基于极化-去极化电流测试的XLPE中陷阱电荷脱陷特性  

Trapped Charge De-trapping Property of XLPE Based on Polarization and Depolarization Current Test

作　　者：李明志 周凯[1] 黄科荣 饶显杰 龚军 LI Mingzhi;ZHOU Kai;HUANG Kerong;RAO Xianjie;GONG Jun(College of Electrical Engineering and Information,Sichuan University,Chengdu 610065,China;Skill Training Centre of State Grid Sichuan Electric Power Company,Chengdu 611133,China)

机构地区：[1]四川大学电气信息学院,成都610065 [2]国网四川省电力公司技能培训中心,成都611133

出　　处：《高电压技术》2020年第9期3194-3201,共8页High Voltage Engineering

基　　金：中国博士后科学基金资助项目(2015T80976)。

摘　　要：为了通过空间电荷脱陷行为反映电缆XLPE绝缘老化程度,提出了一种从XLPE绝缘介质的极化-去极化电流(polarization and depolarization current,PDC)中提取出脱陷电流ide-trap的方法与相应的陷阱电荷密度Anτn和陷阱深度τn的计算方法。通过从脱陷电流中提取出参数τn和Anτn,并利用脱陷电流曲线作出ide-trapt^lnt曲线(t为时间),表征了XLPE中陷阱电荷密度与陷阱深度。在分别改变PDC测试时的极化场强、空间电荷注入时长和试样热老化程度后计算试样中陷阱电荷密度和陷阱深度,结果表明:PDC测试中较高的极化场强更能促进深陷阱中电荷逃逸;随着空间电荷注入时长增加,中等深度陷阱相较于浅陷阱和深陷阱更容易积聚电荷;XLPE的热老化首先经历重结晶阶段,后进入热氧老化阶段,结晶度变化导致XLPE中陷阱数量先增加后减少,而在整个热老化过程中陷阱深度逐渐加深。研究结果表明,基于极化-去极化电流测试可对XLPE中陷阱电荷的脱陷特性进行分析,通过参数τn、Anτn和ide-trapt^lnt曲线可反映XLPE中陷阱电荷密度及陷阱深度并表征XLPE绝缘的老化程度。To characterize the aging degree of XLPE through the de-trapping progress of space charges,this paper presents a method to extract the de-trapping current ide-trap from the Polarization and Depolarization Current(PDC)of an insulating medium,and a method to calculate the trapped charge density Anτn and trap depthτn.The trap depth and the trapped charge density in XLPE are characterized by Anτn andτn parameters and the ide-trapt^lnt curve(t represent time).After changing the polarization voltages in PDC tests and charge injection durations and the thermal aging degree of samples,trapped charge density and trap depth in samples are calculated.The results show that a higher voltage in PDC tests can promote the charge escaping in deep traps;as the space charge injection duration increases,the charges more likely accumulate in medium depth traps than in shallow traps and deep traps;with the aging of XLPE,thermal aging of XLPE first undergoes the recrystallization progress and then enters the thermal destruction period;moreover,the change of crystallinity will first increase the number of traps in XLPE and then decrease while traps gradually deepen during the whole thermal aging process.The results show that the de-trapping progress of trapped charges in XPLE can be analyzed based on polarization and depolarization current tests.The trap charge density and trap depth in XLPE,together with the aging degree of XLPE can be characterized byτn,Anτn parameters and ide-trapt^lnt curves.

关 键 词：极化去极化 空间电荷 XLPE 电荷密度 陷阱深度 

分 类 号：TM75[电气工程—电力系统及自动化]