温度对发电机主绝缘频域介电响应的影响研究  

Research on the Influences of Temperature on Frequency Domain Dielectric Spectroscopy of the Main Insulation of Generator

作　　者：高波[1] 郝长金 尹小兵[1] 王兵[1] 李帅兵[1] 吴广宁[1] 

机构地区：[1]f西南交通大学电气工程学院,四川省成都市610031

出　　处：《中国电机工程学报》2017年第3期915-922,共8页Proceedings of the CSEE

基　　金：国家自然科学基金项目(51177136)~~

摘　　要：为研究温度对大型发电机主绝缘频域介电响应的影响,将频域介电谱技术用于发电机主绝缘老化状态的无损诊断,在不同温度下进行发电机线棒试样的频域介电谱测试,基于双弛豫Cole-Cole模型,分析了温度对环氧云母绝缘频域介电谱特性的影响。结果表明:随着温度升高,复介电常数实部??和虚部??的频谱曲线整体向上和向高频方向偏移;在-103~103Hz范围内,双弛豫Cole-Cole模型可以准确描述发电机主绝缘的频域介电谱;温度升高加强了界面极化强度和偶极子转向极化强度,在虚部??频谱内,界面极化弛豫起主导作用的频率范围变宽;不同温度下的界面极化弛豫时间常数和直流电导率满足Arrhenius方程。根据过渡态理论,计算得到界面极化弛豫对应的活化焓为103.1k J/mol;活化熵随温度升高而增大,表明绝缘体系有序性减小;活化能减小,表明各种极化过程更易完成。因此可用过渡态理论解释发电机主绝缘频域介电谱的温度依存性。To investigate the influence of temperature on frequency dielectric response of the main insulation of large generator, the frequency-domain dielectric spectroscopy（FDS） was utilized for a non-destructive diagnosis of its aging state. Series of experiments were carried out for stator bars at different temperature, firstly. Then influences of temperature on dielectric spectroscopy of stator bar insulation were analyzed based on a double relaxation Cole-Cole model. Experimental results show that the entire spectrums of ε′ and ε′′ moved to the high frequency, and positive vertical direction. In the range of-103-103Hz, the Cole-Cole model can accurately describe the FDS of generator bar insulation. Increasing of the temperature enhanced the strength of interfacial polarization and dipole polarization. In the spectrum of ？′′, the frequency range in which interfacial polarization plays a leading role broadens with the increase of temperature. The interfacial polarization relaxation time and the direct current conductivity satisfy the Arrhenius equation. According to the transition state theory, the value of activation enthalpy is 103.1k J/mol. The activation entropy increases with the increase of temperature, which indicates that the order of the whole system decreases. The decreasing of activation energy indicates that polarization will be established more easier than normal. So the temperature-dependence of FDS of generator insulation can be descripted by the transition state theory.

关 键 词：发电机 温度 FDS COLE-COLE模型 Arrhenius方程 

分 类 号：TM304[电气工程—电机]