• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.547-549
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• 2001

Recently, heating using oil and gas has been continuously replaced by that using midnight power in home, due to increase of oil price. Therefore, midnight power apparatus has been more and more spreading. However, cost of midnight power services is increasing because high fuel cost of generation facilities by existing power generation mix are charge of midnight power services. This paper analyzes trends about rapidly increasing midnight power in winter, and evaluate load pattern and supply cost of midnight power. Also, this study proposes rate direction of midnight power according to introduction of competitiveness system with B/C evaluation of midnight power cost.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.611-614
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• 2009

The present paper relates to an integration power system combining tidal power generation and ocean current power generation, and more particularly, to an integration power system combining a tidal power plant and two ocean current power parks, which is capable of increasing the operating rate of power facilities and efficiently generating electrical energy by using incoming seawater into the lake through turbine generators of a tidal power plant or fast flow of seawater discharged to a sea side through sluice gates of a tidal power dam. It is shown that the integration power system is a new promising ocean power system and the ocean current turbine generators in the ocean current power parks of the integration power system are smaller in size and larger in power generation capacity compared with the tidal current turbine generators in the ocean.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.79-80
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• 2015

With the government's support for new and renewable energy, photovoltaic equipment has rapidly been supplied. However, compared to supply rate, maintenance has not supported enough and relevant research has not much conducted. Therefore, the purpose of this study is to analyze maintenance effectiveness of photovoltaic equipment. What is the most important in maintenance effectiveness is a rise in power generation. It was estimated that if photovoltaic equipment for detached houses is maintained well, power generation increases by 4.0% at least, and by 6.5% on average. As a result, it was analyzed that it is necessary to maximize the effectiveness of the government's budget investment through well maintenance of photovoltaic equipment for detached houses.

• Current Photovoltaic Research
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• v.11 no.4
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• pp.134-143
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• 2023

Efforts are being made to respond to global warming. Interest in and demand for the private sector-led RE100 campaign is also increasing. Self-built solar power generation, one of the implementation tools for RE100, is not expanding. However, it can be an economical means of implementation in the long run. In this study, we intend to analyze the impact on the optimal ratio of self-solar power generation using HOMER simulation. OPR defines the optimal solar power generation ratio and looks into what changes there are in the optimal solar power ratio when self-power consumption increases and external power purchase price changes. As a result, the optimal rate of self-solar power generation has a low impact even if self-power consumption increases. As the external power unit price increases, the optimal ratio increases, and at a power unit price of 100 KRW/kWh, OPR is 24%; at 200 KRW/kWh OPR is 31%; and at 300 KRW/kWh OPR is 34%. This shows that the electricity price replaced during the life cycle has a high impact on the economic feasibility of solar power generation. However, when the external power unit price reached a certain level, the increase in OPR decreased. This shows that it is difficult for domestic companies to achieve RE100 based on the economic feasibility of solar energy alone. Therefore, efforts are needed to supply renewable energy in the public sector.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.5
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• pp.342-348
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• 2021

The PV module of solar power systems requires maximum power point tracking (MPPT) technique because the power-voltage and current-voltage characteristics vary depending on the surrounding environment. In addition, the 120 Hz ripple voltage on the DC-Link is caused by the imbalance of the system voltage and current. The effect of this 120 Hz ripple voltage reduces the efficiency of the power generation system by increasing the output current distortion rate. Increasing the capacity of DC-Link can reduce the 120 Hz ripple voltage, but this method is inefficient in price and size. We propose a technique that detects 120 Hz ripple voltage and reduces the effect of ripple voltage without increasing the DC-Link capacity through a controller. The proposed technique was verified through simulations and experiments using a 1 kW single-phase solar power system. In addition, the proposed technique's feasibility was demonstrated by reducing the distortion rate of the output current.

• Journal of the Korean Solar Energy Society
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• v.40 no.3
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• pp.21-31
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• 2020

The government mandates gradually zero energy building and Photovoltaic power generation systems installed in buildings are emerging as the most realistic alternative to increase the independence rate of building energy. In this study, we propose a method to reduce the power consumption of households by increasing the PV capacity of balconies and applying the method used the charged electric power stored in batteries after sunset. In order to evaluate the electric power energy savings of the residential BESS, a balcony PV 1.2 kW and a battery pack 2 kWh were installed for 9 houses in 4 apartments in Seoul and Gyeonggi-do. The BESS is charged when the balcony PV is generated electric power, and when solar power generation is finished, it supplies power to the electric appliances connected to the load. As a result of installing the solar PV module 1.2 kW and 2 kWh class BESS for 3 households located in Seoul and Gyeonggi-do, the average electric power consumption saving rate was 40%. The reduction in electricity consumption in the case of zero generation surplus power by maximizing the utilization rate of BESS has been improved to about 53%. Therefore, in order to increase the self-sufficiency rate of electric energy in apartment houses, it is effective to increase the solar photovoltaic capacity of the balcony and apply the residential BESS. In the future, it is believed that the balcony PV and home BESS will play a key role in achieving mandatory zero-energy housing.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.2
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• pp.112-118
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• 2018

In recent years, decentralized power have been increasing due to environmental problems, liberalization of electricity markets and technological developments. These changes have led to the evolution of power generation, transmission, and distribution into discrete sectors and the division of integrated power systems. Therefore, studies are underway to efficiently supply power and reduce losses to each sector's demand. This is a major concern for system planners and operators, as it accounts for a relatively high proportion of total power, with a transmission and distribution loss of 4-6%. Therefore, this paper analyzes the status of loss management based on the current transmission and distribution loss rate of each country and transmission loss management cases of each national power company, and proposes a loss rate prediction algorithm according to the long-term transmission system plan. The proposed algorithm predicts the demand-based long-term evolution and the loss rate of the grid to which the transmission plan is applied.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.379-380
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• 2008

Recently, ozone is utilized in various fields and its needs are expanding. In this paper, glass and ceramic plate tyre ozonizer have been fabricated to investigate discharge parameter(input power, flow rate of supplied gas, electrode form, etc.) effect to discharge. And the conditions of discharge parameter have been investigated for optimum ozone generation. Ozone concentration is continuously increased with increasing input power for same discharge space, and ozone yield is also increased until maximum point after that it is saturated. Ozone concentration is inversely proportional to flow rate of supplied gas but ozone generation and ozone vield characteristics are improved.

• Journal of Hydrogen and New Energy
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• v.33 no.1
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• pp.1-7
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• 2022

Interest in hydrogen productions that do not emit carbon dioxide and can produce hydrogen at a low price is increasing. Reforming and electrolysis are widely used, but they have limitations, such as carbon dioxide problems and costs. The methane can be decomposed as hydrogen and solid carbon without carbon dioxide emission at high temperatures. In this research, the methane pyrolysis experiment was conducted at 1,200℃ and 1,400℃ in a ceramic tube. The composition of the produced gas was measured by gas chromatography before carbon blocked the tube. The methane conversion rate and hydrogen selectivity were calculated based on the results. The hydrogen selectivity was derived as 60% and 55% at the highest point at 1,200℃ and 1,400℃, respectively. The produced solid carbon was expected to be carbon black and was analyzed using scanning electron microscope.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.211-212
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• 2008

As a result of environmental concerns, the production of electricity through renewable energy resources is rapidly increasing. Wind energy is among the fastest growing renewable energy resources now being integrated in the power system, and the penetration rate of wind generation has been gradually increased. For power flow analysis of the recent systems, thus, steady-state modeling of wind turbines and their application are of great importance. This paper presents the procedure we applied for implementation of a steady-state wind turbine model in power flow.