Finite Element Analysis of Thermal Problems in Gas-Insulated Power Apparatus With Multiple Species Transport Technique

Thermal analysis is paramount in the design process of gas-insulated power apparatus. In this paper, a multiple species transport technique is proposed to deal with the heat transfer problem of gas-insulated power apparatus, in which the ambient air as well as SF6 gas is included in the solution region. The FEM is employed to investigate the coupled eddy current, fluid, and thermal fields. Temperature-dependent electric and thermal properties of the materials are considered. The power losses calculated from electromagnetic analysis are used as heat input for fluid and thermal analysis, in which the need for convective boundary condition is eliminated. The proposed method is applied to the thermal analysis of both single- and three-phase bus bars and is validated by comparison with the analytical method and experimental results reported in the literature.