Construction, Testing and Operation of a 1 MJ HTS Magnet at a 10.5 kV Superconducting Power Substation

An HTS magnet was designed for the 1 MJ/0.5 MVA SMES with Bi2223/Ag tapes. According to the design, it consists of 44 double pancakes with an inductance of 6.28 H, and the rated operating current is 565 A, the maximum magnetic field is up to 5.72 T. In this paper, the insulation of the tapes and the magnet, the fabrication and tests of the 44 double pancakes, the joints among double pancakes and the assemblage of the magnet are described in detail. And then, the fundamental performances testing of the magnet were carried out at liquid nitrogen and helium, respectively. With zero helium vaporization, the 1 MJ HTS magnet was dip in liquid helium and cooled with four G-M cryocoolers. After the whole 1 MJ/0.5 MVA SMES were field installed and tested, it had been put into operation since Feb. 16 of 2011 at a 10.5 kV superconducting power substation locating in Baiyin, Gansu Province of China.