掺杂纳米Al_2O_3对纤维绝缘纸电寿命的影响及机理

Influence and Mechanism of Doped Nano-Al_2O_3 on Electrical Life of Cellulose Insulating Paper

纳米Al_2O_3掺杂能有效提升纤维绝缘纸的热寿命,为进一步探究其对纤维绝缘纸电寿命的影响,在实验室制备了纳米Al_2O_3改性纤维绝缘纸(质量分数为2%的掺杂量)和普通纤维绝缘纸手抄片,均采用矿物油进行真空浸渍后作为对比研究对象。在多样品绝缘材料电老化试验平台上,对两种油浸绝缘纸分六种不同电压开展加速电老化试验,以绝缘击穿失效作为寿命终点,利用电寿命反幂函数模型,分别计算并对比了其寿命指数,并对其介电性能进行测试。结果表明,相较于改性前的油浸绝缘纸,改性后的油浸绝缘纸具有更低的相对介电常数及介质损耗,寿命指数提高了20%,具有更高的抗电老化性能及更长的电寿命。最后,结合改性前后介质中电场分布、介质损耗及传导电流变化,分析了纳米Al_2O_3掺杂对油纸绝缘电寿命的影响机理。

Nanometer Al2O3 doping has been proved to be effective in improving the thermal life of cellulose insulation paper.In order to explore its further effect on the electrical life of cellulose insulation paper,nano-Al2O3 modified cellulose insulation paper(2%doping amount)and ordinary cellulose insulation paper were prepared in the laboratory.All the experiment samples were impregnated with mineral insulating oil under the same condition.Then the two kinds of samples were carried out accelerating aging test under 6 ranks of voltage with the multi-sample insulation material electrical aging test platform.Taking insulation breakdown failure as the end of life,inverse power function as the electrical aging lifetime model,the index of life expectancy was compared.The results show that,compared to the unmodified oil impregnated paper,modified oil impregnated paper has lower relative dielectric constant and dielectric loss.Moreover,the life index increased by 20%,with higher dielectric aging performance and longer life.Finally,the mechanism of nano-Al2O3 doping on the electrical life of oil paper insulation was analyzed in terms of the electric field distribution,dielectric loss and conduction current change before and after modification.