• 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 for Railway
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• v.13 no.4
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• pp.419-424
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• 2010

Through the process of state estimation in the electric railway substation, this paper presents a new method for improving the reliability of the measurements corrupted by gauge error. Unlike the case of commercial power systems, it has been difficult to perform the state estimation by using the usual methods in the electric railway substation. At some of the monitoring points in the substation, most often, it is hard to define the measurement functions by use of the states or as we set up a new states set with the change of system topology, some of the measurement functions become part of the states themselves, which leads to poor results. To resolve the problems in the existing method caused by the relations between the states and the measurement functions at the monitoring points, the proposed method in this paper exploits the equality constraints. They can be derived numerously and concisely from the current and the voltage attributes of the Scott transformer and the buses connecting conditions, etc. We have proofed the effectiveness of the proposed method by the test on a standard sample substation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.10
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• pp.1523-1527
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• 2015

Traction power is supplied by three-phase alternating current of 154 kV power grid and electric trains are operated on single phase feeding system. It becomes important to use all the three phases equally and convert them into two-phase electric power (90 degree phase rotation) for traction supply. This is achieved by special transformer from the adjacent traction substation which is separated by a neutral section. Neutral section locations are in front of the substation and between the two substations. The first stage of the Seoul-Busan high-speed railway, design curve radius is larger than 7,000 m and the greatest slope is 25‰. The railway track conditions are evaluated as good enough to install a neutral section at the first stage, but a few factors of coasting operation of the train should be considered at the second stage of Seoul-Busan high-speed railway. The neutral section was located at Kim-cheon substation, which made some neutral section problems produced by the operating train, and the neutral section was moved about 1.5 km to the south toward Dong Dae-gu station due to the track operation condition. Some of the trains which stopped at the existing Kim-cheon Gu-mi station produced another motor block failure after moving the neutral section. In this paper, power quality, system performance and track condition, etc. are suggested to solve the problems.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1292-1296
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• 2004

This study is experimented results of running characteristics about electric locomotive. it executed to study a power quality in the substation of Honam electrification line and to promote knowledge, observation and management in electric rail-system. we measured to know the more exactly running characteristics that electric locomotive and electric substation at the same time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.672-678
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• 2020

The parallel-feeding operation of an AC traction power supply system has the advantages of extending the power supply section and increasing the power supply capacity by reducing the voltage drop and peak demand caused by a train operation load. On the other hand, the parallel-feeding operation is restricted because of the circulating power flow induced from the phase difference between substations. Moreover, the power supply capacity is limited because of the unbalanced substation load depending on the trainload distribution, which can be changed by the train operation along the railway track. This paper suggests a Thyristor-controlled Phase Angle Regulator (TCPAR) to reduce the circulating power flow and the unbalanced substation load, which depends on the phase difference and the trainload distribution and provides a feasibility study. A dedicated control model of TCPAR is also provided, which uses substation power supplies as the input to control the circulating power flow and an unbalanced substation load depending on the phase difference and the trainload distribution. Simulation studies using PSCAD/EMTDC shows that the proposed TCPAR control model can reduce the circulating power flow and the unbalanced substation load depending on the phase difference and the trainload distribution. The proposed TCPAR can extend the parallel-feeding operation of an AC traction power system and increase the power supply capacity.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.1
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• pp.9-17
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• 2017

A parallel control algorithm of thyristor dual-converter power system for the DC power supply of railway is proposed. The circulating current and current imbalance generated during parallel operation can be limited to control the output voltage of each power system by using the proposed parallel control algorithm. The proposed control algorithm can also eliminate output current sensor to achieve the same output response without additional costs. The validity of the proposed algorithm is verified through simulation and experiment.

• Journal of the Korean Society for Railway
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• v.18 no.6
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• pp.533-542
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• 2015

This paper suggest away to maintain constant power through trolley wire by transferring increased line voltage to the AC main line while changing the mode from Converter(Forward) to Inverter(Reverse) when the line voltage is increased due to regenerative power when the train stops, This paper suggests a Double Converter DC substation that can create regenerative power when the train stops reusable. We also proposed using a simulation tool, the optimal Thyrister firing angle that can minimize the undershoot and overshoot that occurs when transferring the mode from Converter to Inverter for quality improvement of DC voltage in the Double Converter in the DC substation from the Busan Urban Subway.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.682-687
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• 2005

High quality power supplying of power distribution system in electric railway system is the important function. Power feeding system is complicated witch is compose with distribution line, circuit break, protection facilities and so on. Among this components, role of substation is most important for elevation of reliability in electric power system. Therefore, the enhanced reliability considering the preventive inspection, repair work, replacement is necessary. In this study, a proposed the enhanced reliability method through a calculation of fault probability in power feeding system.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1402-1404
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• 2000

The electrified railway has various power supply schemes. Although the identical trains are operated in same condition and the impedance of track are equal, the genealogy impedance of track is changed according to composition method of feeding scheme. So, the harmonic current flowing into the railway substation are greatly unlike. For simulation of harmonic magnification flowing into the railway substation according to feeding scheme, we propose 6-port network analysis method based on 4-port network, find 6-port equivalent model of each circuit component, and compare and investigate harmonic magnification in the case of parallel post and normal feeding scheme.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.676-681
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• 2005

The regenerative braked cars are being introduced in DC electric railway for energy saving. There has been a recent tendency for DC traction substation with regenerative inverter to increase in number. This is strongly related to the desire for effective utilization of electric power regenerated by DC electric cars and to the aim ensuring stable operation of regenerative braking system. The regenerative inverters DC power feed back from a generative car into AC power at a substation and supplies it to distribution lines. This paper suggest the result of characteristic analysis and capacity simulation. economical analysis in the regenerative inverter system.