Research on Detection of overheat Fault in GIS Equipment Based on Non-isothermal Flow of SF6 Gas

Aiming at the problems of SF6 electric equipment latent period of internal overheating failure and difficult monitoring, and the SF6 gas in the GIS isolation switch gas chamber has the characteristics of non-isothermal flow with invariable volume. The coupled fluid-thermal field is established of SF6 based on the heat conduction differential equation, the fluid motion control equation and the radiation heat transfer equation. The COMSOL finite element simulation software was used to calculate the different temperature of fault points (333.15K~453.15K). The distribution of temperature, velocity and pressure of SF6 gas in different positions of an isolated switch gas chamber is calculated, according to the simulation results, it is the first time to demonstrate the effectiveness of using pressure to detect the internal overheating failure in the gas chamber.