• 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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.3
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• pp.287-291
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• 2006

This paper describes mechanical and electric properties of ACSR $410\;mm^2$ conductor from many of older overhead conductor. Samples of conductors itemized two division according to operation sector, green area, salt and pollution area. Samples of conductors operated various environment conditions have undergone laboratory metallurigical investigation and tensile strength torsional ductility and electrical performance. The steel core were found to have retained their original properties to a large degree in both tensile strength and the number of turns to failure. On the other hand the aluminum conductor showed reductions in tensile strength. To determine the remaining useful life of aged conductor, an unacceptable deterioration level has to established for each diagnostic procedure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.12
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• pp.1152-1158
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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 M wire was austenite and then deformed martensite after drawing process. Strength at room temperature is about $180kgf/mm^2\~200kgf/mm^2$. NM wire developed as core of overhead conductor shows heat resistant characteristics higher than that of HC wire used as core of commercial ACSR overhead conductor, Strength loss was not occur at heat resistant test below $600^{\circ}C$. Fatigue strength of vibration fatigue is about $32kgf/mm^2\~35kgf/mm^2$ and that of tension-tension fatigue is $90kgf/mm^2\~120kgf/mm^2$ which is $50\~65\%$ of tensile strength.

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

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.5
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• pp.112-119
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• 2007

Under normal operating condition, the conductor of overhead transmission line could be always hold it's clearance within the safety margin that is specified in the line design guide of power company. Hence it may be very important to measure/or monitor the dip of the conductor, when building a new line, re-tensioning for an aged conductor, or monitoring dynamic line rating to maximize power capability. In this paper, we suggest a new method to estimate the dip and tension by catenary angle of the conductor. Since most conductors in overhead transmission lines show typical catenary curves, it can be uniquely determined the catenary curve for the conductor from the catenary angle at tower. Based on the catenary curve, the dip or horizontal tension can be easily estimated. Through some simulation and simple experimental results, it is verified that the suggested method can be effectively applied to measure/or monitor conductor dips and tensions in the overhead transmission lines.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.9
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• pp.61-69
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• 2006

The tensile strength of an overhead transmission line's conductor in response to an aging is being assessed in this paper. It is our view that, the decrement in the conductor's tensile strength is a key index that can be used to determine a conductor's end of life and a current limits. This paper describes a probabilistic method of assessing this index for main transmission lines which are responsible for the north bound power flow in the Seoul metropolitan area. Such an assessment can be a useful guide for economic system operation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.7
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• pp.555-562
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• 2013

The new recycling technology for aged aluminum wires in overhead conductor has been carried out. The authors are attempting to develop remanufacturing method for them for more effective way of recycling in stead of its conventional remelting process. The new recycling technology for aged aluminum wire in overhead conductor was composed of four steps in different develop process, destranding process for conductor, surface cleaning process, welding process and drawing process for aluminum wire. This paper investigates the properties during recycle process of aged aluminum wire. The results of microscopic analysis and mechanical properties were discussed to underscore recycling aluminum wire. Various graphs are presented accompanied by discussion about their relevance on the process. In conclusion, we confirmed the possibility of remanufacturing technique by using new process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.4
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• pp.366-371
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• 2009

The authors have published several technical reports on the deterioration of conductor due to forest fire in series so far. This is because even we have been experiencing hundreds of forest fires every year, no systematic research on conductor which is very vulnerable to fire have been fulfilled. This paper describes the sag-tension behavior of conductor under loading current normally when only partial area of a long conductor is exposed to fire. Temperatures of Overhead Conductor were different with measurement position. When the partial area of conductor was heated up to $500^{\circ}C$, 20 % of permanent tension loss was observed. This results in the increase of sag of 1.5 m when span is 300 m. The other results will be presented in the text.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.523-524
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• 2007

Forest fire can give a serious damage to overhead conductors. Therefore, the definite understanding about aging behavior of burned conductor is very important in maintaining the transmission line safely. It is sure that the temperature of conductor itself will be affected by the distance apart from flame. From this point of a view, we monitored the conductor's temperature with distance from flame. As a result, the conductor's temperature decreased as the flame goes away from the conductor gradually. The temperature of conductor was reached up to 55~65% level of its atmospheric temperature. The detailed results will be presented in the text.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.516-517
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• 2007

Because forest fire can give a serious damage to overhead conductors, the thorough understanding about sag behavior of burned conductor is very important in maintaining the transmission line safely. Therefore, a systematic investigation was carried out by heating method. As the heating temperature increases, drastic change of tensile strength of Al wire due to the softening of Al wire occurred. When Al wire is exposed to the flame(about $800^{\circ}C$) during only 13 seconds, the remained tensile strength of Al wire showed under 90%. and then sag of overhead conductor become deteriorated. The detailed results will be given in the text.