摘要发电机是电力系统的关键装置，发电机的各类故障中匝间短路由于故障特征不明显，容易发生误判或延误诊断导致故障恶化。本文针对发电机转子匝间短路和定子匝间短路的故障特征来判定故障。通过探测线圈法得到发电机气隙磁场的动测波形，将小波分析理论运用于汽轮发电机转子绕组匝间短路故障诊断，使用小波变换和故障信号的奇异点模极大值的对称性来检测发电机转子匝间短路故障并确定故障槽的位置。另外定子匝间短路障发生时，励磁电流产生高频分量，通过功率谱和小波能量谱来提取能量分布来判断故障发生。本文用MATLAB对上述理论进行验证，证明以上方法正确。18822
毕业论文关键词 发电机 转子匝间短路 定子匝间短路 故障诊断 MATLAB
毕业设计说明书（论文）外文摘要
Title Study on Fault Diagnosis of Engine Inter-turn Short Circuit
Abstract
Generator is a key device of electrical system, the fault feature of inter-turn short circuit is relatively not obvious compared with other faults, and it’s easy to be misjudged or delayed which would lead to worsen the fault .The paper focus on the fault feature of generator rotor inter-turn short circuit and stator inter-turn short circuit to determine the fault. We can get the waveform of generator Air-gap magnetic field by search coil method, and apply wavelet analysis to detect inter-turn short circuits in turbo-generator rotor winding, According to wavelet transform and the singularity of signal failures as well as the symmetry of modulus maximum, it is easily to detect shorted turns fault and find the fault position in generator rotor windings. The excitation current would contain high frequency component when generator stator inter-turn short circuit occurs, power spectrum and wavelet energy spectrum can be used to extract the content of each frequency to detect stator shorted turns fault. The concerned theory and example above is verified in MATLAB environment concretely.
Keywords generator; rotor inter-turn short circuits; stator inter-turn short circuits; Fault Diagnosis; MATLAB
目 录
1 绪论 1
1.1 课题背景 1
1.2 研究现状 1
1.3 本文研究工作 1
2 发电机转子匝间短路故障诊断 2
2.1 发电机转子基本结构及转子匝间短路故障原因 2
2.2 发电机转子匝间短路故障特点 2
2.3 小波变换原理 4
2.4 发电机转子匝间短路故障信号处理 5
2.5 发电机转子匝间短路故障的结果分析 13
3 发电机定子匝间短路故障诊断 14
3.1 发电机定子基本结构及定子匝间短路故障原因 14
3.2 发电机定子匝间短路故障特点 14
3.3 功率谱密度及小波能量谱分析 15
3.4 发电机定子匝间短路故障信号分析方法的应用 18
结论 24
致谢 25
参考文献 26
附录A 28
1 绪论
1.1 课题背景
发电机是电力系统重要的核心组成部件，而发电机的正常运行也关系着电网的稳定。随着发电机容量的增加，其运行可靠性显得更加重要，一旦机组发生故障，就会给电力系统甚至国民经济带来巨大的损失[1]。在发电机组的各个组成部件中，匝间短路故障是经常发生的故障类型，也是影响发电机安全运行的主要因素之一[2]。匝间短路故障分为转子匝间短路和定子匝间短路，这两种短路故障如果没有及时发现就可能恶化为严重发电机故障。但是由于轻微匝间短路的故障特征并不明显，在实际的发电机保护中很难及时有效地发现此类故障，并且容易发生误判，所以发电机匝间短路的故障分析与识别显得尤为重要[3]。 MATLAB发电机匝间短路故障诊断研究:http://www.youerw.com/zidonghua/lunwen_40367.html