• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1204-1208
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• 2007

In order to prevent railway accidents due to human errors which have been recognized to be the most important cause in the railway accidents, human errors should have been controlled based on systematical analysis of the human errors, and countermeasures should be derived to reduce human error probability. Among several factors inducing human errors, task load (or task complexity) is representative. In order to reduce the human error, a systematic analysis should be undertaken to evaluate task load. In this study, task load according to task types of railway worker who are a safety critical staff have been quantitatively analyzed based on NASA-TLX(Task Load Index).

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.219-222
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• 2009

Green ocean is one of the main issues internationally. Most governments are leading the role in boosting the economy through creating new green market and establishing system of coping with increasing international environmental regulation. Green ocean, which is a solution for the environmental issue of global warming, is applied throughout the industry. Domestic transportation industry including railway is also developing technology for creating green ocean. Transportation must decrease energy consumption at running stages because it shows high environmental loads expecially on using stages during its life cycle. Therefore, There are some tries for developing technologies; new engine through alternative energies, hybrid and lightweight. Railway transportation can not be exception. it is intended for this paper to suggest the direction of manufacturing environmentally friendly railway vehicle through the global warming effect evaluation of several materials being applied to vehicle and comparison of the results.

• 전기학회논문지
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• 제64권8호
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• pp.1262-1268
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• 2015

I In power transmission systems, voltage changes continuously as reactive power is whether over supply or shortage. Reactive power produces in generators and consumes in transmission lines, and loads. Voltages at end points of transmission lines rise which is called Ferranti effect. Excessive voltage rising can reduce transmission equipment life, the voltage rising is usually permitted within the limit of 10%~30% excess. Shunt reactors are installed in transmission lines to put a curb on voltage rising. In this paper, we tried to do modelling for shunt reactor configuration types which are no grounding, grounded and grouded neutral reactor. Simulation are carried out for reactor magnitude for compensating transmission line capacitance.

• 전기학회논문지
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• 제63권1호
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• pp.191-196
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• 2014

For the large scale of electricity consumer, since the price for the electricity consumption depends on the peak power, the issue for peak power reduction have been being studied widely. Electric railway systems, which is one of the most representative large scale of loads, also has assignment to reduce the peak power since they have high peak power and low energy consumption load characteristics. In the aspect of the economic operation through reduction of peak power, this paper proposes a novel algorithm for power management system in electric railway systems using energy storage.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.3124-3132
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• 2011

Scott transformers have widely used to convert three phases into two phases and compensate the unbalance. Theoretically, the loads of the two secondary phases are same, no unbalance appears in the PCC(point of common coupling). But Due to the uncertainty of traction load, the unbalance are generally presented at the PCC. In this paper The amount of the voltage unbalance is expressed in the ratio of the negative sequence voltages to the positive sequence voltage. We tried to compensate the unbalance using SVC(Static Var Compensator）in an unbalance traction loads state by modeling. The SVC are installed and controlled to provide different amounts of reactive power compensation.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2348-2356
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• 2011

In recent years, many researches for DC power distributed system (PDS) are being preformed and the importance of the DC PDS is more and more emphasized. Furthermore, in the railway system, the DC PDS is used in subway station lighting, facilities, etc. In the DC PDS, DC bus voltage instability may be occurred by the operation of multiple parallel loads such as pulsed power load, motor drive system, and constant power loads. Thus, good quality and high reliability for electric power are required and voltage bus conditioner (VBC) may be used the DC PDS. The VBC is a DC/DC converter for mitigation of the bus transients. In this paper, adaptive controller is designed. The simulation results by PSIM are presented for validating the proposed control algorithm.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.836-842
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• 2007

Recently it is a tendency that Diesel rolling stock is committing in the commuter's train route of the suburb for solving commuting traffic congestion. It has advantage which expense of diesel rolling stock is relatively cheaper than electric rail car or high-speed train. In addition, it can be using the exist route without large-scale facility investment. Because of this advantage, the demand of diesel rolling stock occupy regular portion from overseas railway car market. GM/RT 2100 specifies the loads vehicle bodies shall be capable of withstanding, identifies how material data shall be used and presents the principles to be used for design verification by analysis. Therefore, in order to fulfill the structural requirements, Rotem Company has carried out Finite Element Analysis (FEA) to verify whether the carbody structure has enough strength to withstand the loads specified by GM/RT 2100. This research contains the results obtained by the analysis. The analysis was carried out using I-DEAS 12 NX Series

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.91-96
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• 2003

In this report, numerical investigations have demonstrated, that the displacement underneath a moving loa야ng reach a maximum value, if the speed of the load is equal to propagation velocity of the maximum wave. The load speed for which the maximum displacement occurs is called critical speed. The critical speed divides the velocities in a subcritical and a super-critical region. By means of calculations the dynamic behaviour of the slab track-soil is investigated. For concrete slab track dynamic wheel load are given in dependence of relevant excitation mechanism and speed of the train. These loads can be used for the dimensioning of the track as well as for the prognosis of the vibrations at the track and the surrounding soil.

• 한국철도학회논문집
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• 제7권3호
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• pp.186-192
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• 2004

Using the finite element method, rail-wheel contact model has been analyzed for mechanical loads due to passengers and payload of the train. This paper presents an investigation on how tapered wheel and inclined rail surfaces affect the contact stress and displacement of rail-wheel contacting surface under mechanical loads. For a numerical analysis, the tapered faces of the wheel are considered as 2.5% and 5.5%. And two models of the tilted rail are also considered as 40：1 and 20：1 at the bottom of the rail. The computed results based on the contact stress and displacement FE analysis indicate that the tilting ratio of the rail, 20：1 with a tapered face of the wheel, 2.5% may be more stable compared to that of 40：1 tilting model and 5.5% tapered wheel face.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.504-509
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• 2005

Railway noise and vibration has been recognized as major problems with the speed-up of rolling stock. As a kind of solution to these problems, the decrease of stiffness of track pad have been tried. However, in this case, overturning of rail due to lateral force should be considered because it can have effect on the safety of running train. Therefore, above two things - decrease of stiffness of track pad and overturning of rail due to lateral force - should be considered simultaneously for the appropriate determination of spring coefficient of track pad. With this viewpoint, minimum spring coefficient of track pad is estimated through the comparison between the theoretical relationship about the overturning of rail and 3-dimensional FE analysis result. Two kinds of Lateral force and wheel load are used as input loads. Extracted values from the conventional estimation formula and the Shinkansen design loads are used. It is found that the overturning of rail changes corresponding to the change of the stiffness of track pad and the ratio of lateral force to wheel load. Moreover, it is found that the analysis model can have influence on the results. Through these procedure, minimum spring coefficient of track pad is estimated.