基于EPR的聚乙烯基纳米复合电介质电荷陷阱机制及陷阱特性的研究

Traps play an important role in charge transport and space charge suppression in polyethylene based nanocomposite dielectrics. This program intends to reveal the physical and chemical nature of traps and to obtain trap characteristic parameters via studying the physical and chemical environment at the trap sites and around it by using EPR (Electron Paramagnetic Resonance) and EPR-TSC(Thermally Stimulated Current) assisted by basic tools for structure characterization. Based on the obtained results about charge traps, the effect of nanofiller on trap characteristics and its microscopic mechanism will be explored by comparative study and comprehensive analysis of the correlation between the changes of trap characteristics and that of physical and chemical structures. Furthermore, the effect of trap characteristics on charge transport and space charge behavior in the nanocomposite dielectrics will be studied by conduction current and space charge measurement. The investigation on the formation mechanism and characteristics of charge traps has important theoretical guiding significance on the regulating of charge transport and space charge behavior by nanofiller.

陷阱对聚乙烯及其纳米复合电介质中的电荷输运和空间电荷抑制起着重要作用。本项目基于EPR(电子顺磁共振)及EPR-TSC(热刺激电流)联合技术和基本结构表征手段，研究陷阱电荷所在位置及其周围的物理化学环境，获得聚乙烯基纳米复合电介质中电荷陷阱的物理化学本质信息和陷阱特征参数。基于陷阱和基本结构表征结果，研究聚乙烯基纳米复合电介质中陷阱特性与纳米掺杂引起的聚乙烯结构变化的相关性，通过对比研究和综合分析揭示纳米掺杂对陷阱特性的影响及其微观机制，并结合电导特性和空间电荷分布测量进一步研究陷阱对纳米复合电介质中电荷输运和空间电荷行为的影响及其机理。对电荷陷阱机制及陷阱特性的研究，对通过纳米复合调控聚乙烯中电荷输运和空间电荷行为具有重要理论指导意义。

目前高压直流电缆绝缘广泛使用的聚乙烯材料在直流高场下其显著的空间电荷积累会加速绝缘的老化和击穿， 而且空间电荷显著的电场畸变效应使得电缆绝缘中实际电场的计算和设计变得困难。通过熔融共混获得氮化铝含量重量百分比分别为0.1%、0.5%、1%、3%、5%、7%的聚乙烯基氮化铝纳米复合绝缘材料。使用冷场发射扫描电镜仪对LDPE/AlN纳米复合薄膜样品断面形貌进行了表征。对AlN复合材料进行傅里叶红外光谱扫描。测试了不同掺杂浓度复合材料的空间电荷分布，陷阱能级分布及EPR谱图。试制了空间电荷与电导电流联合测量装置。建立基于双极性载流子输运的空间电荷抑制模型。并开发了一款基于电导率随温度，电场变化的电缆绝缘内电热耦合场分布仿真软件。