• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.5
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• pp.248-254
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• 2001

The traction power demand highly varies with time and train positions and the traction load is a large-capacity current at single phase converted from 3-phase power system. Subsequently, each phase current converted from 3-phase power system cannot be maintained in balance any longer and thus the traction load can bring about imbalance in three-phase voltage. Therefore, the exact assessment of voltage unbalance must be carried out preferentially as well as load forecast at stages of designing and planning for electric railway system. The evaluation of unbalance voltage in areas, such as electric railway depots should be a prerequisite with more accuracy. The conventional researches on voltage unbalance have dealt with connection schemes of the transformers used in ac AT-fed electric railroads system and induced formulas to briefly evaluate voltage unbalance in the system(3). These formulas are still being used widely due to their easy applicabilities on voltage unbalance evaluation. Meanwhile, they don't take into account detailed characteristics of ac AT-fed electric railroads system, being founded on some assumptions. Accordingly. accuracy still remains in question. This paper proposes a new method to more effectively estimate voltage unbalance index. In this method, numerous diverted circuits in electric railway depots are categorized in three components and each component is defined as a two-port network model. The equivalent circuit for the entire power supply system is also described into a two-port network model by making parallel and/or series connections of these components. Efficiency and accuracy in voltage unbalance calculation as well can be promoted by simplifying the circuits into two-port network models.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.3
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• pp.526-531
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• 2016

This paper presents an experimental study on the optimal settings for the selected DC fault relay (50F) to improve the operating performance for the high-speed circuit breaker on DC feeding system which ensure safety within rolling stock maintenance depot. In this study, current supplied to overhead contact wire was calculated on 1 ms interval to analyze the correction values of DC fault selective relay for the operation of current supply cutout. Particularly, standards for the accurate detection of accidents between an electric railway vehicle and the electric power facilities are shown by investigating the optimal correction values for detection of fault current, and the results indicated that it takes about 213 ms for the DC fault selective relay(50F) to fully open. In the future, the correction values of DC fault selective relay suggested in this paper will be used as the reference values of protective relay for the safe operation of DC electric railroad system such as urban railway.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1637-1639
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• 2005

The measurement of magnetic field is performed about DC and AC magnetic field in test track of depot. The test point is cap, on the converter/inverter box, on the traction motor, on the APSE and on the line filter, the height of measurement is bottom and 50 cm height. In case of AC magnetic field, the selected specific frequency is measured on the converter/inverter box. The AC magnetic field is checked and analysis through RS-232C and notebook PC. The DC magnetic field is measured by using the Hall Probe, test result is saved and analysis by PXI system. On the line filter, the maximum value is 1.4 mT in case of DC magnetic field and 0.044 mT in case of AC magnetic field at 50 Hz.

• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.356-364
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• 2017

The process of inspecting electric railway vehicles is complicated and these vehicles accompany a risk of safety accidents. This developed system will be a great help in simplifying the shunting process and be very useful in terms of ensuring safety and providing user convenience. In this paper, the results of performance evaluation tests are studied on a movable catenary system for railway vehicles that secured mechanical durability, convenience, and operator safety by applying a specific rigid bar catenary of an existing mobile train line. We presented an analysis of the basic characteristics for site installation including sorting. In conclusion, this developed system was obtained in good results through durability test, durable mechanical load test and safety test in require specifications.

• Journal of The Korean Society For Urban Railway
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• v.6 no.4
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• pp.411-416
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• 2018

It is generally not preferable to install a turnout on a sharp curves but it is not desirable for the safety of a train. However, in a mountainous area or a depot where a sufficient space can not be secured to secure a straight line. In this study, in order to analyze the cause of train derailment accident that occurred in the place where turnout is installed in a sharp curves, we performed derailment analysis using line data and accident vehicle data measured at the location where the accident occurred. This derailment coefficient maximum turnout at the start of the track and derailment curve analysis showed that even big enough to cause a derailment as 1.37 in size, which was found to be consistent with the actual site survey results derailment occurred.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.775-783
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• 2010

The Yong-san rolling stock depot in which KORAIL does the maintenance of PP was required to move to the other place, so there are some disputes how to treat PP rolling stock, that is, early scraping, extending life-span or introduction of intercity EMU, but introducing a new train are very expensive and also very risky, so executed economical analysis for the precision political decision. For the specific analysis, set some scenario, first uses PP to their life span, second, introduces new intercity EMU, third, extends the life-span of PP by rolling stock precision diagnosis. Largely, maintenance cost, operation cost, rolling stock value are used for the economical analysis. This research is the specific case of KORAIL, but this result can be a valuable data in the perspective of operation cost between diesel rolling stock and electric rolling stock.