• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1900-1902
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• 2000

In this paper, the temperature distribution and thermal stress analysis of mold transformer for power distribution system is investigated by FEM. Filler type epoxy is applied for good cooling effect in mold transformer.

• Bulletin of the Korean Mathematical Society
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• v.46 no.1
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• pp.107-116
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• 2009

We consider a single server multi-class queueing model with Poisson arrivals and relative priorities. For this queue, we derive a system of equations for the transform of the queue length distribution. Using this system of equations we find the moments of the queue length distribution as a solution of linear equations.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.44
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• pp.61-68
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• 1997

The algorithm of customer demand decomposition suggested by this study is a reconstruction method of distribution network under the allowance of same level supply. Regional distribution center(RDC) distributes additional inventories of some of the supplying items to retailers under its charge to reduce the time needed for emergency delivery to neighborhood retailer where backlog happened. This also restrict the purpose of the inventories held by RDC as only regular supply. All of which leads to the creation of more realistic method allowing the affiliation of closing related RDC with one in the vicinity. In this study, the role of RDC is restricted only as supplying items regularity and the conruction of distribution system processing through the closing by consideration of the possibility of supplying retailers from the RDC in the vicinity is discussed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.3
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• pp.22-28
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• 2000

In this paper PTW(Power Tools for Windows) application method for analysis the industrial distribution system is proposed. T&D(Transmission and Distribution) and BICC methods is applied for the cable impedance and the X/R of transformer data is estimated by IEEE standard. The effectiveness of this method was improved by the electrical characteristics analysis of the real industrial distribution system.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.151-153
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• 2006

This paper describes the transient phenomena considering transformer model in combined distribution systems with power cables. To evaluate the overvoltage, the change of transformer model and system structure are considered. Transformer parameters calculated by BCTRAN of EMTP are considered to evaluate surge generation in underground distribution systems when underground distribution system has various parameters. It is evaluated that overvoltage value increases and decreases according to the structure of system. However it is confirmed that there is not much effect to overvoltage as transformer is operated in distribution line.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.712-717
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• 1989

A communication system through distribution lines was developed for distribution automation. Since all facilities in distrbution systems are connected by distribution lines, economical communication systems can be realized by using these lines as data transmission lines. But it has a problem in transmission reliability bcause of its sensitivity to noise and impeadance. Therefore, to cope with this problem. measurement and analysis of the communication characteristics are made according to the influence of load impeadence change, signal level and noise generated in load. Field tests were carried out at Kyung Ki branch of the KEPCO for half year starting in Feburary 1988.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.31
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• pp.59-72
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• 1994

This paper deals with ordering policies of consumable goods which have large demand rates in a multi-level distribution system. The system we are concerned consists of one Central Distribution Center(CDC) and N non-identical Regional Distribution Centers(RDCs) which have different demand rates, minimum fillrates, leadtimes, etc. The customer demand on the RDC is stationary poisson and the RDCs demand on the CDC is superposition of Q-stage Erlang distributions. We approximate the RDCs and CDC demand distribution to nomal in order to enhance the efficiency of algorithm. The relevant costs include a fixed ordering cost and inventory holding cost, and backorder cost. The objective is to find a continuous-review ordering policy that minimizes the expected average costs under constraints of minimum fill rates of RDCs and maximum allowable mean delay of CDC. We developed an algorithm for determining the optimal ordering policies of the CDC and the RDCs. We verified and compared the performance of the algorithm through the simulation using the algorithm result as the input parameters.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.3
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• pp.119-124
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• 2018

Recently, LVDC distribution network and DC microgrid with many advantages are being built. However, this LVDC distribution is an IT grounded or ungrounded system, and it is difficult to detect a ground fault because the fault current is small. In this paper, we propose a signal injection method for unipolar LVDC distribution network to detect ground fault in ungrounded LVDC distribution, and various analyzes were performed for ground fault detection.

• The KIPS Transactions:PartA
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• v.12A no.5 s.95
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• pp.405-412
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• 2005

In the process of distributing blood many troubles are arising. In order to establish a drastic solution, the current distribution must be reviewed as well as its problems must be clearly grasped. This paper introduces RFID(Radio Frequency Identification) system to solve the problems, which arise in the process of distribution, and to systemically manage blood. Among various RFID systems, the reader and tag suitable to the blood distribution are designed. Likewise, through constructing a DB that can cognize electronic tags, objects and blood-distributing RFID system are designed.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.315-318
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• 2002

The use of high-temperature superconducting materials for transmission cable application is being realized in prototype situation. HTS cable systems have been installed in laboratories and tested successfully around the world. In korea. the first step in development of superconducting cables is distribution system. In this paper. it is proposed the HTS distribution system modeling using ATPDraw and EMTDC programs. In the multilayer conductor, the inner layers have higher impedance than the outer layers. As a result, the current concentrate$ in the outer layers. This paper presents the result of the current distribution in EMTDC.