Comparison Between the Fault Current Limiting Performance of Bi-2212 Bifilar Components and 2G YBCO Coils

Short-circuit tests with commercial Bi-2212 and with a YBCO 2G tape components were performed. The Bi-2212 bulk coil has been recently improved by the manufacturer, exhibiting higher homogeneity and better transport properties than previous ones. Such bulk components consist of a shunted bifilar coil (Ic = 400 A at 77K). The YBCO 2G tape component consist of two antiparallel 2G shunted coils (Ic = 1200 A at 77 K). Fault current limiting tests were performed under asymmetrical prospective currents varying from 1 kA_rms (2.7 kA_peak) to 30 kA_rms kA_rms (80 kA_peak). The source voltage (Vo) was also varied in order to evaluate the influence of Vo on the limited current (138-400 V_rms). For the same Vo value (200 V_rms), the Bi-2212 components limited prospective currents as high as 80 kA_peak to about 6.5 kA_peak (first peak) and less than 1.5 kA_rms , whereas the YBCO 2G tape component limited the same prospective currents to less than 5 kA_peak (first peak) and less than 2.5 kA_rms. The YBCO 2G component presents a faster actuation than the Bi-2212 component.