表层非线性电导盆式绝缘子表面电荷分布与沿面放电特性

盆式绝缘子表面电荷积聚是影响直流气体绝缘输电管道(direct current gas insulated transmission line,DC-GIL)电场分布与沿面闪络的重要因素，因此探究绝缘子表面电荷积聚机理并提出调控方法，进而改善绝缘子沿面电场分布具有重要意义。该文搭建缩尺直流GIL绝缘子试验平台，研究不同Si C质量分数(23.1%、37.5%、47.4%)的非线性电导涂层对直流电压、金属微粒附着和极性反转工况下盆式绝缘子表面电荷分布与沿面闪络特性的影响规律。结果表明：环氧基Al₂O₃绝缘子的表面电荷极性取决于气固侧电流密度博弈结果，具有显著的场强依赖特性；非线性电导涂层可以自适应调控直流GIL绝缘子的表面电荷与沿面电场分布，显著提高不同工况下的沿面闪络电压。该文的研究结果为高可靠性直流GIL绝缘子的研发提供了一种潜在的解决方案。

Surface Charge Distribution and Discharge Behaviors of Basin Spacer With Surface Nonlinear Conductivity

The surface charge accumulation on the basin-type spacer significantly affects the electric field distribution and the flashover in the direct current gas insulated transmission line(DC-GIL).Therefore,it is of great significance to investigate and regulate the surface charge distribution on the spacer,thus improving the electric field distribution.Based on the experimental platform of a downsized DC-GIL,the influences of different nonlinear conductivity coatings(mass fraction of SiC:23.1%,37.5%and 47.4%)on the surface charging and discharging behaviors of the basin-type spacer were studied under different conditions,i.e.,DC,metal particle,and polarity reversal operation.Results show that the surface charge polarity on the epoxy/Al₂O₃ spacer depends on the competition result between the bulk conduction and the gas conduction,which is significantly field-dependent.The surface nonlinear conductivity(SNC)spacers can adaptively regulate the surface charge and the electric field distributions,thus improving the flashover voltages under different operation conditions.This study provides a potential solution for developing novel DC-GIL spacers with high reliability.