双极性方波场下电晕老化对环氧树脂空间电荷特性的影响  

Effect of Corona Aging on Space Charge Characteristics of Epoxy Resin Under Bipolar Square Wave Electric Field

作　　者：张跃 苏淮北 何明鹏 吴建东[2] 尹毅[2] 梁智明 ZHANG Yue;SU Huaibei;HE Mingpeng;WU Jiandong;YIN Yi;LIANG Zhiming(Dongfang Electric Machinery Co.,Ltd.,Dongfang Electric Group,Deyang 618000,China;Shanghai Key Laboratory of Power Transmission and Power Conversion Control,Ministry of Education,Shanghai Jiaotong University,Shanghai 200240,China)

机构地区：[1]东方电气集团东方电机有限公司,德阳618000 [2]上海交通大学上海电力传输与功率变换控制教育部重点实验室,上海200240

出　　处：《高电压技术》2022年第12期4731-4738,共8页High Voltage Engineering

基　　金：四川省科技计划项目(2020YFSY0056);国家自然科学基金(51737009)。

摘　　要：为研究双极性方波电场下电晕老化对环氧内部空间电荷的影响,检测了电晕老化前、后环氧树脂在50 Hz、20μs双极性方波10~20kV/mm电场范围下的空间电荷响应,并结合松弛电流特性分析了电荷输运特性。结果表明:环氧在去极化电流0.1~3 600 s检测观察窗口内存在3类松弛极化峰,电晕老化后陷阱峰值能级的微弱下降,但陷阱密度均明显增大,这可能与老化后环氧树脂中分子结构形成的大量官能团相关。环氧未老化时在双极性方波电场下表面区均呈现异极性电荷积累,电晕老化后出现同极性电荷分布,且在过零点相位出现了电荷迟滞现象。结合不同类型电荷在正、负半周电场下的迁移方向和源位置,推断未老化时的异极性电荷主要源于内部杂质离子,电晕老化后的同极性电荷可能与环氧表面被腐蚀导致的电极/试样界面注入势垒降低和陷阱密度增大相关。另外,电晕老化后形成的大量同极性注入电荷和电场过零点相位空间电荷迟滞表明,表面区同极性电荷的积累量和过零点相位的空间电荷残留可作为绝缘状态评估的重要指标。In this paper,the space charge behavior of epoxy resin before and after corona aging was detected under 50 Hz and 20μs bipolar square wave of the electric field range of 10~20 kV/mm.Combined with the characteristics of relaxation current,the effect of corona aging on space charge inside epoxy was analyzed under bipolar square wave electric field.The results show that there are three kinds of relaxed polarization peaks in the observation window with the depolarization current from 0.1~3600 s.The peak energy level of trap decreases slightly after corona aging,but the trap density increases significantly.It may be related to the large number of functional groups formed in the molecular structure of epoxy after aging.The surface area of unaged epoxy presents the heteropolar charge accumulation under the bipolar square wave electric field.The homopolar charge distribution appears in aged epoxy,and the charge hysteresis phenomenon appears at the zero-crossing phase.Combined with the migration direction and source location of different types of charges under positive and negative half-cycle electric fields,it is inferred that the heteropolar charge in unaged epoxy is mainly from internal impurity ions.The homopolar charges after corona aging may be related to the decrease of injection barrier at the electrode/sample interface and the increase of trap density.In addition,the large amount of homopolar charge and space charge hysteresis at zero-phase of electric field after corona aging indicates that the accumulation of homopolar charge and the residual space charge at zero-phase can be used as an index for the evaluation of insulation state.

关 键 词：环氧树脂 双极性方波 电晕老化 空间电荷 陷阱能级 

分 类 号：TM215.1[一般工业技术—材料科学与工程]