Effects of Resonance Phenomenon Caused by Power Supply on JT-60SA CS

The maximum voltage between the CS module terminals is designed to be 10 kV, the voltage between the layers under ideal conditions is then about 0.38 kV because the CS module has 52 layers. But, in operating condition, there is a possibility that the voltage between the layers is higher than 0.38 kV due to the voltage fluctuations of the power supply and the inhomogeneous voltage distribution in the CS module induced by the resonance phenomenon. The JT-60SA CS consists of four electrically independent stacked CS modules. It might even produce voltages high enough to damage the insulation between the CS conductors. In the present study, which is based on the results of previous studies, we created a circuit simulation model for the JT-60SA CS (four CS modules), including the structures (ground resistances, CS structure, TFC cases, and EFC covers), and used it to estimate the voltage distribution produced by the resonance phenomenon. From these results, we conclude that the resonance phenomenon caused by power supply frequency components does not impact the insulation between the CS conductors, and hence the JT-60SA CS is electrically stable under normal operating conditions.