Evaluation of Step-Shaped Solenoidal Coils for Current-Enhanced SMES Applications

This paper investigates a step-shaped solenoidal coil for current-enhanced superconducting magnetic energy storage (SMES) applications. Three performance evaluation factors related to the coil inductance, critical current and energy storage capacity are extracted to analyze and evaluate the energy storage characteristics of the step-shaped solenoidal coil. As compared to a conventional solenoidal coil with rectangular cross-sectional shape, the step-shaped one could obtain the same energy storage capacity with reduced tape usage amount; it also improves the critical current significantly. To suit various high-current application conditions such as low-voltage direct-current power transmission, four feasible application schemes of sole step-shaped coil, semi-step-shaped coil, sub-step-shaped coil, and sub-semi-step-shaped coil are explored and discussed.