Study on the Temperature Distribution Characteristics of SF6 Gas in GIS Based on Multi-Physical Field Coupling

The abnormal temperature rise of the conductor in Gas Insulated Switchgear (GIS) can accelerate insulation aging and reduce the mechanical properties of metal materials, and lead to the equipment failure eventually. It is critical to monitor the temperature of the GIS conductor. However, the method of inferring the conductor temperature rise based on the GIS enclosure temperature is inaccurate under the influence of the rapidly changing environment. In contrast, the MEMS temperature sensor can directly measure the temperature of SF
6
gas that are not easily susceptible to external influences in order to realize more accurate inference. The installation of the temperature sensor and the analysis of the results need to be based on the temperature distribution characteristics of SF
6
gas in GIS. Therefore, in this paper, the temperature distribution characteristics of SF
6
gas in GIS are studied based on the electromagnetic-fluid-temperature field coupling simulation model. The model takes account of physical parameters such as GIS structures, voltage levels, ambient temperature, and load current. The results show that the temperature distribution of SF
6
gas presents obvious stratification due to natural convective heat transfer. And the conductor temperature is highly correlated with the temperature of the monitoring point and the ambient temperature. According to the correlation, the temperature of conductor can be monitored precisely through the MEMS temperature sensor at the monitoring point and any temperature sensor outside.