• Proceedings of the KSR Conference
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• 2008.06a
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• pp.499-504
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• 2008

DC substation of urban transit supplies a suitable DC power on electricity vehicles by being supplied from KEPCO. DC substation is verified electrical safety of system through pre-operation inspection on electrical installations to be supplied power from KEPCO. However, because test items and method for DC traction system are unprepared on pre-operation inspection, the general safety and performance verification of DC traction system are very insufficient. Therefore this paper analyze the overseas test examples such as factory equipment tests, factory combined tests and railway tests for the safety and performance verification of DC traction system and present a suitable test items and test standard in domestic.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.505-511
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• 2008

when electric traction system used DC 1500V runs on decline of rail road track and slows down, dc voltage goes beyond regular voltage. In this case extra power is forcibly wasted by resister because rectifier of substation and electric train including power converter and so on are out of order. This paper described a DC electric railway system, which can generate the excessive DC power form DC bus line to AC source in substation for traction system. The purpose of this study was the development of the regenerative inverter system which suppress extra DC-line voltage and regenerate the energy instead of using a resister. That is Developed regenerative inverter system returns the regenerative energy from the DC line voltage to the utility. In addition, the inverter can be compensate the harmonics caused by the power conversion devices used in the DC traction system.

• Journal of the Korean Society of Safety
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• v.25 no.2
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• pp.18-23
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• 2010

This paper describes a cause of fire accidents on power system fire DC electric traction vehicles. We investigated fire scene of power line for DC electric traction vehicles. From analysis results, the cause of fire on power line turned out line to ground fault between a feeder of electric power services(pantagraph) and DC electric traction vehicle roof. Fire accident of DC electric traction vehicles be assumed that electric sparks had been produced between the pantagraph and the power line conductor by repetitively making contact and separation, maybe if some material like branches get in between connecting rod it makes progress line to ground fault. ZnO arresters are widely used to protect DC electric traction vehicles against overvoltages caused by lightning or switching surges. However, the arresters are deteriorated by commercial overvoltages and/or lightning one. The deteriorated arresters could lead power failures, such as line to ground fault by a thermal runaway resulting from the increases in leakage current even in a nominal power system voltage. Finally, the power failures would be causative of the fire accident.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.804-808
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• 2007

when electric traction system used DC 1500V runs on decline of rail road track and slows down, Dc voltage goes beyond regular voltage. In this case extra power is forcibly wasted by resister because rectifier of substation and electric train including power converter and so on are out of order. This paper described a DC electric railway system, which can generate the excessive DC power form DC bus line to AC source in substation for traction system. The proposed regeneration inverter system for DC traction can be used as both an inverter and an active power filter(APF). As a regeneration inverter mode, it can recycle regenerative energy caused by decelerating tractions and as an active power filter mode, it can compensate for harmonic distortion produced by the rectifier substation. In addition, electric traction system products harmonic current and voltage distortion and reactive power because power converter is used so regeneration inverter normally runs such as active power filter(APF) for improving power quality. From the viewpoint of both power capacity and switching losses, the system is designed on the basis of three phase PWM inverters and composed of parallel inverters, output transformers, and an LCL filter.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.4
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• pp.247-256
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• 2008

Regenerative energy generated by regenerative braking of DC traction can cause the system malfunction or damage to the rectifier, or malfunction of the power conversion device in power supply system by DC Line voltage rise in feeder line. Regenerative energy storage system using super capacitor is one of the ways to stabilize DC line voltage. In this paper, energy storage system of DC traction system using super-capacitor bank is implemented and using the field measurement data of the station N and the station S on the Line 2, the operation characteristics of line voltage caused by regenerative energy of electric trains are verified. Also, charge/discharge characteristics of super capacitor are verified as well. Thus, we can verify the operation characteristics of super-capacitor bank for regenerative energy storage system installed in DC Traction. And if we can use field measurement data of DC line voltage, we have obtained cost reduction. The stabilization of the system will be improved by measuring the operation characteristics of regenerative energy storage system in certain section operated by DC traction and predicting the capacity and lifetime of super-capacitor.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1251-1253
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• 2001

This paper presents on capacity design of DC-fed-traction system. The system is introduced including a characteristics of train, feeding network configuration, and design method of substation arrangements. Optimal design procedures is described, and program for capacity computation of the system is presented using the nodal equation, K.C.L, K.V.L, Ohm's law and superposition theory. For the proof of the proposed algorithm, we accomplished the simulation of DC traction system for HA-Nam LRT. By considering whole component in DC traction system the conclusion will be much precise.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.241-247
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• 2008

This paper describes a cause of fire accidents on power system for DC electric traction vehicles. We investigated fire scene of power line for DC electric traction vehicles. From analysis results, the cause of fire on power line turned out line to ground fault between a feeder of electric power services(pantagraph) and DC electric traction vehicle roof. Fire accidents of DC electric traction vehicles be assumed that electric sparks had been produced between the pantagraph and the power line conductor by repetitively making contact and separation, maybe if some material like branches get in between connecting rod it make progress line to ground fault. ZnO arresters are widely used to protect DC electric traction vehicles against overvoltages caused by lightning or switching surges. However, the arresters are deteriorated by commercial frequency overvoltages and/or lightning one. Deteriorated arresters could lead power failures, such as line to ground fault by a thermal runaway resulting from the increases in leakage current even in a nominal power system voltage. The power failures, such as line to ground fault would be causative of the fire accidents.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.11
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• pp.1919-1924
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• 2016

In general, Diode rectifier has been applied to DC traction power supply system. Diode has some characteristics which is voltage drop in inverse proportion of load because of non-controlled switch, and cannot flow a current in reverse bias. So, voltage drop occurs frequently, and regenerated power cannot use in substation. The PWM rectifier is able to control output voltage constantly to reduce voltage drop and to use regeneration power without additional inverter. This paper proposes analysis algorithm for DC traction power supply system with PWM rectifier.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.28-32
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• 2007

In this paper, a unified regenerative inverter and control algorithm are proposed in order to perform regenerative action and active power filter action. While the regenerative mode of traction, it works as regenerative inverter to reduce a excessive power of DC bus line and the powering mode of the traction, it works as active power filter to compensate ac current distortion, power factor, and voltage unbalance. In the paper, a regeneration inverter used PWM DC/AC inverter algorithm. And an active power filter used p-q theory. We are carrying out a mode analysis of DC traction system similar to actual system with MG-set and experimenting with prototype model. Through the simulation and experiment, we were proving the regeneration inverter operation which suggested in this paper.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.164-168
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• 2005

In this paper a statcom is developed to improve the power quality in a dc traction system. The proposed statcom can be used as both inverter and active filter. As an active filter, it can compensate harmonic distortion and reactive power and as an inverter, it can recycle regenerative energy caused by decelerating trains. The simulation results are carried out by using PSCAD/EMTDC software.