油纸绝缘不同老化的微观特征分析研究

Analysis of microscopic characteristics of different oil-paper insulation aging

电热老化是研究电力变压器内绝缘老化的最主要方式。研究通过开展油纸不同加速老化实验,根据聚合度变化和局部放电变化特征,验证实验样本的典型性。通过扫描电子显微镜(SEM)和X射线光电子能谱(XPS),对绝缘纸的表面形貌和电子结合能进行分析,探讨电热老化时油纸裂解过程与其化学性能的关联性。结果表明,电热老化加速绝缘纸的裂化速度,聚合度最先下降至200以内,绝缘纸表面粗糙形态与碳化现象更明显,C元素结合能偏移达到0.58 eV。微观特征的变化与油纸老化裂解机理及化学性能变化一致,电场和温度共同作用下的油纸绝缘老化状态分析是合理的。

Electrical-thermal aging is the most important way to study insulation aging in power transformers.In this study,different accelerated aging experiments of oil paper were carried out to verify the typicality of the experimental samples according to the variation of degree of polymerization and partial discharge characteristics.The micro structures of insulating paper were analyzed through scanning electron microscopy(SEM)and X ray photo electron spectroscopy(XPS),and also the relationship between the cracking process of oil paper and its chemical property during electrical-thermal aging was discussed.The results show that electrical-thermal aging accelerates the aging rate of insulating paper,and the degree of polymerization first decreases to less than 200.The surface roughness and carbonization of insulating paper are more obvious,and the binding energy of C element shifts 0.58 eV.The change of microscopic characteristics is consistent with the aging mechanism and chemical properties of oil-paper.It is reasonable to analyze the aging state of oil-paper insulation based on the combined action of electric field and temperature.