Ultra-low electrical loss superconducting cables for railway transportation: Technical, economic, and environmental analysis

Carbon emission from various transportations is one of the major factors towards global warming. With the increasing energy demand from railway transportation, the conventional copper cables with high electric currents and considerable amounts of resistances are facing challenges, e.g., electric loss and heat. This article proposed a novel ultra-low electrical loss hybrid-energy transmission scheme. A real cable sample was fabricated, and the experiment proved the high-current carrying capability. A cable model was built to study the loss and electromagnetic behaviours by different optimization strategies. A general design guideline was established to help those non-experts to easily design their own hybrid-energy superconducting cables. The technical, economic, and environmental analysis was performed for a 1.5 kV/10 kA superconducting cable to transmit hybrid energy in a railway traction system. Results showed that reducing losses by the proposed method can efficiently reduce annual operating costs, e.g., the loss from 0.9 W/m to 0.46 W/m, the annual operating cost from 16, 644, 000 CNY to 8,935,000 CNY and the annual CO2 emissions form 2518 ton to 1090 ton. Overall, the optimization successfully improved the cable performance, and the analysis validated the technical feasibility and economic/ environmental benefits of the novel hybrid-energy transmission system to be used into railway systems.