Thermal field calculation in gas insulated busbars based on fluid multiple species transport

Thermal stress is an important factor affecting the aging of insulators in Gas Insulated Busbars (GIB). However, at present, there is little temperature monitoring system installed in GIB in the field. Thus, it is impossible to obtain the data of insulator temperature for assessing the aging of insulators directly. In order to solve the problem, a simulation model of thermal field was established, and the temperature of the insulator during service can be obtained based on the proposed model and the operating current. In the model, the heat transfer processes including the heat conduction, heat radiation and thermal convection in GIB were considered. The investigation results show that, the distribution of temperature field in GIB was greatly affected by thermal convection. For the vertically arranged GIB, the insulator temperature of the lower surface was higher than the upper surface. When the ambient temperature was 293.15 K, the maximum insulator temperature in 126 kV GIB was 329 K for the operating current reached 2000 A. The temperature difference between the center conductor and the enclosure reached 30 K. Therefore, the insulator near the center conductor was more susceptible to thermal aging. This simulation model can be used to obtain the temperature of the insulator during service. Moreover, it is hoped to be helpful for assessing the aging of insulators in GIB in future work.