Establishment of Power Cable Dynamic Three-Dimensional Thermal Model Serving Digital Twin

This paper proposes a cable thermal model that serves digital twin, achieving fast response and high-precision calculations. Firstly, a two-dimensional cable thermal circuit model is established, and the heat transfer mode of air gap layer is analyzed. The equivalent thermal parameters of air gap layer are calculated by using the finite element method, solving the calculation accuracy problem caused by the excessive simplification of IEC standard. Secondly, considering the axial heat transfer of the cable and the corrugated structure of sheath, a method for calculating the equivalent outer diameter of corrugated sheath and a three-dimensional thermal model construction method are proposed. The axial heat transfer ability of each layer is analyzed and the three-dimensional model is optimized. Finally, a framework and construction method for a dynamic calculation model are proposed, realizing dynamic calculation of cable capacity while environmental parameters changes. The superiority of this model is verified through speed and accuracy comparisons with finite element method.