In this paper, a new diagnosis method for SF6 gas-insulated switchgear (GIS) is proposed based on decomposition gas analysis. We focus on residual CF4 gas in GIS, which is a decomposition gas generated in GIS via partial or arc discharge. Unlike other decomposition gases, which can be removed by the gas absorbent, CF4 accumulates during in-service operation, enabling trend-based GIS condition monitoring. Because direct CF4 detection using commercially available gas sensors is difficult, we propose a novel indirect detection method in which CF4 is converted into CO and CO2 by a dielectric barrier discharge (DBD). A DBD-treated artificial gas mixture composed of CF4, O2, and SF6 was analyzed via Fourier transform infrared spectroscopy (FTIR). It was found that CO and CO2 are simultaneously generated when the CF4 gas concentration is higher than 100 ppm, which is close to the target CF4 concentration for GIS diagnosis. To demonstrate rapid, simple, and on-site diagnostic capabilities, a commercial electrochemical CO gas sensor was employed to detect DBD-converted CO gas. The CO concentration quantified by the calibrated gas sensor was almost identical to that obtained via FTIR. As the CF4-to-CO conversion rate is expected to improve with an optimum DBD reactor design, the proposed scheme could be applicable to GIS diagnosis.
|Journal||International Journal of Plasma Environmental Science and Technology|
|Publication status||Published - 2021|
All Science Journal Classification (ASJC) codes
- Environmental Science(all)