• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.3
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• pp.62-68
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• 2007

The increasing use of power electronic equipment in distribution system has been the reason for the greater concern about a harmonic in recent time. Therefore, it is necessary for measurement and modelling to analyze a harmonic level and a transfer characteristic in distribution system. In this paper, the Point of Common Coupling (PCC) is selected to analyze harmonic characteristic of distribution system by IEC 61000-3-6. Harmonic voltage and orient were measured at the PCC of real distribution system Harmonic distribution, nonlinear load component and Total Harmonic Distortion(THD) were verified. The effective and accurate modelling of real distribution system were proved through a analysis of harmonic impedance, voltage and current under steady-state. Harmonic transfer characteristic were investigated through a analysis of harmonic voltage and current under harmonic current source.

• Journal of IKEEE
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• v.24 no.2
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• pp.385-391
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• 2020

Overcurrent and abnormal voltages in the distribution system can cause not only burden of power plant but also damage to customers. As a result, researches related to the distribution automation have been widely conducted by utilizing a real time digital simulation to improve the reliability of power supply through rapid failure handing, reduction of power failure intervals and failure recovery. However, the distribution automation systems using the real time digital simulator are expensive and limited to verify actual hardwares. Therefore, in this paper, an external hardware devices was developed based on the distribution system analysis results of the digital simulator. And real-time simulation and functional verification are implemented by the real feeder remote terminal units used in distribution automation. The effectiveness of the proposed system is verified through several experiments.

• Solar Energy
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• v.7 no.2
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• pp.37-53
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• 1987

This study has been prepared for the purpose of developing the system performance prediction method of natural circulation solar hot water system. The storage tank of the natural circulation solar hot water system equipped with flat-plate solar collector is located at higher elevation than the solar collectors. Therefor, the storage tank temperature distribution formed accordance with configuration of storage tank by flow rate of circulating fluid affect system collection efficiency. In this study measure the storage tank temperature distribution with various experimental system under real sun condition and present the theoretical prediction method of the storage tank temperature. Moreover measure the flow rate not only day-time but also night-time reverse flow rate with die injection visual flow meter. Main conclusion obtain from the present study is as follows; 1) The storage tank temperature distribution above the connecting pipe connection position is the same as that of the fully mixed tank and below the connection position is the same as that of stratified tank. 2) The system performance sensitive to the storage tank temperature distribution. Therefore detailed tank model is necessary. Average storage tank temperature can be calculate 3% and storage tank temperature profile can get less than 10% difference with this model system.

• Journal of Power System Engineering
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• v.14 no.1
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• pp.16-21
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• 2010

This research focused on the spray and distribution characteristics of urea solution by applying flow visualization techniques and did durability and driver test on injectors as well. The spray characteristics of urea solution was observed by CCD camera. Also, the distribution characteristics of urea solution was evaluated quantitatively as well by using 3D laser scanner equipment. It was considered that it was reasonable to use the injector for gasoline engine in order to inject the urea. The best distribution chart result was observed near 45cm distance difference between catalyst and urea spray injector. As a result of trapped urea distribution chart analysis, optimal pressure and volumetric flow rates of air and urea were derived in order to improve the distribution of Urea. This information may contribute to provide fundamental data in the future.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.285-288
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• 2001

In this paper we proposed the on line volt/var control schemes of the load Tap Changer (LTC) transformer and shunt capacitor bank for distribution volt/var regulation. In the existing volt/var control of the distribution substation, the voltage of feeders and var of distribution systems is mainly controlled by the LTC transformer tap position and on/off status of the shunt capacitor. The LTC and shunt capacitor bank has discrete operation characteristics and therefore it is very difficult to control volt/var at the distribution networks within the satisfactory levels. Also there is limitation of the operation times of the LTC and shunt capacitor bank because it is affects on their functional lifetime. The proposed volt/var control algorithm determine an optimal tap position of LTC and on/off status of shunt capacitors at a distribution network with the multiple feeders. The mathematical equations of the proposed method are introduced. Simple case study was performed to verify the effectiveness of the proposed method.

• Journal of Electrical Engineering and Technology
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• v.9 no.4
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• pp.1240-1247
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• 2014

The applications of Distributed Generation (DG) in a smart distribution grid environment are widely employed especially for power balancing and supporting demand responses. Using these applications can have both positive and negative impacts on the distribution system. The sizing and location of their installations are the issues that should be taken into consideration to gain the maximum benefit from them when considering the economic aspects. This paper presents an application of the Bat Algorithm (BA) for the optimal sizing and siting of DG in a smart distribution power system in order to maximize the Benefit to Cost Ratio (BCR), subjected to system constraints including real and reactive power generation, line and transformer loading, voltage profile, energy losses, fault level as well as DG operating limits. To demonstrate the effectiveness of the proposed methodology and the impact of considering economic issues on DG placement, a simplify 9-bus radial distribution system of the Provincial Electricity Authority of Thailand (PEA) is selected for the computer simulation to explore the benefit of the optimal DG placement and the performance of the proposed approach.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.4
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• pp.428-433
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• 2010

According as economy grows, demand for power increases and satisfaction of customer about electricity quality is rising. There is in trend that investment expense by continuously increased supply of electric power equipment is on the increase continuously, but management efficiency improvement through curtailment of supply of electric power equipment investment expense through efficient operation is required rather than to increase investment. In this study, reconsidered about 6 divisions 3 ties that is distribution line basis configuration of Daejeon Geumsan area and analyzed division and tie present condition of truthful distribution System. Examined problem analyzing average division number, tie number and tie switch number, searched about most suitable division that consider load. Hereafter, I wish to take advantage of analysis result in most suitable division and tie of truthful distribution system for power failure section reduction and investment expense curtailment.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.60
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• pp.11-22
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• 2000

The main objective of this research is to analyze an order point and an order quantity of a distribution center and each branch to attain a target service level in multi-level inventory distribution system. In case of product item, we use the item with low volume of average monthly demand. Under the continuous review method, the distribution center places a particular order quantity to an outside supplier whenever the level of inventory reaches an order point, and receives the order quantity after elapsing a certain lead time. Also, each branch places an order quantity to the distribution center whenever the level of inventory reaches an order point, and receives the quantity after elapsing a particular lead time. When an out of stock condition occurs, we assume that the item is backordered. For considering more realistic situations, we use generic type of probability distribution of lead times. In the variable lead time model, the actually achieved service level is estimated as the expected service level. Therefore, this study focuses on the analysis of deciding the optimal order point and order quantity to achieve a target service level at each depot as a expected service level, while the system-wide inventory level is minimized. In addition, we analyze the order level as a maximum level of inventory to suggest more efficient way to develop the low demand item model.

• Journal of Distribution Science
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• v.18 no.12
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• pp.45-54
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• 2020

Purpose: Indonesia's maritime logistics and distribution system is currently faced with several challenges, some of which include prolonged export and import time for goods handling as well as the high logistics cost. This study further analyzes the existing business processes in maritime logistics in East Java Province in order to provide solutions to the challenges. Research design, data and methodology: This research was carried out in East Java Province, Indonesia, with data collected through field observations, documentation, and in-depth interviews with all the stakeholders involved. Results: The study showed that the number of stakeholders and activities involved in the flow of goods movement ultimately impacted the length of time. These factors can be classified into the following five: 1) export and import regulations, 2) third party logistics competencies, 3) transportation infrastructure and facilities, 4) adoption of information systems and technology, and 5) maritime line connectivity. Conclusion: Analyzing the three supply chain flows in the maritime logistics and distribution industry called for the need for improvement to increase coordination among related institutions, improve the flexibility of dwelling time to the conditions of each port, enhance service levels, improve transportation infrastructure and facilities, implement information system and technology, and develop shipping routes and networks. Therefore, a collaborative supply chain management system can be realized.

• Journal of applied mathematics & informatics
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• v.5 no.2
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• pp.277-284
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• 1998

The reliability and an estimate for it are derived for series-parallel and parallel-deries stress-strength model under assumption that all components are subjected to a common stress. We also obtain the asymptotic normal distribution of the estimate.