发电机三维气隙偏心与定转子绕组短路耦合故障的机电交叉特性分析及其诊断方法研究

Besides the single failures, there are also coupling faults taking place in the generator, whose failure characters are different and meanwhile not equal to the superposition of the single faults. Therefore, it's significant to investigate the faulty characteristics of the high-frequency coupling failures so that people can identify the failures quickly. This project takes the 3D air-gap eccentricity and winding short circuit coupling faults as the study object, mainly studying in: 1) the radial and axial vibration characters of the stator and rotor under the coupling faults, 2) the fluctuation character of the electromagnetic torque, and 3) the character of the circulating current inside the parallel branch loop of the stator winding. The project expands the air-gap eccentricity from 2D to 3D, taking the radial eccentricity and the axial eccentricity into account at the same time. The feature of the project is to identify the coupling faults with the coupling failure characters, aiming at developing a different method for the coupling fault identification. The proposed project may offer more information and improve the current diagnosis technology. It can also provide a new though and reference for the diagnosis of the complex multy-affected failures.

除了单一性故障外，发电机在许多时候还会处于耦合故障状态。耦合故障的故障特征与单一故障有所不同，并不是构成耦合故障的所有单一故障所对应特征的简单叠加，这对耦合故障的识别与诊断带来了困难。对频率较高的耦合故障进行研究，探索其典型故障特性，从而为其快速识别提供依据意义重大。本课题拟对诱发频率极高的三维气隙偏心与定转子绕组匝间短路耦合故障进行研究，内容包括：1）耦合故障下定转子的径向与轴向振动特性；2）耦合故障下电磁转矩的波动特性；3）耦合故障下的定子并联支路环流特性。本课题将气隙偏心的范围从二维扩展到三维，综合考虑气隙的径向与轴向复合偏心，特色在于通过分析发电机的机电交叉故障特性来识别其机电交叉耦合故障，旨在摸索出一种有别于传统的耦合故障诊断方法，为发电机的运行和检修提供更多确切的信息，使得现有的诊断技术更加精确和完善，同时也为多种因素导致的复杂故障识别与监测提供一种新的思路与参考。

发电机长期高速工作在多场耦合应力情况下，随着时间的推移和机组的磨损老化，容易出现不同类别、不同程度的故障。其中一些故障具有耦合性质，对应的故障特征与单一故障有所不同，而且并不是构成该耦合故障的所有单一故障所对应特征的简单叠加，这给故障的识别与诊断带来了困难。本项目以诱发频率较高的气隙偏心（包括径向与轴向偏心）与定、转子绕组匝间短路耦合故障为研究对象，开展了以下内容研究：1）耦合故障下的定、转子振动特性和电磁转矩波动特性（即机械特性）；2）耦合故障下的定子并联支路环流特性（即电气特性）；3）耦合故障下发电机的外在标志性机电交叉组合故障特性与故障成分的映射关系。项目推导得到了气隙偏心、转子匝间短路、定子匝间短路三个故障成分对耦合故障下磁导与磁势的影响机理，建立了可同时表征气隙偏心类型、气隙偏心程度、绕组匝间短路程度与匝间短路位置的耦合故障模型，获得了故障下定、转子不平衡磁拉力、电磁转矩，以及并联支路电势差的通用解析表达式，总结得到了气隙偏心与定转子绕组匝间短路单故障与耦合故障下的发电机机电交叉组合故障特性，摸索出了一种基于外在机电交叉特性的发电机内部交叉耦合故障识别方法，丰富了发电机故障监测与识别的理论支撑与判据体系，为多种因素导致的复杂故障识别提供了一种新的思路与参考。项目发表了与核心研究内容相关的SCI论文10篇，EI期刊论文6篇，EI会议论文3篇，核心论文3篇，申请发明专利4项，参与国际会议交流研讨6人次，国内会议交流3人次，基本达到预期目标。