• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.161-163
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• 2005

The capability of unity-interactive type in PV generation system depends on its use. In a house, needs such a small capability, a single-phase output of PV can afford. But 3-phase output of PV is required in a case of big capabilities or a PV system directly interactive to 3-phase grid. To verify a validness of a large capable distributed-generation system supplied the proposed method, a 10kW inverter was realized in this paper. And from the results, the system is confirmed its stable operation and validness.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1788-1790
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• 2005

In this paper, an operating characteristics of a 50 kW gird-connected photovoltaic(PV) power system was analysed from 2000 to 2004. The construction of the PV system includes a 3-phase inverter for grid connection, PV module, distribution box, and data monitoring system. The major results of the demonstration test of the 50 kW class gird-connected PV system showed that efficiency of PV system was 11.13%, and the conversion efficiency of the inverter was 92% at a 50% load.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 춘계학술발표대회 논문집
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• pp.80-85
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• 2008

A PVIB(Photovoltaic in Building) system is united by a constituent outer covering and can expect dual effects that reduce expenses for the establishment of a PV system. It is a profitable technology because it does not need a building as it is a stand alone PV system. This paper presents design, operational features analysis, and PCS(Power Conditioning System) of grid-connected 30kW PVIB set up on the library of Dongshin University. For a sustainable photovoltaic system in this area, the data of the PVIB system are collected and analyzed by monitoring system using LabView. PCS of the grid-connected PVIB system, also, is designed for optimal operation with characteristics suggested in this paper.

• 한국정보통신학회논문지
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• 제17권1호
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• pp.127-136
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• 2013

계통연계형 인버터의 중요 성능 중 단독운전 검출기능 및 방지기능은 계통을 유지보수하기 위한 작업자의 안전을 위하여 고려되어야 할 필수 사항이다. 본 논문에서는 태양광을 이용한 계통연계형 태양광발전시스템에서의 AFS(Active Frequency Shake) 단독운전 검출기법을 제안하고자 한다. 먼저 AFS 단독운전 검출 알고리즘을 제안하기 위하여 기존의 능동 주파수 변이기법 알고리즘에 대해 기술한다. 그리고 단독운전 불검출영역을 줄이고, THD(Total Harmonic Distortion)를 개선하며, 기존 알고리즘 보다 검출 속도 또한 향상 시킬 수 있는 알고리즘을 제시하였다. 아울러 제안된 단독운전방지 기법을 3kW 계통연계형 태양광 인버터에 적용하고 시뮬레이션 및 실험을 통하여 제안하는 알고리즘의 타당성을 검증하였다.

• KIEAE Journal
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• 제15권6호
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• pp.5-10
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• 2015

Purpose: To evaluate the economic performance of grid-connected photovoltaic system in residential house, household electricity bill policy of Korea Electric Power Corporation (KEPCO) must be applied precisely, and market tendency and uncertainty of system also need to be considered. In this study, to evaluate the economic feasibility of PV system, we measured PV power generation and electricity consumption of six of Green home in Daejeon through web based remote monitoring system. Method: We applied Monte-Carlo simulation based on life cycle cost analysis, to reflect an uncertainty of main factor in economic feasibility evaluation of photovoltaic system. Result: First, with deterministic analysis, the difference of NPV of cumulative financial savings among households varied from -3,310 ~ 24,170 thousand won, portraying notably big range. Also the possibility of getting the same result was 50% when applying uncertainty. Second, the higher electricity consumption is, the more economic feasibility of photovoltaic system increases because KEPCO uses progressive taxation in household electricity bill policy. Third, The contribution to variance of electricity price increases in NPV varied from 98.5% to 99.9%. While the inflation rate and annual degradation contributed very little to none.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권5호
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• pp.280-286
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• 2006

The paper proposes a new protection algorithm for reliable operation of grid-interfaced PV system, which can flexibly interact with conventional protective schemes of power utility grid not only to prevent damages to utility or public persons and utility apparatus caused by malfunction or failure in distribution network protection system, but also to protect a PV system itself from faults or abnormal conditions of the network. The proposed algorithm is based on reclosing characteristics of the distribution system. As a network fault occurs, the new scheme determines whether it is momentary or permanent and responds in a pre-programmed way to the fault. For permanent outage, the proposed algorithm shuts down inverter's operations but monitoring system voltage and frequency at the point of common coupling with grid. When it comes to the momentary outage, Inverter starts stand-by operation mode so that it can be automatically connected to the grid without start-up procedures as soon as the system voltage and frequency returns into the normal operation range. In order to investigate' and evaluate the PV system operation, simulation study based on PSCAD/EMTDC has been carried out to verify the performance of the proposed protection scheme.

• 조명전기설비학회논문지
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• 제21권9호
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• pp.64-75
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• 2007

Photovoltaic systems utilize the infinite clean energy of the sun, without creating any air pollution or noise and mechanical vibration. A PV system operates without the need of fuel, rotation surfaces, high temperatures or high pressures. It is therefore to do maintain and simple to install as well as having a long life cycle. The global market for PV systems continues to grow rapidly by 30[%] per year. This paper suggests a new design method for the PV system installation that will allow to the improvement of system efficiency. This method is in accordance with the loss parameter compensation method designed for the PV systems and investigated through simulation and practical experimentation. It was applied to an interconnected 10[kW] grid PV system and was demonstrated in the field. Features such as solar array, PCS, system efficiency, performance and stability were considered. Through the proposed optimal parameter design method, the features of the system were studied, and the 10[kW] PV system was demonstrated and analyzed.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.406-407
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• 2011

The dc link voltage in a single-phase PV system has necessarily twice component of fundamental wave. It makes high THD in the grid current, and according to the problem, power quality is lower. This paper proposes the new method for removing ripple voltage. The performance was verified through computer simulation using MATLAB.

• 한국태양에너지학회 논문집
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• 제35권2호
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• pp.11-19
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• 2015

Islanding is a phenomenon that EPS(Electric Power System) is continuously energized by PV PCS(Photovoltaic Power Conditioning System) even when EPS is isolated from the grid. Unintentional islanding will result in safety hazard, power quality degradation and many other issues. So, islanding protection of grid-connected PV PCS is a key function for standards compliance. Nowadays, many anti-islanding schemes are researched. But existing anti-islanding schemes used in PV PCS have power quality degradation and non-detection zone issues. This paper analyses not only detection performance of existed anti-islanding schemes using active frequency drift but also THD of PCS output current according to each value disturbance for anti-islanding. In addition, the lowest value of disturbance in each scheme was tabulated under guarantee of anti-islanding condition.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1077-1078
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• 2008

The growing number of nonlinear loads such as static power converters has posed a problem on the quality of electric power supply. The active filters (AF) have been rapidly expanding with the advancement of power electronics technology. The purpose of the active filters is to compensate current harmonics and/or current imbalance. The authors have studied and introduced the PV-AF system; the PV power system, which is used widely as a dispersed source, including the function of active filter to compensate the harmonics caused by nonlinear loads. The PV-AF system has merits not only to compensate harmonics caused by nonlinear loads but also to increase the utilization of PCS. This paper describes the grid-connected single phase PV-AF system and the PSCAD/EMTDC simulation results.