Copper stabilization of YBCO coated conductor for quench protection

Abstract

The required amount of copper stabilizer to protect a YBCO conductor coil from damage caused by a hot spot due to a quench is studied in this paper. YBCO coated conductors which are made by deposition of thin YBCO film on high resistance metal substrates are highly resistive when they are quenched. Therefore, stabilization and quench protection are more important for YBCO conductors than Bi/Ag sheathed tapes which have low resistance silver matrix. In the work we numerically calculated maximum temperature rise of a YBCO conductor quenched by a local disturbance during the sequence of quench detection and energy dump. In the analysis, necessary amount of copper to keep the maximum temperature of the conductor below a threshold value is calculated for cases of conduction cooled coils of dry windings. Based on the analysis, optimum conductor design is discussed to protect the coil from a quench reliably.

Numerical and Experimental Analysis of Normal Zone Propagation on 2G HTS Wires

“…Our measured NZPV values are in the range of 2-7 cm/s for the analyzed conditions, which is typical for 2G HTS conductors [2,4]. Compared with similar conductors but without Cu-stabilization, these conductors are advantageous since protection of the conductor from damage caused by quenches is more feasible [6]. Fig.…”

“…More important is that the temperature increase during the quench in non-stabilized coated conductors, together with the small NZPV values, results frequently in the damaging or even the burn out of the sample once the quench has been triggered. This effect has also been studied by Fu et al [6], who analysed the amount of copper required to maintain the hot spot temperature after a quench below a certain threshold value, and to allow the detection of the quench. Therefore, copper should be added to these coated conductors to protect the superconductor from damage caused by quenches.…”

Deposition and characterization of YBa2Cu3O7−δ/LaMnO3/MgO/TiN heterostructures on Cu metal substrates for development of coated conductors

“…14,15 Until now, experiments on the growth of multilayer structures consisting of epitaxially oriented oxide buffer layers and YBCO films on Cu (001) substrates have not produced successful results. Pure Cu can be thermomechanically processed to obtain a very sharp cube texture with a true in-plane full width at half-maximum (FWHM) of nearly 4°.…”

Impact of the Normal Zone Propagation Velocity of High-Temperature Superconducting Coated Conductors on Resistive Fault Current Limiters

“…As a consequence, the heat dissipation remains localized and tapes are exposed to thermal instability. A common method to reduce the heat generated near the weak zones of the HTS-CCs and to mitigate the local thermal instability, is to increase the thickness of the stabilizer material [2]. The resistance of the stabilizer is lowered, the transport current is rapidly diverted to the stabilizer layer and the heat diffuses faster within the tape.…”