X射线衍射法研究大电机定子绝缘的老化过程  

Degradation Behavior of Stator Insulation for Large Generators Using X-Ray Diffraction Method

作　　者：郝艳捧[1] 谢恒堃[2] 

机构地区：[1]华南理工大学电力学院,广州510640 [2]西安交通大学电力设备电气绝缘国家重点实验室,西安710049

出　　处：《电工技术学报》2007年第9期16-21,共6页Transactions of China Electrotechnical Society

基　　金：教育部全国百篇优秀博士论文作者专项基金(200541);西安交通大学电力设备电气绝缘国家重点实验室开放基金资助项目。

摘　　要：绝缘老化过程和老化机理的研究是电力设备绝缘状态监测和状态诊断技术的基础。本文研究绝缘常用材料云母在大电机运行应力作用下的老化过程。对300MW/18kV发电机运行23年的定子线棒绝缘进行X射线衍射实验,通过衍射图谱分析绝缘中云母晶体的化学式,探讨了云母的老化过程。结果表明:在运行应力尤其是局部放电的长期作用下,定子绝缘中所有云母晶体都发生了复杂的变化,K原子数由老化前的1减小为0.75,Al离子被Fe离子和Li离子置换,羟基被F离子置换等。但还很难解释其复杂过程。　Insulation condition diagnosis technology is based on the investigation of insulation degradation behavior or aging mechanism. The degradation behavior of mica in stator insulation under operating stresses is invested by X-ray diffraction （XRD） method in this paper. The insulation specimens were cut from a standby and an aged stator bar operating for 23 years in a 300MW/18kV generator. Complicate changes are found through chemical formula analysis of mica crystal based on XRD patterns of insulation specimens. The atom count of K in mica crystal decreases obviously from 1 for the unaged to 0.75 for the aged. This degradation behavior may be an aging progress, in which the edge of mica crystal is corrupted under some acids produced by partial discharges in insulation, and potassium ion is separated from the edge of mica leading to the degradation of epoxy-mica insulation. In addition, the aluminum ion in mica crystal of aged insulation is replaced with ferrum and lithium ions, and the hydroxyl is with fluorine. However, it is difficult to describe the chemical progress during the replacement courses.

关 键 词：定子线棒 环氧云母绝缘 绝缘状态诊断 老化过程 X射线衍射 

分 类 号：TM215.92[一般工业技术—材料科学与工程]