The fast discharge system of ITER superconducting magnets

Song, Inho; Roshal, A.; Tanchuk, V.; Thomsen, Jeff; Milani, F.; Benfatto, I.

doi:10.1109/icems.2011.6073779

Cited by 33 publications

(6 citation statements)

References 4 publications

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“…Fig. 8 shows the FDU circuit model implemented in Ansys Simplorer in which the stray inductances of the DRs and of its connections to the SCB (Lstray) have been inserted: these components, which play an important role on voltage waveforms, have been set equal to 10 H [22,23]. Furthermore, to limit the peaks of transient voltages associated to the high TF current, a clamp capacitor of 3 mF has been connected in parallel to the SCB, while suitable snubber circuits have been positioned in each branch of the SCB and DR.…”

Section: ) Bps Arc-modellingmentioning

confidence: 99%

Transient Electrical Behavior of the TF Superconducting Coils of Divertor Tokamak Test Facility During a Fast Discharge

Messina

Lopes

Zito

et al. 2022

IEEE Trans. Appl. Supercond.

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The paper is focused on the electromagnetic analysis of the Toroidal Field superconducting coils (TFCs) of the Divertor Tokamak Test facility (DTT) when electrical transients occur in the TFCs system: for example, during the operations of the Fast Discharge Units (FDUs) and considering also, the simultaneous occurrence of a fault condition. During the FDU intervention, a transient voltage excitation lasting few milliseconds occurs at the TFC terminals and it electrically stresses the insulations of TFCs itself. To investigate the voltage distribution across, inside and between different Double Pancakes (DPs) of each TFC, a lumped parameters circuital model has been developed and implemented in Ansys Simplorer simulation environment. This model includes both the detailed sub-model of each TFC and FDU. The transient analyses have been carried out for two different scenarios: a reference one and a failure scenario, considering three different fault resistance values and also two different values of the resistance connecting the TF case to ground. In order to verify the correct sizing of the coil insulation and the TF case-to-ground resistance value inserted in the circuit of each TFC, the voltages of each TFC (terminal-to-terminal, terminal-to-ground, across of adjacent DPs and between other circuit points) were computed in the time domain (in the range of milliseconds) for both scenarios. An overview of calculations and simulation results is presented and discussed, pointing out a high sensitivity of fault conditions and of overvoltage values and addressing mitigation strategies.

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Section: ) Bps Arc-modellingmentioning

confidence: 99%

Transient Electrical Behavior of the TF Superconducting Coils of Divertor Tokamak Test Facility During a Fast Discharge

Messina

Lopes

Zito

et al. 2022

IEEE Trans. Appl. Supercond.

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“…Therefore, the energy stored inside the stray inductance of the FDR system is transferred into the capacitor in the form of electricity and eventually the reverse charging voltage is increased. If the reverse charging voltage surpasses the rated voltage for a long time, the life-time and decay speed of charging voltage of the capacitor will be degraded to a large extent [12].…”

Section: The Cpc Capacitor Feasibilitymentioning

confidence: 99%

Structure Optimization of Fast Discharge Resistor System for Quench Protection System

Wang

Song

et al. 2019

IEEE Access

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In the quench protection (QP) process of superconducting fusion devices, the operating reliability and efficiency of power components are affected by stray parameters of the fast discharge resistor (FDR) system, especially the system stray inductance. In this paper, the fundamental condition of the QP operating process and the large power FDR system structure layout for the Large-scale Superconductor Test Facility (LSTF) are presented. The negative affected VCB, CPC circuit action, and the energy discharging process are further analyzed. The stray inductance optimization method of the resistor module and structure connections are proposed to reduce the stray inductance value. Finally, the optimization results are presented by the Q3D module of the FEA software.

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“…In ITER, the system performing the quench protection is called fast discharge unit (FDU); it is composed of a mechanical ByPass Switch (BPS) in parallel to the series of two vacuum circuit breakers (VCB) [25,26]. In normal operation, the mechanical switch is closed and conducts most of the current; in case of quench detection, its opening diverts all the current into the VCBs.…”

Section: Technologies For DC Current Interrupters Adopted In Fusion E...mentioning

confidence: 99%

The new technological solution for the JT-60SA quench protection circuits

Gaio¹,

Maistrello²,

Novello³

et al. 2018

Nucl. Fusion

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An advanced technology has been developed and employed for the main circuit breakers (CB) of the quench protection circuits (QPC) of the superconducting coils of JT-60SA: it consists in a Hybrid mechanical-static CB (HCB) composed of a mechanical Bypass switch (BPS) for conducting the continuous current, in parallel to a static circuit breaker (SCB) based on integrated gate commutated thyristor (IGCT) for current interruption. It was the result of a R&D program carried out since 2006 to identify innovative solutions for the interruption of high dc current, able to improve the maintainability and availability of the CB. The HCB developed for the JT-60SA QPC is the first realization of a dc circuit breaker based on this design approach for interrupting current of some tens of kA with reapplied voltage of some kV. It also represents the first application of hybrid technology with IGCT for protection of superconducting magnets in fusion experiments. The paper aims at giving a comprehensive overview of the main R&D activities devoted to the development of this new technological approach; then, the key aspects of the design, manufacturing and testing of the QPCs for JT-60SA, successfully completed in Naka Site in summer 2015 are presented. Finally, the significance of this research is discussed and the possible future developments, in particular in view of DEMO fusion reactor, are outlined.

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The fast discharge system of ITER superconducting magnets

Cited by 33 publications

References 4 publications

Transient Electrical Behavior of the TF Superconducting Coils of Divertor Tokamak Test Facility During a Fast Discharge

Transient Electrical Behavior of the TF Superconducting Coils of Divertor Tokamak Test Facility During a Fast Discharge

Structure Optimization of Fast Discharge Resistor System for Quench Protection System

The new technological solution for the JT-60SA quench protection circuits

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