• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.354-355
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• 2010

본 논문에서는 5kW급 가정용 DC급전 시스템을 모의하고 시스템 도입 시 발생 가능한 문제점을 실증하기 위하여 5kW급 가정용 DC급전 Test-Bed를 시뮬레이션 및 제작한다. 가정용 DC급전에 필요한 DC link를 5kW급 PWM 컨버터를 이용하여 380V의 고전압 DC link를 구성하고 1kW급 위상 천이 컨버터를 이용하여 12V의 저전압 DC link를 구성하여 고전압, 저전압 DC급전 상황을 비교 분석할 수 있게 한다. 또한 모터 구동 부하를 모의하기 위한 2kW급 인버터를 추가하여 부하 환경에 따라 DC급전 시스템에서 발생 가능한 문제점을 유도할 수 있도록 한다.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.30-33
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• 2001

도시철도 DC 급전시스템은 부하전류가 사고전류보다 클 수 이는 특징을 가지고 이다. 이러한 이유로 DC 급전시스템에서는 di/dt를 측정하여 사고전류를 부하전류로부터 구분하고 있다. 이것은 사고전류의 di/dt와 부하전류의 di/dt는 서로 다른 상이한 특성을 보이고 있기 때문이다. 본문에서는 DC도시철도급전시스템에서 흔히 사용되는 di/dt 계전기와 이의 설정을 위한 사고전류의 분석 및 설정방법에 대해 알아본다.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.502-503
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• 2011

최근 환경 문제 및 화석 에너지의 고갈과 맞물려 신재생 에너지를 사용하는 DC 출력형 분산전원 시스템이 증가 일로에 있으며, 이에 따라 교류 급전시스템보다 에너지 변환 효율이 높은 직류 급전 시스템에 대한 연구개발이 활발히 이뤄지고 있다. 본 논문에서는 유지 보수의 용이성을 확보한 Hot Swap 구조형식의 DC 급전용 100[kW]급 분산 제어기반 모듈형 ESS[Energy Storage System의 개발에 관한 것이다. 실제 33[kW]급 모듈 3대로 구성된 100[kW]급 시스템을 제작하여 전압제어 실험, 병렬운전실험 및 Hot Swap 안정성 실험 등을 수행하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.6
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• pp.138-146
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• 2010

DC railway power supply system generally uses the running rails as negative-polarity return conductor for traction load current, and the induced rail potential and stay current cause serious problems to any electrified matter in the underground and also safety problems to human body. This paper presents a new algorithm for the analysis of the rail potential and the stray current in DC railway power system operated under independent/parallel power feeding mode. The effect of load current fluctuation during train operation is also calculated by using TPS(Train Performance Simulation) program to analysis the variation of the railway potential and stray current along railway track. Simulation program is developed based on the proposed algorithm and case studies are provided.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.6
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• pp.160-168
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• 2010

This paper presents the analysis of the current as stray current and supplied current of the substation, on the DC railway power system. In DC railway power supply system, the running rails are usually used as the return conductor(negative-polarity) for traction load current. This condition mainly focuses on economic considerations, since it does not require the installation of an additional return conductor. But, problems of low resistance between the running rails for the return conductor and earth allows a significant part of the return load current to leak into the earth. This current is normally called to as leakage or stary current. This stary currents creates serious problems for any electrified matter in the underground. Therefore, reduction of stray current of the DC railway power supply system is also of direct benefit to the operational and safety aspects of the DC railway systems. In this paper, deal with the analysis of the current distribution on the DC railway power system applied the common grounding system, using SPLIT of CDEGS program.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.166-168
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• 2007

본 논문에서는 직류 지하철 급전시스템에서 발생하는 회생전력을 활용하기 위한 회생전력 제어용 양방향 DC-DC 컨버터 및 EDLC(Electric Double Layer Capacitor)를 이용한 양방향 DC-DC 컨버터의 효율적 충 방전 제어 알고리즘을 제안하였다. 가선전압의 변화에 따른 제어 방법을 제안함으로서 회생전력의 발생으로 인한 가선전압의 상승을 안정적으로 제어할 수 있도록 하였고, 실측된 가선전압과 동일한 직류 급전시스템의 모의가 가능한 가선전압 모의장치를 사용하여 철도차량용 양방향 DC-DC 컨버터의 효율성을 검증하였다.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.327-329
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• 2006

본 논문에서는 DC 전압을 이용한 전력IT 시스템의 활용을 연구하고 그 효율성을 입증하기 위하여 가정용 전자제품에 전력공급을 기존 AC공급원에서 DC공급원으로 변환하여 그 효율성을 비교하였다. 직류급전시스템은 교류급전시스템에 비해 전력교환장치의 교환단수가 적기 때문에 변환효율로 10%정도 고효율화 할 수 있음을 실험을 통하여 입증한다.

• Journal of the Korean Society for Railway
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• v.12 no.5
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• pp.687-693
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• 2009

An algorithm and a computer software are developed for the analysis of rail potential rise. The algorithm is intended to be integrated with the traction power system simulation program. In the algorithm, rail potentials are obtained by two step process. First the injection currents to the negative rail are obtained from load-flow study. In the next step, a network consisting of negative rail and the injection currents are constructed. Leakage resistance to ground are added to the network. And the network is analyzed for rail potentials. A software is developed to verify the validity of the algorithm. The result of the software is compared with the Simulink/SymPower circuit analysis result. The differences between the two results are with the acceptable range. The advantage of this algorithm is that it can be integrated with the existing traction power supply simulation program easily, which usually ignores negative rail's leakage resistance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.4
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• pp.86-97
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• 2006

For the design of DC traction power supply system at new Light Rail Transit(LRT) construction, it is very important to determine system configuration, location and power capacity of substation. However, a LRT system consists of a number of subsystems such as train movement, power supply and traction drives, which inevitably contains many complexities and diversities. The objective of this paper is to clarify and systematize the design procedure and its assessment for the electrification system of a LRT line. This paper discusses in detail our approach to system design and its assessment. The whole DC-feeding network configuration, characteristics of a train, and design method of substation arrangements is thoroughly investigated for the design. As a result of the investigations, the design procedure is clarified and systematized and a computer program for the design and evaluation of the system is developed using the most suitable iterative method with nodal equation. To verify the proposed design and its assessment procedure, case studies for the DC traction power supply system of a planed Korean LRT line are performed.

• Journal of the Korean Society for Railway
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• v.12 no.2
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• pp.254-259
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• 2009

DC transit system has been adopted in the metropolitan area, Korea since 1974. Electric multiple (EMU) in this system always reiterates that acceleration and retardation. When EMU decelerates using electric breaking, regenerative power occurs. Regenerative power can be consumed in vicinity EMU on the same line or in resistor. If DC transit system has inverter for reusing regenerative power, Energy efficiency in DC transit system and the replacement cycle of brake shoe in EMU will be increased and dust due to mechanical braking decreased. This paper present the developed inverter for regenerative power and its test equipment. Test for developed inverter is performed at test equipment and is divided into three items, which are regeneration mode, active filter mode, and system link test.