• 한국초전도ㆍ저온공학회논문지
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• 제6권1호
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• pp.33-38
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• 2004

This paper presents an effective simulation method for the high temperature superconducting (HTS) transformer using PSCAD/ EMTDC. Although researches and developments are performed for the HTS technologies, problems such as AC loss and quench phenomenon need to be solved for efficient design of HTS transformer. In addition, pre-study on the HTS transformer is a sort of time and cost consuming work, thus it is very worthy or being analyzing the characteristics of the HTS transformer in advance through a proper simulation method. It is very important to analyze the HTS devices by the simulation for seeking suitable and reasonable parameters for the practical application of those apparatuses in advance. A software- based component is suggested for- the simulation of the HTS transformer using PSCAD/ EMTDC and the numerical results are analyzed in detail in this paper.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.108-111
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• 2001

YBCO HTS thick films coated using powder, Y$_2$O$_3$+L, quenched over 1200$^{\circ}C$ was studied. Quenched powder was crushed and mixed well in order to obtain uniformly dispersed Y2ll. Also, the powder was prepared with various condition in other to acquire optimum micro structure. As a result, it was found that the quenched sample on 1300$^{\circ}C$, holding time of 30min, has a bettor characteristic than other sample. On the other hand, the effect of film thickness was investigated. We concluded that the initiate film thickness has to be over 150$\mu\textrm{m}$. Especially, it was found that the film coated over 3 times with 50$\mu\textrm{m}$ m was best quality.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.653-657
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• 2005

The commercial contract was made firstly in the world for one set of high temperature superconducting(HTS) cable system between buyer, Korea Electric Power Research Institute and seller, Sumitomo Electric Industries, Ltd. in August 2004. After fabrication, test and examination, the HTS cable system will be installed at the KEPRI's test field in Gochang, Jeonbuk province from the time of July 2005. KEPRI is preparing measurement and test facilities for field test of the HTS cable system and carrying out researches into the design and construction of superconducting cable test building, evaluation of cooling performance, measurement of AC loss, analysis of the quench phenomena due to excess current and means of linking the HTS cable system to the existing electric power supplying system. The constitution of, the method to install and the plan of test operation of the HTS cable system will be presented in this paper.

• 한국초전도ㆍ저온공학회논문지
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• 제7권4호
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• pp.14-19
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• 2005

A transient numerical simulation was conducted to have variation of temperature on an element of resistive Superconducting Fault Current Limiter (SFCL) under quench condition. It is very important engineering information for an optimum design of cryogenic system for cooling of a resistive SFCL element. A bifilar coil for resistive SFCL for 10 MVA system was incorporated as a model in this numerical study. From the numerical simulation result, it was found that the averaged temperature on the shunt and Bi-2212 element at 500 kW, 100 ms was 711.1 K and 198.4 K respectively. The temperature variation with the change of the hot-spot size and time is also obtained. The maximum temperature was continuously increased in all cases until the hot-spot stops at 100ms and it was going down after then. Such as, the details of temperature distribution on the SFCL element obtained from this numerical study and it should be very valuable information on the decision of the cooling capacity of cryogenic system.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 학술대회 논문집
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• pp.15-18
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• 2003

HTS(High Temperature Superconductor) tapes have dependence on critical characteristics such as electric, magnetic field and temperature. In order to confirm these effects, we examined the current transport characteristics of HTS tapes. First, after being fed DC and AC, the dependence of HTS tapes of 10cm on external magnetic field was investigated. On centeral region of HTS tape, about 1cm, external magnetic field was applied. Second, after applying DC of 50A to HTS tapes, we applied time variable magnetic field about 100mT and investigated the quench characteristics. Finally, AC, which is about 10 times of I$_{c}$, was applied to HTS tapes and over current characteristics were investigated. The data acquired in this study will be used as a source for the study of HTS cable conductor which is supposed to carry on.n.

• 한국막학회:학술대회논문집
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• 한국막학회 1995년도 춘계 총회 및 학술발표회
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• pp.1-4
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• 1995

The microstructure of polymer membranes produced via thermally induced phase separation (TIPS) of polymer solutions is a strong function of both the early-stage (by spinodal decomposition or nucleation & growth) and the late-stage phase separation (referred to in general as coarsening). In the case of early stage effects, the membrane morphology resulting from a nucleation & growth mechanism is either a poorly interconnecsed, stringy, beady structure which is mechanically fragile or a well interconnected structure with highly nonuniform pore sizes. In contrast, spinodal decomposition results in a well interconnected, mechanically strong membrane with highly uniform pore sizes. Here I describe recent quantitative studies of the coarsening effects on the microstructure of membranes produced via TIPS process. The dependence of microstructure on coarsening time, quench depth, solution viscosity, and polymer molecular weight was investigated in order to distinguish among three possible coarsening mechanisms, Ostwald ripening, coalescence, and hydrodynamic flow, which may be responsible for structural evolution after the early-stage phase Separation (spinodal decomposition or nucleation & growth).

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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• pp.246-249
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• 2003

For quite a long time various researches and developments of superconducting magnetic energy storage(SMES) device for enhancement of power qualify control of sensitive electric load. This paper describes the design, fabrication and experimental results for the 3MJ SMES magnet made by using the design code of a SMES device that we developed. A computer code was developed to find the parameters of the SMES magnet which has minimum amount of superconductor for the same stored energy, and the 3MJ SMES magnet was designed based upon that. And 3MJ SMES magnet made base of several research result which was ramp up to 1㎄ without quench.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.958-960
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• 2003

Although the researches and developments are performed for superconducting technologies, many problems such as AC loss and quench phenomenon still remain to design the superconducting transformer. In addition, pre-study on the three phase high temperature superconducting (HTS) transformer is a sort of time and expense consuming work, thus it is very worthy of being analyzing the characteristics of HTS transformer in advance through proper simulation programs and skills. This paper presents an effective simulation method for the three phase HTS transformer using components developed in the PSCAD/EMTDC.

• 한국전기전자재료학회논문지
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• 제24권5호
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• pp.410-415
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• 2011

In this paper, we investigated the fault current limiting and the load voltage sag suppressing characteristics of the flux-lock type SFCL, designed with the additive polarity winding, according to the variations of turn number's ratio and the comparative analysis between the resistive type and the flux-lock type SFCLs were performed as well. From the analysis for the short-circuit tests, the flux-lock type SFCL designed with the larger turn number's ratio was shown to perform more effective fault current limiting and load voltage sag suppressing operations compared to the flux-lock type SFCL designed with the lower turn number's ratio through the fast quench occurrence of the high-$T_C$ superconducting (HTSC) element comprising the flux-lock type SFCL. In addition, the recovery time of the flux-lock type SFCL after the fault removed could be confirmed to be shorter in case of the flux-lock type SFCL designed with the lower turn number ratio.

• Nuclear Engineering and Technology
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• 제25권2호
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• pp.255-258
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• 1993

펄스형 질소레이저를 사용한 time-resolved laser-induced fluorimetry를 이용하여 우라늄 작업자의 뇨속에 함유되어 있는 우라늄의 농도를 간단한 전처리만으로 정량분석하는 방법을 연구하였다. 형광분석할 때에 뇨에 함유된 chloride ion은 우라늄 형광을 심하게 quenching하는 것으로 알려져 있으며, 따라서 이를 제거하기 위한 전처리 과정에서 많은 시간 소모와 큰 실험 오차를 유발하고 있다. 본 방법에서는 10% Fluran 수용액을 뇨에 첨가하여 뇨함량이 약 1% 정도가 되었을 때 뇨속의 chloride에 의한 quenching 영향을 최소한으로 줄일 수 있었으며, 시간 0에서의 형광강도를 계산하여 형광강도의 농도에 대한 직선성을 측정한 결과 우라늄 농도 범위 10-500 ppb에서 우수한 직선성을 나타내었다.