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 thevoltage 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

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, and thus affect the operation of the JT-60SA CS. 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.第26回国際磁石技術会議（MT26 International Conference on Magnet Technology

Evaluation of Voltage between Conductors for Resonance Phenomenon and Transient Response in JT-60SA Central Solenoid

An inhomogeneous voltage distribution in the coil is induced by the resonance phenomenon and transient response caused by the power supply. Therefore, damage to the insulation between conductors in the coils is possible. We created the circuit simulation models of the CS module (the 52-layer pancake coil) with the room-temperature busbar and superconducting current feeder between the power supply and CS module. Then, we evaluated the behavior of the voltage between the conductors for the resonance phenomenon and transient response caused by the supply voltage in the CS module. Based on the results, we can conclude that the influences of resonance phenomenon and transient response on the voltage between the conductors in the CS module is negligibly small under the expected operating conditions. These results therefore represent important information for the safe operation of the JT-60SA.25th International Conference on Magnet Technology (MT-25

Evaluation of Voltage Between Conductors for Resonance Phenomenon and Transient Response in JT-60SA Central Solenoid

An inhomogeneous voltage distribution in the coil is induced by the resonance phenomenon and transient response caused by the power supply. Therefore, damage to the insulation between conductors in the coils is possible. We created the circuit simulation models of the central solenoid (CS) module (the 52-layer pancake coil) with the room-temperature busbar and superconducting current feeder between the power supply and CS module. Then,we evaluated the behavior of the voltage between the conductors for the resonance phenomenon and transient response caused by the supply voltage in theCS module. Based on the results, we can conclude that the influences of resonance phenomenon and transient response on the voltage between the conductors in the CS module is negligibly small under the expected operating conditions. These results therefore represent important information for the safe operation of the JT-60SA

Investigation of Voltage Distribution Affected by ground resistance in JT-60SA CS module

The superconducting magnet system for the JT-60SA consists of 18 toroidal field coils (TFC), the central solenoid (CS) comprising four electrically independent stacked modules, and six plasma equilibrium field coils (EFC). The voltage including fre-quency is applied to the CS module by the power supply in the op-erating conditions. It is possible to induce an inhomogeneous voltage distribution in the coil by causing resonance phenomenon, and to damage the insulation between conductors in the coils. Based on the previous studies, the resonance characteristics and the voltage dis-tribution between the conductors were evaluated considering the in-fluence of structures (ground resistance, CS structure, TFC case, and EFC cover). As a result, it can be concluded that the influence of resonance phenomenon, and the ground resistance on the voltage between the conductors in the CS module is negligible small under the operating conditions. These analyzed results become the funda-mental data to evaluate the electric stability of the coils and to pro-tect coil systems.Applied Superconductivity Conference 2018 (ASC2018

Behavior of Voltage between Conductors due to the grounding resistance in JT-60SA Central Solenoid

The JT-60 super advanced (JT-60SA) project will contribute to the early realization of fusion energy by addressing key physics and engineering issues for the ITER and DEMO fusion projects. Each CS module in the JT-60SA is composed of six octa-pancake coils and a quad-pancake coil. It is important to investigate the voltage behavior between the conductors in the CS module under the expected operating conditions. The maximum voltage between the CS module terminals is designed to be 10 kV, and the voltage between the layers under ideal conditions is about 0.38 kV because each CS module has 52 layers. However, the actual voltage between the conductors can become larger than this under the ideal conditions due to the resonance phenomenon. In this study, the resonance characteristics and the voltage distribution between the conductors were evaluated in consideration of the influence of the grounding resistance.27th International Cryogenic Engineering Conference and International Cryogenic Materials Conference 2018 (ICEC27-ICMC2018