• Proceedings of the KSR Conference
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• 2011.10a
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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.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.493-498
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• 2003

Harmonic current originating from electric locomotives can be magnified due to the impedance characteristics of power supply circuit and bring about various problems. That is, electromagnetic interference with communication lines, operational trouble in signaling, overheat and/or vibration in power capacitor, mis-operation in protection relay and so on. Therefore, the exact assessment of the harmonic current flow must be undertaken at design and planning stage for the electric traction systems. For these reasons, this study propose a new approach to model and to analyse traction power feeding system focused on system response to current and voltage harmonic(PART I ). Measurements of harmonics are also performed for railway power supply systems under normal operation. Spectrum and distortion analyses in measurement data are variously described in PART II

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.499-504
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• 2003

Harmonic current originating from electric locomotives can be magnified due to the impedance characteristics of power supply circuit and bring about various problems. That is, electromagnetic interference with communication lines, operational trouble in signaling, overheat and/or vibration in power capacitor, mis-operation in protection relay and so on. Therefore, the exact assessment of the harmonic current flow must be undertaken at design and planning stage for the electric traction systems. For these reasons, this study propose a new approach to model and to analyse traction power feeding system focused on system response to current and voltage harmonic(PART I ). Measurements of harmonics are also performed for railway power supply systems under normal operation. Spectrum and distortion analyses in measurement data are variously described in PART II

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.137-139
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• 1993

This paper details methods used to verify the adquacy of a dc traction power supply for design in Seoul matropolitain subway Line-6 system. Examples of the approach are given for a major subway presently under construction. The performance of trains operating at maximum system design capacity is modelled using a train simulation program. Using a dc network analyser program, the maximum train operating timetable, and a model of the ac and dc electrical suppy system, the electrical performance of the entire system can be modelled over a 24-hour period. The results of this analysis are used to determime: train voltage at a level sufficient to ensure train schedules: adequacy of traction transformers, rectifier, and switchgear ratings; sizes of the overhead contact systern conductors, and ac and de feeder cables: and power and energy demands at the utility company's supply points for inital and final timetable operations.

• Journal of the Korean Society for Railway
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• v.7 no.1
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• pp.60-64
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• 2004

Harmonic current originating from electric locomotives can be magnified due to the impedance characteristics of power supply circuit and bring about various problems. That is, electromagnetic interference with communication lines, operational trouble in signaling, overheat and/or vibration in power capacitor, mis-operation in protection relay and so on. Therefore, the exact assessment of the harmonic current flow must be undertaken at design and planning stage for the electric traction systems. for these reasons, this study propose a new approach to model and to analyse traction power feeding system focused on system response to current and voltage harmonic(PART I). Measurements of harmonics are also performed for railway power supply systems under normal operation. Spectrum and distortion analyses in measurement data are variously described in PART II.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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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.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.6
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• pp.255-261
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• 2002

Recently, traction motors in trains are supplied with single phase a.c. power. After this power is converted to d.c. power, it is inverted to three phase power to operate traction motors. As going through the process of the conversion, harmonic current is generated in train. The method of conventional analysis on harmonics, studied by RTRI, is modeled with equivalent circuit of ac AT-fed electric railroad system using by the distributed constant circuit. However, this circuit as two-port network model has some difference in comparison with real system. The reason why the conventional method is different from the real system is that the conventional method dose not include three conductor groups, that is catenary, rail, and feeder, and admittance between the conductors for line capacitance. Therefore, this method has a little error. This paper proposes new method to more effectively estimate Harmonic current. In this method, numerous components in electric railway are categorized and each component is defined as a four- port network model. The equivalent circuit for the entire power supply system is also described into a four-port network model with connections of these components. In order to evaluate the efficiency and the accuracy of a proposed method, it is compared with values measured in Kyung-Bu high speed line and ones calculated by the conventional method.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.688-695
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• 2000

This study presents an approach to model and to analyse traction power feeding system focused on the amplification of harmonic current. Through the research we can conclude the following: - The resonance frequency is not depend on the location of vehicle. The magnification of harmonic is, however, a function of the position of a train. - The resonance frequency is lower as catenary length is longer.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.185-191
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• 2006

Auxiliary power supply developed by domestic technology has very important function that not only effect on main power converter & inverter system, traction motor and train control system which are related to performance of train, but also influence on power supply for HVAC(Heat, Ventilation, Air-conditioning) and lighting device which are related to comfort of passengers. This paper shows characteristic test results of auxiliary power supply such as working condition and performance, which is associated with velocity of train, operating mode and surrounding equipment, through test running. Also it shows the results deduced from comparison analysis between designed data and manufactory test data as measuring in put voltage of auxiliary power supply. And, it propose a modification of design parameter for stabilizing operation and improving reliability.

• Journal of the Korean Society for Railway
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• v.10 no.1 s.38
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• pp.84-87
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• 2007

Auxiliary power supply developed by domestic technology has very important function that not only effect on main power converter & inverter system, traction motor and train control system which are related to performance of train, but also influence on power supply for HVAC(Heat, Ventilation, Air-conditioning) and lighting device which are related to comfort of passengers. This paper shows characteristic test results of auxiliary power supply such as working condition and performance, which is associated with velocity of train, operating mode and surrounding equipment, through test running. And, it propose a modification of design parameter for stabilizing operation and improving reliability.