纳米Al2O3掺杂对绝缘纸热老化电气特性的影响

摘要

为探究纳米Al2O3掺杂对纤维素绝缘纸热老化条件下电气特性的影响,在实验室制备了纳米Al2O3掺杂质量分数为2%的复合绝缘纸和普通绝缘纸手抄片,浸油后形成油纸复合绝缘样品,并在130 ℃老化箱中开展加速热老化试验.试验测试了不同老化阶段纳米复合纸与普通纸的电气参数及油纸老化产物,研究了纳米Al2O3掺杂提升绝缘纸电气性能的机理,并分析得到了老化过程对绝缘纸电气性能的影响规律.研究结果表明:掺杂纳米Al2O3的复合绝缘纸具有较好的交直流电气特性和抗热老化性能,认为纳米Al2O3的"介电双层"结构有效减弱了绝缘纸内界面极化和转向极化,降低了绝缘纸的相对介电常数及介质损耗.纳米Al2O3掺杂可以有效降低绝缘纸中载流子迁移率,增大其体积电阻率.Al2O3的高热导率及其与纤维素间的连接作用增大了绝缘纸热导率,加速了绝缘纸内热量扩散,提升了绝缘纸抗热老化性能.%In order to study the effect of nano-Al2O3 on the electrical properties of insulation paper under thermal aging, composite paper with 2% nano-Al2O3 and conventional paper were prepared, then the accelerated thermal aging test under 130 ℃ with conventional oil-paper and nano-Al2O3 composite oil-paper were performed.The main electrical parameters of paper and aging products in oil-paper system were tested.The modification mechanisms of nano-Al2O3 on electrical properties were researched, and the variations in properties of insulation paper during aging process were analyzed.The research results show that nano-Al2O3 improves the electrical properties and anti-aging ability of composite paper.The electric double layer structure of nano-Al2O3 can weaken the interfacial polarization and dipole polarization, which reduces the permittivity and dielectric loss.It is considered that nano-Al2O3 effectively decreases the carrier mobility and increases the volume resistivity of composite paper.High thermal conductivity of Al2O3 and the connection structure between nano-Al2O3 and cellulose chains may increase the thermal conductivity of insulation paper and accelerate the heat diffusion in composite paper, so that the anti-aging ability of composite paper gets enhanced.