• Title, Summary, Keyword: Smart Grid

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A Proposal of the Prediction Method of Decentralized Power on Climatic Change (기후 변화에 따른 분산 전력 예측 방법 제안)

  • Kim, Jeong-Young;Kim, Bo-Min;Bang, Hyun-Jin;Jang, Min-Seok
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.942-945
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    • 2010
  • The development of decentralized power has appeared as part of an effort to decrease the energy loss and the cost for electric power facilities through installing small renewable energy generation systems including solar and wind power generation. Recently a new era for decentralized power environment in building is coming in order to handle the climatic and environmental change occurred all over the world. Especially solar and wind power generation systems can be easily set up and are also economically feasible, and thus many industrial companies enter into this business. This paper suggests the overall architecture for the decentralized renewable power system and the prediction method of power on climatic change. The ultimate goal is to help manage the overall power efficiently and thus provide the technological basis for achieving zero-energy house.

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MIMO-OFDM BPLC over Statistical Power Line Channels with Cross-Talk (크로스 토크를 갖는 통계적 전력선 채널 하에 MIMO-OFDM 광대역 전력선 통신)

  • Yoo, Jeong-Hwa;Choe, Sang-Ho;Pine, Nazcar
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.12B
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    • pp.1565-1573
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    • 2011
  • In this paper, we present a MIMO-OFDM broadband power line communication (BPLC) for Smart Grid and its associated applications and analyze its performance over the 3-phase 4-wire power line channels. For practical BPLC system simulation, we adopt the statistical power line fading channel model instead of the existing deterministic fading channel models (Zimmermann model, MTL model, and so on). In this paper, we implement $2{\times}2$ and $3{\times}3$ MIMO schemes using 3-phase 4-wire power lines. We investigate the capacity loss and BER performance of the proposed MIMO system by considering the effect of cross-talk between antenna paths. We choose space-frequency coding in order to reduce frequency interference between subcarriers and employ maximum ratio combining (MRC) that achieves both multiple antenna path diversity gain and multiple fading path diversity gain. We evaluate the proposed system performance through computer simulation in terms of the impulse noise index and the capacity loss ratio and compare the different signal combining schemes including MRC, equal gain combing (EGC), and selection combining (SC).

A Study on Competency Evaluation and Improvement Plan of Electrical Construction Management Using Importance-Performance Analysis (IPA를 활용한 전기공사 건설사업관리 역량 평가 및 개선방안 연구)

  • Kim, Seungbeum;Byun, Jeongyoon;Kim, Juhyung;Kim, Jaejun
    • Korean Journal of Construction Engineering and Management
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    • v.15 no.3
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    • pp.103-112
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    • 2014
  • Since recent construction projects become larger and complicated, the level of difficulty of management skill is rising, and the risk is increasing accordingly so the necessity of improving management skill of projects is increasing. In order to solve this problem, Construction Management system was preferentially introduced in construction projects but in case of domestic construction industry, separate contracts by business boundary are being made so the actual state is that the function of the Construction Management system is not properly operated over the overall projects. The partial operation of Construction Management system like this may impose many restrictions on converged and combined projects such as smart grid and intelligent buildings etc. in the future. For improvement of management skill of domestic construction projects, the competence of project management skill by work areas that can overcome heterogeneity of the current project management skill shall be secured, and any factor that impedes cooperation ability shall be found and that shall be solved. Therefore, the difference of work competency of project management system of construction and electrical construction is to be analyzed by utilizing IPA model in this study, and a plan to introduce the project management system of electrical construction for efficient operation of projects is to be looked into.

Design and Implementation of File Cloud Server by Using JAVA SDK (Java SDK를 이용한 파일 클라우드 시스템의 설계 및 구현)

  • Lee, Samuel Sangkon
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.8 no.2
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    • pp.86-100
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    • 2015
  • Cloud computing is a computing term that evolved in the late 2000s, based on utility and consumption of computer resources. Google say that "Cloud computing involves deploying groups of remote servers and software networks that allow different kinds of data sources be uploaded for real time processing to generate computing results without the need to store processed data on the cloud. Cloud computing relies on sharing of resources to achieve coherence and economies of scale, similar to a utility (like the electricity grid) over a network. At the foundation of cloud computing is the broader concept of converged infrastructure and shared services. Cloud computing, or in simpler shorthand just "the cloud", also focuses on maximizing the effectiveness of the shared resources." The cloud service is a smart and/or intelligent service to save private files in any device, anytime, anywhere. Dropbox, OAuth, PAClous are required that the accumulated user's data are archives with cloud service. Currently we suggest an implementation technique to process many tasks to the cloud server with a thread pooling. Thread pooling is one of efficient implementating technique for client and service environment. In this paper, to present the implementation technique we suggest three diagrams in the consideration of software engineering.

Characteristics of Open-Loop Current Sensor with Temperature Compensation Circuit (온도보상회로를 부착한 개방형 전류측정기의 특성)

  • Ku, Myung-Hwan;Park, Ju-Gyeong;Cha, Guee-Soo;Kim, Dong-Hui;Choi, Jong-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.12
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    • pp.8306-8313
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    • 2015
  • Open-type current sensors have been commonly used for DC motor controller, AC variable controller and Uninterruptible Power Supply. Recently they have begun to be used more widely, as the growth of renewable energy and smart-grid in power system. Considering most of the open-type current sensors are imported, developing the core technology needed to produce open-type current sensors is required. This paper describes the development and test results of open-type current sensors. Design of C type magnetic core, selection and test of a Hall sensor, design of current source circuit and signal conditioning circuit are described. 100A class DIP(Dual In-line Package) type and SMD(Surface Mount Devide) type open-type current sensors was made and tested. Test results show that the developed open-type current sensor satisfies the accuracy requirement of 2% and linearity requirement of 2% at 100 A of DC and AC current of 60Hz. Temperature compensation was carried out by using a temperature compensation circuit with NTC(Negative Temperature Coefficient) thermistor and the effect of the temperature compensation are described.

Analysis of Packet Transmission Delay in the DC Power-Line Fault Management System using IEEE 802.15.4 (IEEE 802.15.4를 적용한 직류배전선로 장애관리시스템에서 패킷전송 지연시간 분석)

  • Song, Han-Chun;Hwang, Sung-Ho
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.14 no.1
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    • pp.259-264
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    • 2014
  • IEEE 802.15.4 has been emerging as the popular choice for various monitoring and control applications. In this paper, a fault management system for DC power-lines has been designed using IEEE 802.15.4, in order to monitor DC power-lines in real time, and to rapidly detect faults and shut off the line where such faults occur. Numbers were allocated for each node and unslotted CSMA-CA method of IEEE 802.15.4 was used, the performance of which was analyzed by a simulation. For such purpose, a total of 60 bits of the control data consisting of 16 bits of the current, 16 bits of the amplitude, 28 bits of the terminal state data were sent out, and the packet transfer rate and the transmission delay time of the fault management system for DC power-lines were measured and analyzed. When the traffic load was 330 packets per second or lower, the average delay time was shown to be shorter than 0.02 seconds, and when the traffic load was 260 packets per second or lower, the packet transfer rate was shown to be 99.99% or higher. Therefore, it was confirmed that the stringent condition of US Department of Energy (DOE) could be satisfied if the traffic load was 260 packets per second or lower, The results of this study can be utilized as basic data for the establishment of the fault management system for DC power-lines using IEEE 802.15.4.

Development of State of Charge and Life Cycle Evaluation Algorithm for Secondary Battery (이차전지의 상태 감시 및 수명 예측 알고리즘 개발)

  • Park, Jaebeom;Kim, Byeonggi;Song, Seokhwan;Rho, Daeseok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.1
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    • pp.369-377
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    • 2013
  • This paper deals with the state of charge(SOC) and life cycle evaluation algorithm for lead-acid battery, which is essential factor of the electric vehicle(EV) and the stabilization of renewable energy in the smart grid. In order to perform the effective operation of the lead-acid battery, SOC and life cycle evaluation algorithm is required. Specific gravity with the change of electrolyte temperature inside battery case should be obtained to evaluate the SOC of lead-acid battery, however it is difficult to measure the electrolyte temperature of sealed type lead-acid battery. To overcome this problem, this paper proposes the equation of thermal transmission to compensate internal temperature of the lead-acid battery. Also, it is difficult to exactly evaluate the life cycle of battery, depending on the operation conditions of lead-acid battery such as charging and discharging state, self discharging rate and environmental issue. In order to solve the problem, this paper presents the concept for gravity accumulation of charge and discharge cycle, which is the value converted at $20^{\circ}C$. By using the proposed algorithm, this paper propose the test device based on the Labview software. The simulation results show that it is a practical tool for the maintenance of lead-acid battery in the field of industry.

Designing the Promotion Policy of Korea ESCO Industry through the Examination of Foreign Country Exercises (해외사례 조사를 통한 국내 ESCO 산업 활성화 방안)

  • Min, Eunju;Kim, Myeongrok;Nam, Kitae;Kang, Mingoo;Kim, Suduk
    • Environmental and Resource Economics Review
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    • v.26 no.1
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    • pp.103-121
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    • 2017
  • The domestic ESCO project was introduced in 1992 as one of the energy efficiency improvement programs. In recent energy market, the changes in the market conditions such as smart grid, renewable energy, and the importance of demand response became important issues. As the diversified business models are required, examples of overseas exercises are examined. Business areas in Europe or the US where the ESCO industry has been active include measures to improve the efficiency of energy facilities in all areas, ranging from energy supply facilities and energy services to end users. This type of ESCO overseas business model can be classified into various types such as project execution method, supplier demand management, financing method, climate change and emission rights, new and renewable energy, and other criteria. In this study, we propose to adopt IEC (Integrated Energy Contracting) contract method in domestic ESCO market for additional business models. Current convention of listing the specific individual business types being allowed by regulation turned out to be obstacles to the revitalization of the related market. In order to achieve the goal of energy conservation, it is recommended, instead, to revise the current funding guidelines to be a negative system.

A 0.18-μm CMOS Baseband Circuits for the IEEE 802.15.4g MR-OFDM SUN Standard (IEEE 802.15.4g MR-OFDM SUN 표준을 지원하는 0.18-μm CMOS 기저대역 회로 설계에 관한 연구)

  • Bae, Jun-Woo;Kim, Chang-Wan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.3
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    • pp.685-690
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    • 2013
  • This paper has proposed a multi-channel and wide gain-range baseband circuit blocks for the IEEE 802.15.4g MR-OFDM SUN systems. The proposed baseband circuit blocks consist of two negative-feedback VGAs, an active-RC 5th-order chebyshev low-pass-filter, and a DC-offset cancellation circuit. The proposed baseband circuit blocks provide 1 dB cut-off frequencies of 100 kHz, 200 kHz, 400 kHz, and 600 kHz respectively, and achieve a wide gain-range of +7 dB~+84 dB with 1 dB step. In addition, a DC-offset cancellation circuit has been adopted to mitigate DC-offset problems in direct-conversion receiver. Simulation results show a maximum input differential voltage of $1.5V_{pp}$ and noise figure of 42 dB and 37.6 dB at 5 kHz and 500 kHz, respectively. The proposed I-and Q-path baseband circuits have been implemented in $0.18-{\mu}m$ CMOS technology and consume 17 mW from a 1.8 V supply voltage.

The Selection of Optimal Distributions for Distributed Hydrological Models using Multi-criteria Calibration Techniques (다중최적화기법을 이용한 분포형 수문모형의 최적 분포형 선택)

  • Kim, Yonsoo;Kim, Taegyun
    • Journal of Wetlands Research
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    • v.22 no.1
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    • pp.15-23
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    • 2020
  • The purpose of this study is to investigate how the degree of distribution influences the calibration of snow and runoff in distributed hydrological models using a multi-criteria calibration method. The Hydrology Laboratory-Research Distributed Hydrologic Model (HL-RDHM) developed by NOAA-National Weather Service (NWS) is employed to estimate optimized parameter sets. We have 3 scenarios depended on the model complexity for estimating best parameter sets: Lumped, Semi-Distributed, and Fully-Distributed. For the case study, the Durango River Basin, Colorado is selected as a study basin to consider both snow and water balance components. This study basin is in the mountainous western U.S. area and consists of 108 Hydrologic Rainfall Analysis Project (HRAP) grid cells. 5 and 13 parameters of snow and water balance models are calibrated with the Multi-Objective Shuffled Complex Evolution Metropolis (MOSCEM) algorithm. Model calibration and validation are conducted on 4km HRAP grids with 5 years (2001-2005) meteorological data and observations. Through case study, we show that snow and streamflow simulations are improved with multiple criteria calibrations without considering model complexity. In particular, we confirm that semi- and fully distributed models are better performances than those of lumped model. In case of lumped model, the Root Mean Square Error (RMSE) values improve by 35% on snow average and 42% on runoff from a priori parameter set through multi-criteria calibrations. On the other hand, the RMSE values are improved by 40% and 43% for snow and runoff on semi- and fully-distributed models.