Abstract
The liquid-helium-cooled metallic superconducting cable can transmit a few giga-watts of electric power through a restricted small space. Although no resistive loss produces in it, a large amount of additional electric power is required to operate the refrigerators to keep it in the cryogenic temperature. This power must be included in the transmission loss of the superconducting cable. This is regarded as one of its large demerits. However, the superconducting cable would be operated in the established power system. Thus, its transmission loss should be evaluated together with the whole transmission loss of the system. In this paper, two types of a future metropolitan electric power system are supposed. In a “hybrid system”, the superconducting cables transmit a large portion of electric power generated in a satellite power plant to a demand center directly, while, in a “conventional system”, the future demand in this metropolitan area is supplied only by enhanced conventional transmission lines. It is verified through numerical simulations that the total transmission loss energy in kilowatt-hour is smaller in the “hybrid system” than that in the “conventional system” throughout a year. The total transmission loss in kilowatt is also smaller at a peak load period. These beneficial state would be sustained in a future long period when the electric demand would continue to increase.
