• 한국전기전자재료학회논문지
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• 제32권6호
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• pp.512-515
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• 2019

Overhead contact systems (OCS) consist of contact and messenger wires, in which the contact wire supplies electric energy to the railway vehicle by contacting a pantograph. However, this mechanical contact is interrupted during frosts or temperatures below $0^{\circ}C$ in the winter. In these conditions, railway vehicle accidents can occur during operation because of the low energy efficiency that results from the increase in the arcing between the contact wire and pantograph. Therefore, the detection of frost or freezing temperatures is necessary to maintain the stable operation of these trains. In this study, we proposed the development of a frost or freezing condition monitoring system on the OCSs that utilizes wireless communication.

• 한국철도학회논문집
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• 제9권6호
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• pp.652-656
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• 2006

Constant load model is widely used for an electric train to perform the static analysis of AT (Auto Transformer) feeding systems. In this model, the train will be considered as a constant load model when it drives or as a constant source model when it applies regenerative brake. However there must be some constraints imposed on the pantagraph voltage in actual operations. These constraints are established for the reason of protecting the feeding facilities from excessive rise of regenerative braking voltage or guaranteeing the minimum traction power of train. In normal operating situation, the pantagraph voltage of the train should be maintained within these limits. Keeping these facts in minds, we suggest new methods or analyzing AT feeding systems using the constant power models with the conditions of voltage constraints. The simulation results from a sample system using the proposed method illustrate both the states of system variables and the supply-demand relation of power among the trains and the systems very clearly, so it is believed that the proposed method yields more accurate results than conventional methods do. The proposed methods are believed to contribute to the assessment of TCR-TSC for compensating reactive powers too.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.1321-1324
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• 2004

Unbalanced systems, such as distribution systems, have difficulties in fault locations due to single-phase laterals and loads. In this paper, a novel fault location algorithm is suggested for a line to line faults using inverse theorem of matrix on electric power lines. The fault location for balanced systems has been studied using the current distribution factor, by a conventional symmetrical transformation, but that for unbalanced systems has not been investigated due to their high complexity The proposed algorithms overcome the limit of the conventional algorithm using the conventional symmetrical transformation, which requires the balanced system and are applicable to any electric power system but are particularly useful for unbalanced distribution systems. The simulation results oriented by the real distribution system are presented to show its effectiveness and accuracy.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.1075-1076
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• 2006

The wide spread of DC electric railway systems such as urban rapid transits including heavy rail and light rail transits has significant ramification as the stray currents from return conductor rails can cause the electrochemical interference, that is, the electrolytic corrosion of both rails and outside underground metallic infrastructures. The immature understanding of either the railway authority who is responsible for establishing the necessary provisions at the design stage or the affected parties makes it difficult to prepare the optimum range of solutions for the long-pending interference problem. In advanced countries, however, numerous assessment studies have been carried out on the stray current interference, by which protective standards and regulations are provided under the collaboration and agreement of the related parties. In this paper, we introduce a european standard from IEC, namely, "IEC 62128-2:2003 railway applications-fixed installations -part 2: protective provisions against the effects of stray currents caused by d.c. traction systems" and a "Code of Practice" produced by Victorian electrolysis committee (VEC) based on "Electricity Safety Act 1998" and "Electricity safety (stray current corrosion) regulations 1999" of Victoria state, Australia.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.125-131
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• 2011

TSI(Technical Specification for Interoperability) is the highest technical specification in the Europe Railway and is composed by assessment items and essential requirements included by safety, reliability, availability, health, environment protection and technical compatibility. It is used on the research and development in the next generation railway technical. Currently, TSI procedures have been asked to bid for high speed rail business in Europe and Brazil. Also, all the railway systems such as infrastructure, signaling, electric and rolling stock system corresponding with standard of TSI procedures are exported and imported. Recently, Safety Critical System which has been studied on future railway R&D business in Korea is the state of the art train control system. And it is needed for system assessment of TSI procedures before system test and operation. In this paper, basic research is performed for analyzing TSI procedures suitable for the state of the art train control system in Korean railway.

• 전기학회논문지
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• 제67권12호
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• pp.1729-1734
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• 2018

Recently, interest in environmentally friendly transportation systems has been increasing, and study on railway systems has been aggressively conducted. Therefore, lots of studies have been done in railway advanced countries to improve performance of PWM converter. The research on the PWM converter for railway vehicle was mainly carried out on the converter mounted on railway vehicle such as the high-speed railway and metropolitan railway. In also, a lot of study has been carried out to improve converter performance installed in the ground. The high-capacity transform used in this paper converted from AC 22.9kV to AC 590V. The converter changed from AC 590V to DC 950V. In general, in the case of rectifier, the DC power supply system has a negative impact on inverter control characteristics because it can not avoid the pulsating component. In this study, it was performed current control for high-capacity converter using Matlab Simulink. The PWM converter is normally performed through the voltage and current at starting mode, powering mode, and braking mode. In the light-load test and the on-line test, we have studied for the PWM converter characteristics. Using this research, we have founded that the converter has excellent performance.

• 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.

• 한국전자통신학회논문지
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• 제13권6호
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• pp.1161-1168
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• 2018

2018년 4월 27일 역사적인 남북 정상의 판문점 선언을 통해 남과 북은 철도연결을 위한 실질적인 대책들을 마련해 나가기로 합의하였다. 상상이 현실이 되어 당장이라도 부산-유럽 간의 열차가 운행될 것처럼 연일 보도하고 있지만 남한에서 출발한 열차가 북한 철도로 직결 운행하고 대륙철도로 국경을 통과하는 운영노선은 지금까지 한국철도가 취급해보지 못한 미지의 영역으로 본격적인 운행을 위해 상당한 부분을 면밀히 검토해야 한다. 또한 철도교통은 타 교통수단과 달리 종합적인 네트워크 시스템으로 서로 다른 철도망의 직결운행을 위한 표준화와 기술적 조화가 매우 중요하다. 본 논문에서는 남북철도 연결대비 직결운행을 위해 철도 상호운용성에서 주도적인 역할을 하고 있는 유럽사례를 살펴보고, 이를 통하여 남북철도 직결운행을 위한 실질적인 상호운용성 확보에 대하여 고찰하였다.

• 한국안전학회지
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• 제25권5호
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• pp.33-38
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• 2010

Railway is one of popular transportation systems. Due to the safety and in time, the transportation by train is preferred to the others for a long time. However, accidents under railway construction get more serious problems than in case of the other system, because it is the largest mass transportation system. Especially, the railway construction is composed of different kinds of construction works such as civil, architect, electric and mechanic. It is closely/complicatedly connected with various workers, large machines and facilities, regulations etc. In this study the data on safety accidents are corrected during 6 years(2004~2009) and analyzed by time(year, month, week, day, a.m or p.m), place, field, type etc. Results shows that there exists remakable trends on accidents, so efficient treatments should be prepared considering this trend.

• 전력전자학회논문지
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• 제25권3호
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• pp.213-218
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• 2020

In this study, we propose a control algorithm to reduce the unbalanced characteristics of a three-phase system power caused by the unbalanced load of the AC electric railway. Then, we verify its performance through the design of a power compensator and experiments applying it. Like electric railway systems, a Scott transformer is applied, and the load and single-phase back-to-back converters are connected to the M-phase and T-phase outputs. The back-to-back converter monitors the difference in active power between the unbalanced loads in real-time and compensates for the power by using bidirectional characteristics. The active power is performed through PI control in the synchronous coordinate system, and DC link overall voltage and voltage balancing control are controlled jointly by M-phase and T-phase converters to improve the responsiveness of the system. To verify the performance of the proposed power compensation device, an experiment was performed under the condition that M-phase 5 kW and T-phase 1 kW unbalanced load. As a result of the experiment, the unbalance rate of the three-phase current after the operation of the power compensator decreases by 58.66% from 65.04% to 6.38%, and the excellent performance of the power compensator proposed in this study is verified.