基于机电信息融合的发电机励磁绕组匝间短路在线监测

Although the inter-turn short circuit of field windings is a typical fault of of large synchronous generators, on-line monitoring of the fault is always a difficult point in the field of generator fault diagnosis. This project pays attention to fusion of electrical and vibration characteristics, and carries out researches mainly from the following three aspects: (1) Based on electrical characteristics of the fault, a new monitoring principle and a method for improving monitoring sensitivity and reliability are proposed, and via a rotor phase demodulation signal, on-line location of the fault pole is realized. (2) A theoretical analysis model and a calculation model of stator and rotor vibration under the fault are established, vibration characteristics of the fault and influencing factors of the amplitude are deeply analyzed, influencing mechanism of the fault upon vibration is made clear, and unique vibration characteristics of the fault are concluded. (3) The electrical and mechanical information fusion method for monitoring inter-turn short circuit of field windings is proposed, and fault electrical quantities and vibration quantities go through multistage treatment including data-level, feature-level, and decision-level treatment, integrating different monitoring principles into a complete non-dead-zone on-line monitoring scheme. This project is a theoretical innovation of motor fault analysis and monitoring. The research results provide an accurate quantitative basis for overhaul of the generator, improve operation safety of the large generators, and are provided with an important practical meaning and a wide application prospect.

励磁绕组匝间短路是危及大型同步发电机安全运行的一种典型故障，该故障的在线监测一直是发电机故障诊断领域中的难点。本项目注重故障电气特征及振动特征的交叉融合，主要从以下3个方面展开研究：(1)从故障的电气特征入手，研究新的监测原理及提高监测灵敏性和可靠性的方法，并借助于转子鉴相信号实现对故障磁极的在线定位。(2)建立故障情况下定子和转子振动的理论分析模型和计算模型，深入分析故障的振动特性及振幅的影响因素，明晰故障对振动的影响机理，找出故障独有的振动特征。(3)研究面向励磁绕组匝间短路故障监测的机电信息融合方法，将故障电气量和机械振动量进行包括数据层、特征层和决策层的多级处理，使不同的监测原理有机融合为一整套故障的无死区在线监测方案。本项目是对电机故障分析及监测理论的创新，其研究成果将为发电机的停机检修决策提供准确的量化依据，提高大型发电机的运行安全性，具有重要的实践意义和广阔的应用前景。

励磁绕组匝间短路是危及大型同步发电机安全运行的一种典型故障，该故障的在线监测一直是发电机故障诊断领域中的难点。本项目注重故障电气特征及振动特征的交叉融合，主要进行了如下研究：（1）提出了电气特征的励磁绕组小匝数短路灵敏在线监测与定位方法，实现了小匝数短路的灵敏监测及故障磁极的在线定位。（2）考虑转子匝间短路引起的与极对数和定子绕组形式有关的偶数次和分数次不平衡电流分量，提出了一套完整的故障时不平衡磁拉力特征分析方法；建立了计算转子不平衡磁拉力的场路耦合有限元模型及解析计算模型；对故障时电磁转矩特征进行了细致的理论分析与仿真计算。（3）全面考虑各种空间磁场的相互作用及转子热变形等实际因素，对故障后发电机的定子和转子振动特征进行了理论分析；基于Ansys workbench 软件建立了发电机励磁绕组匝间短路故障时电机电磁场和机械振动的协同仿真平台，实现了故障时定、转子振动的计算。（4）建立了励磁绕组匝间短路故障监测的多传感器数据融合机制，确定数据层、特征层和决策层的融合方式；特别是针对无分支电流互感器的大型汽轮发电机，应用所形成的机电信息融合方法，形成了多判据融合的在线监测方案。本项目是对电机故障分析及监测理论的创新，其研究成果将为发电机的停机检修决策提供准确的量化依据，提高大型发电机的运行安全性，具有重要的实践意义和广阔的应用前景。