• 전력전자학회논문지
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• 제13권3호
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• pp.213-220
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• 2008

본 논문에서는 전압강하 보상모드를 갖는 직류 지하철 회생인버터 시스템을 제안하였다. 주 정류기에 고장이 발생하면 직류 지하철은 전원측으로부터 전력을 공급받지 못한다. 실제적으로 사고를 방지하기 위하여 변전소 측에 예비 정류기가 설치되어 있다. 이 논문에서는 전압강하 보상모드가 별도의 예비정류기를 대신하여 회생인버터에 부가된다. 제안된 인버터 시스템은 직류 가선 전압에서 발생한 회생에너지를 계통으로 반환한다. 부가하여, 인버터는 직류 지하철 시스템에서 사용된 전력변환장치에 의하여 야기된 고조파를 보상할 수 있다. 컴퓨터 시뮬레이션에 의해서 제안된 제어 알고리즘의 효용성을 설명하였다.

• 대한전기학회논문지:전력기술부문A
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• 제52권11호
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• pp.639-646
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• 2003

Nowadays traction motors in the urban rail transit vehicle are controlled by VVVF inverter and have capability of regenerative braking. The algorithms to deal with the regenerating vehicle in simulation for the DC traction power supply is introduced in this paper. Substations have to be separated from the system to represent reverse biased rectifiers in substations. The model of the trains in regenerative braking has to be changed from the ideal current source to the constant voltage source since the train input voltage has to be controlled below the certain train maximum voltage. Some mismatches are unevitable because the constraint of the regenerated power can not be imposed with the constant voltage source. The mismatches represent the unused regenerated power. A computer program is developed to verify the validity of the algorithm. The test run result shows the program behaves as it is expected and proves the algorithm's validity.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.581-586
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• 2006

Selection and application recommendations of lightning arresters for DC electric traction vehicles are presented. To decide arrester specification such as continuous operating voltage(COV, $U_c$), rated voltage($U_R$), and nominal discharge current($I_n$), variations of system voltage and surge currents flowing arresters were analyzed in running-service of traction vehicles. System voltages increased up to 1,800V during anti-breaking. Surge currents recorded 3 times per running-service-route and their magnitudes were ranges of $150A{\sim}2kA$. From the field measurement and consideration of EN50163, COV, $U_c$, and $U_R$ for the $1,500V_{DC}$ traction vehicles were proposed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.281-285
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• 2008

Corrosion of metallic structures arises when an electric current flows from the metal into the electrolyte such as soil and water. The potential difference across the metal-electrolyte interface, the driving force for the corrosion current, can emerge due to a variety of temperature, pH, humidity and resistivity etc.. With respect to a given structure, a stray current is to be defined as a current flowing on a structure that is not part of the intended electrical circuit. Stray currents are caused by other cathodic protection installations, grounding systems and welding posts, referred to as steady state stray currents. But most often traction systems like railroads and tramlines are responsible for large dynamic stray currents. This type of stray current is generally results from the leakage of return currents from large DC traction systems that are grounded or have a bad earth-insulated return path. This paper investigates the reports, which is made for protecting the electrical corrosion by the DC traction stray current before the construction period.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1825-1831
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• 2011

One of the major trends in traction power electronics is increasing the switching frequencies. The advances in the frequency elevation have made it possible to reduce the total size and weight of the passive components such as capacitors, inductors and transformers in the DC/DC converter and hence to increase the power density. The traction dynamic performance is also improved. This document describes several aspects relating to the design of resonant DC/DC converter operating at high frequency(10KHz) and the converter topologies and the control method of MAGLEV, which result in soft switching, are discussed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.720-726
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• 2000

The advance of traction motor control technology and the complexity of the traction power supply system makes the simulation essential in determining the dimension of the traction power supply system. The conventional method, use of the simplified and/or empirical equations, becomes inadequate in optimization of the design. The simulator presented in this paper is a numerical time based simulator running on a PC. The input to the simulator includes the track data, the train characteristic, network data and operating data. Basically the simulator conducts train running simulation and loadflow study repeatedly. The principle algorithms and its output is discussed in the paper.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.215-217
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• 2008

DC fraction system can damage human and other facilities due to the rising of rail potential. Therefore the earth fault detection relay protects system using rail potential induced in train operation and ground fault. However the conventional protection system cannot operate due to the fault resistance and might operate unwanted voltage rising due to the other substation ground fault. So this paper models DC traction system using PSCAD/EMTDC and simulates the rail potential rising. We can estimate the rail potential rising in DC traction system through the various simulation.

• 한국안전학회지
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• 제32권6호
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• pp.16-21
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• 2017

Fire or electrical problem while DC electric traction vehicle operation caused by various reasons can lead to not only suspension of the operation, but also severe aftermath such as massive casualty. In this paper, fire analysis on DC electric traction vehicle caused by electrical breakdown on line breaker, which is in connection with the power supply, is presented. When the electric arc, the by-product of frequent line breaker operation, is not fully diminished, it leads to electrical breakdown and fire. Especially, electrical breakdown can be easily induced by the open-and-close operation of inner contractor inside line breaker, eventually followed by ground fault and generation of transient current. Electric arc is consequent on the ground fault and acts as possible ignition source, leading to fire. Also, during the repetitive operation of the line breaker, the contactor is separated each other and some copper powder is generated, and the copper powder provided breakdown path, resulting in fire.

• 전기학회논문지
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• 제61권12호
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• pp.1964-1969
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• 2012

This paper presents to verify the selective grounding fault protective relaying technique for the ungrounded DC traction power supply system. This system selectively blocks fault section when grounding fault occurred. In order to perform this verification, field test facilities have been installed on Oesam substation and Worldcup-Stadium substation, and field test process has been suggested. Also, selective grounding fault protective relaying components and rail voltage reduction device have been tested with the various trial examinations. In order to compare and evaluate performance of the selective grounding fault protective relaying function, field test system was modeled and the system fault simulation results were compared and evaluated with the field test result. Performance of selective grounding fault protective relaying function was evaluated with the above-mentioned process, and the fact that the system recognizes fault section irrespective of insulation between rail and ground and fault resistance from grounding fault.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1519-1520
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• 2006

This paper describes a selection and application recommendations of ZnO arresters on DC electric traction vehicles. We measured and analyzed the system voltages applied to arresters and the surge currents flowing arresters on DC electric traction vehicles under operation to decide the Continuous Operating Voltage($U_C$), the Rated Voltage($U_R$), and the Nominal Discharge Current($I_n$). System voltages measured up to 1,800 V during anti-breaking in 1,500 V-system, and surge currents were recorded up to 3 times per running-service-route and their magnitudes were ranges of $150A{\sim}2kA$. From these results and the standard EN50163, we proposed the Continuous Operating Voltage($U_C$) the Rated Voltage($U_R$) for the $1,500V_{dc}$ electric traction vehicles.