• Title/Summary/Keyword: 전력시설

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A Study on the Application of Bushings Fire Prevent Structure to Prevent Fire Spread of Transformer (변압기의 화재확산 방지를 위한 부싱 방화구조체 적용에 관한 연구)

  • Kim, Do-Hyun;Cho, Nam-Wook;Yoon, Choung-Ho;Park, Pil-Yong;Park, Keun-Sung
    • Fire Science and Engineering
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    • v.31 no.5
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    • pp.53-62
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    • 2017
  • Electric power which is the energy source of economy and industries requires long distance transportation due to regional difference between its production and consumption, and it is supplied through the multi-loop transmission and distribution system. Prior to its actual use, electric power flows through several transformations by voltage transformers in substations depending on the characteristics of each usage, and a transformer has the structure consisting of the main body, winding wire, insulating oil and bushings. A transformer fire that breaks out in substations entails the primary damage that interrupts the power supply to houses and commercial facilities and causes various safety accidents as well as the secondary economic losses. It is considered that causes of such fire include the leak of insulating oil resulting from the destruction of bottom part of bushings, and the chain reaction of fire due to insulating oil that reaches its ignition point within 1 second. The smoke detector and automatic fire extinguishing system are established in order to minimize fire damage, but a difficulty in securing golden time for extinguishing fire due to delay in the operation of detector and release of gas from the extinguishing system has become a problem. Accordingly, this study was carried out according to needs of active mechanism to prevent the spread of fire and block the leak of insulating oil, in accordance with the importance of securing golden time in extinguishing a fire in its early stage. A bushings fireproof structure was developed by applying the high temperature shape retention materials, which are expanded by flame, and mechanical flame cutoff devices. The bushings fireproof structure was installed on the transformer model produced by applying the actual standards of bushings and flange, and the full scale fire test was carried out. It was confirmed that the bushings fireproof structure operated at accurate position and height within 3 seconds from the flame initiation. It is considered that it could block the spread of flame effectively in the event of actual transformer fire.

Reverse Osmosis Treatment of Swine Wastewater with Various Pretreatment Systems (축산 폐수의 전처리 방법과 역삼투압 처리)

  • Park, Soon Ju;Kim, Moon Il;Kim, Do Yun;Chang, Ho Nam;Chang, Seung Teak
    • Clean Technology
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    • v.9 no.2
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    • pp.49-55
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    • 2003
  • The generation of livestock wastewater in Korea amounts to $130,000m^3/day$, 0.43% of the total waste water volume, but which corresponds to 8.6% of total BOD loading. Furthermore this wastewater contains a large amount of nitrogen and phosphorus that are major causes of eutrophication in rivers and lakes. The average volume of livestock wastewater in a Korea's single farm is only $2.5m^3/day$, which necessitates development of a simple and economical process for the removal of nitrogen and phosphorus. Introduction of filtration method removes more than 90% of suspended solids. Subsequent application of reverse osmosis removes more then 95% of total nitrogen and phosphorus in the wastewater. The effluent of this treatment will yield less than 200 mg/L of total nitrogen and 1 mg/L of total phosphorous, which are lower than 260 mg/L of total N and 50 mg/L of total P, the regulation values of Ministry of Environment, Korea. Treating $2m^3/day$ of livestock wastewater was found to be feasible with the application of filtration and reverse osmosis and the electricity requirement was estimated to be about 30 Kwh/month.

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Designing and Realizing the Ground Station Receiver Low Noise Amplifier of the Next-Generation Aeronautical Surveillance System (차세대 항공 감시시스템(ADS-BES) 지상국 수신기 저잡음 증폭기 설계 및 구현)

  • Cho, Ju-Yong;Yoon, Jun-Chul;Park, Chan-Sub;Park, Hyo-Dal;Kang, Suk-Youb
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.10
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    • pp.2273-2280
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    • 2013
  • This article introduces the next-generation air surveillance system and investigates how to design of front-end low noise amplifier of the ground station receiver. In consideration of the international standard documentation and the performance of existing products, the study conducts the link budget on the entire system so that it can be competitive in terms of receive sensitivity or reliability. To obtain a proper low noise amplifier, standards of design are decided so that such factors as gain, gain flatness, and reflective loss can be optimal. In its design, the bias circuit appropriate for the characteristics of low power, low noise, or high gain was built, and according to the results of the simulation conducted after the optimal design, its gain was 16.24dB, noise factor was 0.36dB, input-output reflective loss was -18dB and -28dB each, and frequency stability was 1.11. According to the results measured after the design, its gain was 17dB, noise factor was 0.51dB, gain flatness was 0.23dB, and input-output reflective loss was -18.28dB and -24.50dB each, so the results gained were suitable for building the overall system.

Vulnerability Analysis for Industrial Control System Cyber Security (산업제어시스템의 사이버보안을 위한 취약점 분석)

  • Kim, Do-Yeon
    • The Journal of the Korea institute of electronic communication sciences
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    • v.9 no.1
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    • pp.137-142
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    • 2014
  • Industrial control system (ICS) is a computer based system which are typically used in nation-wide critical infra-structure facilities such as electrical, gas, water, wastewater, oil and transportation. In addition, ICS is essentially used in industrial application domain to effectively monitor and control the remotely scattered systems. The highly developed information technology (IT) and related network techniques are continually adapted into domains of industrial control system. However, industrial control system is confronted significant side-effects, which ICS is exposed to prevalent cyber threats typically found in IT environments. Therefore, cyber security vulnerabilities and possibilities of cyber incidents are dramatically increased in industrial control system. The vulnerabilities that may be found in typical ICS are grouped into Policy and Procedure, Platform, and Network categories to assist in determining optimal mitigation strategies. The order of these vulnerabilities does not necessarily reflect any priority in terms of likelihood of occurrence or severity of impact. Firstly, corporate security policy can reduce vulnerabilities by mandating conduct such as password usage and maintenance or requirements for connecting modems to ICS. Secondly, platfom vulnerabilities can be mitigated through various security controls, such as OS and application patching, physical access control, and security software. Thirdly, network vulnerabilities can be eliminated or mitigated through various security controls, such as defense-in-depth network design, encrypting network communication, restricting network traffic flows, and providing physical access control for network components.

A Study on Load Current and Temperature to Expect Lifetime of High-Power Cables (고전력 케이블의 잔여 수명 예측을 위한 부하 전류 및 온도 연구)

  • Um, Kee-Hong;Lee, Kwan-Woo
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.15 no.4
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    • pp.199-203
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    • 2015
  • With the development of industry these days, the demand for electric power increases and the larger capacity for power transfer is required. The scales of facilities should become larger; and the relative systems are required to operate with a higher degree of reliability. Therefore, stabilization of electric power systems is an important issue. The high degree of reliability required in the process of production and supply of electric power is an essential part of industrial society. Accident such as blackouts causes a hugh amount of economic losses to the high-tech industrial society dependent upon electric power. This paper is about the basic study of the relations between the load current and lifetime of power cables in operation. In order to do the research, we installed a current transformer and an equipment for measuring temperature at the 6.6. kV cables in operation. The two equipments have been installed on the cable systems in operation for the last 20 years. Since the insulation resistance of most of the cables showed the value larger than the threshold, it was not easy to tell the remaining lifetime of cables. The load current of the cables was almost constant. The surrunding temperature was $15{\sim}25^{\circ}C$, little variation of temperature values.

A Study on Analysis of the Social Vulnerable Areas Using GIS Spatial Analysis : Focusing on Local Governments in Seoul Metropolis (GIS 공간분석을 활용한 사회 취약지역의 분석에 관한 연구 : 서울특별시를 중심으로)

  • Lee, Myeong Ho;Yu, Seon Cheol;Ahn, Jong Wook;Shin, Dong Bin
    • Journal of Korean Society for Geospatial Information Science
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    • v.24 no.4
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    • pp.47-58
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    • 2016
  • The purpose of this study was to select the sectoral vulnerable areas index in welfare field and analyze the socially vulnerable areas from comprehensive analysis. For this study, preceding research and theoretical background were reviewed. Through this, we selected for the analysis index and criteria, and data corresponding to the index are collected. Based on the index and criteria, the data analysis was performed in Seoul Metropolitan City selected as the spatial extent of this study. From the results of analysis, the sectoral lower rank 10% of social vulnerable areas was determined. In addition, Junggu, Yongsangu, and Seodaemungu from the comprehensive analysis of individual vulnerable areas were derived as a final vulnerable areas. In particular, Junggu was weak in all sectors; Yongsangu was in the medical sector; and Seodaemungu was poor in housing and education. Lower vulnerability index of all sectors (energy, housing, medical, transportation, and education) in 1st, 2nd, and 3rd residential areas by examining use zoning was showed. From the results of this study, we can expect time and labor saving of policy support in public sector.

The Countermeasures of North Korea's Nuclear Weapon Terror (북한의 핵테러와 대응방안)

  • Kim, Sung Woo
    • Convergence Security Journal
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    • v.14 no.6_1
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    • pp.129-138
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    • 2014
  • South Korea should correspond to the primary threat to North Korea's nuclear weapons. It is necessary to have countermeasures to solve the realistic problems of North Korea's nuclear weapons. We can intensify military pact between the United States and Korea and at the same time strengthening the current military power. Currently, we take note the threat North Korea's missile. We can not control the development of a nuclear weapon and there are possibilities that North Korea have successfully miniaturized nuclear enough to carry by the missile. We should overview and check the Korea's missile defenses system. While the direction of the overall missile defense system deployment with a focus on lower and upper air defense network. And discuss defense research should be to build a system that can be protected with a key strategic facilities and cities. While North Korea have nuclear weapon, the main issues related to North Korea's nuclear threat. The six party talks countries try to solve the problem by the international and diplomatic approach. At the same time we should make somewhat to defend measures such as military defenses of Kill chain system to protect our country. Kill Chain is on of the effective defense system. We know that North Korea do not abandon to develop nuclear weapons by diplomatic efforts. We should performed in fact by a variety of military suppression method.

Evaluation of Heating Performance and Analysis of Heating Loads in Single Span Plastic Greenhouses with an Electrical or Hot-Air Heating (전기히터식 난방, 온풍난방시스템을 채용한 단동 플라스틱 하우스의 열부하 해석 및 난방성능 평가)

  • 허종철;임종환;서효덕;최동호
    • Journal of Bio-Environment Control
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    • v.8 no.2
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    • pp.136-146
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    • 1999
  • A series of experiments were carried out in winter to investigate the indoor thermal environment in greenhouses with different kinds of heating systems, and characterize the energy consumption, heat transport and thermal energy efficiency of each system. By the Quantitative calculation of heat losses which transmit through the covers of greenhouse, the fundamental data of energy-saving of the particular heating system were obtained. And from the analysis of air temperature differences between indoor and outside, it was possible to select more effective energy-saving and comfortable heating system in greenhouses. The electric heater was more stable in thermal environment and cheaper in cost, since it could be used during the surplus time of electric power from 10:00 p.M. to 8:00 A.M. But the low air temperature in greenhouses besides these times resulted in a chilling problem of the crops. The heating system by hot air had the advantage to show nearly uniform temperature difference by the height above the ground. But the system had the disadvantage to require more energy consumption than the electric heating system.

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Implementation of A Millimeter-Wave Multiflare-Angle Horn Antenna (밀리미터파 다중개구각 혼안테나 구현)

  • Oh, Kyung-Hyun;Kim, Ji-Hyung;Yang, Seung-Sik;Shin, Sang-Jin;Cho, Young-Ho;Lee, Byung-Ryul;Ahn, Bierng-Chearl
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.29 no.1
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    • pp.36-41
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    • 2018
  • This paper presents an implementation of a millimeter-wave(W band) multiflare-angle horn antenna. The proposed antenna is a multimode dual-polarized square horn having equal E- and H-plane beamwidths and consists of a multimode generating section, a four-square-waveguide exciter, orthomode transducers, and power combiners for the sum pattern formation. The antenna structure has been designed to allow for easy fabrication and the designed antenna has been fabricated to a precision of ${\pm}0.02mm$ by layer-by-layer machining and diffusion bonding. The input reflection coefficient and the radiation pattern of the fabricated antenna have been measured using a network analyzer and a far-field test facility. Measurements show that the proposed antenna has 17.7~18.3 dBi gain, $25.2{\sim}28.5^{\circ}$ beamwidth, and an input VSWR between 1.02~1.75, within ${\pm}0.5GHz$ from the center frequency.

A Study on the Possibility for Incident Investigation Using PLC Logs (PLC 로그의 사고조사 활용 가능성에 관한 연구)

  • Chang, Yeop;Kim, Taeyeon;Kim, Woo-Nyon
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.30 no.4
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    • pp.745-756
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    • 2020
  • An ICS(industrial control system) is a complex system that safely and efficiently monitors and controls industrial processes such as electric power, water treatment, transportation, automation plants and chemical plants. Because successful cyber attacks targeting ICS can lead to casualties or serious economic losses, it becomes a prime target of hacker groups sponsored by national state. Cyber campaigns such as Stuxnet, Industroyer and TRITON are real examples of successful ICS attacks, and were developed based on the deep knowledge of the target ICS. Therefore, for incident investigation of ICSs, inspectors also need knowledge of control processes and accident investigation techniques specialized for ICSs. Because there is no applicable technology, it is especially necessary to develop techniques and tools for embedded controllers located at cyber and physical boundaries. As the first step in this research, we reviewed logging capability of 4 PLC(Programmable Logic Controller)s widely used in an ICS area, and checked whether selected PLCs generate logs that can be used for digital investigation in the proposed cyber attack scenario.