Towards the development of new DC railway system architectures with the use of superconducting devices

The new railway network envisioned by the French company SNCF must consider ultra-urban requirements and consequently review its architecture. Discovered in 1911, superconductivity is today used in a large range of high power devices and integrated in many domains of the society. Superconducting materials are able to carry high current without dissipating any joules losses during its operation. These materials can transmit current density 100 times higher than copper and they are interesting for applications requiring high transmitted currents. For example, low voltage DC power superconducting cables are well suited where the place for installation is limited such as urban railways grids. Taking the benefit from its transition from the superconducting to the resistive state, an innovative equipment to protect against faults is possible. In this article, two main devices are presented to upgrade the existing grid i.e. high power superconducting cables and fault current limiters. After a short presentation of the concept of superconductivity, these two apparatuses are detailed and their advantages discussed. Two envisioned applications in the railway grid are then presented and their benefits detailed.