Study on PD detection in SF6 using multi-wall carbon nanotube films sensor

The detection of partial discharge (PD) and the analysis of SF₆ gas components in gas insulated switchgear (GIS) have great significance for the fault diagnosis and running state assessment of power equipments. In this paper, a method of detecting SF6 decomposition components caused by PD is proposed. Accordingly, multi-wall carbon nanotube (MWNT) films sensors which is used to detect PD of SF₆ is developed. By adopting a kind of chemical modification with concentrated sulfuric acid and nitric acid, the functional modification to carbon nanotubes (CNTs) was realized, as well as transmission electron microscope (TEM) and infrared spectrum analysis of the CNTs both before and after the modification. The test was conducted for MWNTs films sensor in the laboratory using SF₆ gas PD decomposition component testing device. Test results show that, the MWNTs films sensor has many defects and active functional groups and with strong absorption capacity for SF6 decomposition components; it shows good sensitivity and fast response characteristics, and can reflect the overall state of gas decomposition components.