Numerical Analysis of Space Charge Characteristics in Low-density Polyethylene Nanocomposite Under External DC Electric Field  

作　　者：ZHOU Yuanxiang ZHANG Ling SHA Yanchao TIAN Jihuan 

机构地区：[1]State Key Laboratory of Control and Simulation of Power System and Generation Equipments, Tsinghua University, Beijing 100084, China [2]ABB Corporate Research Center, Beijing 100015, China

出　　处：《高电压技术》2013年第8期1813-1820,共8页High Voltage Engineering

基　　金：Project supported by National Basic Research Program of China （973 Program） （2014 CB239501, 2011CB209400）, National Natural Science Foundation of China （NSFC 50877040）.

摘　　要：The dynamic characteristics of space charge in nanocomposite of low-density polyethylene (LDPE) mixed with inorganic nano- fillers. Different from previous qualitatively theoretical works, we investigated the influence of trap depth, trap volume charge density and injection barrier height on the space charge and the electric field distribution in the nanocomposite under a DC external electric field (100 MV/m) systematically and quantificationally, through numerical simulations based on a bipolar charge transport model. The simulation re- sults showed that, the increase of trap depth would severely distort the balanced electric field distribution with the highest and the lowest electric field of 119 MV/m and 47 MV/m, respectively. It is concluded that the introduction of nanofillers creates more deep traps, which would block space charges by capturing most of them in the vicinity of electrode and hence reduce the local electric field largely. Further theoretical analysis of the simulation indicates that both the high permittivity and the low local electric field of the nanocomposite contri- buted to the increase of injection barrier height, and almost no charge could overcome an injection barrier higher than 1.25 eV. At last, a mechanism of space charge suppression in the LDPE nanocomposite was presented.The dynamic characteristics of space charge in nanocomposite of low-density polyethylene （LDPE） mixed with inorganic nano- fillers. Different from previous qualitatively theoretical works, we investigated the influence of trap depth, trap volume charge density and injection barrier height on the space charge and the electric field distribution in the nanocomposite under a DC external electric field （100 MV/m） systematically and quantificationally, through numerical simulations based on a bipolar charge transport model. The simulation re- suits showed that, the increase of trap depth would severely distort the balanced electric field distribution with the highest and the lowest electric field of 119 MV/m and 47 MV/m, respectively. It is concluded that the introduction of nanofillers creates more deep traps, which would block space charges by capturing most of them in the vicinity of electrode and hence reduce the local electric field largely. Further theoretical analysis of the simulation indicates that both the high permittivity and the low local electric field of the nanocomposite contri- buted to the increase of injection barrier height, and almost no charge could overcome an injection barrier higher than 1.25 eV. At last, a mechanism of space charge suppression in the LDPE nanocomposite was presented.

关 键 词：纳米复合材料 低密度聚乙烯 直流电场 空间电荷 电荷特性 数值分析 无机纳米填料 陷阱深度 

分 类 号：O241[理学—计算数学] TB332[理学—数学]