• Journal of the Korean Solar Energy Society
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• v.33 no.5
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• pp.18-23
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• 2013

This paper presents a simple but valid loss calculation method of grid-connected photovoltaic system based on normalized yield model. The proposed method can be represented as a quantitative value for five losses and performance of grid-connected photovoltaic system with three years monitored data. These results will indicate that it is useful to investigate various loss factors causing the performance obstruction, enhance the lifetime yield for changing meteorological conditions, and determine the optimal design and performance improvement of grid-connected photovoltaic system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.8
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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.

• Journal of the Korean Solar Energy Society
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• v.37 no.3
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• pp.23-32
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• 2017

This paper presents losses comparison and analysis results for different types of fault modes of grid-connected photovoltaic system generated for long-term operation. The approach of losses comparison and analysis by faults is to identify relationship between measured and estimated values of five loss factors which are quantified from irradiance to system output power. This paper presents the symptom results for faults such as snow, shading, sensor defect, blackout, soiling and so on from three years or more monitored data. These results will indicate that it is useful to develop fault detection and diagnosis tool to enhance capacity factor and save operation and maintenance cost of grid-connected photovoltaic system in the field.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.5
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• pp.48-57
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• 2012

This paper analyzes the characteristic of gird connected photovoltaic power generation system which is available to connect the utility. Renewable energy photovoltaic power system has been linked to the system to analyze the impact of photovoltaic system. It is measured that power data for the Grid connected photovoltaic power plant with instantaneous measuring and 3-sec measuring for 7 days. Harmonic field measurements 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.

• Journal of Power Electronics
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• v.11 no.4
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• pp.561-567
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• 2011

This paper presents a high-efficiency power conditioning system (PCS) for grid-connected photovoltaic (PV) modules. The proposed PCS consists of a step-up DC-DC converter and a single-phase DC-AC inverter for the grid-connected PV modules. A soft-switching step-up DC-DC converter is proposed to generate a high DC-link voltage from the low PV module voltage with a high-efficiency. A DC-link voltage controller is presented for constant DC-link voltage regulation. A half-bridge inverter is used for the single-phase DC-AC inverter for grid connection. A grid current controller is suggested to supply PV electrical power to the power grid with a unity power factor. Experimental results are obtained from a 180 W grid-connected PV module system using the proposed PCS. The proposed PCS achieves a high power efficiency of 93.0 % with an unity power factor for a 60 Hz / 120 Vrms AC power grid.

• New & Renewable Energy
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• v.1 no.3 s.3
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• pp.35-41
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• 2005

This paper analyses the economics of grid-connected photovoltaic systems. With the 2003 cost of photovoltaic systems, under prevailing capital market conditions, with a system lifetime of 30 years, and under the best climatic conditions, it appears that the cost of production of grid-connected electricity could be of 0.21 US $/kWh, and under medium climatic conditions, European locations, Switzerland, Japan and South Korean could be of 0.28$/kWh. If the lifetime if the system goes up, due to future technological improvements, to a very large value such as 50 years, these costs can be lowered by 10-20%. Competitiveness of grid-connected photovoltaic electricity, while it still cannot be taken for granted, is a possibility, especially if major technological advances further lowers the costs of photo cells and increases their lifetimes.

• Journal of Power Electronics
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• v.7 no.2
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• pp.174-180
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• 2007

In this paper, a simple control method for two-stage utility grid-connected photovoltaic power conditioning systems (PCS) is proposed. This approach enables maximum power point (MPP) tracking control with post-stage inverter current information instead of calculating solar array power, which significantly simplifies the controller and the sensor. Furthermore, there is no feedback loop in the pre-stage converter to control the solar array voltage or current because the MPP tracker drives the converter switch duty cycle. This simple PCS control strategy can reduce the cost and size, and can be utilized with a low cost digital processor. For verification of the proposed control strategy, a 2.5kW two-stage photovoltaic grid-connected PCS hardware which consists of a boost converter cascaded with a single-phase inverter was built and tested.

• Journal of the Korean Solar Energy Society
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• v.33 no.5
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• pp.89-94
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• 2013

This paper presents a simple but valid design factor calculation method of grid-connected photovoltaic system using normalized yield model. The proposed calculation method can be represented as a quantitative value about five design factors from irradiance to system output power. The validity of this method is identified by analyzing design factor with three years monitored data. These results will indicate that it is useful to determine the optimal design and selection of grid-connected photovoltaic system to meet different user purposes and enhance long-term reliability and stability of grid-connected photovoltaic system.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.333-338
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• 2014

This paper concerns the development of the transformer that can reduce harmonics supplied to the system if the output of photovoltaic inverter in the photovoltaic system is grid-connected, and suggests that problems of harmonics and power factor degradation in the grid-connected photovoltaic system can be improved. In this study, the burden of increasing the investment in new facilities and securing their installation space due to harmonics has been substantially eased through the development of a hybrid transformer possessing unbalanced function and harmonics reduction function using zig-zag coils, and most of all, it is expected that the development of such high efficiency hybrid transformer possessing functions of transformation and reducing harmonics can improve the power quality as well as prevent damages caused by harmonics, leading to suppress unnecessary loss of electric power and thereby contribute to energy savings.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2436-2438
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• 1998

The operating characteristics of a 3 kW grid-connected photovoltaic (PV) power system was studied by analying annual photovoltaic data. The system performance for grid connection was investigated using a DC/ AC inverter. The results of a demonstration test show that the system utilization rate is 15.6% and the system efficiency is 8.03%.