Design and experimental verification of the quench detection system for the CFETR central solenoid model coil

Abstract

To ensure the safe and stable operation of superconducting magnets in fusion devices under high current and complex operating conditions, a highly reliable quench detection system was developed for the Central Solenoid Model Coil (CSMC) of the Chinese Fusion Engineering Testing Reactor (CFETR). The system adopts voltage-based detection as the primary criterion and implements a primary induced voltage compensation architecture based on Co-Wound Wire (CWW) and Co-Wound Tape (CWT) techniques. In addition, a secondary compensation algorithm is introduced to effectively suppress the risk of misjudgment caused by electromagnetic coupling. In the system design, a multi-redundant compensation scheme was proposed with full consideration of the magnet structure and cabling constraints. During the engineering commissioning phase, both room-temperature continuity tests and low-current compensation coefficient calibration were conducted. Induced voltage suppression tests under different current variation rates demonstrated that CWT provides superior compensation performance compared to CWW, with induced voltage suppression rates exceeding 99.8 % for CWW and 99.95 % for CWT. Furthermore, reliability tests under three simulated fault scenarios confirmed that the diagnostic system could accurately identify system states without false triggers, showing strong anti-interference capability and engineering stability. Ultimately, the system was successfully deployed in a high-current energization test of the CSMC, operating at up to 48 kA. It maintained stable performance throughout the test without any false alarms or missed detections, verifying its feasibility and reliability under real engineering conditions. The quench detection compensation methods and system architecture proposed in this study provide a solid technical foundation and practical support for the future development and deployment of the CFETR Central Solenoid superconducting magnet quench detection system.