Analysis of the Sensitivity of K-Type Molecular Sieve-Deposited MWNTs for the Detection of SF(6) Decomposition Gases under Partial Discharge

Sulfur hexafluoride (SF(6)) is widely utilized in gas-insulated switchgear (GIS). However, part of SF(6) decomposes into different components under partial discharge (PD) conditions. Previous research has shown that the gas responses of intrinsic and 4 Å-type molecular sieve-deposited multi-wall carbon nanotubes (MWNTs) to SOF(2) and SO(2)F(2), two important decomposition components of SF(6), are not obvious. In this study, a K-type molecular sieve-deposited MWNTs sensor was developed. Its gas response characteristics and the influence of the mixture ratios of gases on the gas-sensing properties were studied. The results showed that, for sensors with gas mixture ratios of 5:1, 10:1, and 20:1, the resistance change rate increased by nearly 13.0% after SOF(2) adsorption, almost 10 times that of MWNTs sensors, while the sensors’ resistance change rate with a mixture ratio of 10:1 reached 17.3% after SO(2)F(2) adsorption, nearly nine times that of intrinsic MWNT sensors. Besides, a good linear relationship was observed between concentration of decomposition components and the resistance change rate of sensors.