• KIEE International Transactions on Power Engineering
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• 제3A권2호
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• pp.100-108
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• 2003

This paper presents the design and performance results of a pair of 6-kA high-temperature superconducting (HTS)-copper current leads, in which, over a short length at the warm end (e.g.,77K) of each HTS section, comprised of paralleled Bi-2223/Ag-Au tapes, is operated in the current-sharing mode. Because of their reliance on vapor cooling, the leads are applicable only to liquid helium cooled superconducting magnets such as those used in high-energy Physics accelerators and fusion machines. The experimental measurements have demonstrated that key performance data of the new 6-kA HTS-Copper leads agree reasonably well with those expected from design.

• 한국초전도ㆍ저온공학회논문지
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• 제9권3호
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• pp.62-66
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• 2007

Electromagnetic forces (Attractive and repulsive force), interacting between current leads show different tendency according to the arrangement of current leads on the top flange of the cryostat and the distance of each lead. Especially in case of high-current electric power devices or high-field magnets, optimal arrangement of current leads becomes one of the safety issues to be considered for minimizing the electromagnetic for ce acting on them. In this paper, we suggest an optimal arrangement method with three pairs of current leads for a 24kV class 650A superconducting fault current limiter (SFCL) system which has a probability of unpredicted fault currents(i.e, 20kA).

• 전기학회논문지
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• 제59권2호
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• pp.352-354
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• 2010

The effects of Au addition on the structure and the superconducting properties of Bi system bulk have been investigated. Au exists in the metalic form in above materials. It does not affect the formation and structure of the BiSrCaCuO(2223) phase. The superconducting transition temperature Tc does not change for $Bi_{1.7}Pb_{0.3}Sr_2Ca_2Cu_3O$ composite However Au doping can make the grains smaller. Metallic Au can make gathers on the grains boundary and lead to the increment of critical transport current density. The current density of $Bi_{1.7}Pb_{0.3}Sr_2Ca_2Cu_3Au_{0.5}O$ was 1000A/$cm^2$ at liquid nitrogen temperature.

• 한국초전도ㆍ저온공학회논문지
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• 제9권3호
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• pp.46-51
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• 2007

The 22.9kV/630A superconducting fault current limiter (SFCL) is developed by the KEPRI-LSIS collaboration group. This resistive SFCL uses three pairs of conduction-cooled current leads. When the SFCL system is in the fault mode. the current flows 20 times more than the steady state. Therefore. it is important that the current lead is designed to have the thermal stability in order to minimize the heat input of the cold-end. This paper presents the design and performance results of a pair of conduction-cooled brass current leads considering both cases that the SFCL system operates at the steady state and the fault current.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2000년도 KIASC Conference 2000 / 2000년도 학술대회 논문집
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• pp.136-138
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• 2000

1.5kA HTS current leads for a superconducting magnetic energy storage(SMES) magnet, which are connected to a conventional vapor cooled copper leads, were designed. The HTS lead composed of cylindrically arranged Bi-2223/Ag-1 at5Au tapes and a stainless steel tube. The minimum operating current of the lead is 1.71 kA at 77.3K, self magnetic field, and the heat input to the liquid helium from the clod end of the 36 cm lead is 0.5 W/lead.

• 한국전기전자재료학회논문지
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• 제18권4호
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• pp.370-374
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• 2005

AC loss of a superconducting conductor has a strong influence on the economic viability of a superconducting fault current limiter, which offers an attractive means to limit short circuit current in power systems. Therefore, the AC loss characteristics in several fault current limiting elements of a coil type have been investigated experimentally. The test result shows that AC losses measured in the fault current limiting elements depend on arrangement of a voltage lead. The AC loss of a bifilar coil is smallest among the fault current limiting elements of the coil type. The measured AC loss of the bifilar coil is much smaller than that calculated from Norris's elliptical model. However, the loss measured in a meander, which is frequently used in a resistive fault current limiter, agrees well to the theoretical one.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권12호
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• pp.670-675
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• 2002

AC loss is an important issue in the design of high-T$_{c}$ superconducting Power cables. The cables consists of a number of Bi-2223 tapes wound on a former. In such cables tapes have different critical current characteristics intrinsically. And they are electrically connected to each other and current leads by soldering. These make loss measurements considerably complex, especially for short samples of laboratory size. Special cautions are required in the positioning of voltage leads for measuring the true loss voltage. In this work the at losses in a single layer model cable have been experimentally investigated for different contacts and arrangements of voltage leads. The results show that the losses are not dependent on both arrangements and contact positions of the voltage leads. This implies that loss flux is only in a cylindrical conductor section. The measured losses also agree well with those based on a monoblock model and are independent of frequencies. This means that the measured AC loss of the model cable is purely hysteretic in nature.e.

• 한국진공학회지
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• 제16권5호
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• pp.388-396
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• 2007

KSTAR (Korea Superconducting Tokamak Advanced Research) 전류인입선(CL; Current Lead)은 4.5 K의 저온에서 운전되는 초전도 버스라인과 300 K의 실온에서 운전되는 MPS (Magnet Power Supply)를 전기적으로 연결하는 장치이다. 초기 플라즈마 발생시험을 위하여 TF (Toroidal Field) 및 PF (Poloidal Field) 리드박스에 전류인입선이 설치된다. TF 자석용 CL은 17.5 kA급 4 개의 CL에 최대 35 kA의 DC 전류가 인가되며, PF 자석용은 13 kA급 14 개의 CL에 350초간 $20\;{\sim}\;26\;kA$의 펄스 전류가 인가된다. 각각의 전류인입선은 TF 및 PF 자석에 전류를 인가하기 위한 버스라인이 연결되어 있으며, 전류인입선을 통해 초전도 버스라인으로 전달되는 전도열 및 전류인가시 발생되는 주울(Joule) 열을 차단하기 위한 헬륨냉매 제어시스템이 KSTAR 주장치와는 별도로 설치되어 있다. 리드박스 내 외부의 배관 및 제어시스템 설치완료 후 고진공 배기, 헬륨 누설검사, 전류인입선 유량 검사 및 액체질소 냉각시험을 실시하여 장치의 성능검증을 완료하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1106-1107
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• 2015

A flux pump (FP) can inject the DC current into high temperature superconducting (HTS) field coils of a HTS rotating machine without slip ring and current lead. However, it has limits to improve the value of DC current, and has time constants of DC current according to inductances of the HTS field coils. When a large-scale HTS generator with the FP is designed, a proper point about the inductance, field current, and time constant is demanded to decide parameters of the generator. In this paper, a parameter tuning skill of a large-scale superconducting wind power generator for applying a FP has been proposed. The design of the FP has been fixed, and 12 MW HTS generators have been variously designed by adjusting parameters related with the inductance of the HTS field coil. The induced current values have been calculated based on the FP design. The time constants of the induced currents depending on the DC current values and inductances of the generator have been represented. The results of the parameter tuning of the HTS generator have been discussed in detail.

• 한국진공학회지
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• 제17권1호
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• pp.58-66
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• 2008

KSTAR 전류전송제어시스템은 네트워크기반의 실시간 분산제어시스템으로 EPICS (Experimental Physics and Industrial Control System)를 미들웨어로 채용하여 구축하였다. 전류전송제어시스템은 초전도자석시스템에 전류를 전송하기 위한 시스템으로서 전류전송과 동시에 초전도자석이 초전도상태를 유지하기 위한 냉매의 전송도 담당하고 있다. 주제어실에서의 원격운전을 위하여 EPICS IOC(Input Output Controller) 서버를 현장에 설치하였고 이를 통하여 전류전송제어시스템은 고유의 이름(PV)에 적절한 조작 및 감시 명령을 부여하여 주제어실의 운전화면을 통하여 시스템의 감시 및 조작이 가능하도록 하였다. EPICS와 PLC의 통신을 위하여 ether-ip 드라이버를 이용하여 EPICS IOC를 구축하였으며, 시험 결과 안정성 및 운용성 측면에서 만족할 만한 결과를 획득하였다.