Investigation of Transient Response Caused by Power Supply on JT-60SA Central Solenoid

The JT-60SA power supply of the central solenoid (CS) module contains multiple frequency components, and the transient response phenomenon and the resonance phenomenon cause the voltage non-uniformity in the CS. There is thus a possibility that a local voltage between the conductors that is larger than the withstand voltage of the insulation between conductors will be occurred, and the insulation is damaged. Therefore, an estimation of the transient response phenomenon and the resonance phenomenon is important for verifying that the CS is electrically stable. In the present study, the power supply voltage of the JT-60SA CS module was measured, and the effect of the transient response and the resonance phenomenon on the voltage between CS conductors was evaluated using an analysis model that included CS (four modules), the current lead between the power supply and the CS, and the structures surrounding the CS. The simulation results show that when the actual power supply is applied to the CS, the maximum voltage between CS conductors affected by the transient response and the resonance phenomenon is lower than the withstand voltage of the insulation between CS conductors. The results of our analyses provide fundamental data that can be used to estimate the voltage distribution in the CS and thus ensure the electrical stability.