• Journal of Engineering Education Research
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• v.13 no.3
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• pp.11-17
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• 2010

Korea plans to be the world's first country to transform its electricity network into "smart grids," which use information and operational technologies to help to facilitate the reduction of carbon emissions, make more efficient use of existing infrastructure/resources through meeting customer demand/less generation, and support renewable resources with real time monitoring and controls. In this situation, universities do the needful on priority to nurture smart grid engineers who will be responsible for state-of-the-art technologies as today's electric grid transitions to a digital network. This paper thus attempts to permanently turn out high-quality human resources in electrical engineering by fleshing out strategies for training smart electric grid engineers, based on lessons from a national undertaking of nurturing qualified power IT engineers starting on February 1 of 2007.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.129-135
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• 2010

It is well known that distributed generation(DG) system using renewable energy is an alternative to solve the problems which result from the exhaustion of fossil fuel and the environmental pollution. A PWM inverter is required for a power flow control in the DG systems. This paper proposes a SRF power flow control method considering grid impedance in grid-connected single-phase inverter systems. The proposed SRF power flow control method can provide a voltage-reference for the single-phase inverter even without any grid impedance estimation so that the single-phase inverter system could operate in stand-alone mode and grid-connected mode based on the known nominal value of grid impedance. Also independent controls of active and reactive power are achieved by the proposed control method. The effectiveness and the validity of the proposed control method are demonstrated through simulations. The simulation results show that the proposed control method can control properly power flow in grid-connected single-phase inverter systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.8
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• pp.1058-1063
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• 2020

This paper presents a new insulation resistance calculation technique to prevent electric shock and fire accidents due to the dielectric breakdown in the primary insulation section of the IT ground system. The solar power generation market is growing rapidly due to the recent expansion of renewable energy and energy storage systems, but as the insulation is destroyed and fire accidents frequently occur, a device for monitoring the insulation resistance state is indispensable to the IT grounding method. Compared to the conventional algorithm that use a method of multiplying a time constant to a fixed coefficient, the proposed insulation resistance calculation method has a fast response time and high accuracy over a wide insulation resistance range by applying a different coefficient according to the values of the insulation impedance. The proposed dynamic time constant based insulation resistance calculation technique reduces the response time by up to 39.29 seconds and improves the error rate by 20.11%, compared to the conventional method.

• Smart Media Journal
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• v.12 no.2
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• pp.91-102
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• 2023

The Energy Management System (EMS) communicates with power plants and substations, monitors the substations and plant operational status of the transmission and substation system for stability, continuity, real-time, and economy of power supply, and controls power plants and substations. Currently, the power exchange EMS communicates with power plants and substations based on the serial communication-based Distributed Network Protocol (DNP) 3.0 protocol. However, problems such as the difficulty of supply and demand of serial communication equipment and the lack of installation space for serial ports and modems are raised due to the continuous increase in new facilities to perform communication, including renewable power generation facilities. Therefore, this paper presents a TCP/IP-based communication method instead of the existing serial communication method of the power exchange EMS, and presents a security risk analysis that may occur due to changes in the communication method and a countermeasure to the security risk.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.47-52
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• 2021

Recently, the share of wind power in energy markets has sharply increased with the active development of renewable energy internationally. In particular, large-scale wind farms are being developed far from the coast to make use of abundant wind resources and to reduce noise pollution. In addition to the electromagnetic interference (EMI) caused by offshore wind farms to coastal or air surveillance radars, it is necessary to investigate the EMI on global maritime distress and safety system (GMDSS) communications between ship and coastal stations. For this purpose, this study investigates whether the transmitted field of MF/HF band from a ship would be subject to interference or attenuation below the threshold at a coastal receiver. First, using geographic information system digital maps and 3D CAD models of wind turbines, the area of interest is electromagnetically modeled with patch models. Although high frequency analysis methods like Physical Optics are appropriate to analyze wide areas compared to its wavelength, the high frequency analysis method is first verified with an accurate low frequency analysis method by simplifying the surrounding area and turbines. As a result, the received wave power is almost the same regardless of whether the wind farms are located between ships and coastal stations. From this result, although wind turbines are large structures, the size is only a few wavelengths, so it does not interfere with the electric field of MF/HF distress communications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.734-742
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• 2016

Global warming and the depletion of fossil fuels have been caused by decades of reckless development. Wind energy is one form of renewable energy and is considered a future energy source. The wind tower is designed with a fundamental frequency in the soft-stiff design between the 1P and 3P range to avoid resonance. Usually, to perform natural frequency analysis of a wind tower, the boundary condition is set to the Fixed-End, and soil-pile interaction is not considered. In this study, consideration of the effect of soil-pile interaction on the wind tower was included and the difference in the natural frequency was studied. The fixed boundary condition was not affected by the soil condition and depth of the pile and the coupled spring boundary condition was unaffected by the depth of pile but affected by the depth of the pile, and the Winkler spring boundary condition is affected by both the soil condition and the depth of the pile. Therefore, the coupled spring boundary condition should be used in shallow depth soil conditions because the soil condition does not take the shallow depth soil into consideration.

• Journal of Appropriate Technology
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• v.7 no.2
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• pp.127-135
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• 2021

To respond to the threat of global warming, countries around the world are promoting the spread of renewable energy and reduction of carbon emissions. In accordance with the United Nation's Sustainable Development Goal to combat climate change and its impacts, global automakers are pushing for a full transition to electric vehicles within the next 10 years. Electric vehicles can be a useful means for reducing carbon emissions, but in order to reduce carbon generated in the stage of producing electricity for charging, a power generation system using eco-friendly renewable energy is required. In this study, we propose a smart electric mobility operating system integrated with off-grid solar power plants established in Tanzania, Africa. By applying smart monitoring and communication functions based on Arduino-based computing devices, information such as remaining battery capacity, battery status, location, speed, altitude, and road conditions of an electric vehicle or electric motorcycle is monitored. In addition, we present a scenario that communicates with the surrounding independent solar power plant infrastructure to predict the drivable distance and optimize the charging schedule and route to the destination. The feasibility of the proposed system was verified through test runs of electric motorcycles. In considering local environmental characteristics in Tanzania for the operation of the electric mobility system, factors such as eco-friendliness, economic feasibility, ease of operation, and compatibility should be weighed. The smart electric mobility operating system proposed in this study can be an important basis for implementing the SDGs' climate change response.

• Journal of Technology Innovation
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• v.21 no.2
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• pp.25-56
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• 2013

As science and technology are emphasized as national competitiveness, major nations designate new growth engine industry and establish the effective investment and the development strategy to enhance industrial development and competitiveness through science and technology. New industrial sectors such as Biotechnology and renewable energy have been spot lighted as major new growth engines and this competitive situation is getting fiercer. Universities and research institutions in each country selected and announced the future promising technological field which will produce ripple effect in the future on a regular basis. In Korea, various research institutions continue to select and announce the promising technological fields. In this study, we would like to study the method to derive the promising technological field in the field of biotechnology spotlighted as a new growth engine by utilizing patent information. We would like to derive the major technological field by collecting domestic and international patents in the field of biotechnology using IPC code based technological classification and identifying bio technological trends utilizing text mining method for analysis of technological development trends with patents. Patent contour of US and Korea is compared and analyzed through analysis of text mining to derive the general technological development field in the field of biotechnology. After that, we would like to investigate research theme of promising biotechnology focused technological development through details on technological trends through in-depth analysis about technological field which draws interest more and more in Korea and other countries.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.3
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• pp.141-147
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• 2019

Recently, the biggest issue in the electricity industry is the increase in renewable energy, and various technologies are being developed to ensure the capacity of the power system. In addition, super-grids linking power systems are being pushed to utilize eco-friendly energy between countries and regions worldwide. The HVDC transmission technology is required to link the power network between regions with different characteristics of the power system such as frequency and voltage. Until now, Korea has applied HVDC transmission technology that connects mainland and Jeju Island with submarine cables. But, the HVDC transmission technology is still developing for long-distance high-capacity power transmission from power parks on the east coast to load-tight areas near the metropolitan area. Considering the high population density and mountainous domestic environment, it is pushing for commercialization of the design technology of the ${\pm}500kV$ Double Bipole with metallic return wire transmission line to transmit large-scale power of 8 GW using minimal right of ways. In this paper, the insulation characteristics were studied for the design of double-bipole transmission tower with metallic return wire, which is the first time in the world. And the air insulation characteristics resistant to the various overvoltage phenomena occurring on transmission lines were verified through a full-scale impulse voltage test.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.5
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• pp.9-16
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• 2019

In today's global energy market, the importance of green energy is emerging. Hydrogen energy is the future clean energy source and one of the pollution-free energy sources. In particular, the fuel cell method using hydrogen enhances the flexibility of renewable energy and enables energy storage and conversion for a long time. Therefore, it is considered to be a solution that can solve environmental problems caused by the use of fossil resources and energy problems caused by exhaustion of resources simultaneously. The purpose of this study is to efficiently produce hydrogen using plasma, and to study the optimization of DME reforming by checking the reforming reaction and yield according to temperature. The research method uses a 2.45 GHz electromagnetic plasma torch to produce hydrogen by reforming DME(Di Methyl Ether), a clean fuel. Gasification analysis was performed under low temperature conditions ($T3=1100^{\circ}C$), low temperature peroxygen conditions ($T3=1100^{\circ}C$), and high temperature conditions ($T3=1376^{\circ}C$). The low temperature gasification analysis showed that methane is generated due to unstable reforming reaction near $1100^{\circ}C$. The low temperature peroxygen gasification analysis showed less hydrogen but more carbon dioxide than the low temperature gasification analysis. Gasification analysis at high temperature indicated that methane was generated from about $1150^{\circ}C$, but it was not generated above $1200^{\circ}C$. In conclusion, the higher the temperature during the reforming reaction, the higher the proportion of hydrogen, but the higher the proportion of CO. However, it was confirmed that the problem of heat loss and reforming occurred due to the structural problem of the gasifier. In future developments, there is a need to reduce incomplete combustion by improving gasifiers to obtain high yields of hydrogen and to reduce the generation of gases such as carbon monoxide and methane. The optimization plan to produce hydrogen by steam plasma reforming of DME proposed in this study is expected to make a meaningful contribution to producing eco-friendly and renewable energy in the future.