Design and Experiment of CSMC Magnet Online Insulation Monitoring System

The Central Solenoid Model Coil (CSMC) is a preliminary research project for the China Fusion Engineering Test Reactor (CFETR). Its goal is to design and manufacture superconducting model coils while gaining experience to address technical challenges in their design and construction. The CSMC aims for a maximum operating current of 47.65 kA, a maximum magnetic field of 12 T, and a rapid magnetic field change rate of 5 T/s. During operation, the superconducting magnets must withstand high voltage, which could lead to insulation damage. If the device is not stopped in time to repair the insulation, the magnet will lose its superconducting state and be damaged. Therefore, a reliable online insulation monitoring system is essential for early detection of insulation issues, preventing further damage from high voltage. This paper uses the partial discharge method as the method of online insulation monitoring, and uses the high-frequency current method to realize partial discharge detection. The hardware and software of the insulation monitoring system are designed and developed respectively. At the same time, a series of experiments are carried out to extract the partial discharge signal characteristics of the superconducting magnet device as theoretical support. The effectiveness of this system has been verified in the CSMC Paschen test.