• KIPS Transactions on Computer and Communication Systems
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• v.10 no.7
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• pp.199-204
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• 2021

Digital substation refers to a substation that digitizes functions and communication methods of power facilities such as monitoring, measuring, control, protection, and operation based on IEC 61850, an international standard for the purpose of intelligent power grids. Based on the intelligent operating system, efficient monitoring and control of power facilities is possible, and automatic recovery function and remote control are possible in the event of an accident, enabling rapid power failure recovery. With the development of digital technology and the expansion of the introduction of eco-friendly renewable energy and electric vehicles, the spread of direct current distribution systems is expected to expand. MVDC is a system that utilizes direct current lines with voltage levels and transmission capacities between HVDCs applied to conventional transmission systems and LVDCs from consumers. Converting existing lines in substations, where most power equipment is alternating current centric, to direct current lines will reduce transmission losses and ensure greater current capacity. The process bus of a digital substation is a communication network consisting of communication equipment such as Ethernet switches that connect installed devices between bay level and process level. For MVDC linkage to existing digital substations, the process level was divided into two buses: AC and DC, and a system that can be comprehensively managed in conjunction with diagnostic IEDs as well as surveillance and control was proposed.

• Korean Journal of Construction Engineering and Management
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• v.20 no.5
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• pp.21-30
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• 2019

Environmental and energy issues such as abnormal climate and depletion of fossil fuel due to global warming have emerged as a critical task to threaten human survival. As a result, interest in the Zero Energy Building is increasing as it is an innovative building that can significantly contribute to building energy reduction and greenhouse gas reduction. In the market, however, the added cost of construction is a major stumbling block to the revitalization of the Zero Energy certification. In this study, general private apartment complexes were selected for research, detailed elements for Zero Energy certification were presented based on the construction criteria for eco-friendly houses from the initial design stage, and the cost efficiency analysis of the components for certification were presented. It has been analyzed that only Grade 3 certification can be implemented in apartments due to technical level and physical limitations. Also, after reviewing the cost trend during the lifecycle cost, all expenses can be recovered within 13 years after completion only in the case of grade 5 of the Zero Energy Building. The additional costs proposed in the present study are reflected appropriately in the review of projects for apartments scheduled for order in the future to contribute to the revitalization of the Zero Energy Building certification.

• Journal of the Society of Disaster Information
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• v.14 no.4
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• pp.387-398
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• 2018

Purpose: The purpose of this study is to promote the disaster safety village establishment project that fits the characteristics of rural areas by investigating and analyzing the operation cases of contents with regard to disaster safety villages in Korea and Japan. Method: The contents of project related to disaster safety villages in Korea and Japan were classified into resident participation contents, structured contents and unstructured contents, for examining the characteristics of such contents through investigation and analysis, and the contents (draft) of disaster safety village that fitted the characteristics of rural areas were presented. Result: The contents of resident participation include basic safety education, CPR education, life experience training of evacuation shelter, evacuation training, concurrent training of farming activity and disaster activity and creating a village safety map in connection with competent authorities. The enactment of an act and an ordinance for the establishment of disaster safety village, expert dispatch system, storm and flood insurance system and funding system to raise the fund for establishing a village were presented as unstructured contents. In addition, the production of self supporting evacuation shelter, wireless evacuation announcement system, disaster prevention system for a river, emergency evacuation sign, village safety map sign and the establishment of disaster prevention park were presented as structured contents. Conclusion: The unstructured contents are the establishment of foundation for preparing laws and institutions and the structured contents should be installed by utilizing eco-friendly methods in consideration of the environments of rural areas along with securing the safety. Moreover, resident participation should utilize the contents by considering various items such as age, characteristics and environments of residents in rural villages.

• 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.

• Korean Journal of Construction Engineering and Management
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• v.15 no.1
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• pp.101-110
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• 2014

The ministry of Land, Infrastructure and Transport announced that they launched the pilot project to offer Happy House built with modular construction as part of the major projects of incumbent government in 2013. The market size of modular construction is getting increasingly enlarged together with strong will of government. The major challenges that current modular construction encounters can be summed up as lack of standardization of material on the stage of design and fabrication. The portion of material costs in modular construction marks 16 to 17% higher than the existing other construction method, and account for 60 % of total construction cost, which is why material management is the most important factor. However, the imperfect standardization and specification on design causes high loss of materials on fabrication, which makes the construction wastes and total construction cost increasing in accordance with the increase of material costs. This study has been conducted to verify major modules by developing optimization algorithm on gypsum board material among wall finishing materials. It is expected that this paper contributes not only to eco-friendly construction by minimizing the waste factors of materials through these efforts, but also to removing high cost issues which had been recognized as a setback of current modular construction.

• Journal of Environmental Impact Assessment
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• v.26 no.2
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• pp.105-113
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• 2017

Recently mountain tourism has been promoted and introduction of railroads with utilizing mountain resources is being planned. With the government policies to increase the share of eco-friendly transportation on railroad, national double-tracking of single rail and improvement projects are on going. However, the eco-friendly railroad policy suggests the environmental impact assessment items only on air quality, water quality, geographical/geological features, fauna/flora, natural/environmental resources, noise/ vibration, and recreation/landscape. And for fauna/flora and natural/environmental resources, confirming the presence of environmental protection zone is enough to satisfy legal requirement. This study suggested to evaluate environmental/ecological values with quantitative data. Evaluation indices and evaluation items have been selected to provide the data. Each of the subject map and railroad network was overlapped. The study selected naturalness and diversity as major indicators and calculated weight values of the items under the indicators, which are to be usd for the selection of the sites for railway development. This assessment method could be applied to the environmentally friendly construction of railroads in the future.

• Journal of Energy Engineering
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• v.19 no.2
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• pp.116-120
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• 2010

Overall total length of hydraulic pipe to transport the hot water in the domestic district heating network is above 3,000 Km approximately. This long pipe network requires a lots of the transport pumping power by surface friction of fluid. In this study, the drag reduction(DR) of Amin Oxide $C_{18}$ as non-ionic surfactant according to the fluid velocity, temperature and surfactant concentration under the condition of above $80^{\circ}C$ fluid temperature were investigated experimentally. Results showed that new amin oxide $C_{18}$ surfactant had DR of maximum 30% in fluid temperature of $80^{\circ}C$ and had 15% DR in fluid temperature over $100^{\circ}$ under short time test condition. And amine oxide had 155 hours duration time to keep the DR characteristic in the fluid temperature of $80^{\circ}$ and 1000 ppm concentration. But duration time of DR was decreased when fluid temperature increased.

• Journal of Wetlands Research
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• v.18 no.2
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• pp.173-182
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• 2016

Although the ecosystem extends numerous functions for the benefit of humankind, construction of horticultural facilities can potentially lead to the degeneration of some of these functions owing to the expansion of impervious regions and loss of habitats. Thus, this study aimed to examine the effect of construction of horticultural facilities on plant biodiversity. Analysis of the vegetation distribution characteristics showed that horticultural facilities had significantly lower plant diversity than did rice paddies. Hence, the proposed approach involved low-impact development, arrangement of habitat space, plant preservation, restricted use of chemical fertilizer, habitat creation, and reduced preservation cost. Lifestyle analysis suggested the importance of developing favorable environments for the growth of annual plants and aquatic plants. In all, 20 species of naturalized plants belonging to 10 families were identified. Furthermore, the proportion of these naturalized plants was higher in glass greenhouses and multi-span greenhouses, suggesting the advantages of employing natural soil mulching while avoiding concrete mulching. Statistical analysis was performed to validate the results, which suggested that impervious regions be converted to natural soils. Collectively, the findings of this study are expected to be used for establishing policies for the construction of eco-friendly and ecological horticultural facilities; this may aid the maintenance of sustainable agricultural landscapes and large-scale development of the reclaimed lands.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.11
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• pp.1271-1276
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• 2015

The recent trend is that diesel power generation on islands where its prime cost for power generation is high is replaced by new and renewable energy. Therefore, south Jeolla province is progressing the construction project of self-sufficient islands for the areas where power is supplied by depending on diesel generators, which is the project that power is supplied through eco-friendly energy source using sunlight, wind power and energy storage device etc. However, it is difficult to construct new and renewable energy source with the capacity to respond to the load perfectly due to its environmental and geographical conditions regarding capacity design of new and renewable energy. Besides, Microgrid design considering appropriate capacity design of the system components and efficient operation is required through the analysis of climate conditions and load patterns from the design stage for optimal composition of a hybrid system with economic feasibility. Therefore, this study is aimed to conduct a research on optimal combination, capacity calculation and economic feasibility by comprising a hybrid power generation system which will replace 40% of power generation by diesel as new and renewable energy source for Geomun Island where has more than 300 households and requires expansion of the facility among islands located in southwest coast.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.471-478
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• 2020

This study aimed to suggest implications for the future development of agricultural R&D through a priority analysis of excellent agricultural R&D performance considering productivity, marketability, and effects on region, which are important factors of agricultural R&D evaluation. The subjects of analysis were R&D of Rural Development Administration (RDA), which was selected as national R&D excellent Performance from 2006 to 2018, and the priority was analyzed using Analytic Hierarchy Process (AHP). The results are as follows. First, the relative importance of the criteria decreased in the order of marketability(0.423) > regional impact(0.360) > productivity(0.216). Second, as a result of analyzing the relative importance of the sub-criteria, the possibility of commercialization(0.515) was high in the category of marketability. The possibility of technology expansion(0.538) was high in the category of effects on region and the quality improvement(0.464) was high in the category of productivity. Third, the excellent agricultural R&D performance that had high relative importance was the technologies associated with improving the agricultural competitiveness of horticultural crops.