Thermal Problems in Gas-Insulated Transmission Lines Solved by the Finite-Element Method

In this paper, the finite-element method (FEM) is employed to investigate the steady state and the transient temperature distribution of a gas-insulated transmission line (GIL). Eddy current field is calculated and coupled to fluid and thermal model by means of element mapping. Temperature-dependent characteristics of materials constituting GIL are considered. As two different fluid species, insulating gas and ambient air are included in the model. Hence, unlike the generalized methodology, constant temperature boundary condition at the outer boundary of ambient air is substituted for heat transfer coefficient at the interface of surrounding air and the GIL enclosure. The concordance between the predicted temperature values and experimental results in the literature validates the accuracy of the model.