• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1675-1677
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• 1997

In this paper we study the voltage-current characteristics inside the wire-plate precipitators by numerically solving the Poisson's equation and current continuity equation. The effects of a wire size, wire-wire spacing, wire-plate spacing and effective mobility have been considered.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.554-555
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• 2005

In this paper, we analyzed a metallurgical structure and arc properties of copper wire when the over-current flows on electric wire. From the results, The fusing current was related to the fusing time(current rising rate per second). In case of the shorter the fusing time, the fusing current was high, and the fusing time of ac type was larger than that of dc type. The copper wire was bent by the increase of current and heated, the beads were scattered around wire with a flash. We could observed the dendrite structure in 'molten wire at ac and dc current type. According as the current rising rate per second is short, the dendrite structure is distributed in surface of wire.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2215-2216
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• 2011

In this study, the dynamic characteristic of a contact wire and pantograph suppling electrical power to electrical railway vehicle is investigated from an electrical response point of view. To analysis voltage and current waveforms by induced contact loss phenomenon on driving electrical railway vehicle, a hardware Simulator which considered contact loss between contact wire and the pantograph as well as contact wire deviation is developed. It is confirmed that a contact wire and pantograph model are necessary for studying the dynamic behavior of the pantograph system. Throughout prototype simulator and contact wire and catenary wire experiments, it is confirmed that current waveforms is distorted by contact loss phenomenon and in case of driving electrical railway vehicle.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.735-738
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• 2000

The characteristics of wire electrical discharge machining (WEDM) are governed by many factors such as the power supply type, operating condition and electrode material. This work deals with the effect of wire electrode materials on the machining characteristics such as, metal removal rate, surface characteristics and surface roughness during WEDM A wire's thermal physical properties are melting point, electrical conductivity and vapor pressure. One of the desired qualities of wire is a low melting point and high vapor pressure to help expel the contaminants from the gap. They are determined by the mix of alloying elements (in the case of plain brass and coated wire) or the base core material(i.e. molybdenum). Experiments have been conducted regarding the choice of suitable wire electrode materials and influence of the properties of these materials on the machinability and surface characteristics in WEDM, the experimental results are presented and discussed from their metallurgical aspect. And the coating effect of various alloying elements(Au, Ag, Cu, Zn, Cr, Mn, etc.) to the Cu or 65-35 brass core on them was reviewed also. The removal rate of some coated wires are higher than that of 65-35 brass electrode wire because the wire is difficult to break due to the wire cooling effect of Zn evaporation latent heat and the Zn oxide on the surface is effective in preventing short circuit. The removal rate increases with increasing Zn content from 35, 40 and Zn coated wire

• Journal of the Korean Society for Precision Engineering
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• v.27 no.1
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• pp.11-17
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• 2010

This study investigates the non-traditional manufacturing process of dry wire electrical discharge machining (EDM) in which liquid dielectric is replaced by a gaseous medium. Wire EDM experiments of thin workpieces were conducted both in wet and dry EDM conditions to examine the effects of spark cycle (T), spark on-time ($T_{on}$), thickness of work pieces, and work material on machining performance. The material removal rate (MRR) in the dry wire EDM case was much lower than that in the wet wire EDM case. In addition, the thickness of workpiece and work-material were found to be critical factors influencing the MRR for dry EDM process. The relative ratios of spark, arc and short circuit were also calculated and compared to examine the effectiveness of processes of dry and wet wire EDM.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.349-351
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• 1999

This paper presents a new control algorithm for series active power filters that are applied to 3-phase 3-wire and 3-phase 4-wire systems with capacitive loads. It is difficult to reduce harmonic currents in neutral lines of the 3-phase 4-wire systems using conventional series active power filter control methods. 3-phase 4-wire series active power filter systems using the proposed method in this study lower neutral line harmonics. Simulation was carried out to verify the algorithm.

• Journal of the Korean Society of Safety
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• v.27 no.2
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• pp.7-12
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• 2012

This paper describes electrical fire on electric pad caused by defect of hot wires. We analyzed two type electric pad using by carbon type hot wire and magnetic shielded type hot wire. First, a carbon type hot wires electric pad is virtually impossible to connect hot wire as a method of electrical welding or soldering. In order to connect between hot wires, that has to splice carbon type material connector. If junction of hot wires was occurrence of poor connection on electric pad, it increase contact resistance on this junction point. With increasing contact resistance, junction of hot wires on electric pad generates local heating and finally leads to electrical fire. An electric pad using by a magnetic shielded type hot wire happened local heating on signal wire for sensing temperature-rise caused by applying current for magnetic shielded. With increasing local heating of signal wire, insulated coating of hot wire was melted. Finally the magnetic shielded type hot wire electric pad lead to electrical fire with breakdown between signal wire and hot wire. In this paper, we analyzed shape of damage in hot wire caused by electrical local heating and investigated fire cause on electric pad due to defect of hot wires.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.157-162
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• 2010

Power line communication, using 25[kV] high voltage of railway catenary, is to provide information which is real-time safety information for train operations and train workers in driving. Lots of noise were occupied in the contact wire by electrical and communication equipments. A signal attenuation was caused characteristics of the contact wire and messenger wire. For relaying communications to transmit information using the contact wire, catenary the noise and signal attenuation were investigated. And the final goal of the study was realized to transmit video information by power line communication on electric railway.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.12
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• pp.1159-1165
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• 2005

New conductor is developed by using high strength nonmagnetic steel(NM) wire as the core of overhead conductor This conductor is called ACNR overhead conductor(Aluminum Conductor Nonmagnetic Steel Reinforced). Formed by the combination of aluminum alloy wire and high strength nonmagnetic steel wire, it has about the same weight and diameter as conventional ACSR overhead conductor. To enhance properties beneficial in an electrical and mechanical conductor during the Process of high strength nonmagnetic steel wire, we made a large number of improvements and modifications in the working process, aluminum cladded method, and other process. ACNR overhead conductor, we successfully developed, has mechanical and electrical properties as good as or even better than conventional galvanized wire. Microstructure of raw material NM wire was austenite and then deformed martensite after drawing process. Strength at room temperature is about $180kgf/mm^2\~200kgf/mm^2$. The conductivity at 0.78 mm thickness of Aluminum cladded M wire is about $7\%$ IACS higher than $20\%$IACS of HC wire used as core of commercial ACSR overhead conductor. The corrosion resistance is about 3 times higher than that of HC wire.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1601-1602
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• 2011

전 세계적으로 매년 증가하고 있는 전력수요는 높은 부하밀도와 함께 송전계통의 대용량화를 필요로 하고 있다. 단순히 송전회전의 증가를 통한 송전계통의 대용량화는 비용의 증가를 초래하며, 과밀화된 도심에서의 경과지 확보와 환경적인 악영향에 대한 우려 등으로 어려움에 직면하고 있다. 따라서, 높은 부하밀도의 수용가가 집중된 송전계통의 대용량화는 보다 적은 비용과 환경적 영향을 고려하여 지중송전 케이블의 적용이 필요하며, 이러한 특수목적의 송전을 위하여 고효율, 대용량화의 여러 기술이 연구 개발되어 적용 중이며, 일부 기술은 상용화 단계에 있다. 본 논문은 지중송전 케이블의 대용량화 기술 중에 도체의 교류저항을 저감하여 저손실과 대용량 송전이 가능한 소선절연도체(Conductor with insulated wires 또는 Enamelled wires)의 개발과 설치공사에 대하여 기술하고자 한다.