• Journal of Internet of Things and Convergence
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• v.8 no.3
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• pp.55-61
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• 2022

In order to reduce greenhouse gases, the main culprit of global warming, the United Nations signed the Climate Change Convention in 1992. Korea is also pursuing a policy to expand the supply of renewable energy to reduce greenhouse gas emissions. The expansion of renewable energy development using solar power led to the expansion of wind power and solar power generation. The expansion of renewable energy development, which is greatly affected by weather conditions, is creating difficulties in managing the supply and demand of the power system. To solve this problem, the power brokerage market was introduced. Therefore, in order to participate in the power brokerage market, it is necessary to predict the amount of power generation. In this paper, the prediction system was used to analyze the Yonchuk solar power plant. As a result of applying solar insolation from on-site (Model 1) and the Korea Meteorological Administration (Model 2), it was confirmed that accuracy of Model 2 was 3% higher. As a result of comparative analysis of the DNN and RNN models, it was confirmed that the prediction accuracy of the DNN model improved by 1.72%.

• The Magazine of the IEIE
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• v.35 no.7
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• pp.57-71
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• 2008

The last decade has witnessed great improvements in power semiconductor devices thanks to the advanced design and process, which have made it possible to significantly improve the electrical performances of electronic systems while simultaneously reducing their site, weight and perhaps most importantly reducing their cost. Among the power semiconductor devices, IGBT will be a key semiconductor component for power industry since it has a huge potential to cover large areas of power electronics from small home appliances to heavy industries. Currently, only a few limited power semiconductor manufacturers supply most of the industrial consumptions of power IGBT and its modules. Therefore, a large portion of technology in the power industry is dependent on other advanced countries. In this regard, to independently build power IGBT devices and the relevant power module technology, Korean government initiated a new 5-year project 'Power IT,' which also aimed at booming the business of the power semiconductor and the allied industries. With the success of this power IT project, it is expected that the power semiconductor technology will be a basis to foster the high power semiconductor industry and moreover, there will be more innovative developments in the Korea region and globally Also, forming the channel between the customers and suppliers, it is possible to effectively develop the customized power products, which could strengthen the competitiveness of Korean power industry. Furthermore, the power industry including semiconductor manufacturers will be technologically self-supporting and be able to obtain good business opportunities, and eventually increase the share in the growing power semiconductor market, which could be positioned as a major industry in Korea.

• Journal of Drive and Control
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• v.17 no.2
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• pp.38-44
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• 2020

Various efforts have been initiated to reduce the energy consumption of the compressor as it is one of the approaches to saving a large portion of the fixed cost of the production site. Various results of reducing the energy consumption of the compressor have been reported, but to reduce the energy consumption of the compressors fundamentally, regular management of the compressor should ensure optimum operation. This requires periodic on-site visits by experts, but is often overlooked as a cost issue, resulting in the use of the compressor in low-efficiency conditions. Thus, it is necessary to develop a low-cost evaluation technology for compressor condition monitoring and efficiency analysis to ensure that the compressor is always driven at the optimum efficiency without imposing undue burden on the compressor user. In this study, a sensor was installed at the inlet, outlet, and power supply of the compressor, and a method for evaluating the energy consumption of the compressor using the minimum sensor was derived. The experimental results are presented to show the validity of the proposed method. It was confirmed that the energy consumption of the compressor can be easily as well as efficiently evaluated by using the method developed in this study.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.937-944
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• 2022

Electric vehicles (EVs) have been growing to reduce energy consumption and greenhouse gas (GHG) emissions in the transportation sector. The increasing number of EVs requires adequate recharging infrastructure, and at the same time, adopts low- or zero-emission electricity production because the GHG emissions are highly dependent on primary sources of electricity production. Although previous research has studied solar photovoltaic (PV) -integrated EV charging stations, it is challenging to optimize spatial areas between where the charging stations are required and where the renewable energy sources (i.e., solar photovoltaic (PV)) are accessible. Therefore, the primary objective of this research is to support decisions of siting EV charging stations using a spatial data clustering method integrated with Geographic Information System (GIS). This research explores spatial relationships of PV power outputs (i.e., supply) and traffic flow (i.e., demand) and tests a community in the state of Indiana, USA for optimal sitting of EV charging stations. Under the assumption that EV charging stations should be placed where the potential electricity production and traffic flow are high to match supply and demand, this research identified three areas for installing EV charging stations powered by rooftop PV in the study area. The proposed strategies will drive the transition of existing energy infrastructure into decentralized power systems. This research will ultimately contribute to enhancing economic efficiency and environmental sustainability by enabling significant reductions in electricity distribution loss and GHG emissions driven by transportation energy.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.4
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• pp.139-143
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• 2006

Recently, standard of living improved and Information-Communication industry developed rapidly. Thereby, interest about electric power quality is rising worldwide. So, research and Development to enhance electric power quality in various viewpoint until most suitable supply system from each kind device to improve electric power quality. And specially, interest about voltage quality is rising by diffusion increase of information communication appliance and minuteness control appliance etc. Also Power consumption is increasing, but expansion of large size generator by environmental and site security problem is difficult. So, introduction of distribution generation is investigated actively by electric-power industry reorganization. Voltage management of power system had been controlled by ULTC (Under Load Tap Changer) in substation and pole transformer on the high voltage distribution line. But, voltage control device on substation and distribution line is applied each other separatively. Therefore, efficiency of line voltage control equipment is dropping. Also, research about introduction upper limit of distribution generation is consisting continuously. This paper presents cooperation use way between voltage control device and introduction upper limit of distribution generation for most suitable voltage control in distribution power system.

• Journal of Korea Water Resources Association
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• v.55 no.7
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• pp.515-529
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• 2022

Identifying the available water resources amount is an essential process in establishing a sustainable water resources management plan. Dam facility is a major infrastructure storing and supplying water during the dry season, and the water supply yield of the dam varies depending on dam inflow conditions or operation rule. In South Korea, water supply yield of dam is calculated by reservoir simulation based on observed historical dam inflow data. However, the water supply capacity of a dam can be underestimated or overestimated depending on the existence of historical drought events during the simulation period. In this study, probabilistic inflow data was generated and used to estimate the appropriate range of the water supply yield of hydropower dams. That is, a method for estimating the probabilistic dam inflow that fluctuates according to climatic and socio-economic conditions and the range of water supply yield for hydropower dams was presented, and applied to hydropower dams located in the Han river in South Korea. It is expected that the understanding water supply yield of the hydropower dams will become more important to respond to climate change in the future, and this study will contribute to national water resources management planning by providing potential range of water supply yield of hydropower dams.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1173-1176
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• 2007

The breaker noise is one of the main noise sources of construction site. It is very important to assess and measure the breaker noise accurately, because the noise labelling will be in effect January 2008 in Korea. Therefore, It is necessary to measure the sound power level of breakers and use a appropriate test method in accordance with international standard. In this study, we measure the sound power level of breakers by using the breaker noise measurement system. This system makes it possible to measure the breaker noise more accurately than to measure the noise of that attached with excavator, because this system can control main factors affecting breaker noise such as hydraulic input power, hydraulic supply pressure, breaker inlet oil flow and so on.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.197-204
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• 2004

The temporary power installations are to be used for temporarily supplying power during work at construction sites and have a minimum of protective devices to differ from permanent installations. There are many risk factors caused by loose working environments, deterioration of installations at construction sites. To analyze risk factors of temporary power installations, the investigation and the questionnaire were carried out side by side for power receiving system patch and panel boards, and were performed by researcher, the related expert, engineer of Korea Electrical Safety Corporation all over the country. The objects were variable such as an airport, an apartment, a municipal playground As a result, there are many problems such as a bad lock, poor protection of charging department. Solvable methods are improvement of the related regulation safety education, safety check and so on. In the future, the analytical data can be applied to prevent the electrical shock at construction site, and can be used to stabilize electrical installations.

• Journal of Korea Water Resources Association
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• v.54 no.8
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• pp.567-576
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• 2021

Climate change threatens the security of domestic water resources in South Korea. To overcome the potential water shortage, various approaches are being studied by alterning the operation of dams or by integrated operation of multiple dams and reservoirs. However, most of the related researches were developed and applied for multi-purpose dams, and few studies were conducted for the hydropower dams. The main purpose of the hydropower dam is to generate electric energy; however, the potential water shortage due to prolonged droughts brings the idea to supply water from the hydropower dam in the basin. To that end, it is required to estimate the water supply ability of the hydropower dams. In this study, we proposed a methodology to classify the hydropower dam into a "storage-type" and "run-of-river type" dam. The proposed approach was demonstrated using the hydropower dams located in North-han River basin. The results of this study are expected to contribute for further analysis of the hydropower dams, such as evaluation of water supply capacity and drought mitigation purpose operation of the hydropower dams.

• Journal of Power Electronics
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• v.14 no.3
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• pp.572-579
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• 2014

As a non-linear time variant system, the four-quadrant line converter of an electric multiple unit (EMU) was expressed by linear time periodic functions near an operating point and modeled by a steady-state harmonic domain matrix. The components were then combined according to the circuit connection and relations of the feedback control loops to form a complete converter model. The proposed modeling method allows the study of the amplitude of harmonic impedances to explore harmonic coupling. Moreover, the proposed method helps provide a better design for the converter controllers, as well as solves the problem in coordination operation between the EMUs and the AC supply. On-site data from an actual $CRH_2$ high-speed train were used to validate the modeling principles presented in the paper.