A Simplified Method to Estimate Surface Trap Distribution: Potential Decay by Charge Dissipation Along Surface

Gas-insulated equipment is indispensable in dc transmission systems. Under the dc field, the surface charge accumulation could induce insulation failure. While the surface trap characteristic is a significant factor in surface charge accumulation and transportation, the surface trap distribution is often measured by the surface potential decay (SPD) method, where surface charges dissipate through the bulk of the sample. It is however difficult to distinguish this way carriers trapped on the surface and in material bulk. In addition, it is difficult to apply the SPD method in engineering practice because of the limitation imposed by sample thickness. To overcome these difficulties a novel and simplified method of SPD along surface (SPDS) measurement is proposed in this article, which allows for estimating the surface trap distribution and conductivity characteristics of the investigated insulator. As compared with the SPD through bulk (SPDB) method, the distribution of surface traps with micrometer sized metal particles on the surface is obtained.

Automated summary

Gas-insulated equipment is essential for dc transmission systems, but surface charge accumulation can lead to insulation failure. The surface trap distribution is typically measured using the surface potential decay (SPD) method, which dissipates surface charges through the sample bulk. However, distinguishing carriers trapped on the surface and in the material bulk is challenging, and the SPD method is difficult to apply in engineering due to sample thickness limitations. To overcome these challenges, a novel method called surface potential decay along surface (SPDS) measurement is proposed, which allows for estimating the surface trap distribution and conductivity characteristics of the insulator.