Conveners
Sat-Mo-Po.05 - Quench Detection and Protection IV
- Ye Bai (Brookhaven National Lab)
- Giuseppe Montenero (Paul Scherrer Institut)
A magnet undergoing a quench is one of the most challenging scenarios for any operator, often leading to potential failure of the magnet. While quench phenomena are well understood in LTS magnets—where manufacturers deliberately induce quenches during commissioning to ensure reliability—the same cannot be said for HTS magnets. Challenges such as the slow propagation of the normal zone and a...
The results of numerical and experimental studies of fundamentals of the quench monitoring technique based on frequency and time domain reflectometry (FTDR) are discussed. To carry out fast (real time) monitoring of the coolant gas temperature and thus to observe evolution and prevent the quenching in superconducting (SC) magnets the techniques of detection and analysis of microwave...
Screening currents on REBCO magnets are well known as causes of troublesome. The screening current-induced fields cause a low quality; i.e., it deteriorates the field homogeneity or generate unexpected fields. In recent years, the local high strain effect due to screening currents has been investigated. The screening current under high magnetic fields rotate REBCO tapes. It results the REBCO...
High-temperature superconducting (HTS) magnets are essential for advanced applications such as particle accelerators and fusion reactors, requiring effective quench management to ensure safety and performance. No-insulation (NI) coils, which allow current to move between turns during quench events, are commonly used in HTS magnet design. However, the contact conditions between turns in NI...
Active quench protection systems in large superconducting magnets rely on the rapid and efficient delivery of heat from quench heaters to the magnet windings to initiate a controlled quench. However, thermal diffusion is significantly influenced by the multi-layered electrical insulation, thermal barriers, and contact resistance between surfaces. This work presents simulation results that...
High temperature superconductor (HTS) magnet systems, especially those designed for fusion reactors, require effective and reliable monitoring to avoid damaging anomalies. In tokamaks, some of the magnetic coils are time dependent, which cause additional strain and electromagnetic effects within the magnet system. Ionizing radiation can also lead to non-uniform degradation of conductors. The...
This paper presents the quench test results and analysis of no-insulation (NI) REBCO (Rare-Earth Barium Copper Oxide) double pancake racetrack coils under conduction cooling conditions. Two racetrack coils, differing in dimensions and number of turns (280 and 488 turns), were tested at a temperature of 50 K each. The current was ramped up to their critical values until quenching occurred,...
REBCO tapes are promising material for the
construction of high field magnets because of large engineering
critical current densities at high field, however, the slow normal zone propagation velocity (NZPV) makes the protection against
quenches a critical issue. Stability margin of REBCO cables is
two or three orders of magnitude greater than that of lowtemperature superconducting cables,...
