Design of Quench Detection System for Background DC Magnet in the Conductor Performance Research Platform of CRAFT

The conductor performance research platform is part of the Comprehensive Research Facility for Fusion Technology project presently under construction in China, and the background dc magnet system is used to generate a back field of up to 15 T. Its superconducting magnet system is designed with three different cable-in-conduit conductor structures, which are divided into the high-field coil (16 T), the medium-field coil (14 T), and the low-field coil (11 T), of which the high-field/midfield coil is a high-performance Nb<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>Sn superconducting material, and the low-field coil is an international thermonuclear experimental reactor Nb<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>Sn superconducting magnet. The original quench detection system featured a multimodular design for easy maintenance and back-end signal acquisition; however, analog signals were susceptible to interference during long-distance transmission. To optimize the quench detection system and ensure the safe operation of superconducting magnets, a reliable and fast-response quench detection system is essential during plant operation. This article provides a comprehensive introduction to the quench detection techniques applied to the different magnet systems. By analyzing the system's quench behavior, a multisystem complementary detection technique is proposed, which can enhance the reliability of quench detection.