大容量发电机典型工况下定子-绕组系统的复杂力学特性及绝缘磨损规律

The insulation damage of the stator winding is a primary cause for the generator close-down, while the increment of the generator capacity has proposed more requirements for the winding manufacturing technology and the insulation security. Current researches pay much attention to the electromagnetic forces and the vibration responses of the end-windings in normal condition, while the investigation on the forces and vibrations under faulty conditions, as well as the insulation wearing laws caused by the coupled stator-winding forces and vibrations, are significantly requested. This project is going to use the theoretical analysis, the 3D finite element calculation, and the experimental verifications both in laboratory and practice to carry out the study. The research contents include: establishing the transient force coupling model for the stator core-winding system, exploring the coupling mechanism between the twice-forced vibration in the line-windings (transferred from the stator core) and the first-forced vibration in the end-windings (caused by the electromagnetic forces), investigating the relatively static friction and the dynamic friction characteristics in the different stator winding districts of large capacity generators respectively under normal condition, air-gap eccentricity fault, rotor interturn short circuit fault, and air-gap eccentricity & rotor interturn short circuit compound fault, and obtaining the insulation wearing laws of the stator winding and the correspondingly special processing technology schemes. The purpose of the project is to actively prevent the winding insulating damage by the special processing technology in the manufacturing period and the clearly-aimed monitoring scheme during performing. Therefore, the project has a significant academic sense and engineering application values.

定子绕组绝缘损坏是发电机故障停机的重要原因，机组容量的增大对绕组的制造安装工艺及绝缘安全提出了更高要求。现有研究主要关注正常运行下定子端部绕组的电磁力与振动，关于故障下的绕组受载与振动、定子-绕组受载交互作用和振动耦合导致的绝缘磨损规律研究亟待深入。本项目拟采用理论分析、三维有限元仿真计算、动模及现场实验验证结合的方法，建立隔离式接触下铁芯-绕组力学激励的瞬态耦合模型，探索直线段绕组二次强迫振动（定子铁芯传递）与端部绕组一次强迫振动（电磁力激发）的耦合作用机制，研究正常、气隙偏心故障、转子匝间短路故障、气隙偏心与转子匝间短路复合故障四种典型工况下大容量发电机定子绕组不同部位的相对静摩擦特性和动摩擦特性，获取绕组的绝缘磨损规律和对应的特殊工艺处理方案。项目定位于从制造装配源头对绝缘危险位置作特殊工艺处理，结合有针对性的运行监测方案，实现对绝缘破坏的主动预防，具有重要的学术意义和工程应用价值。

大容量发电机是电力生产的主力军，定子绕组绝缘破坏危害严重，是造成故障停机的重要原因。机组容量的增大对定子绕组在高功率密度运行条件下的绝缘安全提出了更高要求。探索典型工况下定子绕组绝缘的磨损规律和破坏的危险位置，针对性地作特殊处理具有重要意义。现有研究主要关注正常运行下定子端部绕组的电磁力与振动，关于故障下的绕组受载与振动、定子-绕组受载交互作用和振动耦合导致的绝缘磨损规律研究亟待深入。本项目采用理论分析、三维有限元仿真计算、动模及现场实验验证结合的方法，建立了隔离式接触下铁芯-绕组力学激励的瞬态耦合模型，揭示了直线段绕组二次强迫振动（定子铁芯传递）与端部绕组一次强迫振动（电磁力激发）的耦合作用机制，得到了正常、气隙静偏心故障、转子匝间短路故障、定子匝间短路、气隙静偏心与定、转子匝间短路复合故障工况下的大容量发电机电枢绕组不同部位的力学响应特性，摸清了绕组在一、二次强迫耦合振动下的绝缘磨损规律，找出了三处失效关键危险位置，提出了两种针对性的特殊工艺处理方案。项目定位于从制造装配源头对绝缘危险位置作特殊工艺处理，以实现对绝缘破坏的主动预防，项目研究成果具有一定的工程应用价值。