Study on GIS Temperature Rise Characteristics and the Related Influencing Factors under Internal Overheating Defect

摘要

In recent years, current-carrying faults caused by overheating of GIS conductors have frequently occurred, posing a serious threat to the safe and stable operation of the power grid. When the GIS conductor has overheating defects, a local overheating area will be formed on the shell surface through the heat transfer of SF6. The overheating defects can effectively be found using the infrared thermometer to detect the temperature of the shell surface. Firstly, 3-D multi-physics coupled model was established to analyze the electromagnetic field, temperature field and gas flow field of 252 kV three-phase sub-aspect bus in GIS. Then, the overheating temperature rise characteristics in GIS and the influence of load current and ambient temperature were analyzed. The results show that the temperature rise distribution of the conductor and the shell shows an exponential decline. Under the convective diffusion of SF6, the shell generates overheating characteristics directly above the overheating defect. The larger the current, the greater the heating power loss, the faster the SF6 convection diffusion rate, and the higher the temperature rise in conductor and shell surface. Ambient temperature has little effect on the temperature rise characteristics of GIS. However, the temperature of the conductor and the shell decreases due to increased heat dissipation as the ambient temperature decreases. And the overheating defects is difficult to find because of the weakness of overheating characteristic spectrum. The research results of this paper are helpful for accurate analysis of the infrared temperature measurement results on site, and have important engineering application value.