硫代受阻酚复合抗氧剂对聚丙烯直流电缆绝缘空间电荷与直流预压击穿特性的影响  

Effect of Hindered Phenolic Antioxidants on Space Charge and DC Prestressed Breakdown Properties of HVDC Cable Polypropylene Insulation

作　　者：刘畅 李忠磊 周硕凡 范铭升 杜伯学 LIU Chang;LI Zhonglei;ZHOU Shuofan;FAN Mingsheng;DU Boxue(School of Electrical and Information Engineering,Tianjin University,Tianjin 300072)

机构地区：[1]天津大学电气自动化与信息工程学院,天津300072

出　　处：《电气工程学报》2021年第2期42-49,共8页Journal of Electrical Engineering

基　　金：国家自然科学基金资助项目(52077148)。

摘　　要：聚丙烯(Polypropylene,PP)高压直流电缆绝缘的电导、空间电荷与击穿特性是评价其电学性能的关键性指标。为此选取了两种具有同分异构结构的硫代受阻酚类抗氧剂4,4’-硫代双(6-叔丁基间甲酚)(AO300)和4,4’-硫代双(6-叔丁基邻甲酚)(AO736),研究了抗氧剂对PP绝缘电导、空间电荷及极性反转下的击穿特性的影响规律和机理。试验结果表明,两种抗氧剂均会在PP中引入深陷阱中心,增大电导活化能,减少空间电荷积聚,并显著提高极性反转后的直流击穿强度。基于量子化学计算获得了两种抗氧剂的能带分布和键解离能(Bond dissociation energy,BDE),发现AO736相较于AO300可引入更多用以捕获高能电子的局域态陷阱,抑制高能电子对PP分子链的破坏过程;同时AO736中的氢氧键具有较低的BDE,反映出其具有更强的自由基清除能力,通过阻止PP中的自由基链式反应从而抑制击穿过程。分析认为,AO736可明显改善高压直流电缆用聚丙烯绝缘空间电荷和极性反转电压下的击穿性能。The conductivity,space charge and breakdown strength are the key indicators to evaluate the electrical properties of polypropylene(PP)for HVDC cables.Two isomeric hindered phenolic antioxidants 4,4’-thiobis(6-tert-butyl m-cresol)(AO300)and 4,4’-thiobis(6-tert-butyl o-cresol)(AO736)are selected to investigate the effects of antioxidants on conductivity,space charge and breakdown after polarity reversal properties for PP.The experimental results show that these two antioxidants can introduce deep trap sites into PP,thereby increasing the conductivity activation energy,reducing the space charge accumulation,and improving the DC breakdown strength after polarity reversal.Based on quantum chemistry calculations,the energy band distributions and bond dissociation energy(BDE)of the two antioxidants are obtained.It is found that AO736 can introduce more trap sites than AO300,which capturing high-energy electrons and suppressing the destruction process of PP molecular chain.Besides,the hydrogen-oxygen bond in AO736 has a lower BDE,reflecting a stronger free radical scavenging ability,and the breakdown process is suppressed by preventing the free radical chain reaction According to the analysis,AO736 can significantly improve the space charge and breakdown after polarity reversal properties of PP for HVDC cables.

关 键 词：高压直流电缆 聚丙烯 抗氧剂 空间电荷 击穿强度 量子化学计算 

分 类 号：TM215[一般工业技术—材料科学与工程]