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  • Title/Summary/Keyword: wind power system

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Development of Hybrid BMS(Battery Management System) Algorithm for Lead-acid and Lithium-ion battery (연축전지와 리튬이온전지용 하이브리드 BMS 알고리즘 개발)

  • Oh, Seung-Taek;Kim, Byung-Ki;Park, Jae-Beom;Rho, Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.5
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    • pp.3391-3398
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    • 2015
  • Recently, the large scaled lead-acid battery is widely introduced to efficient operation of the photovoltaic system in many islands. but the demand of lithium-ion battery is getting increased by the operation of wind power and replacement of the lead-acid battery. And also, under the renewable portfolio standard(RPS) and energy efficiency resource standard(EERS) policy of Korea government, the introduction of energy storage system(ESS) has been actively increased. Therefore, this paper presents the operation algorithm of hybrid battery management system(BMS) using the lead-acid and lithium-ion batteries, in order to maximize advantage of each battery. In other words, this paper proposed the algorithm of state of charge(SOC) and hybrid operation algorithm to calculate the optimal composition rate considering the fixed cost and operation cost of each battery. From the simulation results, it is confirmed that the proposed algorithms are an effective tool to evaluate SOC and to optimally operate hybrid ESS.

Reliability Improvement of the Electronic Security Fence Using Friction Electricity Sensor by Analyzing Frequency Characteristic of Environmental Noise Signal (환경잡음신호의 주파수특성 분석에 의한 전자보안펜스의 신뢰성 향상)

  • Yun, Seok Jin;Won, Seo Yeon;Kim, Hie Sik;Lee, Young Chul;Jang, Woo Young
    • Journal of the Institute of Electronics and Information Engineers
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    • v.52 no.3
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    • pp.173-180
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    • 2015
  • A passive type of fence security system was developed, which was based on electric charge detection technique. The implemented fence security system was installed at outskirts of greenhouse laboratory in the University of Seoul. The purpose of this research is to minimize false alarms by analyzing environmental noise. The existing system determines the intrusion alarm by analyzing the power of amplified signal, but the alarm was seriously affected by natural strong wind and heavy rainfall. The SAU(Signal Analysis Unit) sends input signals to remote server which displays intrusion alarm and stores all the information in database. The environmental noise such as temperature, humidity and wind speed was separately gathered to analyze a correlation with input signal. The input signal was analyzed for frequency characteristic using FFT(Fast Fourier Transform) and the algorithm that differentiate between intrusion alarm and environmental noise signal is improved. The proposed algorithm is applied for the site for one month as the same as the existing algorithm and the false alarm data was gathered and analyzed. The false alarm number was decreased by 98% after new algorithm was applied to the fence. The proposed algorithm improved the reliability at the field regarding environmental noise signal.

A compactly integrated cooling system of a combination dual 1.5-MW HTS motors for electric propulsion

  • Le, T.D.;Kim, J.H.;Hyeon, C.J.;Kim, D.K.;Yoon, Y.S.;Lee, J.;Park, Y.G.;Jeon, H.;Quach, H.L.;Kim, H.M.
    • Progress in Superconductivity and Cryogenics
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    • v.18 no.4
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    • pp.25-29
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    • 2016
  • The high temperature superconducting (HTS) contra-rotating propulsion (CRP) systems comprise two coaxial propellers sited on behind the other and rotate in opposite directions. They have the hydrodynamic advantage of recovering the slipstream rotational energy which would otherwise be lost to a conventional single-screw system. However, the cooling systems used for HTS CRP system need a high cooling power enough to maintain a low temperature of 2G HTS material operating at liquid neon (LNe) temperature (24.5 - 27 K). In this paper, a single thermo-syphon cooling approach using a Gifford-McMahon (G-M) cryo-cooler is presented. First, an optimal thermal design of a 1.5 MW HTS motor was conducted varying to different types of commercial 2G HTS tapes. Then, a mono-cryogenic cooling system for an integration of two 1.5 MW HTS motors will be designed and analyzed. Finally, the 3D finite element analysis (FEA) simulation of thermal characteristics was also performed.

Agro-Environmental Observation in a Rice Paddy under an Agrivoltaic System: Comparison with the Environment outside the System (영농형 태양광 시설 하부 논에서의 농업환경 관측 및 시설 외부 환경과의 비교)

  • Kang, Minseok;Sohn, Seungwon;Park, Juhan;Kim, Jongho;Choi, Sung-Won;Cho, Sungsik
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.23 no.3
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    • pp.141-148
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    • 2021
  • Agrivoltaic systems, also called solar sharing, stated from an idea that utilizes sunlight above the light saturation point of crops for power generation using solar panels. It is expected that agrivoltaic systems can realize climate smart agriculture by reducing evapotranspiration and methane emission due to the reduction of incident solar radiation and the consequent surface cooling effect and bring additional income to farms through solar power generation. In this study, to evaluate that agrivoltaic systems are suitable for realization of climate smart agriculture, we conducted agro-environmental observations (i.e., downward/upward shortwave/longwave radiations, air temperature, relative humidity, water temperature, soil temperature, and wind speed) in a rice paddy under an agrivoltaic system and compared with the environment outside the system using automated meteorological observing systems (AMOS). During the observation period, the spatially averaged incoming solar radiation under the agrivoltaic system was about 70% of that in the open paddy field, and clear differences in the soil and water temperatures between the paddy field under the agrivoltaic system and the open paddy field were confirmed, although the air temperatures were similar. It is required in the near future to confirm whether such environmental differences lead to a reduction in water consumption and greenhouse gas emissions by flux measurements.

A Study on the Analysis of Safety Standard and Evaluation of Safety Performance for the 5 Nm3 /hr Class Alkaline Water Electrolysis System (5 Nm3 /hr급 알카라인 수전해 시스템 안전기준 분석 및 안전성능 평가에 관한 연구)

  • Kim, Ji-Hye;Lee, Eun-Kyung;Kim, Min-Woo;Oh, Gun-Woo;Lee, Jung-Woon;Kim, Woo-Seop
    • Journal of the Korean Institute of Gas
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    • v.22 no.6
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    • pp.65-75
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    • 2018
  • The wind energy produced at night is being discarded because of the excess power generated at night compared to daytime. To solve this problem, In this study, we analyzed the evaluation contents for evaluation of domestic and overseas water electrolysis systems and drew contents for safety performance contents test of the water electrolysis system based on the evaluation contents. The test contents produced the efficiency measurement test, the hydrogen generated pressure test, and the hydrogen purity test. And the safety performance evaluation of the alkaline water electrolysis system of 5Nm3/hr was performed based on the results. As a result, the hydrogen generation was calculated as 5.10Nm3/hr and the stack efficiency was 4.97kWh/Nm3. The purity of the hydrogen generated was 99.993% and it was confirmed that it produced high purity hydrogen. I think will help us assess and build safety performance of water electrolysis systems in the future.

Mechanical Properties of a High-temperature Superconductor Bearing Rotor in a 10 kWh Class Superconductor Flywheel Energy Storage System (10 kWh급 초전도 베어링 회전자의 기계적 특성 평가)

  • Park, B.J.;Jung, S.Y.;Kim, C.H.;Han, S.C.;Park, B.C.;Han, S.J.;Doo, S.G.;Han, Y.H.
    • Progress in Superconductivity
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    • v.13 no.1
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    • pp.58-63
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    • 2011
  • Recently, superconductor flywheel energy storage systems (SFESs) have been developed for application to a regenerative power of train, a power quality improvement, the storage of distributed power sources such as solar and wind power, and a load leveling. As the high temperature superconductor (HTS) bearings offer dynamic stability without the use of active control, accurate analysis of the HTS bearing is very important for application to SFESs. Mechanical property of a HTS bearing is the main index for evaluating the capacity of an HTS bearing and is determined by the interaction between the HTS bulks and the permanent magnet (PM) rotor. HTS bearing rotor consists of PM and iron collector and the proper dimension design of them is very important to determine a supporting characteristics. In this study, we have optimized a rotor magnet array, which depends on the limited bulk size and performed various dimension layouts for thickness of the pole pitch and iron collector. HTS bearing rotor was installed into a single axis universal test machine for a stiffness test. A hydraulic pump was used to control the amplitude and frequency of the rotor vibration. As a result, the stiffness result showed a large difference more than 30 % according to the thickness of permanent magnet and iron collector. This is closely related to the bulk stiffness controlled by flux pining area, which is limited by the total bulk dimension. Finally, the optimized HTS bearing rotor was installed into a flywheel system for a dynamic stability test. We discussed the dynamic properties of the superconductor bearing rotor and these results can be used for the optimal design of HTS bearings of the 10kWh SFESs.

Analysis of Dynamic Positioning System Based on Self-Tuning Control (자기동조 제어기를 이용한 위치확보 시스템에 관한 연구)

  • Sang-M.,Lee;Pan-M.,Lee;Sa-Y.,Hong
    • Bulletin of the Society of Naval Architects of Korea
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    • v.26 no.2
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    • pp.32-40
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    • 1989
  • Dynamic ship positioning(DP) system is used to keep the position and heading of a ship, or a floating platform, above a pre-selected site on the seabed by using thrusters. This paper presents a control system based on filtering technique and optimal control theory. The planar motions of a vessel are assumed to consist of low frequency(LF) component and high frequency(HF) one. The former is mainly due to thrusters, current, wind and second order wave forces, while the latter is mainly due to first order oscillatory component of the wave force. Furthermore position measurement signals include the noise. By means of self-tuning filter and Kalman filter techniques, LF motion estimates and HF ones are seperately achieved from the position measurements of the vessel. The estimated LF motions are used as input to the feedback loops. The total thruster power is minimized using the Linear Quadratic Gaussian control theory. The performance of the vessel with the DP system is investigated by computer simulation.

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Design and Verification of Disturbace Observer based Controller for Windturbine with Two Cooperative Generators (두 대의 협력적인 발전기를 갖는 풍력발전기의 외란관측기 기반 제어기의 설계 및 검증)

  • Lee, Kook-Sun;Cho, Whang;Back, Ju-Hoon;Choy, Ick
    • The Journal of the Korea institute of electronic communication sciences
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    • v.12 no.2
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    • pp.301-308
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    • 2017
  • This paper proposes a disturbance observer based controller design method for generating and yawing control of windturbine with two cooperative generators. Windturbine system with two cooperative generators is a distinct structure in which the wind energy supplied by blade axis is converted into electrical energy by two cooperative generators. In this structure, two generators can be controlled independently and therefore they can generate power, simultaneously performing yawing control of nacelle without extra yawing mechanism by cooperatively controlling generating load in appropriate manner. Using this structural trait, this paper designs a disturbance observer based controller that enables the windturbine system with cooperative generators to generate and yaw stably, and verifies the performance of the controller experimentally by applying it to a small-scale windturbine system with the same structure.

The Installation of Chul-Won Seismo-Acoustic Array (철원 지진-공중음파 관측망 설치)

  • ;;;;;;;Brian stump;Christ Hayward
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 1999.10a
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    • pp.52-57
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    • 1999
  • Korea Earthquake Monitoring System(KEMS) in the Korea Institute of Geology Mining and Materials(KIGAM) as detected more than 1000 events since the end of 1998. But not all events are interpreted as earthquakes because many events are concentrated on daytime. It strongly implies that in addition to earthquake these events include artificial effects such as industrial blasting. Before the determination of eathquake charactertistics in the korean peninsula it is necessary to discriminate the detected events as earthquakes or artificial events. For the discriminant study KIGAM and SMU(Southern Methodist University) installed a triangular four-element 1-km aperture seismo-acoustic array at Chul-Won area northeast of Seoul Korea. Each array element includes a GS-13 seismometer in the bottom of borehole and a Validyne DP250-14 microbarometer sensor mounted inside of the borehole 1,2 meter deep connected to a 11 arm radial array of 10m porous soaker hoses. This array introduce the use of 2.4-GHz radios for inter-array self-contained solar-charged power system and GPS time-keeping system. A 24-bit digital data acquisition system performs 40 SPS in the infrasound and seismometer data. Velocity and direction of wind and temperature are also measured at hub site and included to the data stresam. This seismo-acoustic array will be used to identify and locate associated with industrial blasting and these identified and located events will be applied to form a ground truth database useful to assist the other development of discriminant studies.

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Evaluation of Cryogenic Compressive Strength of Divinycell of NO 96-type LNG Insulation System (NO96타입 LNG 방열시스템 Divinycell의 극저온 압축 강도 평가)

  • Choe, Yeong-Rak;Kim, Jeong-Hyeon;Kim, Jong-Min;Park, Sungkyun;Park, Kang Hyun;Lee, Jae-Myung
    • Journal of Ocean Engineering and Technology
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    • v.30 no.5
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    • pp.349-355
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    • 2016
  • Divinycell, which functions as both insulation and a supporting structure, is generally applied in the NO96-type liquefied natural gas (LNG) insulation system. Polymer-material-based Divinycell, which has a high strength and low weight, has been widely used in the offshore, transportation, wind power generation, and civil engineering fields. In particular, this type of material receives attention as an insulation material because its thermal conductivity can be lowered depending on the ambient temperature. However, it is difficult to obtain research results for Divinycell, even though the component materials of the NO96-type LNG cargo containment system, such as 36% nickel steel (invar steel), plywood, perlite, and glass wool, have been extensively studied and reported. In the present study, temperature and strain-rate dependent compressive tests on Divinycell were performed. Both the quantitative experimental data and elastic recovery are discussed. Finally, the mechanical characteristics of Divinycell were compared to the results of polyurethane foam insulation material.