Numerical Study Of Quench Behavior And Quench Detection Criterion Of HTS

In the application of high temperature superconducting (HTS) magnets, hot spots could be created due to unknown heat disturbance, which will in turn create normal zones in HTS magnets or coils. And the normal zones could propagate, which could quench the whole magnet/coil. Therefore, the quench behavior of HTS magnets/coils is the key to the design of protection method, which protects the HTS magnets/coils from been damaged. Among the factors that affect the quench behavior of HTS tapes, cooling conditions is one of the key factor. On the other hand, quench detection criterion is the key to the quench protection. In this thesis, the quench behavior of two HTS tapes, i.e. YBCO and Bi2223/Ag, are investigated based on numerical simulations, including the following parts:1. A ID numerical model of HTS tapes under constant voltages is presented in this part, based on which the quench behavior of Bi2223/Ag tapes and YBCO coated conductors is investigated through numerical simulations. The numerical result of the minimum quench energy (MQE) and normal zone propagation velocity (NZPV) are obtained and we present the comparison between constant voltages and constant currents.2. Based on a 2D-3D mixed dimensional model the quench behavior of YBCO coated conductors under two kinds of cooling conditions are investigated through numerical simulations. The numerical result of the minimum quench energy (MQE) and normal zone propagation velocity (NZPV) are obtained and we present the comparison on the different cooling condition.3. Based on the 2D-3D mixed dimensional model the quench behavior of YBCO coated conductors under different currents and different heat disturbance is investigated through numerical simulations. And based on the numerical results, quench detection criteria is investigated and proposed.