• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.625-628
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• 1996

Recent power converting system for an electric train has characteristics of a complex electromechanical system, which includes VVVF inverter, bidirectional converter, ac motor and controller and etc. So in order to analysis its dynamic characteristics reliably, a powerful and flexible simulation technique is needed. Concerned with this respect, because the Simulink has a veriety of powerful functions and analysis tools not available in conventional power electronics simulation packages, it can be effectively applied to the simulation of the power converting system. In this paper, a schematically similar model for an electric train power converting system is derived on the Simulink Window, based on the Dynamic Node Technique, and several simulations have been implemented with the model. With the simulation results, the characteristics of the power converting system and the easeness of the proposed Simulink-based simulation technique could be verified clearly.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.5
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• pp.877-884
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• 2017

A method of common earth, which is proposed by French Railway(SNCF) and is applied to high speed railway, minimizes the effect of the traction return current from tracks so that trackside electric devices can be protected and operation and maintenance staffs are kept out from injury in an electric railway environment. According to it, all the new domestic electric railway lines are replaced from existing individual earth method to the common earth method. In this paper, we analyze the correlation between common earth method and traction return current to prove whether the common earth has surely contributed to minimize the effect of the traction return current. The analysis was done based on the measurement of the traction return current at the domestic high speed railway line.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1370-1376
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• 2015

Generally, an autotransformer(AT) feeding system consists of double tracks, up and down, with the trolley wire and feeder wire of the up and down tracks connected in the sectioning post(SP). Consequently, load current or fault current flows on two tracks based on catenary impedance characteristics, making it difficult to estimate catenary impedance accurately. This paper presents a technique for the estimation of catenary impedance using boosting current compensation based on the current division characteristics of an AT feeding system to improve the operation performance of impedance relay. To verify the technique, we model an AT feeding system through a power analysis program (PSCAD/EMTDC) and simulate various operation and fault conditions. Through the simulation, we confirmed that the proposed technique has estimated catenary impedance with a similar degree of accuracy to the actual catenary impedance

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.1-7
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• 2007

Generally, an electric railroad feeding system has many problems due to the different characteristics in contrast with a load of general three-phase AC electric power system. One of them is harmonics problem caused by the switching device existing in the feeding system, and moreover, the time-varying dynamic loads of rail way is inherently another cause to increase this harmonics problem. In Korea power systems, the electric railroad feeding system is directly supplied from the substation of KEPCO. Therefore, if voltages fluctuation or unbalanced voltages are created by the voltage and current distortion or voltage drop during operation, it affects directly the source of supply. The trainloads of electric railway system have non-periodic but iterative harmonic characteristics as operating condition, because the electric characteristic of the electric railroad feeding system is changed by physical conditions of the each trainload. According to the traditional study, the estimation of harmonics has been performed by deterministic way using the steady state data at the specific time. This method is easy to analyze harmonics, but it has limits in some cases which needs an assessment of dynamic load and reliability. Therefore, this paper proposes the probabilistic estimation method, moments matching method(MW) in order to overcome the drawback of deterministic method. In this paper, distributions for each harmonics are convolved to obtain the moments and cumulants of TDD(Total Demand Distortion), and this can be generalized for any number of trains. For the case study, the electric railway system of LAT(Intra Airport Transit) in Incheon International Airport is modeled using PSCAD/EMTDC dynamic simulator. The raw data of harmonics for the moments matching method is acquired from simulation of the LAT model.

• Journal of the Korean Society for Railway
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• v.19 no.3
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• pp.314-323
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• 2016

Overhead line voltage of DC railway traction substations has rising or falling characteristics depending on the acceleration and regenerative braking of the subway train loads. The suppression of this irregular fluctuation of the line voltage gives rise to improved energy efficiency of both the railway substation and the trains. This paper presents parameter estimation schemes using the RC circuit model for an overhead line voltage at a 1500V DC electric railway traction substation. A linear artificial neural network with a back-propagation learning algorithm was trained using the measurement data for an overhead line voltage and four feeder currents. The least square estimation method was configured to implement batch processing of these measurement data. These estimation results have been presented and performance analysis has been achieved through raw data simulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.9
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• pp.1391-1397
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• 2015

Recently, various researches are conducted in the application of regenerative energy produced during the operation of an electric locomotive. Regenerative energy is produced by a generator in the brake procedure. The generator is operated by kinetic energy of an electric railroad using an electric motor. The process of producing regenerative energy varies with the current type of a railroad and its running condition. The quality of electric power can be improved and electric energy can be utilized effectively, especially in the use of an energy storage system (ESS). Thus, it is necessary to apply ESS into AC section and high speed railway. This study analyses the composition of the regenerative ESS equipment installed in Yong-Jeong sectioning post, operational principle, charge and discharge algorithm and energy efficiency. The analysis shows that CO2 emissions can be reduced about 0.5 ton per a day. In addition, ESS helps saving the energy and the compensation of the voltage drop caused by the operation of high speed train when it is installed at the end of the feeder section. The number of high speed train will be increased continuously related to the electrification rate. Therefore, applying the ESS to high speed railway is expected to solve the instability of the feeder voltage and the equipment capacity problem caused by the high speed trains.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1776-1781
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• 2015

Electric power trains receive electric power from overhead cables via a pantograph system. Power collector system in trains increase the cross section of tunnel and require a massive coreless filter reactor in propulsion inverter because of the power disturbance by contact loss phenomenon of a train. In this paper we proposed a wireless train which can run to next station with charging energy of ultra-capacitor module block. We designed DC-DC converter to charge and discharge ultra-capacitor modules by using Next Train running test results and confirm the feasibility of the proposed system through simulation.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.451-458
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• 2017

An Electric Vehicle (EV) is operated with the electric energy of a battery in place of conventional fossil fuels. Thus, a suitable charging infrastructure must be provided to expand the use of electric vehicles. Because the battery of an EV must be charged to operate the EV, expanding the number of EVs will have a significant influence on the power supply and demand. Therefore, to maintain the balance of power supply and demand, it is important to be able to predict the numbers of charging EVs and monitor the events that occur in the distribution system. In this paper, we predict the hourly charging rate of electric vehicles using transformation matrix, which can describe all behaviors such as resting, charging, and driving of the EVs. Simulation with transformation matrix in a specific region provides statistical results using the Monte-Carlo Method.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.901-902
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• 2006

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.275-277
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• 2001

열차제어시스템의 소프트웨어는 높은 신뢰성과 안전성이 요구된다. 이를 위해 철도에서는 고장회피(Fault Avoidance) 기법과 고장허용(Fault Tolerance)기법을 사용하고 있다. 그러나 최근 신호설비의 소프트웨어 신뢰성을 좀더 향상시키기 위해 일본, 프랑스, 스웨덴 등에서는 안전에 치명적인 시스템에 사용되고 있는 정형기법(Forma) Method)을 포함하여 많은 연구를 수행중이다. 본고에서는 국외 관련분야를 분석하고, 열차제어시스템 소프트웨어의 신뢰성 향상에 관하여 기술하고자 한다.