• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.719-723
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• 1998

Prevention of the islanding phenomena is one of the most important issues because it can damage electrical equipment connected to the utility system and endanger human life. It is very difficult to detect an islanding condition of a power distribution line with conventional voltage of frequency relays, while the output power and the load power of utility interactive PV inverter units are in nearly balanced state in both active power and reactive power. This paper describes the protective equipment that prevents the PV system connected to the utility grid from starting islanding. Both predictive ocntrol method and harmonic injection method are used for a current control and islanding detection for operating safety.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.130-131
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• 2013

In this paper, it suggests offset compensation method of output current in single phase PV-BES system which is connected with grid. The algorithm applied removes grid's frequency ingredient using a notch filter and it extracts only DC offset current. It can reduce problems as saturation of power transformer cause by DC current when it is indoctrinated to grid.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1298-1300
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• 1996

The application field of photovoltaic system which has no-pollution and no-fuel distinctives is being spreaded inspite of its high installation cost. At present, there are three PV systems within the country, which were already installed and have been operated to supply the electric power in remote island. In this paper, the electrification plan of our government on the unelectrified or subelectrified islands is introduced, and the operation results of three PV systems are investigated to discuss the diffusion possibility of PV system as a power supply option.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.6
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• pp.498-505
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• 2001

This paper shows how to design a global control of water pumping system using PV array, and tracked maximum power point of PV array only the inverter using the vector control of BLDC motor, and finding the relationships among the DC magnitudes and AC ones in order to omit the DC/DC converter. Conventional MPPT controller was unstable of reason of the ripple-current of DC link in three-phase invertor. Thus, in this paper the control algorithm of BLDC motor using $i_qs$ current is composed to improve the insecurity of conventional MPPT controller To prove the excellence of the proposed method, the contents of this paper is analyzed by means of simulation and testing for the results applying the method that J. A Domfnguez had applied to asynchronous motor to BLDC motor and that of the proposed method in this paper.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2951-2957
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• 2010

In solar industry the development of tracking PV power generation devices progresses favorably because of its efficiency, comparing with fixed PV power generation devices. Tracking PV power generation device are not only preserving the amount of solar radiation per unit area but also maximizing the efficiency of solar battery. Therefore accurate and low-priced solar position tracking devices are very important to improve the economical efficiency and lower invest price. This research is concerned with solar position algorithm with uncertainties equal to 1 minute($0.016^{\circ}$) using the mathmatics and astronomg. Proposed algorithm in this paper, lowers the implementation price and improves power generation efficiency. In view of the result so far achieved, maximum error has 30 secend($0.008^{\circ}$). And the solar cell generating system applied by this algorithm showed the gain of the fixed type contrast average 23W(about 18%).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.1
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• pp.12-17
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• 2008

In this paper, an I-V characteristics of bypass diode has been studied by counting the shading effect in photovoltaic module. The shadow induces hot spot phenomenon in PV module due to the increase of resistance in the current path. Two different types of PV module with and without bypass diode were fabricated to expect maximum output power with an increasing shading rate of 5 % on the solar cell. Temperature distribution is also detected by shading the whole solar cell for the outdoor test. From the result, the bypass diode works properly over 60 % of shading per cell with constant output power. Maximum power generation in case of solar cell being totally shaded with bypass diode decreases 41.3 % compared with the one under STC(Standard Test Condition). On the other hand, the maximum output power of the module without bypass diode gradually decreases by showing hot spot phenomenon with the increase of shading ratio on the cell and finally indicates 95.5 % of power loss compared with the output under STC. Finally the module temperature measured increases around $10^{\circ}C$ higher than that under STC due to hot-spots which come from the condition without bypass diode. It has been therefore one of the main reasons for degrading the PV module and shortening the durability of the PV system.

• Journal of Climate Change Research
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• v.7 no.3
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• pp.217-229
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• 2016

Increased evidences reveal that the global climate change adversely affect on the environment. Smart grid system is one of the ways to reduce greenhouse gas emissions in the electricity generation sector. Since 2013, Korea Electric Power Corporation (KEPCO) has installed smart grid station in KEPCO office buildings. The goal of this paper is two folds. One is to quantify the reduction in greenhouse gas emissions through smart grid stations installed in KEPCO office buildings as a part of pilot project. Among components of smart grid stations, this research focused on the photovoltaic power system (PV) and energy storage system (ESS). The other is to estimate the reduction in greenhouse gas emissions when PV is applied on individual houses. Results show that greenhouse gas emissions reduce 5.8~11.3% of the emissions generated through the electricity usage after PV is applied in KEPCO office buildings. The greenhouse gas emissions reduction from ESS is not apparent. When PV of 200~500 W is installed in individual houses, annual greenhouse gas emission reduction in 2016 is expected to be approximately $2.2{\sim}5.4million\;tCO_2-eq$, equivalent to 6~15% of greenhouse gas emissions through the electricity usage in the house hold sector. The saving of annual electricity cost in the individual house through PV of 200 W and 500 W is expected to be 47~179 thous and KRW and 123~451 thousand KRW, respectively. Results analyzed in this study show the environmental effect of the smart grid station. In addition, the results can be further used as guidance in implementing similar projects.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.127-131
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• 2005

The paper addresses modeling and analysis of a grid-connected photovoltaic generation system (PV system). PSCAD/EMIDC. 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. An equivalent circuit model of a solar cell has been used for modeling solar array. 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

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.478_479
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• 2009

It is important to find the maximum efficient conditions for the output of the photovoltaic(PV) system to determine the optimal installation location of the PV system. The output of PV system depends on the irradiance. Therefore, this paper introduces the pilot experiment set to track the output of PV system according to the variance of irradiance and analyzes the result of experiment using this set. The pilot experiment set consists of the PV modules and the inverter to convert DC power to AC power. For this experiment, the fixed and tracked modules are used.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1090_1091
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• 2009

In 2008, the global photovoltaic(PV) market reached 5.6GW and the cumulative PV power installed totalled almost 15GW compared to 9GW in 2007. Due to a favourable feed-in-tariff, Korea emerged in 2008 as the 4th largest PV market worldwide. PV power installation rose 495.5 percent to 268MW in 2008 compare to 45MW in 2007. And PV manufacturer will increase the capacity of production facilities by 910MW in 2009. If the 500MW cap is removed, the growth of the korea market will reach up to 1GW by 2013.