• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1643-1645
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• 2005

A newly-built inverter has to undergo a series of stress tests in the final stage of production line. This can be achieved by connecting it to a dynamometer consisting of a three-phase machine joined by a rigid shaft to a DC load machine. The latter is controlled to create some specific load characteristic needed for the test. In this paper a test method is proposed, in which no mechanical equipment is needed. The suggested test stand consists only of a inverter to be tested and a simulator converter. Both devices are connected back- to-back on the AC-side via smoothing reactors. The simulator operates in real-time as an equivalent load circuit, so that the device under test will only notice the behaviour of a three-phase machine under consideration of the load. In odor to wove rightness of the suggested test method, the simulation and actural experiment rallied out emulation for a 2.2kW induction motor.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1601-1603
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• 2005

현재 국내에서의 견인전동기 개발현황은 직류전동기는 655kW, 교류전동기는 210kW정도이며, 주행속도가 200km/h이상인 고속에 적용되는 1,000 kW급 이상 유도전동기 기술은 한국형 고속전철이 국내에서는 최초이다. 최고 주행속도 300km/h급의 고속전철용 1,130kW 동기전동기에 대한 제작 및 시험기술만을 프랑스에서 이전 받아 유도전동기를 제작하였다. 고속철도 차량용 견인전동기는 한정된 공간에 취부되어야 함으로 경량화가 필수적이다. 또한 전력기기에 대한 에너지 고밀도화가 가능해야 함으로 열적 특성에 대한 분석이 체계적으로 이루어져야 한다. 본 연구를 통해 외기 온도, 주행 속도 및 운행 시간에 따른 견인전동기의 온도 특성변화를 살펴봄으로써 고속전철용 견인전동기의 고정자 온도 특성을 확인할 수 있었다.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.429-433
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• 2009

Since the "Low Carbon, Green Growth" as a social requirements is attracted public attention, the policies and investments of the railway which have been less estimated than road is re-considered. Since the starting the commercial service (2004. April), the KTX have been operated successfully while transport passengers over 100million for years. And also the project for development of KHST (Korea High Speed Train ; G7) had been accomplished with a good result, the first trainset of KTX-II which base on G7 project was manufactured and testing now. On the other hand, the world's technology of the high speed train is more faster, and changing to a distributed traction system. To catch up the world's leading technology, the HEMU(High-speed Electric Multiple Unit) project will secure new technology and aims to promote the technology of domestic high-speed train. The authors indicates the result of detail review such as a curve, slope of the track and electrical dead section of the catenary to test at 400kph and also the performance simulation of the developed rolling stock in this paper. As the result, the authors devise the test scenario to perform a maximum speed test (stability at max. speed, acceleration & deceleration etc) with the restricted conditions such as track length, track available time etc by considering above result.

• Design & Manufacturing
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• v.16 no.4
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• pp.40-45
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• 2022

The EV electric vehicle market is growing rapidly worldwide. An electric vehicle means a vehicle that uses energy charged through an electricity source as power. The precision of the press is important to mass-produce the drive motor, which is a key component of the electric vehicle. The size of the driving motor is increasing, and The size of the mold is also growing. In this study, the precision of large high-speed presses for mass production of driving motors was measured. A study was conducted on the measurement method of press and the analysis of measurement data. A drive motor is a component that transmits power by converting electrical energy into kinetic energy. EV driven motors have key material properties to improve efficiency. The material properties are the thickness of the material. As a method for improving performance, use a 0.2mm thin steel sheet. Mold is also becoming larger. As the mold grows, the size of the high-speed press for mass production of the driving motor is also increasing. Also, the precision of the press is the most important because it uses a thin iron plate material. So the importance of large press precision is being emphasized. In this study, the effect of large high-speed press structure on precision was verified

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2169-2173
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• 2003

The development project of Korean High Speed Train (KHST) was started in 1996. As a national research project, the KHST project aims for a development of the next generation prototype train that has a maximum speed of 350 km/h. The development process of prototype KHST including 7 vehicles was completed last year and currently the prototype train is on its way of test running over the test track with gradually increased speed. The prototype KHST uses the real time network called TCN (Train Communication Network) for exchanging information between various onboard control equipments. After 10 years of development and modification period, TCN was confirmed as international standard (IEC61375-1) for the electrical railway equipment train bus. In the prototype KHST, all major control devices are connected by TCN and exchange their information. Such devices include SCU (Supervisory Control Unit), ATC (Automatic Train Control), TCU (Traction Control Unit), and so forth. For each device that sends and receives data using TCN, a device has to find out whether TCN is in normal or failure state before its data exchange. And also a device must have a proper method of data validation that was received in a normal TCN state. This is a one of the major important factors for devices using network. Some misleading information can lead the entire system to a catastrophic condition. This paper briefly explains how TCN was implemented in the prototype KHST train, and also shows what kind of the fault diagnosis method was adopted for a fail safe operation of TCN system

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.5
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• pp.83-89
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• 2002

The purpose of this paper is to assess experimentally system stability of the 154［㎸］transmission system due to the current of the forthcoming AC High-Speed Railway (HSR) era. It introduces a simple method to evaluate the system stability. The proposed method also shows the relationship between stability and power losses, and the stability indices made by the numerical process proposed in this paper will be used to assess whether a system can be stabilized or not. This paper also presents the improvement of the stability via loss reduction using a shunt compensator. Reactive power compensation is often the most effective way to improve both power transfer capability and system stability. The suitable modeling of the traction power system should be applicable to the PSS/E. The proposed method is tested on a practical system which will be expected to accommodate the heavy HSR load.

• The Journal of Korean Medicine
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• v.39 no.3
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• pp.51-60
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• 2018

Objectives: This study aimed to investigate the opinions of Korean medical doctors on how to elucidate possible remedial measures for expanding the health insurance benefits coverage item of Korean medicine (KM). Methods: An online survey was conducted to all members who had registered e-mail address in the association of Korean medicine from 1 to 17 November, 2016. Statistical analysis was performed and odds ratio with 95% confidence interval were calculated by each subgroup. Results: A total of 743 members answered the questions and the response rate was 4.1%. The priorities for expanding health insurance benefits were as follows: thermographic imaging, Sasang constitution typing test, and pulse wave among examinations; pharamacopuncture, embedding acupuncture, and acupotomy among procedures; Chuna manual therapy, manual therapy for meridian muscle, and Daoyin exercise therapy among manual therapies; low-frequency electrical therapy, traction, paraffin bath, and light therapy among physical therapies; and aromatherapy, enema therapy, and color therapy among activities of KM. Conclusions: It should be covered by the national health insurance (NHI) of KM that thermographic imaging, pharmacoacupuncture, Chuna manual therapy, low-frequency electrical therapy, aromatherapy as a top priority. We also suggest that basic medical tests, such as blood, urine, or imaging, should be included in the coverage of the NHI of KM. It is necessary to review the expertise and public opinions about the plans and priorities for the conversion of the desired medical services to be covered by the NHI.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.9
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• pp.1343-1347
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• 2013

This paper presents an analysis methods for current collection quality in catenary system by means of video image based monitoring system. Arcing is the sparking at the interface point between pantograph and contact wire when the electric trains have traction current values at speed. Percentage of arcing at maximum line speed is measurable parameters for compliance with the requirements on dynamic behaviour of the interface between pantograph and contact wire in accordance with requirement of IEC and EN standards. The arc detector and video is installed on a train aim at the trailing contact strip according to the travel direction. The arc detector presented and measured verity of value such as the duration and power density of each arc and the video image is measured a image when the arc is occurred in pantograph. In this paper we analysis of video image in accordance with power density of arcing from arc detector and compared with video image and power density of arcing so as to produce quality of arcing from image.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.6
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• pp.160-168
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• 2010

This paper presents the analysis of the current as stray current and supplied current of the substation, on the DC railway power system. In DC railway power supply system, the running rails are usually used as the return conductor(negative-polarity) for traction load current. This condition mainly focuses on economic considerations, since it does not require the installation of an additional return conductor. But, problems of low resistance between the running rails for the return conductor and earth allows a significant part of the return load current to leak into the earth. This current is normally called to as leakage or stary current. This stary currents creates serious problems for any electrified matter in the underground. Therefore, reduction of stray current of the DC railway power supply system is also of direct benefit to the operational and safety aspects of the DC railway systems. In this paper, deal with the analysis of the current distribution on the DC railway power system applied the common grounding system, using SPLIT of CDEGS program.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1482-1504
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• 2007

An electrical railway system uses high voltage system for train traction and low voltage system for train control. Railway systems are broadly distributed across mountains, sea sides and cities. Electrical accidents provoke the death and injury of a human being and the damage of the equipment by the overcurrent due to the catenary dropping and by the overvoltage due to lightning. Grounding systems are adopted for the protections of the system from the overcurrent and the overvoltage. Isolation grounding for each system can be easily installed. However, the closed circuits between grounding systems can be occurred. The currents flow through the closed circuits cause the abnormal operation of the system. To overcome the problem of the isolation grounding, the equipotential bonding is usually adopted. The equipotential bonding should have very small grounding resistance. In this paper, we showed the transition from the isolation grounding system to the common grounding system and presented the comparison and the analysis of two grounding systems by simulation. In addition, we proposed the direction for a new grounding system of electric railway.