• Title/Summary/Keyword: AFD(Active Frequency Drift)

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A Study of Non-Detection Zone using AFD Method applied to Grid-Connected Photovoltaic Inverter for a variety of Loads (계통연계형 태양광발전 인버터에 사용된 AFD기법의 다양한 부하에 따른 단독운전 불검출영역에 대한 고찰)

  • Ko, Moon-Ju;Choy, Ick;Choi, Ju-Yeop
    • Journal of the Korean Solar Energy Society
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    • v.26 no.1
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    • pp.91-98
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    • 2006
  • Islanding phenomenon of utility-connected photovoltaic power conditioning systems(PV PCS) can cause a variety of problems and must be prevented. If the real and reactive power supplied by PV PCS are closely matched to those of load, islanding detection by passive methods becomes difficult. The active frequency drift(AFD) method, called the frequency bias method, enables islanding detection by forcing the frequency of the voltage in the islanding to drift up or down. In this paper, non-detection zone(NDZ) of AFD is analyzed for the islanding detection method of utility-connected PV PCS by the simulation software tool PSIM.

A Novel Active Anti-islanding Method for Grid-connected Photovoltaic Inverter

  • Jung, Young-Seok;Choi, Jae-Ho;Yu, Gwon-Jong
    • Journal of Power Electronics
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    • v.7 no.1
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    • pp.64-71
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    • 2007
  • This paper proposes a novel active frequency drift (AFD) method to improve the islanding detection performance with minimum current harmonics. To detect the islanding phenomenon of grid-connected photovoltaic (PV) inverters concerning the safety hazards and possible damage to other electric equipment, anti-islanding methods have been described. The AFD method that uses chopping fraction (cf) enables the islanding detection to drift up (or down) the frequency of the voltage during the islanding situation. However, the performance of the conventional AFD method is inefficient and causes difficulty in designing the appropriate cf value to meet the limit of harmonics. In this paper, the periodic chopping fraction based on a novel AFD method is proposed. This proposed method shows the analytical design value of cf to meet the test procedure of IEEE Std. 929-2000 with power quality and islanding detection time. To verify the validation of the proposed method, the islanding test results are presented. It is confirmed that the proposed method has not only less harmonic distortion but also better performance of islanding detection compared with the conventional AFD method.

Novel AFD method of islanding detection with a periodic zero current for improving on islanding detection for grid-connected Photovoltaic inverters (계통연계형 태양광발전 인버터를 위한 주기적인 영전류 구간을 가지는 새로운 AFD 단독운전 검출기법)

  • Ko, Moon-Ju;Choy, Ick;Choi, Ju-Yeop;Song, Seung-Ho;Lee, Ki-Ok
    • Journal of the Korean Solar Energy Society
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    • v.26 no.4
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    • pp.17-23
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    • 2006
  • This paper proposes a novel active frequency drift (AFD) method for the islanding prevention of grid-connected photovoltaic inverter. To detect the islanding phenomenon of grid-connected photovoltaic (PV) inverters concerning about the safety hazards and the damage to other electric equipments, many kinds of anti-islanding methods have been presented. Among them, AFD method using chopping fraction enables the islanding detection to drift up (or down) the frequency of the voltage during the islanding situation. In this paper, injecting the periodic zero current into the basic AFD method is proposed. This proposed method shows the analytical design value of cf to meet the test procedure of IEEE Std. 1547 with various load conditions. Detection of islanding is verified using simulation tool PSIM.

Simulation of Non-Detection Zone using AFD Method applied to Utility-Connected Photovoltaic Systems for a Variety of Loads (다양한 부하에 따른 계통연계형 태양광발전 시스템에 적용된 AFD 기법의 단독운전 불검출영역 시뮬레이션)

  • Ko, Moon-Ju;Choy, Ick;Choi, Ju-Yeop;Won, Young-Jin
    • 전자공학회논문지 IE
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    • v.43 no.2
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    • pp.63-69
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    • 2006
  • Islanding phenomenon of utility-connected PV power conditioning systems(PV PCS) can cause a variety of problems and must be prevented. If the real and reactive powers supplied by PV PCS are closely matched to those of load, islanding detection by passive methods becomes difficult. The active frequency drift(AFD) method, called the frequency bias method, enables islanding detection by forcing the frequency of the voltage in the islanding to drift up or down. In this paper, non-detection zone(NDZ) of AFD is analyzed for the islanding detection method of utility-connected PV PCS by simulation tool PSIM.

Active Frequency Drift Method for Islanding Detection Applied to Micro-inverter with Uncontrollable Reactive Power

  • Kwak, Raeho;Lee, June-Hee;Lee, Kyo-Beum
    • Journal of Power Electronics
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    • v.16 no.5
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    • pp.1918-1927
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    • 2016
  • This paper proposes active frequency drift (AFD) as an anti-islanding method applied to micro-inverters with uncontrollable reactive power. When using ordinary inverter topologies, such as full bridge inverters in photovoltaic systems, the islanding phenomenon can be detected with reactive power-based methods, such as reactive power variation. However, when the inverter topology cannot control the reactive power, conventional anti-islanding methods with reactive power cannot be utilized. In this work, the topology used in this paper cannot control the reactive power. Thus, an anti-islanding method that can be used in topologies that cannot control the reactive power is proposed. The conventional anti-islanding method of the topology that cannot control reactive power is introduced and analyzed. Unlike the conventional AFD method, the proposed method extends a zero current interval every predetermined cycle. The proposed method offers certain advantages over conventional AFD methods, such as total harmonic distortion. The proposed method is validated through simulation and experiment.

THD Analysis of Output Current for Active Frequency Drift Method in Anti-islanding (능동적 주파수 변환기법의 출력전류 고조파 왜형율 분석)

  • Lee, Ki-Ok;Choi, Ju-Yeop;Choy, Ick;Yu, Gwon-Jong;An, Jin-Ung
    • Journal of the Korean Solar Energy Society
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    • v.30 no.1
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    • pp.7-12
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    • 2010
  • As many grid-connected photovoltaic power conditioning systems (PVPCS)are installed in many residential areas simultaneously, these have raised potential problems of network protection on electrical power system. One of the numerous problems is an Islanding phenomenon. In this paper, active frequency drift (AFD) method, one of the anti-islanding methods which is analyzed by current magnitude compensation and calculation of the fundamental component. Both harmonic component and RMS value of the output current for THD analysis are provided and verified by simulation.

Output Power Analysis of Active Frequency Drift Method for Anti-Islanding (단독운전방지를 위한 능동적 주파수 변환기법의 출력전력 분석)

  • Lee, Ki-Ok;Choi, Ju-Yeop;Choy, Ick;Yu, Gwon-Jong;An, Jin-Ung
    • Journal of the Korean Solar Energy Society
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    • v.29 no.6
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    • pp.75-80
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    • 2009
  • Recently, as the grid-connected photovoltaic power conditioning systems (PVPCS) are installed in many residential areas, these have raised potential problems of network protection on electrical power system. One of the numerous problems is an Islanding phenomenon. In this paper, active frequency drift (AFD) method, one of the anti-islanding methods which is analyzed by current magnitude compensation and calculation of RMS value of the output power is proposed and verified by simulation.

Analytical comparison of AFD and RPV methods for Anti-Islanding (단독운전방지를 위한 AFD 와 RPV 방식의 비교 분석)

  • Ba, Yasgalan;Lee, Young-Jin;Jeong, Byong-Hwan;Kim, Hong-Sung;Choe, Gyu-Ha
    • Proceedings of the KIPE Conference
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    • 2008.10a
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    • pp.64-67
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    • 2008
  • To detect islanding mode when the grid is being tripped is a major safety issue in the Utility Interactive Distributed Generation (UIDG) system. In this paper, analytical design method is suggested for AFD & RPV method under IEEE929-2000 recommended islanding test condition. We have discussed that there is a same point. we injected reactive component of the current by AFD & RPV methods, but the current reference generated is other waveform. Possible if amount of reactive components in this methods are same each method, there is happened same rates frequency variation. To verify the validity of the analytical comparison, this paper presents simulation and experimental results from single phase, 3[kW] inverter for the transformerless UIDG system.

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Novel islanding detection method for grid connected PV system (계통연계형 태양광발전시스템의 새로운 단독운전 검출기법)

  • Jung, Young-Seok;So, Jung-Hun;Yu, Byung-Gyu;Yu, Gwon-Jong;Choi, Jae-Ho
    • Proceedings of the KIEE Conference
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    • 2005.07b
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    • pp.1705-1707
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    • 2005
  • This paper proposes a novel active frequency drift(AFD) method for the islanding prevention of grid-connected photovoltaic inverter. To detect the islanding phenomenon of grid-connected photovoltaic(PV) inverters concerning about the safety hazards and the damage to other electric equipments, many kinds of anti-islanding methods have been presented. Among them, AFD method using chopping fraction(cf) enables the islanding detection to drift up(or down) the frequency of the voltage during the islanding situation. However, the performance of the conventional AFD methods, which have a certain value of cf only, is inefficient and difficult to design the appropriate cf value analytically to meet the limit of harmonics. In this paper, the periodic chopping fraction based on an AFD method is proposed. This proposed method shows the analytical design value of cf to meet the test procedure of IEEE Std. 929-2000 with the power quality and islanding detection time. To verify the validation of the proposed method, the islanding test results are presented. It is confirmed that the proposed method has not only less harmonic distortion but also good performance of islanding detection compare with the conventional AFD method.

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Output Power Analysis for Active Frequency Drift Method (AFD 기법의 출력전력 분석)

  • Lee, Ki-Ok;Choi, Ju-Yeop;Choy, Ick;Yu, Gwon-Jong
    • 한국태양에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.297-302
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    • 2009
  • As the grid-connected photovoltaic power conditioning systems (PVPCS) are installed in many residential areas, these have raised potential problems of network protection on electrical power system. One of the numerous problems is an Islanding phenomenon. In this paper, active frequency drift (AFD) method, one of the anti-islanding analyzed by current magnitude compensation and calculation of RMS value of the output power.

  • PDF