• Proceedings of the KSR Conference
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• 2000.11a
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• pp.704-711
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• 2000

This study is carried out using a circuit model approach. First, the self and shunt impedances of all the conductors in the rail system and the mutual impedances between different conductors are computed. Then, a circuit representing the both rail systems at interfaces including the rails, feeders, protection wires, contact wires, ground wires is built. Auto-transformers in the system are also represented in the circuit model. The circuit model is then 1]recessed using a circuit solver based on a double-elimination method. Several different scenarios are analyzed, including the load conditions and a few fault conditions with different fault locations. The effect of the buried ground wires is also analyzed by comparing the results with and without the presence of the ground wires. The analysis procedure presented in the paper demonstrated an accurate way of computing fault current distribution and EMC at interfaces between both systems. The results presented in the paper can be used as a reference for estimating interference levels in similar rail systems.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.628-635
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• 2000

The catenary system supported by the tunnel bracket which has been used uniquely in KNR was selected as the catenary inside narrow existing tunnel in the electrification of Kyeung-Bu Line for operation of Korea High Speed Train(KTX). It was demanded to judge the maximal operable speed of KTX in this catenary system to implement the planning. To do this, the tunnel bracket was firstly tested to obtain the characteristic data. The stiffness of this bracket are computed depending on the location which catenary installed on. Moreover, the catenary using tunnel bracket is modelled numerically respecting the bracket stiffness. Based on these, the dynamics between this catenary and KTX pantograph are simulated with the program developed by ourselves independently. The simulation result are evaluated according to the generally acceptable criteria. Consequently, the maximal operable speed of KTX in the catenary using KNR(Korean National Railroad) tunnel bracket is predicted and some items which are needed to be kept in the processing of implementation are drawn.

• Journal of the Korean Society for Railway
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• v.7 no.2
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• pp.107-113
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• 2004

This study presents a development of DeCatS(Detail Design of High Speed Catenary System) which is a software to design high speed catenary system automatically. The program is developed by Korea Railroad Research Institute with the support of KHSR. A process of developing it and a comparison with LEXCAT. in order to demonstrate a preciseness of that, were performed. In the program, decision of H-beam, cantilever fitting, management of materials, automatic drawing and etc. according to input conditions can be accomplished. In this study, especially the program algorithm for the decision of mast was introduced.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.875-880
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• 2007

Due to increasing demands for environment-friendly railway system, bronze wires with cadmium, which is a potential environmental hazard, have been no longer permitted as messenger wire for electric railway system. One of materials being considered as the replacements is copper-clad steel conductor(CCSC), which is currently used as contact wire for high speed operation in the Japanese shinkansen. However, there have been few studies for the application as messenger wire by the CCSC. This study deals with requirements and performances of the messenger wire stranded by the CCSC, especially for high speed electric railway. And the tentative evaluation items and methods to be specified as the Korean railway standard(KRS) are proposed.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1878-1884
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• 2010

Currently in Korea, neutral sections in front of substations and sectioning posts are greatly divided into AC/DC sections and AC/AC sections. Considering catenary damage and safety issues trains pass crossover by coasting driving at notch-off. However in cases of Japan, China, or Taiwan, the usage of automatic crossover system makes it possible to pass at notch-on, enhancing high-speed railway operation for efficiency, and stability. These are the purposes of developing automatic power crossover system in neutral sections. This paper introduces two methods to detect the position of a train required to activate automatic crossover systems in neutral sections. The optimal method is expected in terms of the distance of neutral section.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.928-931
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• 2007

In answer to the increase of demand for the safety in railroad, the safety activities are tried out. According to 'KORAIL Instruction number 2001-49', the project for developing Integrated Centralized Traffic Control Center has been carried out and the safety activities are guaranteed by documents named 'Safety Plan' and 'Safety Requirements' from this project. However the development system is not enough for the full safety activities. Therefore this paper we describes the relationship of safety activities and development systems and proposes the efficient direction of safety activities.

• Journal of Veterinary Clinics
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• v.9 no.2
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• pp.483-488
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• 1992

This experiment was carried out to establish the grade of adhesion formation and changes of blood following artificial injuries such as abrasion, incision and electrocautery on colon and uterine horns in rats. 36 rats (abrasion-, incision-, electrocautery-treated groups) had laparotomy and abdominal injuries, twelve rats( control group) had only laparotomy, Ten days fellowing abdominal injuries, the score of adhesion formation and changes of blood were noted 1. Electrocautery-treated group was significant evident in adhesion formation in colon(p<0.01) and electrocautery and incision-treated groups were more evident than abrasion and control group in uterine horns(p<0.01) 2. Changes of erythrocytes number and PCV were tended to decrease during 5 days after operation, but recover normal level 10 days after operation. 3. Changes of leucocytes number were showed to significantly increase in electrocautery and incision-treated groups 5 days after operation. 4. The electrocautery-treated group was showed to significantly decrease in plasma protein and increase in plasma fibrinogen concentration.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1044-1045
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• 2008

DC transit system has been adopted in the metropolitan area, Korea since 1974. EMU in this system always reiterates that acceleration and retardation. When EMU decelerates using electric breaking, regenerative power occurs. Regenerative power can be consumed in vicinity EMU on the same line or in resistor. If DC transit system has inverter for reusing regenerative power, Energy efficiency in DC transit system will be increased. This paper present the adoption of developed inverter in commercial railway line and the test result procedure of developed inverter is presented.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1617-1618
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• 2015

This paper analyzed catenary impedance characteristics of relays installed in substation and sectioning post to protect power feeding circuit in the extended power feeding conditions. For this, we modelled AT feeding system using PSCAD/EMTDC and calculated catenary impedance. The relay installed in substation calculated catenary impedance of the extended power feeding area adding catenary impedance of self protection zone. But, the relay installed in sectioning post calculated catenary impedance of the only protection area. Therefore, we confirmed that the more reliable protection way can be utilized using the relay installed in sectioning post.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1577-1578
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• 2015

전세계적으로 신재생 에너지를 활용한 기술에 대한 관심이 대두되고 있는 가운데, 국내외에서 활발히 연구 중인 연료전지를 철도차량에 적용하는 연구를 수행하였다. 연료전지를 동력으로 사용하는 철도 차량시스템은 계통에서 전력을 공급받아 구동하는 철도차량과 달리 배터리를 적용한 토폴로지를 사용한다. 배터리는 역행시 철도차량 견인전동기를 구동하거나 회생시 발생되는 전류를 저장한다. 본 논문은 수소연료전지 발전시스템을 적용시 사용되어야하는 배터리 시스템의 충방전 토폴로지에 대해 분석하였다. 견인전동기 역행 및 회생특성을 반영하여 배터리 충방전 토폴로지 적용가능성을 분석하였고 시뮬레이션을 통해 제어 특성을 확인하였다.