Diagnostic of the Decomposition of Sulphur Hexafluoride (SF₆) in Gas-Insulated Equipment, Due to Partial Discharges, Using Hollow Carbon Nanotubes

Sulphur hexafluoride, SF₆ gas has excellent physical and chemical properties and insulation arc extinction performance. It has been widely used in electric power systems and other electrical equipment due to such advantages, as compact size and high reliability. SF₆, can be decomposed into different gases, when the equipment exhibits arc discharge, local heating of contactor, and partial discharge. It is important to detect decomposition of insulating gas SF₆, caused by partial discharges for gas-insulated switchgear. Partial discharge in gas-insulated switchgear can lead to the generation of multiple decomposition products of SF₆, and the detection and analysis of these decomposition products is important for fault diagnosis. The detection of decomposition components is needed to maintain on-line running state monitoring. Recently, interest in carbon nanotubes has been rapidly growing in various scientific and engineering fields, because of their faster response, higher sensitivity, lower operating temperature and a wider variety of detectable gas. In this paper, a molecular dynamics simulation software package, Materials Studio, is used to model accurately the processes by which single-walled carbon nanotubes could detect studied gases. All calculations were performed using the DMol³module of the Materials Studio. We compute the preferential adsorption sites, bonding configurations, and adsorption geometry for molecular adsorption. Results of analysis of electrical characteristics reveal that SWCNTs show different responses to the decomposed gases