Thermal and Electromagnetic Design of DC HTS Cables for the Future French Railway Network

Abstract

The use of High Temperature Superconducting (HTS) cables as a technology is considered as key to increasing the power of the electrical grid while reducing the volume of installation. In addition, when transmission currents exceed a few kA, DC HTS cables significantly reduce power losses, rights-of-way and total system mass. This article describes the various studies that need to be carried out in order to correctly size HTS DC cables for the new railway network envisaged by the French company SNCF, which must consider ultra-urban needs. The process used to design DC cables for operating powers of 10, 20 and 30 MW at a nominal voltage of 1.5 kV using commercial (RE)BCO tapes is presented. In this sizing process, the critical current density Jc(B, θ, T) dependence of the superconducting tapes, the thermal properties of the materials and the different cooling modes are taken into account. Several solutions are suggested to ensure that the cable can withstand fault currents and reduce recovery time in the initial state. Finally, with the help of analytical models and industrial data, once the cables have been designed, the various system losses are reported as well as the power or size of the various auxiliary components.

SuperRail–World-First HTS Cable to be Installed on a Railway Network in France

“…In this regard, the GREEN laboratory at the University of Lorraine is actively developing computational tools to simulate superconducting cables in railway networks. The models take into account electromagnetism, heat transfers, hydraulics and circuit equations, including the structure of electrical network [42]- [44]. These models will be validated using data from the SNCF-AEF type test loop and the Montparnasse-Fig.…”

Design and modelling tools for DC HTS cables for the future railway network in France

“…In this part, we determine the expressions of the magnetic field from the relation (2), then from the passing conditions (10), (11) and (12). We determine the expressions of the coefficients of the three magnetic field components in each region.…”

“…In such a case, where the determination of the twisting pitch of the tapes and the calculation of the axial component of the magnetic field are not taken into account, the mass and total length of the tapes used in the cable may be underestimated. In addition, the steady state thermal model of the various cooling systems in [11] has not been fully covered. This is because the calculation of pipe heating as a function of length does not take into account the heat generated by the fluid flow in a pipe, as this assumption may not be appropriate for very long cables.…”

“…In a previous study [11], an iterative procedure has been developed for the complete sizing of the DC superconducting cable for the RN. The sizing process and obtained results are based on the minimization of the total number of tapes with a 2D electromagnetic model.…”

Impact of Superconducting Cables on a DC Railway Network

“…The same cooling system is used for both topologies of cables. The algorithm developed to dimension the system is found in [38]. This algorithm estimates the heat losses of the HTSC cable, the terminations, and the components of the cooling system.…”