• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.3
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• pp.486-492
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• 2017

In recent years, renewable energy sources have been mentioned as solution to environmental regulation and energy supply-demand. Energy storage systems are needed to mitigate the intermittent output characteristics of renewable energy sources and to operate micro grid efficiently using renewable energy generation systems. However, despite the necessity of energy storage system, this cannot secure the economical efficiency of the energy storage system by high initial cost. In this paper, a micro grid is constructed to supply electric power to industrial customers by using solar power generation system and energy storage system among renewable energy generation power sources and operated to improve energy independence. In the case study, we use photovoltaic system which is representative renewable energy generation system. Unlike conventional photovoltaic system, this system uses floating photovoltaic system with the advantage of having high output and no land area limitations. It is operated for the purpose of improving energy independence in the micro grid. In order to secure economical efficiency, the energy storage system operates a micro grid with a minimum capacity. Finally, this paper calculates the appropriate subsidy for the energy storage capacity.

• Journal of the Korean Solar Energy Society
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• v.28 no.4
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• pp.62-67
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• 2008

In this study, we analyze the electrical characteristics of amorphous silicon thin film photovoltaic module which are installed about 5 years ago. Four modules from PV system are extracted and measured the maximum power change ratio using solar simulator(Class A). Also, infrared camera is used to get thermal distribution characteristics of system. The external appearance change is compared with initial module by naked eye examination. Through this experiment, 31% maximum output power drop is observed. The detail description is specified as the following paper.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.5
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• pp.207-217
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• 2018

Recently, the importance of energy demand management, particularly peak load control, has been increasing due to the policy changes of the Second Energy Basic Plan. Even though the installation of distributed generation systems such as Photovoltaic and energy storage systems (ESS) are encouraged, high initial installation costs make it difficult to expand their supply. In this study, the power consumption of a university building was measured in real time and the measured power consumption data was used to calculate the optimal installation capacity of the Photovoltaic and ESS, respectively. In order to calculate the optimal capacity, it is necessary to analyze the operation methods of the Photovoltaic and ESS while considering the KEPCO electricity billing system, power consumption patterns of the building, installation costs of the Photovoltaic and ESS, estimated savings on electric charges, and life time. In this study, the power consumption of the university building with a daily power consumption of approximately 200kWh and a peak power of approximately 20kW was measured per minute. An economic analysis conducted using these measured data showed that the optimal capacity was approximately 30kW for Photovoltaic and approximately 7kWh for ESS.

• Journal of the Korean Solar Energy Society
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• v.31 no.1
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• pp.8-14
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• 2011

Recently, a number of large-scale photovoltaic(PV) power generation system has been installed all over the world. Thus, in order to improve the system efficiency, the optimal design of the large-scale PV systems has become an important issue. DC cable loss of PV array is one of the design factors related to the system efficiency. This paper introduces the array design method of a 500kW Photovoltaic power plant. Three types of the PV array are suggested. Also, string cables, sub-array cables and array cables are designed within 1% of voltage drop in the line, and the DC cable losses are analyzed. The results of this paper show that the DC cable loss of large-scale PV array can be reduced by adopting a proper sub-array design method.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1602-1613
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• 2014

The continuous growth of electric vehicles has caused electric power shortages in conventional utilities owing to the charging of electric-vehicle batteries. In order to increase the capacity of these utilities, photovoltaic systems may be an appropriate solution because of their benefits. However, a large amount of loss is generated in a conventional charging structure using photovoltaic sources owing to the many power conversion processes. This paper describes a simple integrated battery charger that utilizes a PV generation system. Moreover, the system control algorithm is deduced by analyzing the operation modes in order to control the proposed integrated system. The proposed system and algorithm are verified by a 3.3-kW prototype, resulting in an increase in the efficiency of approximately 7% to 15% compared with the conventional system. And, to examine the feasibility of the proposed system, the simulation for multi-charger with various conditions are progressed.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.103-106
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• 2009

In this paper, the implemented photovoltaic array simulator is the power supply based on a common photovoltaic characteristic. This simulator is consisted of a common DC power supply and PC for controlling output. User can select the number of PV modules and solar radiation energy and then can get output whatever user wants. This simulator is a very helpful system to PV generating test and unexpensive than the existing PV simulators.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.3
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• pp.491-498
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• 2020

Recently, In the production line of batteries, charge and discharge tests are essential to verify battery characteristics. In this case, the battery charging uses a unidirectional AC/DC converter capable of output voltage and current control, and the discharge uses a resistive load. Since this method consumes energy during discharge, it must be replaced with a bi-directional AC/DC converter system capable of charging and discharging. Although it is difficult to replace the connected inverter part of the bi-directional AC/DC converter system due to the high cost, the spread of the solar-connected inverter rapidly increases as the current solar supply business is activated, and thereby the solar-connected type Inverter prices are plunging. If it can be used as a power converter for battery discharge without program modification of the solar-powered inverter, it will have competition. In this paper, propose a new battery discharge system using a combination of a photovoltaic DC/DC simulator and photovoltaic PCS using a battery to be used as a power converter for battery discharge without program modification of a low-cost photovoltaic inverter. In addition, propose an optimal solar characteristic curve for the stable operation of PCS. The validity of the proposed system was verified using a 500[W] class solar DC/DC simulator and a solar PCS prototype.

• International Journal of Computer Science & Network Security
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• v.22 no.5
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• pp.5-10
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• 2022

Photovoltaic systems provide a reliable green energy solution. The sustainability and low-maintenance of Photovoltaic systems motivate the integration of Photovoltaic systems into the electrical grid and further contribute to a greener environment, as the system does not cause any pollution or emissions. Developing methodologies based on machine learning techniques to assist in reducing the burden of studies related to integrating Photovoltaic systems into the electric grid are of interest. This research aims to develop a methodology based on a unsupervised machine learning algorithm that can reduce the burden of extensive studies and simulations related to the integration of Photovoltaic systems into the electrical grid.

• KIEAE Journal
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• v.12 no.1
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• pp.105-112
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• 2012

When a building is planned and designed, the design should be able to minimize the cost during the whole life cycle of the building. This study has begun to analyze LCC about the alternative design which is applicable to renewable energy facility construction. It is reviewed domestic and foreign papers about the trend of LCC technology and it is determined the analytical method to analyze the LCC of renewable energy. Regarding the review of alternatives, it is chosen the three alternatives which are able to designed combing the renewable energy facilities and it is performed the LCC analysis about each alternative. Alternative 1 is Photovoltaic + Solar Thermal + Photovoltaic /Wind Power, Alternative 2 is Geothermal + Photovoltaic, and Alternative 3 is Photovoltaic + Solar Thermal. The LCC analysis is present value method, its analytical period is 40 years and it is applied 3.2% of real discount rate. As a result, it is proved that Alternative 1 and Alternative 3 are not able to collectible the early investment cost during the analytical period and Alternative 2 is analyzed that its pay-back period of early investment cost is about 31 years. As the final outcome of this study on case analysis, it is more advantageous to use the combination of Geothermal and Photovoltaic energy than to use the other combination in LCC aspect.

• 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.