Abstract
The purpose of this research was to investigate the efficiency of the state-of-the-art quench protection heater technology applied to a high-temperature superconductor (HTS)-based accelerator type magnet. The heater delays, i.e., the time delay between the heater activation and consequent normal zone initiation in the winding, were simulated using the 2-D thermal modelling tool CoHDA, which has been successfully used for low-temperature superconductor (LTS) coils. In addition to the quench onset criterion used for LTS, requiring the cable maximum temperature to reach the current sharing temperature (T cs ), a criterion accounting for the current redistribution within a cable was introduced in the model. The heater delays were analysed as a function of various heater parameters, their value ranges were based on the heaters in the recent LTS magnets: heater powers (PPH(t = 0) = 20-200 W/cm 2 ), heating station lengths (down to 10 mm) and insulation thickness's (up to 150 μm Kapton). The simulated delays in the reference YBCO-cable (T op = 4.5 K, I = 5 kA, B = 20 T (parallel to cable's wide surface), Tcs = 16.5 K) were mainly between 20 and 100 ms. The heater efficiency seriously decreased for T cs above 20 K when the cable energy margin approached the energy provided by the protection heater. Although experiments are needed to confirm these results, it seems clear that heater based quench protection for HTS-based accelerator magnets requires significant technology developments.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.