• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1295_1296
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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. Temperaures 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.

• 한국전기전자재료학회논문지
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• 제19권5호
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• pp.480-485
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• 2006

A research was undertaken on the thermal properties and behavior of the conductors in a controlled chamber, which was designed to implement the outdoor air temperature, heat and wind conditions With ACSR $410mm^2$ overhead conductors, we measured the maximum temperature of the conductors and the temperature gradient from the core to the surface regions as a function of current, tension, wind velocity and outdoor air temperature. This test also provided a comparative analysis between the measured temperature values of conductors in the controlled chamber and the theoretical calculations of ANSI/IEEE at normal condition. There was not much influence of tension on the conductor temperature. However, the compactness of conductor wires increased with an increase in tension, which eventually increased the coefficient of effective thermal conductivity and, accordingly the conductor temperature was reduced more or less.

• 전기학회논문지
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• 제56권10호
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• pp.1791-1795
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• 2007

Small ions generated at conductor corona sources remain in the atmosphere until they recombine with ions of opposite polarity, attach to aerosols, or make contact with an object. Ion current density is major factor to design conductor configuration of DC overhead transmission line. Several techniques have been used to measure the ion current of HVDC overhead transmission line. In this study, the ion current density was measured by a plate electrode made of a metal flat board at DC corona cage. The sensitivity of the plate electrode is $0.156uA/m^2/V$. To obtain an useful database on corona discharge, it is necessary to do corona test on several kinds of conductor bundles. Therefore, a number of experiments were conducted on several kinds of conductor bundles. To reliably analyze ion effects, corona cage test data were obtained over a long period of time under various weather conditions and expressed as a statistical distribution. Ion current density distribution in foul weather shows a significant increase in levels over the corresponding fair weather. Based on this results, we evaluated the environmental characteristic caused by ion flow of three candidated conductor bundles.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.576-585
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• 2017

Dynamic thermal rating (DTR) of overhead transmission lines can provide a significant increase in transmission capacity compared to the static thermal rating. However, the DTR are usually estimated by the traditional thermal model of overhead conductor that is highly dependent on the solar, wind speed and wind direction data. Consequently, the estimated DTR would be unreliable and the safety of transmission lines would be reduced when the solar and wind sensors are out of function. To address this issue, this study proposed a novel thermal model of overhead conductor based on the thermal-electric analogy theory and Markov chain. Using this thermal model, the random variation of conductor temperature can be simulated with any specific current level and ambient temperature, even if the solar and wind sensors are out of function or uninstalled. On this basis, an estimation method was proposed to determine the DTR in the form of probability. The laboratory experiments prove that the proposed method can estimate the DTR reliably without measured solar and wind data.

• 전기학회논문지
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• 제67권3호
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• pp.467-473
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• 2018

R-Bar(Overhead Rigid Conductor system) is being developed for the high-speed in Europe because it has an advantage of cross section area reduction of tunnel compared with OCS (Overhead Catenary Line). Because there are lots of underground sections and mountains in korea, it is necessary to develop the R-Bar for a high-speed line. In this study, a method on speed-up of transition section between OCS and R-Bar is proposed. The commercial program, DAFUL, is used to predict a dynamic characteristics between Overhead Line and pantograph. The program is evaluated according to EN 50318 which is the European Norm for evaluation of the program. Using the evaluated modeling and method, a method for the max. speed of 250 km/h of transition section is proposed.

• 전기학회논문지
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• 제66권4호
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• pp.740-744
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• 2017

Overhead Line is divided by two systems which are OCS (Overhead Catenary Line) and R-Bar (Overhead Rigid Conductor system). R-Bar has an advantage of maintenance and economic aspect comparing with OCS. R-Bar in Korea has developed for the max. speed of 120km/h, but it is evaluated up to the max. speed of 250 km/h in Europe. There are lots of mountains and underground sections in korea, it is really necessary to develop the R-Bar for a high-speed line. In the study, design parameters for the max. speed of 250 km/h of R-Bar was proposed. A bracket space, stiffness, and especially an installation tolerance of contact wire height at a bracket were considered as a parameter, and a dynamic behavior between a contact wire and pantograph was predicted by evaluated FEM simulation tool. The installation tolerance and bracket space are more important for the high-speed system. The proposed parameters was decided very conservative. Because the aerodynamic characteristics of a pantograph in tunnel is more severe than an open route and the simulation tool is not considered the such kind of aerodynamic characteristics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1446-1448
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• 2002

The short-time permissible temperature of an overhead distribution line conductor is determined by the softening characteristics of ACSR-OC, ACSR AW/OC 160, typical conductors employed in the overhead distribution line. Transient heat transfer equation and Newton's cooling law were applied to analyze the heating and cooling effects of the insulating conductors, respectively, and the error of co-relation was calibrated after simulating the softening test to assess the short-time characteristic of the insulating conductor. In order to verify the softening characteristic, the conductors were tested with heat cycle. The test was totally carried out 200 cycles, and 1 cycle was to heat and cool at 1.1 times permissible current of the conductor, 1.15 times for 120 minutes, respectively. After heating, the tensile strength and surface of the conductor were observed. In case of ACSR-OC, as the result of 100 hour heating test, the tensile strength of the insulator was 0.8 times the initial value. This is equivalent to the value of the conductors which are used for 10 years at sites.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.459-460
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• 2008

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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.77-79
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• 1995

In performing lightning and fault studies in GISs, it is of great importance to accurately model the conductor network consisting of the grounding systems and overhead conductor structures. In particular, the overhead grounded pipe enclosures of the GIS should be appropriately modelled. In this paper, the overhead pipe enclosures of a 500 kV $SF_6$ breaker and substation grounding system are presented in detail. During a phase-to-ground fault, scalar potentials and electromagnetic fields are computed at different frequencies for various conductor network configurations is defined by varying the number of conductors used to represent the pipes at different frequencies are obtained. Such knowledge will be very useful in reducing computation time for a transient ground potential rise study which will be performed in the future.

• 한국전기전자재료학회논문지
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• 제26권5호
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• pp.415-420
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• 2013

The new recycling technology for aged Aluminum wires in overhead conductor have been carried out. We are attempting to develop remanufacturing method for them for more effective way of recycling in stead of its conventional remelting process. The weld of aged aluminum wires play a vital role in remanufacture process. The paper investigates the mechanical properties during cold welding process of aged Aluminum wire. The tensile tests and microscopic analysis results are discussed to underscore the hardening features of welded aluminum wire. Various graphs are presented accompanied by discussion about their relevance on the process.