摘要
交联副产物等杂质解离易引起异极性空间电荷的积累,导致局部场强畸变。同时,交联聚乙烯(XLPE)直流电缆脱气处理后交联副产物杂质会在绝缘层中形成“内高外低”的浓度梯度分布,而杂质浓度梯度对空间电荷的影响尚不清晰。为此基于双极性电荷输运模型,引入杂质浓度梯度并考虑杂质离子对载流子的散射作用,仿真计算交联副产物杂质均匀分布与梯度分布对XLPE空间电荷与电场分布的影响,并分析影响杂质梯度效应的各种因素。结果表明:杂质梯度分布下XLPE空间电荷和电场分布表现出明显的杂质梯度效应,即低浓度侧异极性电荷积聚增多,导致其附近电场增强;而杂质解离势垒和杂质分布浓度是影响杂质梯度效应的主要原因,在杂质浓度梯度一定时,活化能越低,温度越高,解离势垒越低,载流子的迁移率相应降低,导致杂质梯度效应越明显;绝缘层厚度越大,杂质分布浓度越高,杂质梯度效应也越明显。
The dissociation of impurities such as crosslinking by-products can easily lead to the accumulation of heteropolar space charges,resulting in local field strength distortion.At the same time,after the cross-linked polyethylene(XLPE)DC cables is degassing,the crosslinking by-product impurity in the insulating layer will form a concentration gradient distribution of"high inside and low outside",and the effect of impurity concentration gradient on the space charge is still unclear.Therefore,based on the bipolar charge transport model,the effect of cross-linked by-products impurity with uniform distribution and gradient distribution on the XLPE space charge and electric field distribution were simulated and calculated,and various factors affecting the gradient effect of impurity were analyzed.The results show that under the impurity gradient distribution,the space charge and electric field distribution of XLPE show obvious impurity gradient effect,that is,there are more opposite polarity charges accumulated on the low concentration side,which leads to the enhancement of the nearby electric field.While the impurity dissociation barrier and the impurity distribution concentration are the main reasons of affecting the impurity gradient effect.When the impurity concentration gradient is constant,the lower the activation energy,the higher the temperature,the lower the dissociation barrier,and the lower the carrier mobility,which results in the impurity gradient effect more obvious.The larger the insulation layer thickness,the higher the concentration of impurity distribution,and the more obvious the impurity gradient effect.
作者
宋柯
王伟
钱定冬
鲍国栋
金煜知
SONG Ke;WANG Wei;QIAN Dingdong;BAO Guodong;JIN Yuzhi(Beijing Key Laboratory of High Voltage&Electromagnetic Compatibility,North China Electric Power University,Beijing 102206,China)
出处
《绝缘材料》
CAS
北大核心
2023年第4期40-47,共8页
Insulating Materials
基金
国家自然科学基金资助项目(51377056)。
关键词
交联聚乙烯
杂质
浓度梯度
空间电荷
电场
XLPE
impurity
concentration gradient
space charge
electric field
