• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1027-1036
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• 2007

Since the opening of the Seoul Metro in 1974, the electric railway passengers have been increased rapidly and as the advanced equipments(OC,PSD) were introduced, additional power facilities were built in a limited area for the comfortable transportation environment. Present grounding system were built according to old Electric equipment standards and all the electric signal, communication and electronic equipments were built only for the purposes of protecting building structure, people and electronic equipments. Grounding system which was additionally built in the limited area caused problems with the building structure and it caused secondary damages when earth fault happens. One of the problems is grounding system of the building structure; grounding system does not work properly since grounding equipments are not separated from each other. So, existing grounding system needs to be improved and unified grounding system in the building should be established. The purposed of this study is to analyze all the grounding systems that had been built in different year and to establish unified grounding system of Seoul Metro.

• 전기학회논문지
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• 제65권3호
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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.

• Structural Engineering and Mechanics
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• 제17권5호
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• pp.641-654
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• 2004

This paper presents a theoretic model of a smart structure, a transversely isotropic piezoelectric thick square plate constructed with three laminas, piezoelectric-elastic-piezoelectric layer, by adopting the first order shear deformation plate theory and piezoelectric theory. This model assumes that the transverse displacements through thickness are linear, and the in-plane displacements in the mid-plane of the plate are not taken to be account. By using Fourier's series expansion, an exact Navier typed analytical solution for deflection and electric potential of the simply supported smart plate is obtained. The electric boundary conditions are being grounded along four vertical edges. The external voltage and non-external voltage applied on the surfaces of piezoelectric layers are all considered. The convergence of the present approach is carefully studied. Comparison studies are also made for verifying the accuracy and the applicability of the present method. Then some new results of the electric potentials and displacements are provided. Numerical results show that the electrostatic voltage is approximately linear in the thickness direction, while parabolic in the plate in-plane directions, for both the deflection and the electric voltage. These results are very useful for distributed sensing and finite element verification.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.699-704
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• 2005

In the station of the railway and the subway various illumination equipment and a general power equipment for a passenger convenience, the signal equipment and the communication equipment which is necessary to the train operation provided. At the all of like this equipment from the electric room which is established in each station by changing from high voltage to low voltage and it supplies from the illumination transformer, the power transformer and the signal transformer. If it supplies to the equipment from the high voltage to the low voltage, it must be established to contact protection device in between the high voltage coil and the low voltage coil. Also it must do the grounding faulting device at the low voltage lines, the earthing devices at apparatus for the protection of an electric shock and an electric fire by the electric relation law. Compared the related regulations between the facilities which require protective functions such as grounding fault or earthing in public utilities like subway stations, and the facilities which do not require line earthing or protective functions such as electricity supplied for signalling the train. Also, will describe a countermeasure for the accident from a grounding fault.

• 한국전기전자재료학회논문지
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• 제32권6호
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• pp.507-511
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• 2019

The purpose of an electric railway system contact wire is to supply electric energy to trains through a contacted pantograph. This energy is then converted into mechanical energy. Recent developments in overhead contact lines include the increase in the tension force up to 34 kN according to train speeds that reach up to 400 km/h with a verified safety. Rigid conductor catenary (R-Bar) for high speeds of up to 250 km/h have been developed in tunnels to save on construction costs. This is significant because minor defects in R-bars in aspects, such as height and stagger affect installation conditions. In this study, we propose the use of a detector that measures the static characteristics to reduce the R-bar installation errors. This detector has been developed to measure the height and stagger of the contact wire using video images.

• 한국철도학회논문집
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• 제13권4호
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• pp.419-424
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• 2010

본 논문은 전철변전소를 대상으로 상태추정을 통하여 계측기 오차 등에 의해 손상된 측정값의 신뢰도를 높이는 새로운 방법에 대하여 기술하였다. 일반적인 전력계통의 상태추정과는 달리 전철변전소에서는 종종 관제점에서 측정값의 함수를 계통 상태변수로 정의하기가 곤란한 경우가 있으며, 계통의 토폴로지 변경에 따라 상태변수를 재설정하는 경우에 측정값 함수의 일부가 상태변수 그 자체를 나타내게 되어 상태추정이 곤란하였다. 본 논문에서 제시하는 방법은 기존의 방법에서 문제가 되는 관제점의 측정값 함수와 상태변수와의 관계를 등식제약조건을 이용하여 해결하는 것으로서, 이들 제약조건은 스코트 변압기의 전압 및 전류 특성과 모선 연결조건 등으로부터 간결하면서도 다양하게 유도될 수 있다. 제시된 방법은 표준 샘플변전소를 대상으로 하여 그 유효성을 입증하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1407-1413
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• 2011

This paper studied on the VVVF Inverter for 1C4M propulsion system of railway traction. The paper includes the comparison along a VVVF Inverter electric power conversion element for an electric railcar(GTO, IGBT). These inverters are composed of high power IGBTs and controlled by compact control units. The stack is simplified and optimized by using plate bus and IGBT driver units of hybrid-type.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.272-274
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• 2003

This paper investigates contactless power transfer system for electric railway which makes use of electromagnetic induction among the coils. The transmission line efficiency and the quality factor are introduced to analyze the performance of the contactless power transfer system. Several instances of the mobile loads using contactless power transmission are described to understand practical usefulness.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.1286-1291
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• 2004

This paper was showed evaluation method and technical items for measurement test of new catenary system of Honam(Daejeon - Mokpo) conventional railway electrified. This line have tested by three type new electric rolling stocks in order to test construction quality and operation safety of a new catenary system with speed-up than conventional speed. We have some important experiences through measurement test of catenary system by new device installed on train roof.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 추계학술대회 논문집
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• pp.187-191
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• 2001

Diesel locomotive engine is the main source of train noise in these days but hard to reduce the level by barrier for it emitted from high location. For the passing high level noise properties of diesel locomotive engine, there are needs of changing the environmental railway limit to maximum level from equivalent. In this study we investigate the noise characteristics of the diesel electric locomotive according to the change of notch. From the result we found out the frequency of engine cycle noise and the shape of noise spectrum.