• 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.

• Current Photovoltaic Research
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• v.8 no.1
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• pp.39-43
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• 2020

In this study, we predict the generation of end-of-life photovoltaic modules when Feed in Tariff applied, in Republic of Korea. Based on the installation of photovoltaic modules, we prepared three different senarios in order to estimate the generation of end-of-life photovoltaic modules. The senarios are i) early worn-out, ii) mid worn-out and iii) late-worn out senario. We selected the mid worn-out senario to estimated the amount of end-of-life photovoltaic modules in this study. Establishment of the end-of-life module generation scenario predicted generation of end-of-life photovoltaic module, and forecasted generation amount of end-of-life module to which Feed in Tariff was applied in consideration of installed photovoltaic modules installed by Feed in Tariff support. The generation of Feed in Tariff-applied end-of-life modules increased from 2021 to 2025 compared to without Feed in Tariff, and since then, the Feed in Tariff-applied end-of-life modules were generated as waste modules during the relevant period (2021 ~ 2025).

• Journal of the Korean Electrochemical Society
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• v.12 no.2
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• pp.119-130
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• 2009

This article reviews recent R&D trends in SOFC development with an emphasis on industries that can produce the SOFC stack and power generation system. SOFC is an electrochemical device that can convert the chemical energy of fuel into the electrical energy with environment friendly system and high efficiency. SOFC power generation system could be classified as the portable power generation system, auxiliary power unit(APU), residential power generation(RPG) and large size distributed power generation. In the case of more than 10kW system, the major R&D trends are focused on the tubular type SOFC system with high efficient and long term stability to meet the commercialization of SOFC power generation system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.1
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• pp.68-75
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• 2013

This paper presents a scheme to improve transient stability using Newton's Approach for generation rescheduling. For a given contingency, the energy margin and sensitivities are computed. The bigger energy margin sensitivity of generator is, the more the generation of the generator effects to the transient stability. According to energy margin sensitivity, the control variables of generation rescheduling are selected. The fuel cost function is used as objective function to reallocate power generation. The results are compared to the results of time simulation to show its the effectiveness.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.12
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• pp.1031-1035
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• 2002

The development of the solar and the wind power energy is necessary since the future alternative energies should have no pollution and no limitation. currently power generation system of MW scale has been developed, but it still has a few faults that its operation depends on with the weather condition. In order to solve these existing problems. combined generation system of photovoltaic(400W) and wind power generation system(400W) was suggested. It combines wind power and solar energy to have the supporting effect from each other. However. since the combined generation system cannot always generate stable output with ever-changing weather condition, power compensation device that uses elastic energy of spiral spring was added. In an experiment. when output of system gets lower than 12V(charging voltage), additional power was from the stored rotational energy of spiral spring.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.303-306
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• 2008

The wind power generation systems have a fluctuating or intermittent power output due to the variability of the wind speed. The amount of wind generation which can be connected to the grid without causing voltage stability problems is limited. In this study, the simulation of the wind power generation including energy storage system were performed to reduce the fluctuation of wind power output and to obtain the optimal operation planning of energy storage system.

• Journal of Power Electronics
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• v.10 no.1
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• pp.72-78
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• 2010

In this paper the operation of a double-fed wound-rotor induction machine, coupled to a wind turbine, as a generator at sub-synchronous speeds is investigated. A novel approach is used in the analysis, namely, the rotor power flow approach. The conditions necessary for operating the machine as a double-fed induction generator (DFIG) are deduced. Formulae describing the factors affecting the range of sub-synchronous speeds within which generation occurs are deduced. The variations in the magnitude and phase angle of the voltage injected to the rotor circuit as the speed of the machine changes to achieve generation at the widest possible sub-synchronous speed range is presented. Also, the effect of the rotor parameters on the generation range is presented. The analysis proved that the generation range could increase from sub-synchronous to super-synchronous speeds, which increases the amount of energy captured by the wind energy conversion system (WECS) as result of utilizing the power available in the wind at low wind speeds.

• Journal of the Korean Solar Energy Society
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• v.26 no.4
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• pp.47-54
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• 2006

The current power generation is very suitable renewable energy for the application to Korean western and south coastal regions where characterized as having high current speed. Being different from tidal power generation that needs tremendous dam structure to preserve water, the current power generation utilizes the ocean current flow without damaging to estuary area and its environment. There are still many areas to understand the characteristics of current power generation for the actual field installation. As designing muti module with several rotors, the interaction between rotors will occur that would affect the efficiency and RPM of each rotor. In this study, the interactions caused by gaps between rotors in multi module are studied.

• Transactions of the Korean hydrogen and new energy society
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• v.16 no.3
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• pp.209-218
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• 2005

To find a suitable metal component in oxygen carrier particles for chemical-looping hydrogen generation system(CLH), oxygen transfer capacities of metal components were compared and Ni has been selected as the best metal component. The proper operating conditions to achieve high hydrogen generation rate have been investigated based on the chemical-equilibrium composition analysis for water splitting reactor. Moreover, suitable compositions of syngas from gasifier of heavy residue to achieve high energy efficiency have been investigated by calculation of heat of reaction. Based on the selected operating conditions, the best configuration of two interconnected fluidized beds system for the chemical-looping hydrogen generator has been investigated as well.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.109.1-109.1
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• 2011

KEPCO was operating power plants with diesel generators in 49 islands including Baekryeong-Do, and the generation capacity was about 66 MW in 2008. The cost of fuel is increasing by the international oil price inflation and continuous rise of oil price is predicted. For the stabilizing of electric power supply to the separate islands, renewable energy and fuel cell systems were considered. Hydrogen is made using renewable energy such as wind power and solar energy, and then a fuel cell system generates electricity with the stored hydrogen. Though the system efficiency is low, it is treated as the only way to secure the stable electric supply using renewable energy at this present. The analytic hierarchy process was used to select suitable candidate island for the system installation and 5 islands including Ulleung-Do were selected. Economic evaluation for the system composed of a kerosene generator, a wind power, an electrolysis, and a fuel cell system was conducted with levelized generation cost based on present value methode. As the result, the necessity of renewable energy combined generation system and micro grid composition in the candidated islands was confirmed. Henceforth, the development of an integration technology which connects micro grid to the total power grid will be needed.