• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.3
• /
• pp.443-450
• /
• 2007

We overview the current distribution automation system in Korea and point out the limitations of the distribution services which can be provided by the current system. In this paper we propose a new distribution system architecture which is based on the peer-to-peer communication model. In this decentralized architecture the intelligent FRTUS can initiate data transmission without any interruption of a central server, and can exchange data with other FRTUS as peers. In order to support the peer-based distribution system, we specify the requirements for new communication network and suggest a way of improving the current distribution network where we adapt an intelligent module for protection and restoration, called MASX, and utilize the open communication network protocols. We also show how the new architecture can enhance major distribution services such as protection, automatic restoration, and equipment management.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.7
• /
• pp.1060-1067
• /
• 2006

This study was undertaken to determine the effect of reservoirs on water quality and the distribution of pathogenic and indicator bacteria in a drinking water distribution system (total length 14km). Raw water, disinfected water, and water samples from the distribution system were subjected to physicochemical and microbiological analyses. Most factors encountered at each season included residual chloride, nitrate, turbidity, and phosphorus for heterotrophic bacterial distribution, and hardness, heterotrophic bacteria, sampling site, and DOC (dissolved organic carbon) for bacteria on selective media. No Salmonella or Shigella spp. were detected, but many colonies of opportunistic pathogens were found. Comparing tap water samples taken at similar distances from the water treatment plant, samples that had passed through a reservoir had a higher concentration of heterotrophic bacteria, and a higher rate of colony formation with 10 times as many bacteria on selective media. Based on the results with m-Endo agar, the water in reservoirs appeared safe; however, coliforms and opportunistic pathogenic bacteria such as Pseudomonas aeruginosa were identified on other selective media. This study illustrates that storage reservoirs in the drinking water distribution system have low microbiological water quality by opportunistic pathogens, and therefore, water quality must be controlled.

• Journal of Korean Society of Water and Wastewater
• /
• v.22 no.6
• /
• pp.609-617
• /
• 2008

Water pipes are supposed to deliver the predetermined demand safely to a certain point in water distribution system. However, pipe burst or crack can be happened due to so many reasons such as the water hammer, natural pipe ageing, external impact force, soil condition, and various environments of pipe installation. In the present study, the reliability model which can calculate the probability of pipe breakage was developed regarding unsteady effect such as water hammer. For the reliability model, reliability function was formulated by Barlow formula. AFDA method was applied to calculate the probability of pipe breakage. It was found that the statistical distribution for internal pressure among the random variables of reliability function has a good agreement with the Gumbel distribution after unsteady analysis was performed. Using the present model, the probability of pipe breakage was quantitatively calculated according to random variables such as the pipe diameter, thickness, allowable stress, and internal pressure. Furthermore, it was found that unsteady effect significantly increases the probability of pipe breakage. If this reliability model is used for the design of water distribution system, safe and economical design can be accomplished. And it also can be effectively used for the management and maintenance of water distribution system.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.5
• /
• pp.898-904
• /
• 2009

The objective of the present study lies in constructing web-based GIS system providing broad range of information applicable for power/telecommunications distribution facilities through cable. Nowadays, Korea is renowned forits faste sttele communications network across the nation enjoyable for being a test-runbed by worldwide contents providers. It is not too much to say that the trend is caused by the fact that Korea utilizes the cobweb-like power transmission cables applicable for the nationwide telecommunications networking. In particular, the trend has been all the more encouraged by the governmental drive to expedite the telecommunication network by way of the established power transmission facilities deemed as publicutility. Nevertheless, few can deny that the overexcessive competition among telecommunication service providers increasingly gives rise to unauthorized, arbitrary facilitation of distribution devices, which becomes much burden in operating the normal power/telecommunications distribution facilities by a power-generating company. In this regard, the study, to cope with such problems, attempts to develop a web GIS-based information management system compatible with NDIS(New Distribution Information System), a distribution facility management system now under operation by KEPCO, making advantage of GE Energy's SIAS(Smallworld Internet Application) technology. The model provided by this study is expected to get closer into effective operation of distribution facilities along with better sharing of information among conventional telecommunications operators, while getting rid of infringed facilitation cases

• Proceedings of the Korea Information Processing Society Conference
• /
• 2003.11c
• /
• pp.2021-2024
• /
• 2003

Information security is becoming a more important factor in distribution of digital contents. Generally, illegal facsimile of high-quality multimedia products such as DVDs, MP3s and AACs is possible without damaging quality. Thus, the illegal distribution of duplicated contents on the Web is causing digital content providers great economic loss. Therefore, a study of security and efficient distribution of digital contents is required. The most important issues in the design of a digital content distribution system are user convenience, execution speed and security. In this study, we designed a digital contents distribution system that uses web caching technology and encryption/decryption techniques in hierarchical structures. We propose a digital content distribution system that improves user convenience, security and execution speed. The superior performance of the proposed system has been proven in the tests. The results of experiment show that the developed system has improved the security of DC without decreasing process speed.

• Nuclear Engineering and Technology
• /
• v.50 no.7
• /
• pp.1079-1087
• /
• 2018

There are many parameters that affect the natural circulation flow, such as height difference, heating power size, pipe diameter, system pressure and inlet temperature and so on. In general analysis the heating power is often regarded as a uniform distribution. The ANSYS-CFX numerical analysis software was used to analyze the flow heat transfer of supercritical water under different heating power distribution conditions. The distribution types of uniform, power increasing, power decreasing and sine function are investigated. Through the analysis, it can be concluded that different power distribution has a great influence on the flow of natural circulation if the total power of heating is constant. It was found that the peak flow of supercritical water natural circulation is maximal when the distribution of heating power is monotonically decreasing, minimal when it is monotonically increasing, and moderate at uniform or the sine type of heating. The simulation results further reveal the supercritical water under different heat transfer conditions on its flow characteristics. It can provide certain theory reference and system design for passive residual heat removal system about supercritical water.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.1
• /
• pp.102-108
• /
• 2015

This paper proposes a new fault isolation methodology for a smart protective device which plays an agent role on the smart grid distribution system with the distributed generation. It, by itself, determines accurately whether its protection zone is fault or not, identifies the fault zone and separates the fault zone through the exchange of fault information such as the current information and the voltage information with other protective devices using bi-directional communication capabilities on the smart grid distribution system. The heuristic rules are obtained from the structure and electrical characteristics determined according to the location of the fault and DG (Distributed Generation) when faults such as single-phase ground fault, phase-to-phase short fault and three-phase short fault occur on the smart grid distribution system with DG.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.9
• /
• pp.81-86
• /
• 2007

Electric utility companies have the responsibility of providing good electricity for their customers. They have introduced the DAS(Distribution Automation System) to automate the power distribution networks. DAS engineers require state-of-the-art applications, such as a way to actively manage the distribution system and gain economic benefits from a flexible DAS architectural design. The existing DAS is not capable of handling these needs. It requires operator intervention whenever feeder overloading is detected while operator error could cause the feeder overload area to be extended. It also utilizes a closed architecture and it is therefore difficult to meet the system migration and future enhancement requirements. This paper represents a web based, platform-independent, flexible DAS architectural design and active database application. Recent advanced Internet technologies are fully utilized in this new DAS architecture allowing it to meet the system migration and future enhancement requirements. By using an active database, the DAS can minimize the feeder overloading area in the distribution system without operator intervention, thereby minimizing mistakes due to operator error.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.8_9
• /
• 2009

This paper shows us the analysis of the Recloser-Fuse coordination in power distribution system. Recloser has been installed with fuse to coordinate in power distribution system to protect against fault current efficiently. However, in power distribution system with SFCL, fault current couldn't be clear if occurred it as the operation of the Recloser-Fuse coordination couldn't be done. Therefore, this paper analysed the operation of the Recloser-Fuse coordination and found the method of the Recloser-Fuse coordination in power distribution system with SFCL using PSCAD/EMTDC.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.1
• /
• pp.35-40
• /
• 2007

The one step type and two step type pole are used in distribution line. If the three phases are not balanced, the communication line can be damaged by induced voltage. This paper calculates the neutral current using KEPCO's distribution system model which is only composed by one step type pole. The used system model is modelled by using ATPDraw and the neutral current is calculated by using EMTP/MODELS. Many cases for abstracting the neutral current characteristics in KEPCO's distribution system are simulated and analyzed.