• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.06a
• /
• pp.365-366
• /
• 2009

This study researched into the manufacture of current-limit module of using YBCO coated conductor. Regarding over-current of exceeding the critical current, the quench characteristics were researched according to the stabilizing layer through tendency in resistance, which is generated in conductor, by applying over-current to YBCO coated conductors, which have stabilizing layer. YBCO coated conductors, which were used in experiment, include one kind such as the conductor, which used stainless as the stabilizing layer. The critical current is 70 A. And, the critical temperature is with 90 K. First of all, the quench generation was researched under over-current of exceeding the critical current by using this YBCO coated conductors. The tendency of a rise in the detected voltage according to the applied current was measured. And, the tendency of a rise in resistance through voltage-current curve was measured. As a result, the point of time in thermal quench of conductor, which has stainless as the stabilizing layer, could be confirmed to be fast.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.3
• /
• pp.230-236
• /
• 2013

This paper presents the numerical calculation for input impedance of a conductor located in the loss media by using the program with MATLAB. The input impedances of the conductor were numerically calculated with the moment of method. To increase an accuracy of results, the Galerkin's method which both the basic function and the weight function are the triangle function was applied. And by applying the modified image method, image sources of the conductor located in air were considered. According to the comparison between the current distributions at the conductor which were calculated with the MATLAB program and the NEC program, the reliability of the self-made program with MATLAB was obtained. In case of the conductor located in soil, which length are 1 m and 2 m, the input impedance were simulated as a function of both a conductivity and a frequency. Finally, input impedances and phases of the conductor located in soil were measured, and those results were compared with simulated results which calculated under the same conditions.

• Progress in Superconductivity and Cryogenics
• /
• v.10 no.1
• /
• pp.10-14
• /
• 2008

Differently from BSCCO tapes which are fabricated by powder-in-tube method, the coated conductors are made by the evaporation of YBCO on metal substrate. Due to this structural merit, although the coated conductors are generally used for large current transportation, they are expected to be favorable to the purpose of the fault current limitation as well. In this study, using YBCO coated conductor having copper stabilizer formed by plating technique(produced by Superpower Co.), we investigated the over-current characteristics of the coated conductor. The coated conductors had 85 A $I_c$ and 90 K $T_c$. The resistance of the conductor was 0.93 $m{\Omega}/cm$ at 300 K and 0.17 $m{\Omega}/cm$ at the temperature right above $T_c$. To the coated conductors, we applied the voltages of the range from 150 $V_{rms}$ to 230 $V_{rms}$ and measured the V-I curves using four probe method. From the results, we could analyze the electric behavior of the coated conductor in flux flow state. As the current exceed $I_c$, the currents were distributed into the superconductor and metal stabilizer. The amounts of the currents shared through both current paths were calculated under the assumption that the ,Joule heating was perfectly eliminated by $LN_2$ surrounding the conductor. Finally, the condition for the stable current flowing state which does not affect the conductor was established from the analysis on the over-current characteristics.

• 한국초전도학회:학술대회논문집
• /
• v.11
• /
• pp.27-27
• /
• 2001

• 한국초전도학회:학술대회논문집
• /
• v.11
• /
• pp.11-11
• /
• 2001

• 한국초전도학회:학술대회논문집
• /
• v.15
• /
• pp.5-5
• /
• 2005

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.20 no.4
• /
• pp.107-116
• /
• 2006

The international standard to determine grounding conductor size can be applied for a wide range of items because it includes the specific physical characteristics, but it has a problem where the numerical formula is complicated. However the JIS and domestic standard numerical formula are simple but have many constraints. The new grounding conductor size selecting method is necessary in order to solve such problems. Therefore, in this study, we suggested an improved method for selecting the grounding conductor size and simple numerical formula with a numerical formula control modeling. and we verified reliability of paper used case study.

• Progress in Superconductivity and Cryogenics
• /
• v.20 no.1
• /
• pp.19-22
• /
• 2018

The thermal and electrical properties of the conductor are critical parametersfor the design and optimization of the superconducting magnet. This paper presents simulation code to analyze electrical and thermal stability characteristics of the second generation (2G) high-temperature superconductor (HTS) by varying copper stabilizer thickness. Two types of commercial 2G HTS coated conductor tapes, YBCO and GdBCO were used in this study. These samples were cooled by Liquid Nitrogen ($LN_2$) having boiling at 77.3 K and an equivalent electrical circuit model for them is choosen and analysed in details. Also, an over-current pulse test in which a current exceeding a critical current was performed. From the simulation results, the influences of the copper stabilizer thickness on the stability characteristics of these samples are presented.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.06a
• /
• pp.363-364
• /
• 2009

For the application of superconductor technology, we need critical properties of superconductors such as a critical current ($I_c$). $I_c$ is varied as processing method by action of flux pinning center. Our research activities are reported on the establishment of standard measurement method for critical current in coated conductor. And then, we researched pre-studies for standardization of critical current evaluation method using IEC/TC 90 standard.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.25 no.1
• /
• pp.7-13
• /
• 2016

With the increasing running speed of trains, new railway lines in metropolitan areas, and the rising demand for green transportations, the number of underground and tunnel sections are constantly becoming larger, and installations of overhead rigid conductor systems are becoming wider. However, domestic commercial products for overhead rigid conductors are limited to 120 km/h train speeds. In this study, to develop a high-speed (250 km/h) overhead rigid conductor, R-Bar (Rigid Bar), the electrical and mechanical stability was enhanced through the improvement of the cross sectional shape of the R-Bar; the transition structure was also designed for flexibility and natural frequency isolation. In addition, the evaluation of contact forces between a pantograph and the overhead rigid conductor system for 250 km/h train speeds was performed using dynamic analysis.