• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 학술대회 논문집
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• pp.261-262
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• 2003

We performed unsymmetrical analysis of a single line-to-ground fault in a three-phase system. The current limiting elements were meander type YBCO stripes coated with Au shunt. When the fault occurred, short circuit currents were effectively limited within 1-2 msec after fault instant. The unsymmetrical rate of fault phase was distributed from 6.4 to 1.4 and most of the fault current flowed in the grounding line due to its direct grounding system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1652-1654
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• 1994

The Extra-high voltage XLPE cable is characterized by low transmission loss, large capacity, and high reliability. Conventionally, for XLPE cables of l54kV and above, aluminium sheath was used to be moisture barrier (thus preventing water tree deterioration of the insulation) and to protect cable core from physical stresses. However, as transmission capacity of the cable increases, so does the cable diameter and the corresponding aluminium sheath outer diameter and thickness. As a result, eddy-current loss in the sheath is increased, limiting the maximum current capacity of the cable itself. As an alternative to aluminium sheath, we have adopted stainless steel sheath with non-magnetic properties and a large resistivity, The new XLPE cable with stainless-steel sheath (CSZV cable) has drastically reduced eddy-current loss in the sheath.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.296-297
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• 2005

We have investigated the quench performance of shunt reactors in the parallel connection of resistive type superconducting fault current limiter (SFCL) components based on YBCO films. To increase voltage rating, components are connected in series and to increase current level, they are connected in parallel. This method has cauesd the unbalanced quench between each components. To improve the problem, we have compared the quench properties between the current limiting components without and with shunt reactors connected in parallel. To improve the quench performance, across individual SFCL components connected the shunt reactor in parallel. The components with shunt reactors successfully produced simultaneous quench, resulting from the bypass of the fault current in the direction of the shunt reactor.

• 한국전기전자재료학회논문지
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• 제14권6호
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• pp.518-524
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• 2001

We report the current limiting properties of superconducting fault current limiters (SFCL). Our SFCL was patterned in a spiral type on a YB $a_2$C $u_3$$O_{7-x}$(YBCO) film deposited using rf sputtering techniques and was coated with a gold shunt layer in order to disperse the heat generated at hot spots in the YBCO film. Current increased up to 13.5 $A_{peak}$ at 60 Hz for the voltage of 13 $V_{peak}$, which is the minimum quench point, and increased up to 17.6 $A_{peak}$ at 60 Hz fo the voltage fo 141.4 $V_{peak}$. The quench completion time was 5 msec at 13 $V_{peak}$ and 4 msec at 141. $V_{peak}$ respectively. we think that this architecture using spiral-type SFCL can be useful for the protection of the power delivery systems from fault currents.s. currents.s.

• KIEE International Transactions on Electrophysics and Applications
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• 제11C권3호
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• pp.58-62
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• 2001

Since Metallo-Porphyrin (MP) is very interesting compound due to its unique electronic and redox properties and it is also chemically and thermally stable, MP has been studied for potential memory and switching devices. In this study, thin films of 5,10,15,20-Tetrakis-Octadecyloxymethylphenyl-Porphyrin-Zn(II) were prepared by the Langmuir-Blodgett (LB) method and characterized by using UV/vis absorption spectroscopy and cyclic voltammetry. It was found that the proper transfer surface pressure for film deposition was 25 mN/m and the limiting area per molecule was 135 ${\AA}^2$/molecule. The current-voltage (I-V) characteristics of these films were investigated. Further details on the electrical properties of Porphyrin-Zn(II) derivative films will be discussed.

• Geomechanics and Engineering
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• 제15권5호
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• pp.1071-1080
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• 2018

The study of behavior and values of deformations in the geological medium makes the scientific basis of the methodology of synthesis of true values of parameters of its physico-mechanical and density properties taking into account the influence of geodynamic impacts. The segments of continuous variation of homogeneous elastic uniform deformations are determined under overall compression of the medium. The limits of these segments are defined according to the criteria of instability (on geometric form changes and on "internal" instability). Analytical formulae are obtained to calculate current and limiting (critical) values of deformations within the framework of various variants of small and large initial deformations of the non-classically linearized approach of non-linear elastodynamics. The distribution of deformation becomes non-uniform in the medium while the limiting values of deformations are achieved. The proposed analytical formulae are applicable only within homogeneous distribution of deformations. Numerical experiments are carried out for various elastic potentials. It is found that various forms of instability can precede phase transitions and destruction. The influence of these deformation phenomena should be removed while the physico-mechanical and density parameters of the deformed media are determined. In particular, it is necessary to use the formulae proposed in this paper for this purpose.

• The Korean Journal of Physiology and Pharmacology
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• 제5권1호
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• pp.33-40
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• 2001

The aim of present study was to define the cellular mechanisms underlying changes in delayed rectifier $K^+\;(K_{DR})$ channel function in isoproterenol-induced hypertrophy. It has been proposed that $K_{DR}$ channels play a role in regulation of vascular tone by limiting membrane depolarization in arterial smooth muscle cells. The alterations of the properties of coronary $K_{DR}$ channels have not been studied as a possible mechanism for impaired coronary reserve in cardiac hypertrophy. The present study was carried out to compare the properties of coronary $K_{DR}$ channels in normal and hypertrophied hearts. These channels were measured from rabbit coronary smooth muscle cells using a patch clamp technique. The main findings of the study are as follows: (1) the $K_{DR}$ current density was decreased without changes of the channel kinetics in isoproterenol-induced hypertrophy; (2) the sensitivity of coronary $K_{DR}$ channels to 4-AP was increased in isoproterenol-induced hypertrophy. From the above results, we suggest for the first time that the alteration of $K_{DR}$ channels may limit vasodilating responses to several stimuli and may be involved in impaired coronary reserve in isoproterenol-induced hypertrophy.

• 대한전기학회논문지:전력기술부문A
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• 제49권8호
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• pp.418-423
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• 2000

In this paper, we reported the current limiting properties of superconducting fault current limiters (SFCL). Our SFCL was patterned in a coil-type on a YBCO film deposited using rf sputtering techniques and was coated with a gold shunt layer in order to disperse the heat generated at hot spots in the YBCO film. Current increased up to 13.5 Apeak at 60 Hz for the voltage of 11.5 Vpeak, which is the minimum quench point, and increased up to 17.6 Apeak at 60 Hz for the voltage of 80 Vpeak. The quench completion time was 5 msec at 11.5 Vpeak and 4 msec at 80 Vpeak respectively. We think that this architecture using coil-type SFCL can be useful for the protection of the power delivery systems from fault currents.

• 전기학회논문지P
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• 제57권3호
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• pp.323-327
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• 2008

We investigated the quench characteristics of a flux-lock type superconducting fault current limiter (SFCL) depending on the methods of the serial and parallel connections between the superconducting elements. The flux-lock type SFCL consists of two coils. The primary coil is wound in parallel to the secondary coil through an iron core, and the secondary coil is connected to the superconducting elements in series and parallel. In this paper, the analyses of voltage, current, and resistance of the superconducting elements connected in serial and parallel were performed to increase the power capacity of the flux-lock type SFCL. A part of the superconducting elements was not quenched in $2{\times}2$ serial connection between the elements and then the power burden of the quenched elements was increased. However the elements with $2{\times}2$ parallel connection was all quenched. This means that the power burden of each superconducting element can be reduced under the same conditions. We found that $2{\times}2$ parallel connection was more profitable for the current limiting effects and the increase of the power capacity.

• 한국초전도ㆍ저온공학회논문지
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• 제11권3호
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• pp.10-14
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• 2009

Since a stabilizer of YBCO coated conductor (CC) plays a very important role of bypassing over-current and transferring heat generated in the moment of fault, it is one of big issues to determine the material of the stabilizer and its dimension for the high performance of the HTS power application system. Especially, in the case of a superconducting fault current limiter (SFCL), which requires it to react immediately to the occurrence of fault, characteristics of stabilizer are decisive in limiting fault current and recovering superconducting properties during and after quenching. In this paper, the quench / recovery characteristics of YBCO CCs with various thickness of stabilizer were analyzed. The quench/recovery test carried out at 20 $V_{rms}$, 5 cycles (60 Hz) and results showed that as the thickness of the stabilizer decreased, both the final approach temperature and the recovery time decreased.