应用极化/去极化电流法分析油纸绝缘微水扩散暂态过程

Analysis of Transient Moisture Diffusion in Oil-paper Insulation Using Polarization and Depolarization Current Method

为将极化/去极化电流法用于油纸绝缘的微水扩散暂态过程研究,通过建立油纸绝缘微水扩散不平衡时的时域极化模型,提出了根据微水扩散达到稳态时的极化/去极化电流特性求解微水扩散不平衡时的极化/去极化电流的方法,并通过试验验证该方法的有效性。研究结果表明:随着水分含量的增加,油纸绝缘的极化/去极化电流增大,纸中微水分布的不均匀性产生的极化严重影响了油纸绝缘的极化/去极化电流特性,自由电荷迁移和界面极化建立变得困难和缓慢,极化/去极化电流减小;微水扩散不平衡时绝缘纸的电导率分布与纸中微水质量分数分布密切相关,可以作为表征纸中微水分布的特征量。

In order to apply the polarization and depolarization current method to analyze disequilibrium moisture diffusion process in oil-paper insulation,we put forward a novel method for calculating the polarization and depolarization current of disequilibrium moisture diffusion according to the polarization and depolarization current of equilibrium moisture diffusion,established a time-domain polarization model of oil-paper insulation with disequilibrium moisture diffusion for the calculation,and verified the proposed method by experiments.The results show that the polarization and depolarization current increases with moisture content;moreover,due to concentration polarization induced by disequilibrium moisture distribution,the migration of free charge and the establishment of interfacial polarization become difficult and slow,which will result in decrease of the polarization and depolarization current.It is concluded that the conductivity distribution of insulation paper is closely related to the distribution of moisture content in it,and can be used as a characteristic parameter for the moisture diffusion.