• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1431-1440
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• 2009

A subway in Seoul has had a major role of public transportation after the opening of Seoul Subway Line 1 on August 15, 1974 and it has reached 34.7% of the transportation of Seoul citizens. The extended length of the subway system suppled with DC power in Korea is about 500km. In this system, the devices which are proper for regenerative power system are being required because of changeover from old braking and ATS signal system to regenerative braking and ATO signal system. In this paper, we reviewed the safety standards for the insulated hangers in overhead contact line. These hangers which have depended on foreign imports are being developed in Korea considering ease of demand and supply and economic effects.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.2
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• pp.125-131
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• 2001

This paper presents a application of vector control strategy to 1.2MVA traction drive for railway vehicle. The vector control required the control of the phase and amplitude of output voltage vector. But in case of traction system for railway vehicle, the one-pulse mode is used at high speed region in order to utilize the link voltage fully. So it is impossible to control the flux and torque axis current instantaneously and independently in the region. So this paper proposes a mixed control algorithm, where the vector control strategy at low speed region and slip-frequency control strategy at high speed region is used. And precise switching technique between the two different control strategy is proposed. The proposed strategy is verified by experimental results with a 1.2MVA traction drive system with four 210kW induction motors.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.416-418
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• 2001

In the feeding system of electric railways it is necessary to divide the power lines for either ac or dc system. At this dead section, the system is damaged by the abrupt change of the coming-in power. This paper present the relationships. Between the feeding system and the trail-cars, and the counter plans to reduce the electrical arc and the breakdown at the dead section.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.51-53
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• 2005

At the railway feeding system, a role of dead section is very important. Because, dead section is essential installation that AC feeding system meets DC feeding system or phase is changed between AC feeding systems. But, in dead section it is possible that an electric train meets interruption. In Korea, a study on the dead section isn't yet accomplished in depth. Accordingly. In this paper, when electric train is in dead-section power quality problem on electric train was dealt. Modeling and simulation using PSCAD/EMTDC was accomplished to analyze.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1131-1136
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• 2008

The single-phase PWM converter employing power semiconductors is currently applied to the power unit of high-speed rail vehicle and increasingly used as the front-end converter with properties of near unity power factor. Power factor and harmonics are increasingly important needs for drive system of high-speed rail vehicle. The proposed approach has many advantages which include fewer semiconductor components, simplified control, high performance features and satisfies IEC 555 harmonic current standards. Simulation results show that the dc-link voltage control obey the reference value during constant load and input current is near sinusoidal.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.644-647
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• 1999

The main objective of this paper is to design and test a new type of polymer ZnO surge arrester for DC power system of railroad vehicles. The rated voltage is 1500v direct current. The main research works are focused on structure design by finite element method, rat ing vol tape, temporary over vol tape and studies of character int ice of polymeric surge arrester .

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.41-47
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• 2006

This paper presents harmonic evaluation of an IAT(Intra Airport Transit) system in Incheon International Airport. It will be used for electric vehicles with 80[kW] per car produced by Mitsubishi Heavy Industries Ltd, and which is constructed with SIV(Static Inverter), VVVF controller and two induction motor. The vehicles operated in the IAT system can be treated as rapidly changing DC loat and at a feeding substation, 3-phase electric power is transferred to DC 750[V] by rectifier. Since vehicles are changing continuously, the voltages for the load fluctuate in the IAT system, and moreover, the voltage fluctuation generates high-order harmonics. It results the difficulty in maintaining power quality in KEPCO systems' side. The power quality of the IAT system in Incheon International Airport is evaluated using PSCAD/EMTDC simulator in the paper. The THD(Total Harmonic Distortion) of voltages and TDD(Total Demand Distortion) of currents, indices are calculated for the IAT system using the results of PSCAD/EMTDC dynamic simulation.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.930-939
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• 2009

A bimodal tram is being developed to combine the flexibility of a bus with the punctuality of a train. The propulsion system is a series hybrid type using a set of CNG engine generator and Li-polymer battery. This paper presents the experimental results of the series hybrid propulsion power unit using an active loader which can simulate powering and regenerative braking conditions of the propulsion equipments continuously. The power sharing scheme between PWM converter and a battery pack has been observed. The measurement results of DC link voltage and SOC(State Of Charge) of battery pack are presented.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.332-338
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• 2008

This paper handles, implementation of multiple access bidirectional serial communications protocol using two common DC power lines, whict are power supply and ground, connecting multiple devices. Communication between the host and the multiple clients are performed using unique packet data with device ID unique to each devices connected on the common power lines. Host initiates data communications by transmitting command packet to the designated client with the client's ID and the client responds by transmitting response packet to the host and in this way, multiple clients and host exchange the packet through the common power lines. The normal voltage of the power communication line maintains 24V corresponding to level 1 and the host drops the voltage to 12V on sending level 0 signal, also the clients normally keeps the line voltage to 24V use pull-down circuit to drop the voltage to 12V on sending level 1 signal. Power supply originates from the host, the host senses the voltage level of the power communication lines and when the clients activates pull down circuit to send level 0 signal and the voltage drops to 12V, the hosts switches power source from 24V to 12V. Also, when clients deactivate pull down circuit to send level 1 signal, the host senses the voltage increase and switches the power source from 12V to 24V. Experimental circuit is designed with one hosts and four clients and verified the power line voltage switching operation depending on the data signal levels on the power line. The proposed research result can be applied to two wire power communications system with one host and multiple low current consumption clients.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1214-1221
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• 2006

In this paper, development and performance characteristic of propulsion system(Converter/Inverter) using IPM(Intelligent Power Module) for 120km/h AC electric vehicle is proposed. The proposed propulsion system is comprised of IPM converter and inverter stack which uses natural air-cooling system, DC-Link, OVCRf unit and control unit. And also 2-Parallel operation of two PWM converter is adopted for increasing capacity of system and the VVVF inverter control is used a mixed control algorithm, where the vector control strategy at low speed region and slip-frequency control strategy at high speed region. The proposed propulsion system is verified by main line test results as well as combined test results.