• Journal of Power Electronics
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• v.15 no.6
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• pp.1628-1639
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• 2015

Line-interactive uninterruptible power supply (UPS) systems are good candidates for providing energy storage within a microgrid. In this paper, a control scheme for a line-interactive UPS system applied in a low-voltage microgrid is presented. It is based on the Q-w and P-E droop control to achieve a seamless transition between grid-connected and stand-alone operation modes. Moreover, a new model for designing the controllers is built in the dq-frame based on the instantaneous power definition. The new-built model takes into account the dynamic performance of the output impedance of the inverter in the dq-frame and can be evaluated in the time domain. Compared to the traditional model based on the instantaneous power definition, the new-built model is more accurate to describe the dynamic performance of the system. Simulation and experimental results obtained with a microgrid consisting of two 40-kW line-interactive UPS systems are given to validate the control strategy of the line-active UPS system and the accuracy of the new-built model.

• 전기의세계
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• v.18 no.1
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• pp.24-29
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• 1969

This is preliminary study concerning the future construction and operation of 345KV power transmission line in Korea which will be added to the existing 161KV power system by the end of 1970 in order to increase the power carrying capacity between Seoul and Pusan area; 350 kilo meters aparts, in accordance with the ambitious second five years power development schedule of Korea Electric Company. The result of this study says that an intermidiate switching station should be installed at the middle position of the line to improve the transient stability of the system, considerable amount of capacitors or synchronous condenser are to be installed to reduce the voltage drop at receving end of line during the heavy load hours, and also in some measure to avoid the voltage rise by self-excitation of power generators during the light load hours and while energizing the line. This is the first attempt to realize the EHV power transmission line in Korea so that the additional study is necessary on the kind and size of conductors, the necessary number of insulators and the suitable clearance distances between conductor and steel tower or earth from the technical and economical view points. These are necessary steps to be taken by the writer before getting into the calculation on the transient stablity of the power system.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.499-503
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• 2009

In this study, the dynamic characteristic of a contact wire and pantograph suppling electrical power to high-speed trains are investigated from an electrical response point of view. To analysis power line disturbance by induced contact loss phenomenon for high speed operation, a hardware Simulator which considered contact loss between contact wire and the pantograph as well as contact wire deviation is developed. It is confirmed that a contact wire and pantograph model are necessary for studying the dynamic behavior of the pantograph system. One of the most important needs accompanied by increasing the speed of high-speed train is reduced that an arc phenomenon by loss of contact brings out EMI. In case of a high-speed train using electrical power, as comparison with diesel rolling stock, PLD(Power Line Disturbance) such as harmonic, transient voltage and current, EMI, dummy signal injection etc usually occurs. Throughout experiment, it is verified that an arc phenomenon is brought out for simulator operation and consequently conducted noise is flowed in electric circuit by power line disturbance.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.149-156
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• 2003

Recently, the importance of plant maintenance(PM) was highly raised to provide efficient plant operation which highly affects the productivity. For this reason, a number of engineering methodologies, such as riskbased inspection(RBI), fitness for service guidelines(FFS), plant lifecycle management(PLM), have been applied to improve the plant operation efficiency. Also, a network-based business operation system, which is called ERP(Enterprise Resource Planning), has been introduced in the field of plant maintenance. However, there was no attempt to connect engineering methodologies to the ERP PM system. In this paper, a knowledge-based information system for the plant operation of steel making company has been proposed. This system, which is named as K-VRS(Knowledge-based Virtual Reality System), provides a connection between ERP plant maintenance module and knowledge-based engineering methodologies, and thus, enables network-based highly effective plant maintenance process. The developed system is expected to play a great role for more efficient and safer plant maintenance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.11
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• pp.1933-1940
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• 2003

Recently, the importance of plant maintenance(PM) was highly raised to provide efficient plant operation which highly affects the productivity. For this reason, a number of engineering methodologies, such as risk-based inspection(RBI), fitness for service guidelines(FFS), plant lifecycle management(PLM), have been applied to improve the plant operation efficiency. Also, a network-based business operation system, which is called ERP(Enterprise Resource Planning), has been introduced in the field of plant maintenance. However, there was no attempt to connect engineering methodologies to the ERP PM system. In this paper, a knowledge-based information system for the plant operation of steel making company has been proposed. This system which is named as K-VRS(Knowledge-based Virtual Reality System), provides a connection between ERP plant maintenance module and knowledge-based engineering methodologies, and thus, enables network-based highly effective plant maintenance process. The developed system is expected to play a great role for more efficient and safer plant maintenance.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.162-167
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• 2004

The ascent and descent market screen door (PSD-Platform Screen Door) between the electromotive car which is in the process of operating from the subway ascent and descent market and the passenger it is an immediacy and crisis as the system which it intercepts currently the inside and outside of the country of course signal system automatic operation signal system (ATO) establishment is operated from the segment. Manual operation signal system (the ATS and the ATC) almost it is a condition which is wholly lacking from the segment. This year from second half of the year 2 line manual operation signal system (ATS). It established the shutting tightly elder brother and the railing elder brother in PSD system in segment 12 reverses and the death accident due to the passenger hurt accident which occurs from the subway. It prevented an energy curtailment in the same time when it raises air cooling efficiency, It gathered it restricted the underground space which is comfortable in the use citizen and and and service it did interface the electromotive car and PSD entrance and exit literature course from the manual operation segment to sleep technically optimizationt. It researched a minute dust diffusion.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.136-141
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• 2009

The platform screen door(PSD) is installed in the station of the Seoul Metro 9th line for passengers' safety and comfortable environment of the station. The track way exhaust system(TES) is also operated with PSD to exhaust heat released from train. TES can also be used for the purpose of the heat and smoke control in an emergency case of the carriage fire. When the fire is occurred, operation of TES is switched to the smoke exhaust mode form its normal ventilation mode. In the present study, a subway station of Seoul Metro 9th line is modeled, and a 3-D CFD simulation is performed to investigate effectiveness of designed TES in case of fire. A scenario that a train under fire is arriving the station is simulated for several possible operation modes of the TES using moving mesh technique. As a result, temperature and CO concentration distribution in the station is obtained for each operation modes of TES. The effectiveness of TES operation in case of fire is also discussed.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.877-882
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• 2005

The definition of multi-coupled operation is that coupled two trainsets is able to be operated one trainset identically. That is to say, the one driver, coupled two trainsets can operate the traction and braking system, control vehicle doors, phanto-graph, HVAC and passenger room lighting system etc, such as one trainset controlling. This study will provide high speed train design engineer with introducing multi-coupled operation system electrically and presentation automatic complex coupler mechanism, and then this paper will be applied to design next generation high speed train system such as Jun-la/Ho-nam line

• Proceedings of the KSR Conference
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• 2006.11a
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• pp.199-207
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• 2006

Because of many advantages of Maglev(magnetic levitation) trains, the study of Maglev technology has been accelerated rapidly throughout the world. As a results of that, German commercialized the super-speed magnetic train in Shanghai at the world-wide beginning. Japan started the first commercial service for the low speed Maglev train system in Nagoya in the world. For the commercial service of Maglev trains, signal system must be installed on the operation line and be controlled by operation control center In this paper, Maglev train operation systems of the inside and outside of the country are investigated and what is supplied for domestic Maglev train system is investigated.

• Journal of the Korean Society for Railway
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• v.6 no.3
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• pp.156-162
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• 2003

Due to almost all tracks of new Kyoungbu high-speed lines(HSL) consisting of bridges and tunnels, HSR operational safety management is very important factor for passenger safety and preventing catastrophic event. Especially, it is important to approach the scene of the accident and assist in saving lives as soon as possible under emergency conditions. Therefore it is essential to prepare access methods and available resources in advance in order to support emergency correspodances promptly and effectively. This paper persents an application of geographical information system(GIS) for developing emergency management system as well as batabase system on tracks and facilities, electric/communication equipment and safety equipment required to support emergencies. The on-site information on the proximity of HSL is expressed on the numerical map, which can be helpful to call external supports such as medical service, local authorities, police offices, fire brigades, and etc. for the emergency situations.