Test Results of an Experimental Coil with Bi-2212 Rutherford Cable for High Energy-density HTS-SMES

Abstract

Since FY 2004, a four-year Japanese national project has been ongoing to develop an HTS-SMES as a sub-program of the Development of Superconducting Power Network Control Technology. The purpose of this project is to confirm the performance of a high energy density SMES coil with Bi-2212 cables. This coil system is composed of an NbTi outer coil and a Bi-2212 inner coil, consisting of 16 double pancakes. A Bi2212 cable of 140 m length is used for the double-pancake windings, and reinforcing materials are co-wound with the cable. A winding inner diameter of 360 mm was set according to the bending tolerance of the cable. The magnet is to be cooled at 4.2 K by liquid helium in order to obtain high overall current density. In the first year of this project, a conceptual design and various experiments for HTS magnet were carried out. This paper describes the test results of the HTS experimental coil that was developed to evaluate the electrical and thermal characteristics of an HTS. It is important to minimize deterioration and damage to the cable, because such defects cause fatal impact to the coil. Consequentially, high accuracy measurement of V-I characteristics up to10−8 V/cm range was performed in this experiment.