Development of high current density superconducting magnet for smes

The MJ class superconducting magnets for superconducting magnetic energy storage (SMES) are modeled for the toroid, multi-solenoid and single solenoid configurations. The single solenoid magnet, with the most economical superconducting material usage, is chosen as the 1MJ superconducting magnet congfiguration in spite of its stray field limitations. Single strand NbTi/Cu round wire is used for high current density magnet windings. The narrow liquid helium channels are formed between layers to enhance the cooling effect during magnet charging and discharging. The inner diameter, outer diameter and height of the magnet are 439, 600 and 550 mm respectively. The central magnetic field is 4 T at an operating current of 305 A, wile the maximum field is 4.9 T. Inductance of the magnet is designed as 22.1 H. Tests on the magnet in a compact liquid helium cryostat have been performed and the results show that the maximum operating current is 303A and the discharging power is over 100 kW. The magnet can be used for demonstrating UPS-SMES experiments.