• 한국정보통신학회논문지
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• 제12권2호
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• pp.290-298
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• 2008

본 논문에서는 모니터링 시스템의 데이터 취득과 처리 과정에 있어 데이터를 효율적으로 저장, 복원시킬 수 있는 방법을 제시한다. 타겟 시스템에서 취득된 원시 데이터로부터 보간법을 기반으로 최소의 데이터를 추출한다. 이는 TCP/IP 통신에 의해 모니터링 PC로 전송되어 저장되며, 보간법을 통해 다시 원 신호로 복원된다. 따라서 통신 패킷양이 저감되어 데이터 통신 속도가 향상되며, 데이터 저장 공간을 줄일 수 있어 장시간에 걸쳐 취득되는 데이터를 효율적으로 관리할 수 있는 모니터링 시스템 설계가 가능하다. 제안된 데이터 취득과 복원 알고리즘은 큐빅 헤르미트 보간법에 기반을 둔다. 데이터 처리 방법의 타당성을 검증하기 위해 시뮬레이션 결과를 제시하며, 타 보간법 적용에 의한 결과와 비교하여 우수성을 검증한다. 계통연계형 태양광 발전 인버터의 모니터링 시스템에 적용하여 제안된 방식의 효율성을 실험적으로 검증한다.

• 한국조경학회지
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• 제40권4호
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• pp.28-35
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• 2012

최근 지속 가능한 도시시스템 구축을 위해 신, 재생에너지 시스템에 대한 사회적 관심이 집중되고 있으며, 이에 따른 관련 연구가 활발히 진행되고 있다. 전체 에너지 소비의 40% 이상을 차지하고 있는 건설부문 또한 이러한 경향이 두드러지고 있다. 조경부문도 재생에너지설비가 적용된 다양한 조경시설물이 제작, 설치되고 있으나, 계획, 설계단계에서 활용 가능한 체계적인 연구가 아직 국내에 보고되고 있지 않다. 본 연구는 조경시설물에 재생에너지 시스템을 적용하면서 발생되는 에너지, 경제적 효과를 정량적으로 도출하여 조경계획 및 설계에 활용하고자 한다. 이를 위해 서울, 인천, 대구의 도시공원 내 가로등 전력을 계통연계형 태양광시스템으로 대체하는 스마트 가로등 적용 시나리오를 적용하여 에너지, 경제적 해석을 수행하였다. 전산모의는 NASA Satellite Meteorological Data를 이용한 청정에너지 전산모의 프로그램인 RETScreen$^{(R)}$을 적용하였다. 결과적으로 해당 도시의 기후적 특성에 따라 발전량 및 경제성의 차이를 보였으며, 본 연구결과는 향후 조경계획 및 설계에 건전한 재생에너지 시스템 적용을 위한 의사결정에 활용될 것으로 사료된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.994-995
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• 2006

This paper presents a grid-connected photovoltaic (PV) system with direct coupled power quality control (PQC) algorithm, which uses an inner current control loop (PRT : polarized ramp time) and outer feedback control loop to improve grid power quality and maximum power point tracking (MPPT) of PV arrays. To reduce the complexity, cost and number of power conversions, which results in higher efficiency, single stage CCVSI (Current Controlled Voltage Source Inverter) is used. The proposed system operation has been divided into two modes (sunny and night). In night mode, the proposed system operates to compensate the reactive power demanded by nonlinear or variation in loads. in sunny mode, the proposed system performs PQC to reduce harmonic current and improve power factor as well as MPPT to supply active power from the PV arrays simultaneously. it is shown that the proposed system improves the system utilization factor to 100% which is generally low for PV system (20%). To verify the proposed system, a comprehensive evaluation with theoretical analysis and simulation results are presented.

• 조명전기설비학회논문지
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• 제25권8호
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• pp.88-98
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• 2011

Development and use of renewable energy due to environmental problems and depletion of energy affect grid-connected power system around the world. Therefore this paper analyzes the characteristic of gird connected photovoltaic power generation system which it is available to connect the utility. Renewable energy photovoltaic power system has been linked to the system to analyze the impact of photovoltaic system. MATLAB / Simulink program is modeled and analyzed on power quality of a photovoltaic power plant. It is measured that power data for the Grid connected photovoltaic power plant with instantaneous measuring, 3sec measuring, 10min measuring for 7 days. Harmonic field measurement have shown that the harmonic contents of a waveform varies with time. A cumulative probability approach is the most commonly used method to solve time varying harmonics. so, it is used 50[%] cumulative probability approach. This paper provides an in depth analysis on power quality field measurement of the Grid connected photovoltaic power plant.

• 대한전기학회논문지:전력기술부문A
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• 제54권3호
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• pp.107-116
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• 2005

The paper addresses modeling and analysis of a grid-connected photovoltaic generation system (PV system). PSCAD/EMTDC, an industry standard simulation tool for studying the transient behavior of electric power system and apparatus, is used to conduct all aspects of model implementation and to carry out extensive simulation study. This paper is aimed at sharing with the PSCAD/EMTDC user community our user-defined model for PV system applications, which is not yet available as a standard model within PSCAD/EMTDC. An equivalent circuit model of a solar cell has been used for modeling solar array. A series of parameters required for array modeling have been estimated from general specification data of a solar module. A PWM voltage source inverter (VSI) and its current control scheme have been implemented. A maximum power point tracking (MPPT) technique is employed for drawing the maximum available energy from the PV array. Comprehensive simulation results are presented to examine PV array behaviors and PV system control performance in response to irradiation changes. In addition, dynamic responses of PV array and system to network fault conditions are simulated and analysed.

• 전기학회논문지P
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• 제54권3호
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• pp.111-118
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• 2005

Since the residential load is an AC load and the output of solar cell is DC power, the photovoltaic system needs the DC/AC converter to utilize solar cell. In case of driving to interact with utility line, in order to operate at unity power factor, converter must provide the sinusoidal wave current and voltage with same phase of utility line. Since output of solar cell is greatly fluctuated by insolation, it is necessary that the operation of solar cell output in the range of the vicinity of maximum power point. In this paper, DC/AC converter is three phase PWM converter with smoothing reactor. And then, feed-forward control used to obtain a superior characteristic for current control and digital PLL circuit used to detect the phase of utility line.

• 전기학회논문지
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• 제56권1호
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• pp.8-13
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• 2007

During the last years, there has been an increased interest in the new energy such as photovoltaic(PV) system from the viewpoint of environmental pollution. In this regard, this paper estimates the power quality of grid-connected PV system. As the maximum power operating point(MPOP) of photovoltaic(PV) power systems alters with changing atmospheric conditions, the efficiency of maximum power point tracking(MPPT) is important in PV power systems. Moreover, grid-connected PV system occurs some problems such as voltage inequality and harmonics. Therefore, this paper presents the results of a grid-connected PV system modeling that contains incremental conductance MPPT controller by PSCAD/EMTDC simulator and investigates the influence that can occur in the grid-connected PV system from aspect of power quality, i.e. voltage drop, total harmonic distortion(TDD) and total demand distortion(TDD). For the case study, the measured data of the PV way in Cheongwadae, Seoul, Korea is used.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.133-136
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• 2004

Since the residential load is an AC load and the output of solar cell is a DC power, the photovoltaic system needs the DC/AC converter to utilize solar cell. In case of driving to interact with utility line, in order to operate at unity power factor, converter must provide the sinusoidal wave current and voltage with same phase of utility line. Since output of solar cell is greatly fluctuated by insolation, it is necessary that the operation of solar cell output in the range of the vicinity of maximum power point. In this paper, DC/AC converter is three phase PWM converter with smoothing reactor. And then, feedforward control used to obtain a superior characteristic for current control and digital PLL circuit used to detect the phase of utility line.

• 전력전자학회논문지
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• 제19권3호
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• pp.201-210
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• 2014

In this paper, dc-link voltage control of a grid-connected QZSI is presented. Since the input current of the ZSI is discontinuous, a capacity with relatively large capacitance should be connected to the output of the PV array in order to reduce the current ripple. Due to the presence of the impedance network inductor in series with the PV array, the QZSI can achieve continuous input current flow. Several dc-link voltage control methods are compared and the method for power quality improvement is also presented. The performance of the proposed method is verified through both simulation and experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1253-1255
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• 2003

Since the residential load is an AC load and the output of solar cell is a DC Power, the photovoltaic system needs the DC/AC converter to utilize solar cell. In case of driving to interact with utility line, in order to operate at unity power factor, converter must provide the sinusoidal wave current and voltage with same phase of utility line. Since output of solar cell is greatly fluctuated by insolation. it is necessary that the operation of solar cell output in the range of the vicinity of maximum power point. In this paper DC/AC converter is three phase PWM converter with smoothing reactor. And then, feedforward control used to obtain a superior characteristic for current control and digital PLL circuit used to detect the phase of utility line.