Design and test of HTS coils for resistive fault current limiter

This paper presents the design, manufacturing and test results of HTS coils for single-phase resistive current limiters using two different Bi-2223/Ag tapes. Two coils were separately wound on cylindrical G-10 tubes with helical path. One of the coil was wound in a bifilar conductor arrangement aiming at reducing the self-inductance. The maximum flux density is 40 mT on the HTS tape for both coils and the calculated inductance is 5.76μH for the non-inductively wound coil and 28.3μH for the conventional one. The two coils were individually tested under DC and AC currents. The DC power loss was calculated from the measured voltage-current values product and the AC power loss was determined by the liquid nitrogen mass boil-off measurement. The acquired voltage AC waveforms were analyzed through the separation of distinct contributions due to magnetic flux and to a resistive component in-phase with the current. It was observed an inflection point common to the DC and AC power losses curves close to I_c attributed to the AC transition current.