Impulse Flashover Characteristics in SF6 Gas for Insulating Spacer Model of GIS Fabricated Using Nano-micro Composites

摘要

The authors investigate the effect of nano-micro composite(NMC) on creepage discharge withstand voltage characteristics in SF6 gas for miniaturization of gas insulated switchgear(GIS). In this paper, nano-micro composites (NMC) material were prepared used for investigating the effect of NMC on flashover properties of epoxy spacer model. Micro composite(MC) was firstly prepared by mixing Bisphenol A type epoxy resin (EP) and microfiller SiO2 filled to 47 vol% with respect to epoxy resin. MC were filled with 1 vol% nanofiller (SiO}2, TiO2, SrTiO3) to prepare NMC. The insulating spacer model electrode with reduced dimensions from an actual spacer was prepared to measure the flashover voltage (FOV) in SF6 gas by applying one shot of negative standard lightning impulse voltage that causes flashover at the wave front to discuss the improvement effect. It was found that FOV of NMC filled with nSiO2, nTiO2 and nSrTiO3 increases by 19 %, 16 % and 22 %, respectively, as compared to that of MC. The FOV increase of the spacer consisting of NMC is interpreted to be due to suppression of electron emission from the sample surface by introducing deep electron trap levels by adding the nanofiller.