▎ 摘　　要

GIS plays an irreplaceable role in the modern electrical system. However, partial discharge will inevitably occur under insulation defect conditions and may lead to serious insulation malfunction. The online monitoring method based on gas sensor is a feasible method to diagnose the severity of partial discharge in GIS. In this paper, metal oxide (TiO2, Fe2O3, NiO) cluster-modified single-layer graphene was proposed as a novel gas sensor to detect the characteristic components of SF6 decomposition products, SOF2 and SO2F2. Density functional theory calculations were carried out to study the gas adsorption and sensing mechanisms. The adsorption structures of gas molecules and the metal oxide cluster-modified single-layer graphene were built and optimized. Then, the most stable structure was selected to analyze the corresponding adsorption parameters. Calculation results showed that metal oxides decoration reduces the energy gap, improving the electrical conductivity and enhancing the adsorption activity of the graphene surface. According to DOS and CDD analyses, TiO2 modification obtained the best adsorption effect. Calculation results show that the metal-oxide-modified graphene sensor provides an effective method for effectively estimating the operating state of GIS by detecting SF6 decomposition products. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.