnetic excitation is derived by mode superposition.It is found that the resonance of end winding occurs only when the following two conditions are satisfied simultaneously：（1） the frequency of the electric-magnetic excitation equals to or approximates the natural frequency of the end winding;（2） the circumferential traveling-wave number of modes equals to the pole number of the generator.This is named as ＂two-coincidence condition＂ of resonance for end winding in large generators.According to the two-coincidence condition,one can choose adjusting the natural frequency of end winding far from 100 Hz,or modifying its structure to avoid the elliptical mode shape to prevent stator end winding of large two-pole turbogenerator with rating speed of 3 000 r/min from resonance.
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2013年第7期80-84,113,共6页
Journal of Xi'an Jiaotong University
基金
国家"863计划"资助项目(2007AA04Z1A1)
关键词
大型汽轮发电机
定子端部绕组
振动
共振
large two-pole turbogenerator
stator end winding
vibration
resonance
