• Proceedings of the KSR Conference
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• 2004.06a
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• pp.602-607
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• 2004

Several countries such as Japan, France and so on gradually operate double deck trains as efficient, reliable and comfortable mass transportation systems. However, the double deck trains have relatively big cross sectional areas and high mass centers that cause unsafe vehicle running performances and interface problems between the vehicles and infrastructures, and do not have enough spaces for electric equipments. Therefore, prior to operate double deck trains on the existing lines in Korea, careful investigations should be performed. In this study, we have roughly designed a double deck EMU train system for the existing lines around Seoul metropolitan area.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.589-593
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• 2007

Due to sustainable development, international environmental regulations have been reinforced continuously. Especially, Kyoto protocol related to energy consumption affects to national production system seriously. Even if railroad is the most environmental- friendly transportation, it is necessary to improve its environment. Life cycle assessment (LCA) is a representative tool to evaluate the environment impacts of a product. In the EU's railroad companies, the recycling efficiency and the waste emissions of rolling stocks have improved considering their environment impacts with LCA from a design step. Also, the LCA system of Korean electric motor units has been developed to build an environmentally sound railroad as one of national transportation core technology R&D projects. Therefore, the introduction of LCA will be required to decrease environmental impacts released from rolling stocks in the future.

• Journal of Power System Engineering
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• v.5 no.1
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• pp.80-88
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• 2001

The spot welding method has been used in the joining of structures, automotive body, railway carriage, aircraft, household electric appliances, precision parts etc., because of brief working, easy automation, available mass production, and convenience. In this paper, the effects of welding conditions on the fatigue life and the prediction of fatigue life based on fracture mechanics theory of spot welded joint were investigated. Fatigue tests were conducted with the tensile-shear specimens welded in the various current using cold rolled steel sheets. Fatigue life of spot welded joint was predicted and compared with experimental results. Using FEM(finite element method), we analysed the distribution of stress and the condition of deformation on the environments of nugget.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1079-1080
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• 2006

This paper presents the methods to save energy by using load consumption pattern analysis. Base on the substation annual power usage data, the characteristic of the substation power consumption have investigated. With this investigation effective electrical billing condition and the control target load has been determined. Most of power usage comes from the motor car, so power system and load table of motor car were reviewed. And in the metropolitan area the peak power consumption occurs at summer or winter rush hours because of its typical characteristics. From this data control point of time are determined. Through the whole study the methode to control the power Peak consumption are proposed and prototype was designed.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.640-645
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• 2004

In this thesis, the impact analysis for the shunting procedure using the dynamic buffer characteristics of the coupler was developed. In this study, each car was modeled as one dimensional element by using the equivalent system. After the impact, the slip exists only between wheel and rail in the braked trainset. For this analysis the analysis code named the POTAS-MSM (Power Transmission Analysis Software Multi Slip Mechanism) which was developed for the numerical analysis of dynamic system is developed. The validation of this analysis was proven by comparing the numerical results with the results of world-famous S company which is located in Europe.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.204-209
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• 2001

The more sophisticated patterns of propagation model is presented in this paper, which includes three different source characteristics (spherical, cosine and dipole). The spherical, cosine and dipole radiation characteristics compared, and sound event level and the maximum sound level are calculated by experiment and calculation. It is shown that patterns of propagation have dipole characteristics for low speed range (below about 150Km/h) at electric multiple system. We know that push-pull high speed system has cosine characteristics of noise propagation at low speed range (below about 200Km/h).

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.724-729
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• 2005

Winter weather condition can cause icing and ice coats on 25 kV overhead contact wire. This generates shocks at the mechanical interface of the collecting strips of the pantograph and the contact wire and extra electrical resistance, which may affect quality of current collection at the contact wire / collecting strips of pantograph interface. De-icing operations should he performed just before train operation to avoid the formation of another ice layer. Thus, the work in this paper is investigation and analysis of de-icing system which could be applied to the electric car line of railways.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.606-610
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• 2003

The 200 class insulation system which adopted to traction motor have excellent dielectric strength but weaken to thermal stress therefore deterioration phenomena analysis according to thermal stress is necessary. Accelerated thermal aging tests have been used to determine thermal reliability of stator coils used as traction motor in electric multiple unit. The conventional aging test is carried on according to IEC 60034-18-31 and IEEE Std. 275-1992. Variation in insulation resistance, P.I, capacitance, dielectric loss($tan{\delta}$) and partial discharge are measured during the aging cycle. Sample coils for traction motor were tested by accelerated aging test which composed of heat, vibration and moisture. Reliability and expected life were evaluated on the insulation system for traction motor.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.412-417
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• 2003

In recent years, efficient commuter transportation has become one of major issues to be taken into account around Seoul metropolitan area. In oder to solve the problems, several countries such as Japan, France and so on gradually operate double deck trains as efficient, reliable and comfortable mass transportation systems. However, the double deck trains have relatively big cross sectional areas and high mass centers that cause unsafe vehicle running performances and interface problems between the vehicles and infrastructures, and do not have enough spaces for electric equipments. Therefore, prior to operate double deck trains on the existing lines in Korea, careful investigations should be performed. For these reasons, we have studied the double deck train system for the existing lines around Seoul metropolitan area as an alternative way to carry heavy transportation efficiently and comfortably.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.878-884
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• 2006

Grounding fault and short of the DC power supply systems are detected and protected by high-speed circuit breaker, linked breaking device, ground relay and fault selective device, all of which are installed and operated in substaions. however, there have been many cases in which the protective devices did not detect grounding of of the over head catenary systems on concrete support for an extended period of time. Such cases often cause severe damages to the supports with high grounding resistances. If grounding accidents occur repetitively, the earth current and the rise of earth potential can damage not only passenger and staff but also electric facilities and equipment, necessitating high cost and endeavor to restore. The following study points out various problems that can be occurred occur as a result of high impedance grounding accident, and proposes a new system which can protect and intercept them.