CNFs 取向对 CNFs／LDPE复合材料空间电荷的影响

摘要

Under high voltage condition ,space charge is the key that inhibit the performance of the DC cable .Polyethylene nanocomposites have excellent space charge inhibition characteristics ,and has been successfully used in high-voltage DC cables .In this paper ,the semi-conductive materials as the matrix ,the carbon nanofibers (CNFs) were surface-metallized and the CNFs oriented along the magnetic field direction in the semi-conductive materials ,and then with LDPE composite made double samples .Use pulsed electroacoustic (PEA ) method ,analysis space charge behavior in the applied voltage and short circuit .The results showed that the space charge of the composite material had great influence due to the doping concentration and orientation .Oriented CNFs/LDPE were successful in changing the carrier transport and suppressing the injection of the space charge along the thickness direction .That was extremely meaningful in HVDC .%高压直流电缆绝缘材料中空间电荷特性是制约直流电缆性能的关键因素。聚乙烯纳米复合材料因具有优异的空间电荷抑制特性，而被成功运用于高压直流电缆。本文研究了以半导电料为基体，以CNFs粒子，通过对其进行表面改性，使CNFs在材料中沿磁场方向取向，而后再与LDPE进行复合，制成双层样片。并且使用电声脉冲法（PEA ）分析了复合材料在加电压与短路时的空间电荷的分布。研究发现，掺杂浓度与取向对复合材料的空间电荷影响较大。取向CNFs/LDPE半导电层的添加改变了载流子的输运方式，抑制了空间电荷由电极向绝缘层中的注入。这对于取向CNFs/LDPE复合材料在高压直流输电中的应用是非常有意义的。