• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.238-240
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• 2007

This paper present adaptation method of rail potential test to verify DC railway system's performance and safety. For protection of person and utility caused by rail potential rise, international standard to limit rail potential rise is made and rail potential is tested at the time of plan and construction of DC railway system in foreign country. So, we need rail potential test at the opening time and prepare a continuous monitoring technique of rail potential and a limitation method of rail potential rise. For these, we describe cause of rail potential rise, international standard about rail potential, protection principle, an example of calculation and measurement, and adaptation method for performance test.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.97-99
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• 2008

It is possible to suppress voltage drops, power loading fluctuations and regeneration power lapses for DC railway systems by applying an energy storage system. Recently the electric double layer capacitor (EDLC) of the rapid charge/discharge type has been developed and used in wide ranges. The on board energy storage system with supercapacitor for railway vehicles presented in this paper seems to be a reliable technical solution with an enormous energy saving potential. In this paper, an efficient charge and discharge control method of a bidirectional DC-DC converter using the supercapacitor is proposed.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권4호
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• pp.272-281
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• 2000

This paper deals with the parallel operation of several numbers of PWM converters for a high speed railway train application. Several considerations are made to reduce the transformer interaction which can cause a current control problem in severe case. Also, in this paper, novel control strategy is proposed to achieve a harmonic free primary-side current control under a light load condition using one current sensor independent of the number of converters. In addition, the modified predictive current controller, which is suitable to a digital current controller with a relatively large sampling period, is used. Finally, to verify the system validity, digital control system with TMS320C44 micro-processor and small scale simulator are made and tested.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 에너지변화시스템부문
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• pp.201-203
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• 2009

This paper presents the real time stray current monitoring techniques on the DC railway system. These techniques are two types. The first one is the rail potential measurement technique between running rail and earthing mats on the important locations such as substation, station, and so on. And the second one is measurement technique of stray current through substation earthing mats and from collection mats, and continuous monitoring of return currents through the running rails. We need to apply these techniques on DC railway system to monitor stray current periodically and maintain the system properly.

• 전기학회논문지
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• 제60권4호
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• pp.892-898
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• 2011

In DC electric railways, while an electric rail car is driving, a part of the working current returned to the substation through rails leaks into the ground. Such a stray current causes railway facilities and metal objects to corrode electrolytically. Therefore, change of stray current needs to be monitored constantly. But so far in domestic, the research on stray current measuring techniques and system adaption are insufficient. To estimate stray current, this paper addresses a method of monitoring the return current that is returned into the negative pole of the substation in real time.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.307-309
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• 2004

A DC railway system has low feeder voltage, The remote fault current can be smaller than the current of load starting. So it is important to discriminate between the small fault current and the train starting current. The train starting current increases step by step but the fault current increases all at once. So the type of $\bigtriangleup I\;relay(50F)$ was developed using the different characteristics between the load starting current and the fault current. As for the train starting current, the time constant of train current at each step is much smaller than that of the fault current. To detect faults in U railway systems, an algorithm that is independent of train starting current. This algorithm use the time constant calculated by the method of least squares is presented in this paper.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1654-1660
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• 2011

The korea Electric Railway feeder voltage is DC 1500V and AC 250000V. The auxiliary power supply of the vehicle auxiliary power units for domestic electrical feed has been developed with domestic technology hyeonchae mounted station, and domestic uses, such as voltage, have been exported to other countries. However, do not use at domestic that can be used for DC 3000V voltage auxiliary power unit does not develop, vehicle exports global. This has already been replaced by imported products from other nations is a real situation. Thus, our auxiliary power unit for the DC 3000V was developed, it will be exported to Ukraine. In this paper, We introduced circuit and structure of developed auxiliary power supply unit, and verified the performance with output characteristic of the auxiliary power unit.

• 한국철도학회논문집
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• 제19권3호
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• pp.314-323
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• 2016

직류 전철변전소의 가선전압은 전동차들의 회생제동 및 역행가속패턴에 따라 급격히 상승 또는 하강하는 특성을 갖는다. 가선전압 순시 변동폭을 최소로 유지함으로써, 전철변전소와 전동차들의 에너지 효율을 개선시키기 위한 다양한 연구들이 이루어지고 있다. 본 논문은 직류전철 변전소의 가선전압의 급격한 변동특성을 모델링하고 선형인공 신경망 알고리즘을 이용한 가선전압 회로모델의 파라메터 추정 방법을 제안하며, 최소자승법을 이용한 추정방법과의 비교를 통해 이 방법의 타당성을 입증한다. 가선전압 및 피더전류들의 누적 측정값을 사용하여 일괄처리 최소자승법으로 RC 병렬회로의 파라메터들을 추정한 결과를 제시하며, 실시간 가선전압 및 피더전류 측정값을 이용하여 오차역 전파방식으로 학습되는 선형인공신경망 기법 추정 결과를 분석한다.

• 한국철도학회논문집
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• 제10권6호
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• pp.717-722
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• 2007

본 논문에서는 직류 1500V 지하철 변전소의 가선전압과 피더별 전류량을 측정한 결과를 분석한다. 선릉과 양동시장 변전소들의 피더별 소비 및 회생전력을 측정하고, 피더별로 발생된 회생전력이 타 피더로 전달되는 전력량을 계산하였다. 전철변전소에서 회생전력이 교류될 수 있는 거리를 타 변전소와의 중간지점으로 가정하고, 전동차 1편성의 회생전력량을 기초로 변전소에서 발생되는 총 회생전력량을 근사식으로 계산하였다. 이렇게 얻어진 값과 측정된 피더간 교류된 회생전력량을 사용하여 변전소의 회생전력 실효전력량을 계산하고 회생인버터가 설치된 후 재활용할 수 있는 회생전력량을 근사적으로 얻었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1489-1497
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• 2009

The rectifier for Electric railway is one of the most important facilities in DC urban railway which converts power from KEPCO(AC 22.9kV) to the electric mil car(DC 1.5kV), therefore it should be managed as the best condition for the drive. There are several things to cause performance degradation and deterioration of parts such as pollutants occurred by it established under the ground such as dust or foreign substances, rapid changes of driving current, and pyrogen which put the rectifier for Electric railway in malfunction. On the flow of time, the rectifier for Electric railway is causing a malfunction or failure which drive electric rail car in operations as well as loss of life. In this research we try to find the way of removing the various components of mal-functions in the performance of the rectifier for Electric railway by Over-Haul and reform itself, which gives us to get the chance investment of the reduction, the reliability of power supply to the electric rail car.