Preliminary evaluation of the energy-saving effects of the introduction of superconducting cables in the power feeding network for dc electric railways using the multi-train power network simulator

Thanks to the recent developments, the superconducting cables using high-temperature superconducting (HTS) materials are now expected to reduce feeding losses in the power supply network for DC electric railways. However, by connecting the HTS cables with the normal conducting wires electrically, heat intrusion is inevitable; to suppress heat intrusion to an acceptable level, interconnection becomes a large and costly installation. This means that the use of HTS cables as the replacement for normal conducting feeder wires in the DC railway feeding network is unrealistic because of the need for frequent interconnections between the feeder and contact wires. By combining the results obtained by a number of cases of multi-train simulation and a preliminary estimate of the refrigeration losses, the author shows that, by using HTS cables to replace some of the feeding substations, rather than the feeder wires, the introduction of HTS cables in the feeding network of DC electric railways may have positive effects of saving energy.