• 한국초전도학회:학술대회논문집
• /
• v.9
• /
• pp.405-408
• /
• 1999

A prototype of solenoidal superconducting magnet using Bi-2223/Ag multi-filamentary tapes was fabricated and tested to investigate its performance. The Bi-2223/Ag tapes were prepared by powder-in-tube method. The dimensions of magnet, which was stacked with 9 double pancakes, were 90 mm in height, 74 mm in outer diameter and 40 mm in clear core. The axial maximum magnet field at the center of the solenoidal magnet was about 0.12 T, and the critical current of coil conductor was about 9 A at 77.3 K.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 1999.02a
• /
• pp.69-72
• /
• 1999

During the fast current and field ramp up experiment with CICC (Cable-In-Conduit Conductor) non-insulated 3 strand superconducting magnet, the unbalanced current distribution associated with the loop current has been obtained directly from the shunt resistor voltage data. To explain the generation of the loop current during the current ramp up, the steady-state three strand loop current model was proposed. This model gives an explanation for the relation between the loop current and the relation between the loop current and the twist geometry of the strands. According to this model, the twist geometry of the strand has significant influence on the generation of the loop current especially in the large superconducting magnet.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2000.02a
• /
• pp.12-16
• /
• 2000

The mission of SSTF is test of superconducting cables for KSTAR magnets. To make realistic environment for superconductor in SSTF, background magnets are required. Cable-in-conduit conductors (CICC) are widely used for large scale superconducting magnets such as ITER and KSTAR. Main design criteria for conductor of superconducting magnets are stability, operating margin and cable cooling requirement, caused by peak field and the gradient of fields with respect to time, in system. ZERODEE which used energy balance method, is applied for the calculation of stability. To increase conductor performance, three different strands, such as HP-I, HP-II, and HP-III, are tested. The present configuration of CICC is used for main coils of background magnet in SSTF and Central Solenoid coils of KSTAR magnets.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2000.02a
• /
• pp.147-149
• /
• 2000

Samsung Superconducting Test Facility (SSTF) will be built at SAIT, Taejeon. The superconducting cables to be used for KSTAR magnets are going to be tested in SSTF. The background magnet in SSTF is needed to simulate harsh magnetic environment for testing short CICC samples as well as full-scale magnets. The main coils can make central magnetic field of up to 8 Tesla and the blip coils can maintain fast ramping rate of 20T/s. The cancellation coils reduce the disturbance of main coils due to blip coils. The magnetic field distribution of these coils has been obtained with finite element method as well as the direct integration method.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2002.02a
• /
• pp.56-59
• /
• 2002

Since the KSTAR magnet structure should be maintained at cryogenic temperature of about 4.5 K, even a small amount of heat might be a major cause of the temperature rising of the superconducting magnet structure. The Joule heating by eddy current induced on the magnet structure during the KSTAR operation was found to be a critical parameter for designing the cooling scheme of the magnet structure as well as defining the requirements of the refrigerator for the cryogenic system. Based on the Joule heating calculation, it was revealed that the bulk temperature rising of the magnet coil structure was less than 1 K. The local maximum temperature especially at the inboard leg of the TF coil structure increase as high as about 21 K for the plasma vertical disruption scenario. For the CS coil structure maximum temperature of 8.4 K was obtained from PF fast discharging scenario.

• Proceedings of the KIPE Conference
• /
• 2015.11a
• /
• pp.227-228
• /
• 2015

우리나라가 조달하는 ITER(국제핵융합시험로) 초전도자석 전원장치용 변압기는 CCU/L(Correction Coil Upper/Lower) 컨버터 형식용 6대, CCS(Correction Coil Side) 컨버터 형식용 3대, VS1(Vertical Stabilization 1) 컨버터 형식용 2대, CS(Central Solenoid) 컨버터 형식용 6대 그리고 TF(Toroidal Field) 컨버터 형식용 1대로 구성되어 있다. ITER한국사업단은 (주)효성과 컨버터 변압기의 공급계약을 2011년에 체결하고 예비 설계를 시작하여 2014년에 최종설계를 마친 후 동년 후반부터 CCU/L, CCS 및 VS1 컨버터 형식용 각 1대씩의 초도품 변압기 제작에 착수하였다. 각 변압기는 제작이 완료되어 CCU/L 및 CCS 형식은 FAT(Factory Acceptance Test)를 완료하였고 VS1 형식은 공장 자체시험을 완료하고 현재 전기연구원에서 실시할 단락시험을 준비하고 있다. 이어 CS 형식의 초도품과 1대만 조달하는 TF 형식의 제작을 착수할 예정이고, 각 형식별 초도품 1대씩은 단락시험을 포함하는 형식시험(Type Test)을 실시하여 형식별 적합성을 검증하고, 나머지 물량은 정기시험(Routine Test)을 실시한 후 2017년까지 두 번으로 나누어 프랑스 남부에 위치한 ITER 현장에 운송 및 설치할 예정이다. 설치를 마친 변압기들은 각각의 컨버터 짝과 통합시험을 포함하는 SAT(Site Acceptance Teat)를 거친 후 ITER 기구에 인계될 예정이다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.19 no.4
• /
• pp.328-332
• /
• 2007

A superconducting magnetic energy storage (SMES) system has shorter response time and longer life time, and is more economical, and environment-friendly than other uninterruptible power supply (UPS). A conduction cooling system is well answer for the high temperature superconductor (HTS) SMES system. Because the conduction cooling system is simple, light and small structure. The purpose of this paper is to design and verify the effective conduction cooling system for the HTS SMES system. The analysis of heat loads in cryostat is performed. Thermal shield heat loads, temperatures of HTS coil surface and conduction Cu plate are estimated and measured.

• Proceedings of the KIEE Conference
• /
• 2003.07b
• /
• pp.780-782
• /
• 2003

60 Hz의 전력분야에 고온초전도체를 적용 하는데 있어 가장 큰 장애요소인 교류손실에 대한 연구의 일환으로서 한 일간의 상이한 시험방법 및 장치에 대한 신뢰성과 정밀도를 상호 확인하기 위해 동일한 샘플 및 동일 시험조건으로 양측에서 round-robin테스트를 하였다. 그 주요 결과는 양측에서 측정한 자화손실은 시험 방법 및 장치의 상이함에도 불구하고 비교적 잘 일치하였다. 이는 자화손실 측정 시, 금기사항으로 되어있는 철심자석의 사용이 문제가 되지 않음을 의미하며, 이는 다시 기존 자화손실 시험장치의 공심자석 및 자석용 전원 설비가 대단히 소형화될 수 있음을 의미한다.

• Progress in Superconductivity and Cryogenics
• /
• v.11 no.3
• /
• pp.20-25
• /
• 2009

The quench detection system of the KSTAR (Korea Superconducting Tokamak Advanced Research) primarily uses the resistive voltage measurement due to a quench. This method is to detect the resistive voltage generated by a quench, which is continuously maintained above the preset voltage threshold for a given holding time. As the KSTAR PF (Poloidal Field) coils are operated in the pulse current mode, the large inductive voltages are generated. Therefore the voltage threshold and the quench holding time should be determined by considering both the inductive voltages measured during the operation, and the maximum conductor temperature rise through the quench analysis. In this paper, the compensation methods for minimizing the inductive voltages are presented for the KSTAR PF coils. The quench hot spot analysis of the PF coils was carried out by the analytical and numerical methods for determining the proper values of the quench voltage threshold and the allowable quench protection delay time.

• Progress in Superconductivity and Cryogenics
• /
• v.11 no.3
• /
• pp.1-5
• /
• 2009

It is important to predict AC loss in $Nb_3Sn$ and NbTi cable-in-conduit-conductor (CICC) reliably for the design and operation of large superconducting coils. The hysteresis loss in the superconducting filaments and coupling loss within strands and among strands in a cable or composite are dominant ac losses in superconducting magnets. The coupling loss in a superconductor can be characterized by identifying the coupling constant time $n{\tau}$. To reduce the coupling loss, all the strands (superconductor and Cu) in KSTAR (Korea Superconducting Tokamak Advance Research) are chromium plated with thickness of $l{\pm}0.5{\mu}m$. The ac losses of PF1, PF5 and PF6 coils has been measured by calorimetric method while applying trapezoidal current pulses with various ramp rate from 0.5 kA/s to 2 kA/s. The coupling time constants for $Nb_3Sn$ coils are $25{\sim}55$ ms and the values are not co-related with the coil size, the time constants for NbTi coil is 30 ms.