• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.246-251
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• 2000

In this paper, Wire electric discharge grinding(WEDG) method for manufacturing the micro shaft was introduced and the machining characteristics was investigated. from the experimental results, it was concluded that high surface integrity could be obtained by use of dielectric fluid spraying method and small capacitive condenser.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.521-523
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• 2005

A Jumper wire is currently used to connect each fixed power line on both sides of dead end tower for overhead transmission line, but in case of a jumper wire swing under circumstances of typhoon, etc. and the air clearance is deficient then a flashover fault may Happen. Now the angle tower has the jumper support string to prevent a swing of jumper wire and to secure the air clearance between jumper wire and tower main body, but the flashover fault by swing of jumper wire was happened yl times across all over the country, because of the typhoon 'Rusa' in year 2002 and 'Maemi' in year 2003. This paper presents the design and development of 'Counter Weight' which enables to keep the swing angle of jumper wire under 40 degree in design condition to prevent a flashover fault by swing of jumper wire by a high wind pressure load in case of typhoon and have completed a mechanical and electrical characteristic test.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1818-1823
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• 2015

In this paper, we analyzed the optimal configuration of protection wire that have been installed in the electric railway power supply system. Protection wires are to suppress the ground potential rise when the short circuit fault between contact wire-rail(C-F), and protect the electronics equipments(signalling and communication) that are facility the wayside. The role of protection wires must be feed back quickly the fault current to the substation when a short circuit fault occurs. In this paper, we proposed that only one line to install the protection wire. Comparing how to newly proposed and existing system, most of the performance is similar. The reason is that most of the current flowing in the protection wire near the location where the fault occurred. There is no problem even if in one line for human safe and the low impedance of the return circuit in dimension to ensure the safety of the facility during the fault. To ensure safety during an fault occurs, it is sufficient even by one line. But, In the protection wire of facilities planning it is necessary to design taking into account the potential utility.

• KEPCO Journal on Electric Power and Energy
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• v.8 no.1
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• pp.1-4
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• 2022

In this study, a tensile test, one of the mechanical tests, was performed with the collected natural aging ACSR. In order to be used as basic data for predicting the replacement cycle of ACSR, the tensile strength with the normal cables was compared for cables which was caused white rust due to exposure of the hard-drawn aluminum wire surface. Among the ACSR wires collected from various regions, white rust was found on the surface of the small wire, and by checking the tensile strength of them, we would like to suggest the criteria for the ACSR replacement cycle, focusing on changes in mechanical properties.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.3
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• pp.321-330
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• 2011

We experimentally investigated the effect of applied DC electric fields on the flame spread over polyethylene-coated electrical wire. The flame-spread rates over electrical wire with negative and positive DC electric fields from 0 to ${\pm}7$ kV were measured and analyzed. We compared the results for DC electric fields with previous results for AC electric fields. We explored whether or not various flame shapes could be obtained with DC electric fields and the main reason for the flame-spread acceleration, particularly at the end of the electrical wire, for AC electric fields. We found that DC electric fields do not significantly affect the flame-spread rates. However, the flame shape is mildly altered by the ionic wind effect even for DC electric fields. The flame-spread rate is relevant to the flame shape and the slanted direction in spite of the mild impact. A possible explanation for the flame spread is given by a thermal-balance mechanism and fuel-vapor jet.

• Fire Science and Engineering
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• v.31 no.6
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• pp.83-90
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• 2017

If an overcurrent exceeding the rated value is applied to an electric wire, the temperature of the electric wire increases, and the electric wire covering deteriorates to cause a short circuit. The upper limit temperature of the wire varies according to the magnitude of the overcurrent. When a short circuit occurs at each upper temperature limit, a cooling speed difference occurs during the solidification process due to the temperature difference between the short circuit temperature and the wire surface temperature. At this time, the pattern characteristics of the dendritic structure formed on the molten cross section are different. In this study, the upper temperature limit, which varied according to the overcurrent magnitude, was measured. At the time a short circuit occurred, the second branch spacing (dendrite Arm Spacing : DAS) of the dendrite was analyzed and the numerical value was quantified. The experimental results showed that the upper temperature limit increases with the magnitude of the overcurrent, and that the second branch spacing increases with increasing wire temperature.

• Journal of electromagnetic engineering and science
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• v.6 no.2
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• pp.130-134
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• 2006

This paper presents the reduction characteristics of penetrated electromagnetic fields through a narrow slot in a planar conducting screen of infinite extent. When a plane wave is excited to the narrow slot, the aperture electric field is controlled by the parallel wire or parallel plate connected on the slot. The magnitude of penetrated electromagnetic fields through a narrow slot is controlled by electric field distributions on the slot. An integral equation for the aperture electric field on narrow slots is derived and solved by applying Galerkin's method of moments. The results show that the magnitude of the penetrated electromagnetic field can be effectively reduced by installing the parallel wire or parallel plate on the slot.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1826-1828
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• 2004

최근 XLPE 케이블의 신뢰성 향상을 위한 지속적인 연구 및 기술개발이 성과를 나타내면서, 지난 한세기동안 세계적으로 실선로에 적용되어 그 신뢰성을 인정받던 OF 케이블이 XLPE 케이블의 상대적으로 낮은 송전 손실, 높은 방염 특성 및 유지보수와 설치의 편이성에 밀려 그 수요가 급격히 감소하고 있는 추세이다. 이러한 추세에 따라 기존의 OF 케이블 선로의 증설 또는 이설 공사의 경우, 기설 OF 케이블 선로에 XLPE 케이블을 연결하여 사용하는 경향이 많아지며, 이 이종의 케이블을 상호간 연결하는 중간접속함의 필요성이 대두되었다. 이 이종케이블 접속함은 각 케이블의 제반 특성을 최대한 유지하는 동시에 장기적인 신뢰성 확보가 최대 과제이며, 기설의 전력구에 사용하기 위한 경량화 또한 요구된다.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1296-1298
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• 1995

This paper presents the power cable with the concentric neutral wires of S-Z stranding. This type Cables, 22.9KV CN/CV Cables used in the distribution systems have been developed in order to improve bend, bend after torsion and tension charateristics. We have designed and made S-Z stranding machine, testing equipment etc., and have established the manufacturing technology of the equipment and the testing technology.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1229-1231
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• 1995

XLPE cable, which has excellent electrical and thermal performance, has been widely used for HV transmission & distribution lines. The most important thing to produce the cable products having good performance is to set the optimal operating conditions of cable machinery. Because it is very difficult to measure the temperature of cable under curing process practically, it is necessary to evaluate the cable temperature by using the method to simulate real conditions numerically. In this work, We investigate the basic theory on transient heat transfer between curing tube and cable for making a numerical simulation program using computer. In this program, a differential equation is approximated by a infinite differential method and a few assumptions are used to simplify the model and minimize the calculation time of program.