Application of combined SF6 gas decomposition products and partial discharge detection technology to detection and location of latent faults of basin insulators

UHV basin insulator has the dual functions of the mechanical support and electrical insulation. Especially under the UHV level, the long-term combined effect of high voltage/ large current/strong load has become the weak link of ultra long distance GIS/GIL pipeline. On the other hand, super long GIS/GIL pipelines are generally filled with SF6 insulating gas. Therefore, for UHV basin insulators, there are complex interface environments such as metal interface epoxy resin interface (solid solid interface) and epoxy resin interface SF6 insulating gas interface (solid gas interface). Under the action of UHV AC/DC voltage for a long time, it is easy to generate local high field strength areas at the interface. Moreover, under the action of large current, there is the thermal expansion and contraction mechanical stress, and void defects tend to appear in the interface area under action of repetitive/long-term tensile/shear stress, so partial discharge signals appear at the same time. Local high temperature and local electric field concentration also lead to the decomposition of SF6 gas. Due to the presence of epoxy resin solid materials of the basin insulator and the presence of carbon and fluorine decomposition products, the combination of SF6 gas decomposition products and partial discharge detection technology can be applied to the detection and location of latent faults of the basin insulator. Based on this, starting from the electrical performance of the hybrid system of epoxy resin and alumina of UHV basin insulator, this paper further analyzes topology optimization design of basin insulator, and applies UHF technology and photo-acoustic spectroscopy technology to high-sensitivity detection of SF6 gas decomposition products and partial discharge. In the detection, the type of decomposition gas such as CF4/SO2/CO shall be focused, and the type of bubbles and free metal particles in the solid insulation shall be focused on for partial discharge. The research shows that there is a strong correlation between the decomposition products of SF6 gas and the results of partial discharge detection data, and the latent fault detection and historical data prediction of UHV basin insulator can be realized through data intelligent fusion algorithm. The research results of this paper have the good guiding significance and the scientific research value for the troubleshooting and operation maintenance of the UHV basin insulators.