A Real-Time Monitoring System for Investigating Electromagnetic Behaviors of an HTS Coil
Jeseok Bang, Seong Hyeon Park, Jeonghwan Park, Geonyoung Kim, Jung Tae Lee, Kwangmin Kim, Seungyong Hahn, D. C. Larbalestier
Abstract
This paper presents a system for real-time monitoring spatial and temporal electromagnetic behaviors of a high temperature superconductor (HTS) coil with the no-insulation (NI) winding technique. We implemented a real-time monitoring system that consists of Hall sensors and voltage taps to measure spatial and temporal magnetic fields, and local voltages. An NI HTS test coil was wound, and the real-time monitoring system was combined with the test coil. An experimental study was performed in a liquid nitrogen bath at 77 K, where the test coil was charged with a constant ramp rate of 0.05 As <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><inline-formula><tex-math notation="LaTeX">$-1$</tex-math></inline-formula></sup> up to its operating current of 100 A. To describe measurement results, including local voltages and magnetic fields, we propose a set of simulations for coil voltages and currents, current density including <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">screening current</i> , and field gradient including <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">screening current induced field</i> . Using this set, we successfully simulated spatial and temporal electromagnetic behaviors generated by the test coil to a reasonable extent. The discussion section will provide comparison results between calculations and measurements.