• Title/Summary/Keyword: Electric Energy

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Study on The Supplying effect of Gas Air Conditioning Systems (가스냉방 보급효과에 대한 연구)

  • Han, J.O.;Chae, J.M.;Choi, K.S.;Hong, S.H.
    • Journal of the Korean Institute of Gas
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    • v.15 no.3
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    • pp.19-25
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    • 2011
  • Generally, the generation methods of cooling energy are electric air conditioning (EAC) and gas air conditioning (GAC). The EAC system is caused by increasing peak power during summer. Because the electric energy has a characteristic of non-storage, the peak electric load has been issued social problem annually whether the facility to supply is enough or not. Another way to supply cooling energy, GAC system is worked by gas energy. The absorption chiller and gas engine heat pump have been commercialized for cooling. However, the total capacity of GAC is much less than EAC and it almost depends on EAC for small market. This paper described the status of cooling energy consumption in domestic and expected the cooling energy to be consumed by electric and gas energy up to 2024 year. And also the benefit of GAC was analyzed with the case of its expansion and it was aimed to give background to fit the GAC policy.

Transient Characteristics and Physical Constraints of Grid-Tied Virtual Synchronous Machines

  • Yuan, Chang;Liu, Chang;Yang, Dan;Zhou, Ruibing;Tang, Niang
    • Journal of Power Electronics
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    • v.18 no.4
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    • pp.1111-1126
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    • 2018
  • In modern power systems, distributed generators (DGs) result in high stress on system frequency stability. Apart from the intermittent nature of DGs, most DGs do not contribute inertia or damping to systems. As a result, a new control method referred to as a virtual synchronous machine (VSM) has been proposed, which brought new characteristics to inverters such as synchronous machines (SM). DGs employing an energy storage system (ESS) provide inertia and damping through VSM control. Meanwhile, energy storage presents some physical constraints in the VSM implementation level. In this paper, a VSM mathematical model is built and analyzed. The dynamic responses of the output active power are presented when a step change in the frequency occurs. The influences of the inertia constant, damping factor and operating point on the ESS volume margins are investigated. In addition, physical constraints are proposed based on these analyses. The proposed physical constraints are simulated using PSCAD/EMTDC software and tested through RTDS experiment. Both simulation and RTDS test results verify the analysis.

A Study on Optimal Application Strategies of SFES through Comparison Studies for Energy Storage Devices (에너지 저장장치 비교연구를 통한 초전도 플라이휠의 최적 활용 방안 연구)

  • Lee, Han-Sang;Song, Ji-Young;Jang, Gil-Soo;Lee, Jung-Pil;Han, Young-Hee;Sung, Tae-Hyun
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.472_473
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    • 2009
  • It is fascinated research theme to store electric energy as much as possible and to utilize it at the point of proper time. Especially, the demand for energy storage devices has been increased based on the interest for distributed generation and smartgrid. As the results for a number of researches on it, various types of energy storage devices have been developed. Each devices have its own dynamic characteristics, power capacity, and storage capacity followed by storage mechanism. In this paper, the comparison research for various energy storage devices has been performed based on power capacity, storage capacity, discharging time, lifetime, efficiency, and cost. Application researches of SFES(superconducting flywheel energy storage), characterized as 300kW-100kWh, have been performed also.

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An Assessment of the Residential Electric Energy Consumption Induced by Global Warming (지구온난화에 의한 가정용 전력에너지의 소비평가)

  • Lim, Han-Cheol;Byun, Young-Hwa;Kwon, Won-Tae;Jhun, Jong-Ghap
    • Atmosphere
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    • v.18 no.1
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    • pp.33-41
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    • 2008
  • This study provides an impact assesment of climate change on energy consumption, based on active-deal scenario. This approach assumes that the amount of electric energy consumption depends on human spontaneous acts against local (REC) has ben developed by using monthly mean temperature and monthly amount of electric energy consumption in the 6 major cities over the 19-205 period. The statistical model is utilized to estimate the past and future REEC, and to assess the economic benefits and damage in energy consumption sector. For an estimation of the future REEC, climate change scenario, which is generated by National Institute of Meteorological Research, is utilized in this study. According to the model, it is estimated that over the standard period (1999~2005), there might be economic benefits of about 31 bilion Won/year in Seoul due to increasing temperature than in the 1980s. The REC is also predicted to be gradually reduced across the Korean peninsula since the 2020s. These results suggest that Korea will gain economic benefits in the REC sector during the 21st century as temperature increases under global warming scenarios.

The Study of Hybrid system using FC and IPT for Railway system (철도용 연료전지 및 유도급전을 이용한 Hybrid system 연구)

  • Han, K.H.;Lee, B.S.;Park, H.J.;Kwon, S.Y.;Baek, S.H.
    • Proceedings of the KIEE Conference
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    • 2008.10c
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    • pp.218-220
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    • 2008
  • Urban air quality, including carbon-dioxide emissions, and national energy security are related issues affecting the rail industry and transportation sector as a whole. They are related by the fact that (in the United States) 97-98% of the energy for the transport sector is based on oil, and more than 60% is imported. A fuelcell locomotive combines the environmental advantages of a catenary-electric locomotive with the higher overall energy efficiency and lower infrastructure costs of a diesel-electric. Catenaryelectric locomotives, when viewed as only one component of a distributed machine that includes an electricity-generating plant and transmission lines, are the least energy-efficient locomotive type. The natural fuel for a fuelcell is hydrogen, which can be produced from many renewable energies and nuclear energy, and thus a hydrogen-fuelcell locomotive will not depend on imported oil for its energy supply. This paper proposes a base models of Hybrid fuel cell/IPT railway vehicle power system, the necessary of this research.

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Lithium-ion Battery Energy Storage System for Power Quality Improvement in Electrical Propulsion Ships (전기추진선박의 전력품질 개선을 위한 리튬-이온 배터리 에너지저장시스템 적용)

  • Ku, Hyun-Keun;Seo, Hye-Rim;Kim, Jang-Mok
    • The Transactions of the Korean Institute of Power Electronics
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    • v.20 no.4
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    • pp.351-355
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    • 2015
  • This paper explained the application of a lithium-ion battery energy storage system to electric propulsion ships. The power distribution in electric propulsion ships has low power quality because of the variation in the power consumption of the propulsion motor. For proper operation of the ship, the power quality needs to be improved, and the battery energy storage system is used to solve power-quality problems. The simulation models of electric propulsion ship and battery energy storage systems are constructed on MATLAB/Simulink to verify the improvement in power quality. The proposed system is applied in various scenarios of the propulsion motor state. The power quality achieved by using the battery energy storage system in both voltage and frequency satisfies the standards set by IEC-60092/101.

Rotational Performance Test for the Flywheel Energy Storage System (플라이휠 에너지 저장장치 회전 성능 평가)

  • Lee, Jeong-Phil;Han, Snag-Chul;Han, Young-Hee;Park, Byeong-Cheol;Jung, Se-Yong;Park, Byung-Jun;Sung, Tae-Hyun
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.692_693
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    • 2009
  • 본 논문은 초전도 플라이휠 에너지 저장장치(Superconductor Flywheel Energy Storage System : SFES)의 고속회전 시험을 통하여 휠의 진동 특성을 평가 하였다. 초전도 베어링(Superconductor Magnetic Bearing : SMB)은 동작시키기 않고 플라이휠의 외부 외란이나 예측하지 못한 진동을 억제할 수 있도록 설치된 전자석 댐퍼(Electric Magnetic Damper : EMD) 만을 이용해 휠을 부양하고 고속회전 시험을 수행하였다. 이를 통하여 플라이휠의 고속 회전 운전영역에서 EMD는 충분한 진동억제 능력을 보임을 확인 하였다.

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BESS Modeling and Application to Voltage Compensation of Electric Railway System (BESS 모델링 및 전기철도 급전계통에의 전압보상 적용)

  • Yoo, Hyeong-Jun;Son, Ho-Ik;Kim, Hak-Man
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.3
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    • pp.417-423
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    • 2013
  • The load of electric railroad can generate voltage fluctuation in the electric railway system because of high speed of the electric railroad and frequent movement and stop. This voltage fluctuation of electric railway system can cause not only voltage imbalance but also harmonic in the utility grid. Therefore the electric railroad system is in need of the reactive power compensation, such as static synchronous compensator (STATCOM) and static var compensator (SVC). Especially, the battery energy storage system (BESS) can control the real and reactive power at the same time. In this paper, the electric railway system using BESS has been modeled to show its voltage compensation effect using Matlab/Simulink.

Static Properties of Superconductor Journal Bearing Substator for Superconductor Flywheel Energy Storage System (초전도 저널베어링 Substator의 특성평가)

  • Park, B.J.;Jung, S.Y.;Lee, J.P.;Park, B.C.;Jeong, N.H.;Sung, T.H.;Han, Y.H.
    • Progress in Superconductivity
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    • v.10 no.1
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    • pp.55-59
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    • 2008
  • A Superconductor Flywheel Energy Storage System(SFES) mainly consists of a pair of non-contacting High Temperature Superconductor(HTS) bearings that provide very low frictional losses, a composite flywheel with high energy storage density. The HTS bearings, which offer dynamic stability without active control, are the key technology that distinguishes the SFES from other flywheel energy storage devices, and great effort is being put into developing this technology. The Superconductor Journal Bearing(SJB) mainly consists of HTS bulks and a stator, which holds the HTS bulks and also acts as a cold head. Static properties of HTS bearings provide data to solve problems which may occur easily in a running system. Since stiffness to counter vibration is the main parameter in designing an HTS bearing system, we investigate SJB magnetic force through static properties between the Permanent Magnet(PM) and HTS. We measure stiffness in static condition and the results are used to determine the optimal number of HTS bulks for a 100kWh SFES.

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Development of Alkali Metal Thermal-to-Electric Converter Unit Cells Using Mo/TiN Electrode

  • Seog, Seung-won;Choi, Hyun-Jong;Kim, Sun-Dong;Lee, Wook-Hyun;Woo, Sang-Kuk;Han, Moon-Hee
    • Journal of the Korean Ceramic Society
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    • v.54 no.3
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    • pp.200-204
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    • 2017
  • Molybdenum (Mo), an electrode material of alkali metal thermal-to-electric converters (AMTEC), facilitates grain growth behavior and forms Mo-Na-O compounds at high operating temperatures, resulting in reduced performance and shortened lifetime of the cell. Mo/TiN composite materials have been developed to provide a solution for such issues. Mo is a metal that possesses excellent electrical properties, and TiN is a ceramic compound with high-temperature durability and catalytic activity. In this study, a dip-coating process with an organic solvent-based slurry was used as an optimal coating method to achieve homogeneity and stability of the electrodes. Cell performance was evaluated under various conditions such as the number of coatings, ranging from 1 to 3 times, and heat treatment temperatures of $800-1100^{\circ}C$. The results confirmed that the cell yielded a maximum power of 9.99 W for the sample coated 3 times and heat-treated at $900^{\circ}C$.