环氧复合材料表面电位衰减与直流电导特性

Surface Potential Decay and DC Conductivity Characteristics of Epoxy Composites

气体绝缘输电管道（GIL）绝缘子通常由环氧树脂／Al2O3复合材料浇注而成。在直流电压及负载温升作用下，绝缘子表面易积聚电荷造成电场畸变，进而引发沿面闪络。本文为探索非线性ZnO填料对环氧树脂／Al2O3／ZnO复合材料绝缘性能的影响规律，对直流电压下不同ZnO含量的环氧复合材料表面电位衰减进行了测量，分析了不同温度对表面电荷特性的影响，得到了基于电荷消散的非线性电导变化规律。研究结果表明：直流电压下，ZnO颗粒掺杂可以明显促进环氧复合材料表面电荷消散；随着温度升高，载流子迁移率增大，表面电荷的消散速度加快；当ZnO含量超过一定阈值时，电导率在高场下呈现非线性特性，从而抑制环氧树脂复合材料表面电荷积聚。相关结果为非线性电导复合材料在调控直流气体绝缘输电管道绝缘子表面电荷特性方面的应用提供了参考。

Epoxy/Al2O3 composites are usually used to cast GIL insulators. Under the effects of DC voltage and temperature rise caused by load, the charges are prone to accumulate on the insulator surface and thus cause electric field distortion, which may in turn cause surface flashover. In order to explore the effect of non-linear ZnO fillers on the dielectric properties of Epoxy/Al2O3/ZnO nonlinear composites, the surface potential decay of epoxy composites with different ZnO contents under DC voltage was measured. The effects of different temperatures on the surface charge characteristics were analyzed and the nonlinear conductivities based on charge dissipation was obtained. The results show that ZnO particles can significantly promote the surface potential degradation of epoxy composites under DC voltage. With the increase of temperature, the carrier mobility increases and the surface charge dissipates faster. When the ZnO content exceeds a certain threshold, the conductivity shows a nonlinear behavior in the high field, which suppresses the surface charge accumulation of the epoxy composite. The results provide references for the application of nonlinear conductivity materials in the control of surface charge characteristics of insulators in DC gas insulated lines.