• Title/Summary/Keyword: utility-connected

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Electrical Power System Studies for an Industrial Cogeneration Power Plant (자가발전설비가 있는 산업플랜트의 전력계통 응동 해석)

  • Yun, Jae-Hun;Lim, Seong-Ho
    • Proceedings of the KIEE Conference
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    • 1999.07c
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    • pp.1215-1217
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    • 1999
  • Electrical studies are required to assure the proper integration of cogeneration facility into a industrial plant electrical system and the connected utility grid. Details of such study efforts are presented, including boundary limit for the system modeling, short-circuit and load flow studies, stability studies, load shedding studies, and harmonics studies.

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Digital PLL Control for Grid-Connected Photovoltaic System (계통 연계형 태양광 발전 시스템을 위한 디지털 PLL 제어)

  • Kim, Yong-Kyun;Choi, Jong-Woo;Kim, Heung-Geun;Lee, Dong-Choon;Choi, Young-Tae;Kim, Jin-Kyu
    • Proceedings of the KIEE Conference
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    • 2003.04a
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    • pp.327-330
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    • 2003
  • The frequency and Phase angle of the utility voltage are important in many industrial systems. In this paper, the analysis and generalized approach of single-phase PLL control have been presented. The experimental results have been presented and demonstrated the feasibility of proposed methods.

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Islanding Detection Algorithm Based on a Harmonic for Distributed Generators (고조파을 이용한 분산전원 고립운전 검출 알고리즘)

  • Ko C. J.;Kwon Y. J.;Kang S. H
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.301-303
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    • 2004
  • This paper presents an islanding detection algorithm based on the second harmonic. When the DG(distributed Generator) was connected with utility supply, for maintenance and repair of equipment, an islanding occurred. So islanding detection algorithm must be developed for safety of human. Although the DG generating power is similar to power consumption. the proposed algorithm can detect the islanding condition very successfully.

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A Novel Power Frequency Changer Based on Utility AC Connected Half-Bridge One Stage High Frequency AC Conversion Principle

  • Saha Bishwajit;Koh Kang-Hoon;Kwon Soon-Kurl;Lee Hyun-Woo;Nakaoka Mutsuo
    • Proceedings of the KIPE Conference
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    • 2006.06a
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    • pp.203-205
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    • 2006
  • This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit incorporating boost-half-bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switching mode and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation as compared with those of the previously developed high-frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation (PWM) and pulse density modulation (PDM) control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The power converter practical effectiveness is substantially proved based on experimental results from practical design example.

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Novel control algorithm for smart PCS with harmonics and reactive power compensation (고조파와 무효전력 보상기능을 가지는 Smart PCS의 새로운 제어 알고리즘)

  • Seo, Hyo-Ryong;Jang, Seong-Jae;Park, Sang-Soo;Kim, Sang-Yong;Kim, Gyeong-Hun;Park, Min-Won;Yu, In-Keun
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.1053_1054
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    • 2009
  • A significant number of renewable energy systems have been connected to the grids as supplement power source. The renewable energy systems require control algorithm to maintain the power-supply reliability and quality. This paper proposes a novel control algorithm for smart Power Conditioning System (PCS) with harmonics and reactive power compensation. The smart PCS is used to feed Photovoltaic (PV) power to utility and compensate harmonics and reactive power at the same time. The experimentation is carried out on the proposed grid-connected PV generation system, and controlled by digital signal processor. The grid-connected PV generation system injects PV energy into the grid and performs as Active Filter (AF) and Static Synchronous Compensator (STATCOM) without additional devices. The experiment results show that the proposed control algorithm is effective for smart PCS with harmonics and reactive power compensation.

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Grid-Connected Variable Speed Wind Power Generation System Using Cage-Type Induction Generators (농형 유도발전기를 이용한 계통연계형 가변속 풍력발전시스템)

  • 김형균;이동춘;석줄기
    • The Transactions of the Korean Institute of Power Electronics
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    • v.9 no.4
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    • pp.397-404
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    • 2004
  • This paper proposes a variable speed control scheme of grid-connected wind power generation systems using cage-type induction generators. The induction generator is operated in indirect vector control mode, where the d-axis current controls the excitation level and the q-axis current controls the generator torque, by which the speed of the induction generator is controlled according to the variation of the wind speed In order to produce the maximum output power. The generated power flows into the utility grid through the back-to-back PWM converter. The line-side converter controls the dc link voltage by the q-axis current control and can control the line-side power factor by the d-axis current control. Experimental results are shown to verify the validity of the proposed scheme.

Seamless Transfer of Single-Phase Utility Interactive Inverters with a Synchronized Output Regulation Strategy

  • Xiang, Ji;Ji, Feifan;Nian, Heng;Zhang, Junming;Deng, Hongqiao
    • Journal of Power Electronics
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    • v.16 no.5
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    • pp.1821-1832
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    • 2016
  • This study presents a strategy using the synchronized output regulation method (SOR) for controlling inverters operating in stand-alone and grid-connected modes. From the view point of networked dynamic systems, SOR involves nodes with outputs that are synchronized but also display a desirable wave shape. Under the SOR strategy, the inverter and grid are treated as two nodes that comprise a simple network. These two nodes work independently under the stand-alone mode. An intermediate mode, here is named the synchronization mode, is emphasized because the transition from the stand-alone mode to the grid-connected mode can be dealt as a standard SOR problem. In the grid-connected mode, the inverter operates in an independent way, in which the voltage reference changes for generalized synchronization where its output current satisfies the required power injection. Such a relatively independent design leads to a seamless transfer between operation modes. The closed-loop system is analyzed in the state space on the basis of the output regulation theory, which improves the robustness of the design. Simulations and experiments are performed to verify the proposed control strategy.

Changes in Use and Functions of Second Doors in Detached Houses of Rural Area (농촌 단독주택 부출입문의 기능 및 이용변화에 대한 사례조사)

  • Byun, Kyeonghwa;Lee, Yunjeong;Kwon, Young-Gyu
    • Journal of the Korean Institute of Rural Architecture
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    • v.17 no.4
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    • pp.57-65
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    • 2015
  • In contrast to apartments, detached houses offer the possibility of more than one entrance connecting interior and exterior spaces. This study examines the location, function, and use of second doors in detached houses in rural areas. The study employs survey and interviews conducted in 2015, focusing on 18 detached houses among 40 houses previously surveyed in 1995. In 1995, 21 second doors were found, while in 2015, 19 were found. The study led to the following conclusions. First, most houses did have second doors installed by 1995 or 2015. Second doors tended to be installed in kitchen and utility rooms. The function of second doors was most closely connected to the kitchen because utility rooms were placed adjacent to kitchens. Secondly, changes in the use and number of second doors were changes in family life cycle and composition, the need for new equipment facilities, the use of new architectural materials, and the installation of new second doors for extension of space. Finally, exterior spaces accessed by second doors tend to be a meeting of semi-interior or semi-exterior space and exterior space only. Those spaces tended to be designed for kitchen fixtures or to support kitchen activities.

Economic Feasibility of Energy Storage System connected with Solar /Wind Power Generation (태양광/풍력 연계 기반의 ESS 경제성 분석)

  • Lee, Yong Bong;Kim, Jeong Ho
    • Journal of Energy Engineering
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    • v.24 no.3
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    • pp.74-81
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    • 2015
  • Currently, the government is encouraging the introduction of energy storage system to reduce carbon emissions and peak power demand. The government is planning the cumulative capacity of ESS of 2GW in 2020. By utilizing charge and discharge of the ESS, it is possible to sell the surplus power to utility and electricity market. This paper suggests the model that economic feasibility of energy storage system for planning the construction of power generation facilities in 2035. Our results of simulation indicate the energy storage plan of utility for constructing renewable energy facilities is need to incentives from the government to encourage power utilities and expansion of ESS.

A Novel Hybrid Anti-islanding Method to Improve Reliability of Utility Interactive Inverter for a PMSG-based Wind Power Generation System (PMSG 기반 풍력발전용 계통연계 인버터의 신뢰성 향상을 위한 새로운 하이브리드 단독운전 방지기법)

  • Kang, Sung-Wook;Kim, Kyeong-Hwa
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.27 no.11
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    • pp.27-36
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    • 2013
  • Islanding in a gird connected inverter of wind power generation system may influence a bad effect on equipments or yield safety hazards on grid so it should be detected rapidly and exactly. A passive method to detect islanding is comparatively simpler than an active method but suffers from non detection zone (NDZ). On the other hand, the active method can significantly reduce NDZ by injecting a disturbance into inverter output. To improve the reliability of islanding detection, this paper proposes a hybrid anti-islanding detection method combining the conventional passive method as well as the active method based on novel harmonic injection method using fourier transform. The proposed scheme is fast to detect islanding when NDZ does not exist because it has the nature of passive method. Under NDZ, the active method can detect occurrence of islanding reliably. The effectiveness and validity of the proposed scheme is proved through comparative simulations.