接枝聚丙烯电缆绝缘材料的电树枝特性及机理  

Electrical Tree Characteristics and Mechanism of Grafted Polypropylene Cable Insulation

作　　者：张雯嘉 王伟[1] 袁浩 李琦[3] 何金良[3] Zhang Wenjia;Wang Wei;Yuan Hao;Li Qi;He Jinliang(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University,Beijing 102206,China;SINOPEC(Beijing)Research Institute of Chemical Industry Co.Ltd,Beijing 100013,China;State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]新能源电力系统全国重点实验室(华北电力大学),北京102206 [2]中石化(北京)化工研究院有限公司,北京100013 [3]电力系统及发电设备控制和仿真国家重点实验室(清华大学电机系),北京100084

出　　处：《电工技术学报》2024年第1期88-98,共11页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金重点项目(52237001);国家重点研发计划项目(2018YFE0200101);国家自然科学基金项目(51921005)资助。

摘　　要：开发高性能的可回收聚丙烯电缆绝缘材料已成为近年来电绝缘领域的研究热点之一。该文对纯聚丙烯(PP)及甲基丙烯酸甲酯(MMA)接枝改性聚丙烯试样的电树枝引发和生长特性进行了研究。试验结果发现,相较于纯聚丙烯试样,接枝试样的电树枝引发时间显著提高,电树枝劣化区域和生长速率明显减小。分析表明,接枝MMA单体在聚丙烯试样内部引入了大量深陷阱,并减小了球晶尺寸,有利于抑制载流子的输运行为并显著压缩了非晶区通道的空间尺度,进而改善了接枝试样的电树枝引发特性。此外,接枝试样的球晶尺寸减小使得非晶区通道更为曲折狭长,显著增加了电树枝沿着电场方向生长的阻力,进而改善了接枝试样的电树枝生长特性。随着MMA单体掺杂含量的增多,接枝试样的电树枝引发和生长特性逐渐提升。研究结果可为高性能接枝聚丙烯电缆绝缘材料的研发提供参考。To meet the requirements of increasing the transmission capacity of the power grid,the development of recyclable polypropylene(PP)cable insulation material has become a hotspot in recent years.The electrical tree is a serious electrical ageing phenomenon of insulation.When the cable runs in a high voltage environment for a long time,the ageing deterioration process will introduce a large number of defects in the insulating layer,and these defects will produce a local high electric field,which may initiate an electrical tree and result in insulation failure.A large number of research results show that graft modification can stably improve the dielectric properties of PP materials,but it is not clear whether graft modification can improve the electrical tree properties of PP cable insulation materials under long-term operation and the related mechanism.In this paper,the methyl methacrylate(MMA)monomer is grafted by the aqueous suspension method.A needle-needle electrode structure is applied in the electrical tree test.The needles are pre-embedded to avoid mechanical damage.The results show that compared with pure PP,the electrical tree initiation time of grafted PP is significantly improved,and the deterioration area and growth rate of the electrical tree are significantly reduced.With the increase of the MMA content,the electrical tree performance improves monotonously.Although the morphology of the trees is branch-like,the number of branches decreases as the grafting content increases.The trap distribution characteristics are studied,and it is found that after the MMA is grafted onto the PP matrix,the level of deep traps increases.As MMA content increases,the density of the deep traps increases gradually.The crystallization characteristics are studied in this paper.The results of differential scanning calorimetry show that the crystallinity drops when MMA is grafted,for the steric hindrance effect of the large side group volume of MMA monomers that hinders the orderly folding of PP chains.The spherulite morpholog

关 键 词：聚丙烯 接枝改性 电树枝 可回收电缆 

分 类 号：TM211[一般工业技术—材料科学与工程]