• KIEE International Transactions on Power Engineering
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• v.3A no.4
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• pp.222-230
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• 2003

This paper presents reference designs for vapor-cooled HTS/Copper leads rated at 25 kA and 40 kA and that satisfy a protection criterion. Each HTS section is cooled by the effluent helium vapor boiling from a 4.2-K bath. Each HTS section is based on a design concept in which a short portion of its warm end (77.3 K) operates in the current-sharing mode; such operation results in a considerable saving for HTS materials required in the HTS section. Two designs of "fully superconducting" vapor-cooled HTS sections, one rated at 25 kA and the other at 40 kA are also presented as comparison bases for the new HTS sections. Each warm end of HTS sections is coupled to an optimal vapor-cooled copper lead rated at the same current as that for the HTS section. The extra coolant required at 77.3 K at the coupling station, an optimal length of the copper section will be shorter than that optimized for helium-vapor cooling between 4.2 K and room temperature.mperature.

• Nuclear Engineering and Technology
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• v.40 no.6
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• pp.439-450
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• 2008

The KSTAR device succeeded in first plasma generation on $13^{th}$ June of 2008 through comprehensive system test and commissioning. Among various kinds of the key factors that decisively affected the project, success in the construction and assembly of the major tokamak structure was most important one. Every engineering aspects of each structure were finally confirmed in the integrated commissioning period, and there were no severe troubles and failures prevented the KSTAR device from operating during the commissioning and the first plasma experiments. As a result, all of the experiences and technologies achieved through the KSTAR construction process are expected to be important fundamentals for future construction projects of superconducting fusion devices. This paper summarizes key engineering features of the major structures and of the machine assembly.

• Progress in Superconductivity and Cryogenics
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• v.10 no.4
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• pp.23-28
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• 2008

As a part of the plasma control system (PCS) for the first plasma campaign of KSTAR, seven sets of fast feedback control loop for the superconducting poloidal field magnet power supply (PF MPS) have been implemented. A special real-time digital communication interface has been developed for the simultaneous exchanges of the current/voltage data from the 7 sets of 12-thyristor power supplies in a 200 microsecond control cycle. Preliminary power supply tests have been performed before actual cooldown of the device. A $29mH/50m{\Omega}$ solenoid dummy has been fabricated for a series of single power supply tests. Connectivity and response speed of the plasma control system have been verified. By changing hardware cabling, this load was also used to estimate mutual inductance coupling effects of two geometrically adjacent solenoid coils on each power supply. After the cooldown was complete, each pair of the up/down symmetric PF coils has been serially connected and tested as part of the device commissioning process. Bipolar operation and longer pulse attempts have been investigated. The responses of the coils and power supplies corresponding to the plasma magnetic controls in plasma discharges are also analyzed for the future upgrades.

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.253-254
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• 2011

ITER AC/DC 컨버터는 ITER(국제핵융합실험로) 초전도자석에 최대 68 kA의 전류를 공급하는 전원장치이다. ITER AC/DC 컨버터 구조물의 재질선정, 구조설계, 구조 및 전자기력 해석 등을 통하여 컨버터 단위모듈의 실제크기 시제품을 제작하여 정격전류(22.5 kA) 및 단락전류(250 kA) 시험을 성공적으로 완료하였다.

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.251-252
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• 2011

ITER 기구는 초전도자석 전원장치가 운전 중 발생 가능한 부하의 단락으로부터 장치를 보호하기 위하여 FSC(Fault Suppression Capability) 조건에 만족할 것을 요구하고 있다. 본 연구에서는 모의시험을 통해 FSC 조건에서 발생되는 단락 전류에 의한 소자 이상 유무 및 전자기력의 크기와 방향을 확인하였고, 해석을 통해 전자기력이 전원장치 구조물에 미치는 영향을 검토하였으며, 실제 시험을 통해 모의시험 및 해석 결과가 타당함을 검증하였다.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.239-240
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• 2012

ITER 초전도자석 전원공급장치는 대전류를 흘리기 위한 자체 지지구조 버스바와 이를 지지하기 위한 구조물로 구성된다. 장치설계에 있어 버스바와 지지구조물은 단락 시 전자기력에 대한 내성, 통전전류에 의한 버스바 발열 등의 요구조건을 만족하여야 한다. 본 논문은 ITER 초전도자석 전원공급장치에 유한요소해석을 적용하여 여러 요구조건에 부합하는 설계의 적합성을 검증한다.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.241-242
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• 2012

ITER 초전도자석 전원공급장치에 심각한 고장이 발생할 경우 전원장치뿐만 아니라 그 부하인 초전도코일에도 영향을 줄 수 있다. 초전도코일이 파괴될 경우 수리가 어려워 프로젝트 자체에 중대한 영향을 미칠 수 있어 전원공급장치의 보호는 매우 중요하다. 본 논문에서는 ITER 초전도자석 전원공급장치에서 발생할 수 있는 주요 고장 항목을 소개하고, 전원장치 보호시퀀스에 따른 보호능력의 적합성을 검증한다.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.740-745
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• 2001

The plastic deformation behavior of formed CICC fur the superconducting Tokamac fusion device was examined and appropriate manufacturing information was provided. A relation between travel of the bending roller and spring back displacement was obtained via virtual manufacturing. The radius of CICC after forming was expressed as a function of the bend-roll travel. The maximum von Mises stress after spring back was also monitored fur the SAGBO prediction. Next, the variation of the CICC cross-sectional area was examined during the first turn and during conduit bending with the largest curvature. Finally, the coil radius was measured and compared with the data generated from the virtual manufacturing. The measured data showed similar pattern as predicted one. Using the mapping function found to match with the real data, the data from the virtual manufacturing may facilitate accurate manufacturing.

• Progress in Superconductivity and Cryogenics
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• v.18 no.1
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• pp.55-58
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• 2016

Quench Detection System (QDS) is essential to guarantee the stable operation of the Korea Superconducting Tokamak Advanced Research (KSTAR) Poloidal Field (PF) magnet system because the stored energy in the magnet system is very large. For the fast response, voltage-based QDS has been used. Co-wound voltage sensors and balanced bridge circuits were applied to eliminate the inductive voltages generated during the plasma operation. However, as the inductive voltages are hundreds times higher than the quench detection voltage during the pulse-current operation, Central Difference Averaging (CDA) and MIK, where I and K stand for mutual coupling indexes of different circuits, which is an active cancellation of mutually generated voltages have been suggested and studied. In this paper, the CDA and MIK technique were applied to the KSTAR magnet for PF magnet quench detection. The calculated inductive voltages from the MIK and measured voltages from the CDA circuits were compared to eliminate the inductive voltages at result signals.

• Journal of the Korean Vacuum Society
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• v.16 no.6
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• pp.483-488
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• 2007

Current feeder system (CFS) for Korea superconducting tokamak advanced research(KSTAR) project plays a role to interconnect magnet power supply (MPS) and superconducting (SC) magnets through the normal bus-bar at the room temperature(300 K) environment and the SC bus-line at the low temperature (4.5 K) environment. It is divided by two systems, i.e., toroidal field system which operates at 35 kA DC currents and poloidal field system wherein 20$\sim$26 kA pulsed currents are applied during 350 s transient time. Aside from the vacuum system of main cryostat, an independent vacuum system was constructed for the CFS in which a roughing system is consisted by a rotary and a mechanical booster pump and a high vacuum system is developed by four cryo-pumps with one dry pump as a backing pump. A self interlock and its control system, and a supervisory interlock and its control system are also established for the operational reliability as well. The entire CFS was completely tested including the reliability of local/supervisory control/interlock, helium gas leakage, vacuum pressure, and so on.