Superconducting cables have benefits over traditional cables: they can carry much higher power levels on the same underground cross-section, and their greater transport efficiency in both AC and DC makes them suitable for many current and future uses. Furthermore, they are more sustainable due to the absence of copper. However, their technological maturation and commercialization will still require at least a decade for HV cables.
In order to understand the possible configurations of SC cables, their performance and the related technical and economic aspects, in recent years RSE has developed various mathematical models in the context of System Research that allow for the simulation of the thermo-fluid-dynamic behavior of cryogenic fluids conveyed in forced convection in cryostats of superconducting cables, and implemented these models in dedicated calculation programs. In particular, this report describes the activities that concern the validation of fluid dynamic models and the development of electrical models for technical-economic evaluations.
As regards the first point, methodologies have been developed to check the accuracy and numerical precision of the RSE model in order to understand the discrepancies that emerged in the comparison with benchmarks with the 4C software of the Politecnico di Torino. Numerical simulations for cables with new data on thermal inputs into the cryostat and friction factors: results and controls according to the developed methodologies. Furthermore, new formulations were identified and implemented for the thermal power entering the cryostat and for the friction factor between fluid and cryostat.
Regarding the second point, a methodology has been developed to optimize the configuration of coaxial HTS cables in different operating conditions. The activity, carried out in collaboration with the University of Bologna, is part of the general analysis of the electrical behavior of superconducting cables for the national electricity grid, aimed at defining any technical-economic advantages compared to conventional resistive cables. The study focuses on medium voltage alternating current (AC) power lines, made with high critical temperature superconducting (HTS) materials.

This work intends to provide a computational methodology aimed at determining the optimal configuration of coaxial HTS cables, and the related cost, with different operating conditions.