• International Journal of Advanced Culture Technology
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• 제10권4호
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• pp.569-575
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• 2022

This is a research thesis on the development of a monitoring and diagnosis device that prevents the risk of an accident through monitoring and diagnosis of a modular Main Circuit Breaker (MCB) using Vacuum Interrupter (VI) for Korean high-speed rolling stock. In this paper, a comprehensive MCB monitoring and diagnosis was performed by converging vacuum level diagnosis of interrupter, operating coil monitoring of MCB and environmental temperature/humidity monitoring of modular box. In addition, to develop an algorithm that is expected to have a similar data processing before the actual field test of the MCB monitoring and diagnosis device in 2023, the cluster analysis and factor analysis were performed using the WEKA data mining technique on the big data of Korean railroad transformer, which was previously researched by Tae Hee Evolution with KORAIL.

• 한국철도학회논문집
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• 제20권4호
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• pp.448-457
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• 2017

본 논문에서는 불연속 변조 기법을 이용한 고속철도 추진제어장치용 단상 PWM 컨버터에 대해 연구하였다. 기존 PWM 컨버터는 대 전력 특성으로 인해 스위칭 손실을 줄이기 위해 주파수 변조지수를 10 이하로 낮게 사용함에 따라 제어의 대역폭이 감소하고, 안정적인 역률 제어를 위해 추가의 보상 기법을 필요로 하는 등의 문제점을 가지고 있다. 이를 해결하기 위해 3상 PWM 인버터에서 사용하는 불연속 변조 기법을 단상 PWM 컨버터에 적용하였다. 제안한 방식은 옵셋 전압 기법을 활용하여 간단히 구현될 수 있으며 동일 스위칭 손실 대비 주파수 변조 지수를 2배 증가시켜 제어 특성을 향상시키고 스위치 간의 동특성도 동일하게 가져갈 수 있다. 100 kW급 PWM 컨버터에 대한 시뮬레이션을 통해 제안한 불연속 변조 기법에 대한 타당성을 검증하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.194-200
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• 2007

The tilting train is able to tilt its body towards the center of the turning radius, preventing roll-over of the train as it runs on a curved rail at high-speed. This train, widely accepted for commercial purpose internationally is very beneficial in that the operating time is shortened without much capital investment to the infrastructure where there are many curved rails. Over several years, the Korea Railroad Research Institute(KRRI) has developed such a train. In this paper, the safety of the Korean tilting train express(TTX) is investigated using a dynamic simulation model. Since, proper safety standards have not been established for the TTX, those for the Korean train express(KTX) is employed instead to analyze the safety and ride comfort of the TTX. This study will prove useful in predicting the behavior of the TTX and ride comfort, and conforming that designed TTX measures up to the safety standards. It would be useful to recommend proper normal operating speed and determine the maximum safety speed, according to the result. Furthermore, it would be possible to provide basic reference data when analyzing the dynamic effect of the catenary system and the fatigue of the bogie.

• 전기학회논문지
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• 제64권5호
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• pp.824-829
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• 2015

The rotary type testing machine undergoes mechanical stress as an external force is applied. In case of the rotary type testing machine, even a tiny flaw results in a fatal demage because the size of the machine is huge. Therefore, when designing the rotary type testing machine, it is necessary to secure a safety factor with the mechanical stress analysis in order to prevent the machine from being destroyed due to scattering or transformation of rotating field. This thesis proposes a LSM rotary type tesitng machine which rotates at the speed of up to 600km/h. And the mechanical stress is considered in order that the safety factor remains above 1.5 at the maximum speed. In addition, because normal force as well as thrust occurs in the machine, the normal force exerted was considered through the strength analysis. Finally, a design plan which enables to weaken the normal force affecting the rotary type testing machine is introduced and its validity is proved by the results of FEM analysis.

• 한국산학기술학회논문지
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• 제19권11호
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• pp.350-356
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• 2018

팬터그래프(Pantograph)와 전차선간의 동적 상호작용인 접촉력(contact force)은 차량에 대한 안정적 전원공급 특성인 집전성능을 평가하는 중요한 지표이다. 본 연구에서는 동력분산형 고속열차 시험차량인 HEMU-430X(High-speed Electric Multiple Unit - 430km/h eXperiment) 차량의 팬터그래프 동적 접촉력 특성을 전차선 장력에 따라 분석하였고, 이를 팬터그래프-전차선 동적 상호작용 모델을 이용한 해석결과와 비교하였다. 시험결과와 해석결과를 비교한 결과, 주요 동적접촉력 특성인 평균접촉력 및 접촉력 표준편차가 비교적 잘 일치하는 것을 확인하였다. 또한 해석모델을 이용하여 전차선 장력과 접촉력과의 상관관계를 차량 운행속도에 따라 제시하였으며, 이를 이용하여 각 운영속도별 최적 전차선 장력을 제시하였고 이를 국제규격과 비교하였다. 그 결과 해석을 통해 도출된 결과와 국제 규격에서 권장하는 전차선 장력이 비교적 잘 일치하는 것을 알 수 있었다.

• 한국산학기술학회논문지
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• 제16권4호
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• pp.2906-2910
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• 2015

철도 선로선형은 한번 건설되면 변경하기가 매우 어렵다. 따라서 철도에서 선로선형의 변경은 일반적으로 큰 경제적비용을 수반한다. 본 연구에서는 기존 고속철도 및 일반철도의 속도향상을 위한 선형개량 시, 경제성을 고려한 평면선형의 허용개량범위 결정에 설계초기조건(교각)이 미치는 영향에 대해 분석하였다. 분석결과, 교각(Intersection Angle)이 클수록 직선부에 지장물이 있는 경우가 허용범위에 큰 영향을 미친다는 것을 알 수 있었다. 또한 교각이 클수록 최대 허용곡선반경은 작아지며, 허용완화곡선장은 길어짐을 알 수 있었다. 본 연구를 통해 교각의 크기 및 지장물 위치에 따른 개량허용범위를 쉽게 예상할 수 있으며, 속도향상 및 선로개선을 위한 선형 개량시 지장물을 고려한 경제적 설계가 가능할 것으로 예상된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1427-1439
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• 2008

The quality of track-bed fills of railways has been controlled by field measurements of density (${\gamma}_d$) and the results of plate-load tests. The control measures are compatible with the design procedures whose design parameter is $k_{30}$ for both ordinary-speed railways and high-speed railways. However, one of fatal flaws of the design procedures is that there are no simple laboratory measurement procedures for the design parameters ($k_{30}$ or, $E_{v2}$ and $E_{v2}/E_{v1}$) in design stage. A new quality control procedure, in parallel with the advent of the new design procedure, is being proposed. This procedure is based upon P-wave velocity involving consistently the evaluation of design parameters in design stage and the field measurements during construction. The key concept of the procedure is that the target value for field compaction control is the P-wave velocity determined at OMC using modified compaction test, and direct-arrival method is used for the field measurements during construction. The procedure was verified at a test site and the p-wave velocity turned out to be an excellent control measure. The specifications for the control also include field compaction water content of $OMC{\pm}2%$ as well as the p-wave velocity.

• Tribology and Lubricants
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• 제30권6호
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• pp.330-336
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• 2014

Sintered metallic brake pads and low alloy heat resistance steel disks are applied to mechanical brake systems in high energy moving machines that are associated with recently developed 200km/h trains. This has led to the speed-up of conventional urban rapid transit. In this study, we use a lab-scale dynamometer to investigate the effects of the composition of friction materials on the tribological characteristics of sintered metallic brake pads and low alloy heat resistance steel under dry sliding conditions. We conduct test under a continuous pressure of 5.5 MPa at various speeds. To determine the optimal composition of friction materials for 200 km/h train, we test and the evaluate frictional characteristics such as friction coefficients, friction stability, wear rate, and the temperature of friction material, which depend on the relative composition of the Cu-Sn and Fe components. The results clearly demonstrate that the average friction coefficient is lower for all speed conditions, when a large quantity of iron power is added. The specimen of 25 wt% iron powder that was added decreased the wear of the friction materials and the roughness of the disc surface. However when 35 wt% iron powder was added, the disc roughness and the wear rate of friction materials increased By increasing the amount of iron powder, the surface roughness, and temperature of the friction materials increased, so the average friction coefficients decreased. An oxidation layer of $Fe_2O_3$ was formed on both friction surfaces.

• 한국안전학회지
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• 제25권3호
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• pp.112-117
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• 2010

This study presents a methodology to evaluate the driving safety of vehicles against localized high wind on the roads over the valleys or along the coasts. Risk level for vehicle accident is derived from the side slip caused by cross wind, and then safety criteria based on reliability for driving stability are defined. The level of safety is classified according to probability of exceeding against wind speed using the concept of extreme value statistics. To attain the safety level of vehicle on bridges, numerical simulations using Computational Fluid Dynamics(CFD) are performed. Based on this result, risk reduction and quality improvement is expected through analysis for each alternative in bridges design, construction and operation & maintenance stage with proposed process

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1978-1983
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• 2008

With the increase in population, the area of human activities has expanded, resulting in the dramatic increase in the need for transportation system. Various infrastructures necessary for efficient logistics, however, have not been supplied enough and the logistics efficiency in Korea is in a bad situation now. As a result of the situation, the demand for the railroad transportation system that can provide large volume transportation has increased dramatically. An electric railway system is composed of high-tech subsystems, among which main electric equipment such as motors and converter are critical components determining the performance of electric vehicle. Among the on-board equipments, traction equipment is important part that has influence on safety and performances of vehicles. We is studied for high-speed train of foreign countries. From this research, we knows that axle weight of HEMU-400x is reasonable within 13ton.