纳米碳化硅/液体硅橡胶复合材料非线性电导特性

Non-linear Conductivity Characteristic of Si C/LSR Nanocomposite

为解决高压直流电缆附件中因复合绝缘材料电导率差异而引起的电场分布不均问题,采用纳米碳化硅为填料,对附件绝缘加成型液体硅橡胶进行改性,制备了具有非线性电导特性的纳米碳化硅/液体硅橡胶复合材料。同时对比研究了纯硅橡胶和质量分数分别为1%、3%、5%的纳米碳化硅/液体硅橡胶复合材料的非线性电导特性和介电特性。研究结果表明:相比于纯硅橡胶,纳米碳化硅/液体硅橡胶复合材料的电导率从原来的10-15 S/m增加到10-14~10-13 S/m左右,非线性系数由0.3提高到1.03,相对介电常数增加了0.46,介质损耗因数基本不变。为了验证非线性纳米碳化硅/液体硅橡胶复合材料在直流电缆附件内均化电场的效果,采用Comsol-Multiphysics软件,对其电缆终端和中间接头内的电场分布进行了仿真分析。仿真结果表明:将非线性纳米碳化硅/液体硅橡胶复合材料应用于高压直流电缆附件应力锥处,其电场集中最大值下降了80%,实现了均化电场的目的。

To solve the problem of non-uniform electric field distribution in high voltage direct current （HVDC） cable accessory, which was caused by the difference of conductivity of the composite insulation materials, nano silicon carbide （SIC） was added to the liquid silicone rubber （LSR） to prepare the nanocomposites with non-linear conductivity charac- teristics. The conductivity and dielectric properties of pure LSR and SiC/LSR nanocomposites with mass fraction of 1%, 3% and 5% were tested and studied. The results show that the conductivity of SiC/LSR nanocomposites increases from 10-15 S/m to 10-14 S/m-10-13 S/m, nonlinear coefficient increases from 0.3 to 1.03, the relative dielectric constant increas- es by 0.46, and the dielectric loss factor hardly changes compared to those of the pure LSR. In order to verify the effect of electric field homogenization of SiC/LSR nanocomposite within DC cable accessory, the simulation of electric field dis- tribution in DC cable accessory is analyzed by Comsol-Multiphysics. The results show that non-linear SiC/LSR nanocomposites applied to cable accessory stress cone can make the maximum electric field concentration decreased by 80% and realize the homogenization of electric field.