热老化下双层聚酰亚胺薄膜绝缘特性研究  

Research on Insulation Characteristics of Double-layer Polyimide Films Under Thermal Aging

作　　者：梅冰笑 姜雄伟 王文浩 韩睿 曹文斌 MEI Bingxiao;JIANG Xiongwei;WANG Wenhao;HAN Rui;CAO Wenbin(State Grid of Zhejiang Electric Power Research Institute,Hangzhou 310014,China)

机构地区：[1]国网浙江省电力有限公司电力科学研究院,杭州310014

出　　处：《高压电器》2022年第12期147-155,共9页High Voltage Apparatus

基　　金：国网浙江省电力有限公司科技项目(5211DS210009)。

摘　　要：为研究热老化下介质直流和操作冲击结果的演变规律及其影响机制,文中以热老化处理的(190℃,220℃)双层聚酰亚胺薄膜(PI)为研究对象,采用等温松弛电流法(IRC)对不同热老化程度介质的空间电荷特性进行研究,基于双极性电荷输运模型(BCT),仿真研究陷阱密度对直流击穿结果的影响机制。基于局域态电荷吸收能量的频率依赖模型,数值分析空间电荷和介电参量对冲击击穿结果的影响机理。结果表明,随着热老化时间增加,介质陷阱密度逐渐减小,电荷注入效应增强,介质内部的电场畸变程度增大,故直流击穿场强逐渐下降;中低频区域介质tanδ值逐渐升高,局域态电荷的能量吸收能力增强,其更容易从陷阱逃脱,对绝缘结构产生破坏,导致冲击击穿电压逐渐下降。提高热老化温度后,上述现象更加严重。For studying the evolution and its influencing mechanism of dielectric DC and switching impulse result under thermal aging,the double-layer polyimide film(PI)treated with thermal aging treatment(190 ℃,220 ℃)is taken as the research object,the isothermal relaxation current method(IRC)is adopted to study the space charge characteristics of dielectric with different thermal aging degrees. The influence mechanism of trap density on DC breakdown results is simulated and studied on the basis of bipolar charge transport model(BCT). Based on the frequency-dependent model of localized charge absorption energy,the influence mechanism of space charge and dielectric properties on switching impulse breakdown results is numerically analyzed. The results show that with the increase of thermal aging time,the density of traps of the dielectric decreases gradually,the effect of charge injection increases,the degree of electric field distortion inside the dielectric increases and the DC breakdown field strength decreases gradually. The tanδ value of dielectric in medium and low frequency region gradually increases,and the energy absorption ability of local state charge increases,which makes it easier to escape from traps and damage the insulation structure,resulting in the gradual decrease of impulse breakdown voltage.After increasing the thermal aging temperature,the above phenomenon becomes more serious.

关 键 词：热老化 空间电荷 双极性电荷输运 频率依赖 

分 类 号：TM47[电气工程—电器] TQ317[化学工程—高聚物工业] TB383.2[一般工业技术—材料科学与工程]