• 전기학회논문지
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• 제58권2호
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• pp.242-247
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• 2009

Forest Fire can cause a serious damage to overhead conductors. Therefore, the detailed investigation for the changes of mechanical and electrical properties of damaged conductors should be carried out to understand the effect of forest fires on conductors. This is very much important to maintain transmission line safely. Oxidation of overhead conductor was increased with temperature and time(maximum time : 30min). Conductivity of Al conductor was decreased by Agents. The detailed will be given in the text.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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• pp.21-23
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• 2003

MOCVD method is one of promising techniques which can fabricate YBCO coated conductors in a low Price A continuous reel-to-reel MOCVD device using a dispersed solid source was designed and manufactured. YBCO films were deposited on various substrates of metallic silver, (100) MgO and SrTiO3 single crystals. The chemical composition of the metal organic sources was changed to optimize the processing condition associate to the deposition of the stoichiometric Y3a2Cu3O7-y. We report the superconducting transition temperature, surface morphology and chemical composition of the YBCO film surfaces.

• 한국초전도ㆍ저온공학회논문지
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• 제21권4호
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• pp.39-43
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• 2019

The breaking of a circuit in DC grid could pose a challenge because of the absence of zero-crossing instant for both current and voltage when a fault occurs. An additional fault current limiting function will be very helpful for reducing the burden of the DC circuit breaker by limiting the fault current to a reasonable value. In this paper, we studied the overcurrent characteristics of several HTS conductors so that we could use the selected conductors for the basic design work of a resistive type fault current limiting module as a part of the circuit breaking system. According to the short-circuit test results, we suggested and compared two different basic design parameters of the HTS fault current limiting module, which will be connected in series to the DC circuit breaker.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.78-81
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• 1987

The scattering characteristics are analysed for the dielectric cylinder with arbitrary cross section partially covered by thin conductors. The integro differential equations consistant with boundary conditions of conductor and dielectric boundaries are derived by the equivalence principle. They are transformed into matrix equations by moment method. The circular dielectric cylinder covered by conductors at the upper and bottom side of the cylinder is chosen for the numerical example. Current distributions on conductors and scattering cross section by the cylinder are computed for incident wave perpendicular to the conductor plane.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.679-680
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• 2007

The oscillation is very dangerous in bundled transmission lines, especially 345kV 4 bundle transmission lines are very weak for subspan oscillations. In some cases, subspan oscillations are continuously occurred in the same subspan. In order to develop the control method of the above subspan oscillation, this paper suggests a method of applying spacers for 2 bundled conductors to the subspans. In the future we will try to observe and analyze the oscillation after installing the spacers for 2 bundled conductors, and suggest the effective method for controling subspan oscillations.

• 한국초전도ㆍ저온공학회논문지
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• 제22권4호
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• pp.24-30
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• 2020

The test results of the ITER toroidal field conductors demonstrated a decrease of the current sharing temperature (Tcs) with an increase in the number of electromagnetic cycles in general. This is associating with several factors. One of them is the superconducting Nb3Sn filaments cracking and another one is the redistribution of the relative deformation of the Nb3Sn strands under Lorentz forces. Despite these factors, some conductors have shown the absence or significantly less degradation of Tcs during electromagnetic cycling. This article considers another possible reason for a more stable conductors Tcs behavior, namely, the local compression of Nb3Sn wires in the cross section of a conductor. In this article presents the results of a quantitative analysis Nb3Sn superconducting filaments cracking of strands extracted from a conductor that has passed electromagnetic cycling and the model of a conductor compaction, as well as calculation results based on this model are presented also.

• 한국초전도ㆍ저온공학회논문지
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• 제24권4호
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• pp.78-83
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• 2022

REBCO coated conductors are widely used for HTS power application, high magnetic field magnet application, and etc. A thermal stability of the REBCO conductor is essential for the operation of HTS-based device, and thermal conductivities of the conductor are relevant parameters for modeling cryogenic heat transfer. REBCO conductors consist of a REBCO layer, copper layers for electrical stabilization and a hastelloy substrate. At cryogenic temperature, thermal conductivity of copper and silver strongly depend on the purity of the material and the intensity of the magnetic field. In this study, thermal conductivities of the laminated composite structure of REBCO conductor are evaluated by using the thermal network model and the multidimensional heat conduction analysis. As a result, the thermal network model is applicable to REBCO conductors configured in series or parallel alone and multidimensional heat conduction analysis is necessary for complex cases of series and parallel configuration.

• 한국초전도ㆍ저온공학회논문지
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• 제10권2호
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• pp.24-26
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• 2008

[ $Gd_{1+x}Ba_{2-x}Cu_3O_7$ ] (GdBCO) coated conductors on IBAD-MgO templates have grown by pulsed laser deposition. Critical current of the films were measured as about 90 A/cm by a four-probe method. The optical response of the films was investigated by Raman scattering spectroscopy. According to the Raman scattering spectra, the peaks at $328\;cm^{-1}$, $451\;cm^{-1}$, $504\;cm^{-1}$ were found and assigned to one $B_{1g}$ mode and two $A_{1g}$ modes, respectively. The high critical-current carrying behaviors of the GdBCO coated conductors are ascribed to their 123-structure without exchange of cation and incorporation of oxygen into the cuprates.

• 한국초전도ㆍ저온공학회논문지
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• 제12권2호
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• pp.21-24
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• 2010

This paper deals with numerical analysis on a high-$T_c$ superconducting (HTS) electrodynamic suspension (EDS) simulator according to the variation of the ground conductor conditions. Because the levitation force of EDS system is formed by the magnetic reaction between moving magnets and fixed ground conductors, the distribution of the magnetic flux on a ground conductor plays an important role in the determining of the levitation force level. The possible way to analyze HTS EDS system was implemented with 3D finite element method (FEM) tool. A plate type ground conductor generated stronger levitation force than ring type ground conductor. Although the outer diameter of Ring3 (335 mm) was larger than that of Ring2 (235 mm), the levitation force by Ring2 was stronger than that by Ring3. Considering the results of this paper, it is recommended that the magnetic flux distribution according to the levitation height and magnet current should be taken into account in the design of the ground conductors.

• 한국초전도ㆍ저온공학회논문지
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• 제25권4호
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• pp.40-44
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• 2023

For high-temperature superconducting power applications that need large current capacity, a large current conductor manufactured using multiple superconducting tape is required. Conductors being studied for large currents capacity such as CORC, TSTC, and RACC have advantages and disadvantages, and in order to use these conductors in coil form and apply them to AC power devices, research on magnetization loss occurring in superconductors due to external magnetic fields is essential. To accurately measure magnetization loss in a conductor that is twisted by stacking straight conductors like TSTC, the correlation between the measuring system and the shape of the sample must be clearly known to accurately measure the loss. In this paper, we will confirm the difference in magnetization loss measurement values according to the correlation between the length of the pickup coil and the twist pitch of the sample in CORC and TSTC shapes, and review considerations for accurate magnetization loss measurement from the results.