Quench Detection of HTS Current Lead Using Hall Probe

The studies on the high temperature superconducting (HTS) current lead for superconducting magnets are actively underway with rapid advancement in HTS conductor technology recently. HTS leads reduce the heat load to superconducting magnets. HTS current lead consists of several HTS tapes in parallel which are soldered to the copper blocks. The quench occurs first in the HTS tape with lowest critical current among HTS tapes during charging of the transport current. Conventionally, HTS current leads use the equipotential voltage signal to detect quench but it is difficult to estimate the quench of an HTS current lead in fault because the quench voltage level of an HTS tape in a current lead is very low. In this paper, the quench detection of an HTS current lead using a hall probe was investigated. First, the magnetic field distributions of an octagonal shaped HTS current lead before and after quench in charging of transport current were computed using Comsol. Then, this octagonal-shaped HTS current lead was fabricated and tested in order to measure its central magnetic field. Based on the results, the application feasibility of the quench detection of HTS current lead using hall probe was confirmed.