Quench behavior of superconductors during the operation of superconductor-triggered fault current limiters

Yim, S.W.,Park, C.R.,Yu, S.D.,Kim, H.R.,Hyun, O.B.,Sim, J.,Park, K.B.,Oh, I.S. North-Holland 2009 Physica. C, Superconductivity Vol.469 No.15

In the first-peak non-limiting type superconductor-triggered fault current limiter (STFCL), which was developed by the collaborative work of KEPRI and LSIS, the first half cycle of fault currents is passed, unlimited. Due to these characteristics, information needed for the fault judgments can be provided to the protection relays, which is useful for the protective coordination of power system. In this fault current limiter, superconductors are used as a fault detector that does not generate resistive loss in normal operation state. Therefore, high J<SUB>c</SUB> and fast occurrence of large resistance are the essential properties of superconductors for the application to fault detectors. In this study, for the design of superconducting fault detector (SFD), we investigated the quench behavior of two kinds of superconductors, stabilizer-free coated conductors (SF-CC) and Au/YBCO/sapphire substrate, during the operation of the first-peak non-limiting type STFCL. The dimension of SF-CC was 12mm widex1000mm long and that of Au/YBCO/sapphire was 20mm widex100mm long. Their critical current (I<SUB>c</SUB>) values were 250A and 200A, respectively, and the critical temperature (T<SUB>c</SUB>) was both 90K for both superconductors. When fault currents of over 3kA were applied, the STFCL carried out the current limitation successfully. At the beginning of the quench, SF-CC generated a resistance of 150mΩ, and 394mΩ was generated in the Au/YBCO/sapphire substrate, when 150V<SUB>rms</SUB> was applied. After the first half cycle, the resistance of the superconductors increased up to 263mΩ, and 846mΩ, respectively, and the temperature reached 132K and 127K. In addition, we also investigated the recovery characteristics of the SFDs. The SF-CC and Au/YBCO/sapphire substrate recovered the superconductivity by 353ms and 357ms, respectively. Based on the results of the analysis, we determined the required length of the superconductors for the SFD application.

연속주조공정의 열해석

이상민,구윤서,신영길,임창희,오경식,이인열 대한금속재료학회(대한금속학회) 1991 대한금속·재료학회지 Vol.29 No.12

In order to verify the accuracy of a one-dimensional computer program of finite difference heat transfer model for heat flow analysis in continuous casting process, computed surface temperature and solidified shell thickness were compared with measured values. The computed results showed a good agreement with measured values. This implies that the computer program is effective means for predicting temperature profile and solidified shell thickness of slab. The computed solidification constant(k) with S3 cooling pattern(Specific water flow : 0.57㎏-water/㎏-steel) was 23.8㎜/min^(0.5) and k with FK cooling pattern(Specific water flow : 0.94㎏-water/㎏-steel) was 26.3㎜/min^(0.5) in No.2 Continuous Slab Caster of POSCO. Relationship between heat transfer coefficient(h : J/㎡ see·℃) and water flux on the surface of hot slab was obtained as following equation by the laboratory scale experiment. h=14.02 W^(0.7◎)

보 구조물의 강성도 최적화 설계기법

임홍재(H.J.Yim),이상범(S.B.Lee),장현수(H.S.Jang),유헌일(H.I.Yoo) 한국자동차공학회 1996 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1996 No.11_1

Dynamic and static characteristics of the beam structure are mainly influenced by the shape of the cross section and material properties. Since the shape of the cross section determines the stiffness of the beam. such as I_x. I_y. J. an optimal shape of the cross section of the beam must be searched for the optimal stiffness design of the beam structure. In this paper an optimal design methodology for the thin-walled beam structure is presented.<br/>

수직원통형 빙축열조내 얼음의 외향용융과정시 전열특성에 관한 실험적 연구

김동환(D.H.Kim),김동춘(D.C.Kim),김일겸(I.K.Kim),김영기(Y.K.Kim),임장순(C.S.Yim) 한국태양에너지학회 1996 한국태양에너지학회 논문집 Vol.16 No.2

본 연구는 수직원통형 빙축열조 내에 상변하물질로서 순수한 물을 -10℃의 초기 과냉온도로 응고시킨 후, 작동유체의 입구온도를 7℃,4℃,1℃로, 작동유체의 유입방향을 상향과 하향으로 각각 변화시키면서 외향용융시켰을 경우, 시간경과에 따른 축열매질의 온도분포, 상경계면의 형상, 용융율, 용융에너지를 실험적으로 구하여 이를 비교·검토한 것이다.<br/> 작동유체의 입구온도가 7℃,4℃의 경우에는 작동유체의 유입방향이 상·하향 모두 물의 최대밀도점인 4℃ 부근에서 일시적으로 온도가 상승하지 않고 일정 시간동안 정체하는 온도정체구간이 나타났다. 또한, 용융이 진행됨에 따라 물이 축열조의 하부에 적체되고, 이에 따라 하부에서의 용융이 활발히 진행됨으로써 상경계면 형상은 전체적으로 종모양 형태의 곡선을 나타낸다. 작동유체의 입구온도가 7℃인 경우, 용융율(Vl/Vtot)과 용융에너지는 작동유체의 유입방향이 상향인 경우가 하향인 경우세어보다 크게 나타난 반면, 작동유체의 입구온도가 4℃,1℃인 경우는 7℃의 경우와는 달리 하향인 경우가 상향인 경우에서보다 큰 것으로 나타났다. This study presents experimental results of heat transfer characteristics of P. C. M. during outward melting process in a vertical cylinder. The experiment was carried out in six conditions, i. e. , three different inlet temperature (7℃, 4℃ and 1℃) and two directions of working fluid (upward and downward). Melting P. C. M. produced a bell-shaped phase change interface. When the inlet temperature was 7℃, the lower region remained at 4℃ until the temperature of upper region reached 4°C. This was due to the state of maximum density of the lower region. When the direction of the working fluid in the case of 7℃, inlet temperature, was upward, the rate of melting and the total melting energy were higher than when it's direction was downward. But the rate of melting and the total melting energy appeared higher value as it's direction was downward when the inlet temperature is 4℃ and 1℃.

좌측 측뇌실에 발생한 거대한 수막종 : 1례 보고 Case Report

임만빈,변인수,김인홍 대한신경외과학회 1980 Journal of Korean neurosurgical society Vol.9 No.1

The authors present a case of huge intraventricular meningioma in a 45 year-old female located in the left lateral ventricle. Meningiomas occurs only rarely in the ventricles of the brain. The diagnosis of choice is CT scanning to determine the site, size, density, and vascularity of the lesion. Surgical morbity and motality are low despite the deep location of the lesion, and the prognosis is favorable. Literature concerned were reviewed.

Evaluation of Pharmacokinetics and Skin Irritation of Transdermal Piroxicam Patch(Trast[R])

Kim, H. K 大韓臨床藥理學會 1995 臨床藥理學會誌 Vol.3 No.2

Conray-60을 이용한 뇌실조영술의 임상적 경험

정혁인,변영우,임만빈,변인수,김인홍 대한신경외과학회 1979 Journal of Korean neurosurgical society Vol.8 No.1

Adequate demonstration of the structures of the posterior fossa and the midline cerebral ventricular system is one of the most difficult problems in neuroradiology. During the last 2 years, we have performed conray ventriculography on 31 patients with clinical evidence of intracranial hypertension, in whom posterior fossa lesion was suspected or a supratentorial hemispheric lesion was not evident by carotid angiography. The patient is placed in the supine position and drilled 5cm above the nasion and 3cm to one side of the midline of nondominant hemisphere. A No. 20 spinal needle is inserted through the tract and aimed toward the anterior horn of the lateral ventricle. About 4 to 6cc of conray is introduced into the anterior horn with head flexed. The head is slowly extended. Serial roentgenograms are used to follow the conray trough the ventricular system.

松果腺部의 胎生癌 : A Case of Report

변영우,임만빈,정혁인,김인홍,장은숙,정재홍 대한신경외과학회 1980 Journal of Korean neurosurgical society Vol.9 No.2

The authors are reporting a extremely rare case of an embryonal carcinoma which arose in the pineal region of an eleven-year old boy. Surgical biopsy and autopsy performed arid be died about 4 month after the onset of the symptom. His clinical and autopsy findings are described.

THE ¹³CO OUTER GALAXY SURVEY OF TRAO USING MULTIBEAM ARRAY RECEIVER SYSTEM

Lee, Young-Ung,Kim, B.G.,Jung, J.H.,Kim, H.G.,Yim, I.S.,Kim, K.D.,Kang, H.W.,Choi, J.H. The Korean Astronomical Society 2007 Journal of The Korean Astronomical Society Vol.40 No.4

A survey project of TRAO with the fifteen beam array receiver system is presented. A multibeam array receiver system has been purchased from FCRAO, and is being installed on TRAO 14m telescope. The target region of the survey is from ${\iota}=120^{\circ}{\sim}137^{\circ},\;b=-1^{\circ}{\sim}+ 1^{\circ}$, and velocity resolution would be 1 km/sec after smoothing from the original resolution of $0.64km\;s^{-1}$ in the transition of J = 1-0 of $^{13}CO$. The survey region is a part of the $^{12}CO$ Outer Galaxy Survey(OGS), and would be an extension of the Bell Laboratories $^{13}CO$ Galactic Plane Survey. By combining with the existing $^{12}CO$ database of the Outer Galaxy Survey, we will derive physical properties of identified molecular clouds and will conduct and statistical analysis of the Outer Galalxy molecular clouds. Reduction process and analysis methods will be introduced.

수직원통형 빙축열조내 외향용융과정시 열전달특성에 관한 연구 -작동유체의 유동방향 및 축열조 형상비에 따른 열성능 비교-

김동환,김동춘,김일경,김영기,임장순,Kim, D.H.,Kim, D.C.,Kim, I.G.,Kim, Y.K.,Yim, C.S. 대한설비공학회 1997 설비공학 논문집 Vol.9 No.2

During the day time in summer, peak of air conditing load, and electric power management system lies under overloaded condition. The reason is the enlarged peak load value of electric power caused by increased air-cooling load in summer. To prevent load concentration during day time and overloaded condition of power management system, some energy storage methods are suggested. One of these methods is ice storage system. Water has some good properties as P.C.M.(Phase Chang Material) : Its melting point is the range of required operation temperature. It has large specific latent heat and is chemically stable compared to other organic or inorganic substances. It is cheap and easy to treat. This study represents experimental results of heat transfer characteristics of P.C.M. under the outward melting process in a vertical cylinder. We experimented with twelve combinations of conditions, i.e., three different inlet temperatures($7^{\circ}C,\;4^{\circ}C\;and\;1^{\circ}C$), two working fluid directions(upward and downward), and two aspect ratios, H/R(4 and 2). At the inlet temperature of $7^{\circ}C$ and $4^{\circ}C$, there was temperature stagnation region where the temperature of P.C.M. remains constant at $4^{\circ}C$ regardless of aspect ratio and direction of working fluid. This temperature stagnation occurs as the water, at its maximum density, flows down to the lower region. The phase change interface formed bell-shaped curve as the melting process continued. With a new set of conditions(4H/R, inlet temperature $4^{\circ}C$ and $1^{\circ}C$, downward/upwerd inlet direction), the movement of phase change interface was faster when the working flued inlet direction was downward. With the same set of conditions, melting rate and total melting energy were larger when the working fluid inlet direction was downward. The results were reversed when the other sets of conditions were applied.