Performance Study on the No-Insulation HTS Coil Wound With Narrow-Stacked Wire

As a novel high-temperature superconducting (HTS) conductor structure composed of the stacked 1-mm wide REBCO tapes, Narrow-Stacked (NS) wire has been demonstrated to have a significant reduction effect of AC loss and screening current induced field (SCIF) in the insulated HTS coils. Thus, NS wire is a promising HTS conductor design for practical HTS applications. Meanwhile, compared with traditional insulated HTS coil, no-insulation (NI) HTS coil has obvious advantages in engineering current density, thermal stability and self-protecting ability, and these features benefit for HTS magnets. Although NS wire was regarded as an improvement for insulated HTS coil, the NS wire effects on NI coil are not confirmed yet due to the special characteristics of the NI coil. In this paper, NI pancake coils were wound with NS wire and conventional HTS tape respectively. To evaluate the performance of NI coil wound with NS wire, its characteristic resistance and charging delay were analyzed at the liquid nitrogen temperature of 77 K. Besides, the over-current test results show that NI NS coil also has the satisfied self-protecting feature. This paper intends to provide a possible reference for NS wire application on NI HTS magnets.