Effects of Resonance Phenomenon on Voltage Between Conductors in JT-60SA PF Coils

The JT-60SA Poloidal Field (PF) coils system comprises four Central Solenoid (CS) modules and six Equilibrium Field (EF) coils, and the cryostat, vacuum vessel (VV), and stabilizing plate (SP) are installed around the PF coil. Evaluating the voltage between conductors in the PF coils is one of the most critical factors in the energized coil operation and the insulation design. The power supply voltage of the PF coils has some frequency components caused by the voltage control system. The resonance phenomena caused by the voltage fluctuations of the power supply induce a non-uniform voltage distribution in the coil. The locally concentrated voltage may exceed the withstand voltage of the insulation, affecting the operation of the JT-60SA. In this study, a circuital model was assembled including four CS modules and six EF coils, to estimate the resonance frequency effect into the coil voltage distribution. In addition, the effects of the cryostat, VV, and SP on the voltage between conductors in the PF coils were evaluated.