• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.5
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• pp.18-24
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• 2006

This paper proposed UPS system parallel connected in battery and ultracapacitor to compensate instantaneous voltage drop. Ultracapacitor parallel connected with battery compensate instantaneous voltage drop at failure and it's reduced the voltage regulation of output voltage. We are produced for fast instantaneous voltage drop compensation of ultracapacitor at UPS system and experiments are achieved. Experimental result was verified that the ultracapacitor indicated the fast compensation characteristics and regulation of the output voltage satisfied within 5[%] by using ultracapacitor.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.191-193
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• 2009

최근 국내 신재생에너지설비의 설치가 급증하고 있다. 전국적으로 신재생에너지원의 설비가 산재되어 있음에도 불구하고 관리 및 운영 시스템은 미비한 수준이다. 따라서 사후관리 체계 구축과 설비 이용률 향상을 목적으로 가동현황을 파악하여, 신재생에너지원의 효율적인 관리와 통합 운영을 위한 시스템이 필요하다. 이를 위해 본 논문에서는 통신 및 모니터링 기술기준에 제정된 공용규격에 따라 다수의 계측기와 데이터를 수집, 변환, 저장하고, 중앙서버로 데이터를 전송할 수 있는 시스템을 구현하여 더욱 효율적인 신재생에너지원의 운영을 돕는다. 본 시스템은 신재생에너지원의 계측기와 RS-232 혹은 RS-485를 이용한 하위통신을 하여 관리에 사용될 여러 정보를 수집하여 저장한다. 상위통신으로 PIRP(Platform Independent Reporting Protocol)에 맞는 데이터로 변환하여 중앙서버에 데이터를 보내게 된다. 또 한, 유저가 원한다면 중앙서버에서 과거의 데이터를 획득할 수 있도록 시스템을 구현하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.9
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• pp.1281-1286
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• 2010

Power plants have many components and equipment. It is difficult for operators to know the time of failure or the equipment that fails. Plants incur heavy economic losses due to unexpected failure. The equipment in power plants is constantly monitored by various sensors and instruments. However, prevention of failure is very difficult. Therefore, engineers are developing many types of failure-alarm systems that can detect the abnormal functioning of equipment. Such failure-alarm systems inform only about the abnormal functioning of equipment and do not indicate the cause of failure or the parts that have failed. In this study, we have developed a failure-prediction system that can provide details on the cause of trouble and the maintenance method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.8
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• pp.1-7
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• 2010

The reliability of a power system has close relationship with the maintenance of the distribution systems. This paper presents the method of the maintenance planning of the distribution systems by minimizing the interruption cost. The interruption cost for the equipment failures is formulated using time varying failure rate and minimized by optimization of the object function. The proposed method provides the priority list for the investment of the maintenance subject to the limited investment budget by the economic analysis. In order to test the proposed method, the modified distribution system of a rural area is introduced for the testing system. Test results show that the proposed method is good enough by evaluating the improvement of the reliability of the power system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.8
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• pp.93-98
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• 2009

Cogeneration means the highly energy-efficient generation system that improves energy ratio by generating electricity and heat, and it really affects the improvement of overall efficiency by using industrial process, district heating, and hot-water supply etc. after the energy produced through supplying power to system collects. This thesis indicates the screen of cogeneration flow in LabVIEW and the heat power control system that can be in long-distance control of a district energy system using TCP/IP. We simulated on four computers so that the heat power control system proves long-distance control possible.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.11
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• pp.971-975
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• 2013

In general, the solar photovoltaic power increases with higher solar insolation. However, the solar cell generation efficiency reduces because the solar cell surface is heated by solar insolation. According to advanced research, with a $1^{\circ}C$ increase in the solar cell surface temperature, the generation efficiency decreases by ~0.5%. To solve this problem, we conducted experiments in which we attempted to reduce the solar cell surface temperature using a water jet spray. In this study, we found the long-term experimental results of increases in solar power generation. The experimental results show a comparison of the site with and without cooling and cleaning equipment being installed. The results of the long-term experiments show that solar photovoltaic power generation is increased by at least 13% up to 19% with cooling and cleaning.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.4
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• pp.321-328
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• 2010

The study performed an actual fire experiment in order to propose the heat release rate of automobile that is the most basic architectural element for the fire safety design in a tunnel, whose importance has been recognized as the underground traffic tunnels are planned in Korean metropolitan cities. The heat release rate of a van is measured by the large scale calorimeter, in which the law of oxygen consumption is applied, and the fire expansion characteristics in a tunnel by placing two passenger cars nearby one another in the tunnel. As the results, the heat release rate of the van was revealed to be 5.9 MW, and carbon monoxide was emitted 482 ppm at a maximum. In case of two passenger car experiment for the fire expansion characteristics, the adjacent car was ignited about 3 minutes 30 seconds after the fire occurrence, and the complete fire was developed after 15 minutes. The maximum heat release was 9 MW. The results from the actual fire experiment can be an important input data for future quantitative analysis as well as an element applicable to a tunnel disaster preventive equipment design.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4447-4454
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• 2013

In October 2011, a commercialized 100kW class floating photovoltaic system positive plant was installed at Hapcheon dam a multi-purpose reservoir the first time ever in the nation. Floating photovoltaic system differs in water float, mooring device and underwater cable process from land photovoltaic system. As for land and building photovoltaic power generation equipments, many installation cases and skilled experiences are available, and thus installation is not difficult. However, commercial power generation floating photovoltaic system, which is attempted for the first time in the nation, requires to be designed and installed through a series of processes like technical review and verification of data by process in comparison with similar cases. The structure of floating photovoltaic system, an equipment for float photovoltaic module and other electrical equipment, is required to withstand weather environments like wind or typhoon etc and yet not affect water quality negatively, and for implementation of this system, construction efficiency and economy etc should be considered comprehensively. In this paper, the techniques of installing floating photovoltaic structure, mooring device, underwater cable, electrical equipment and remote monitoring control system are explained. The 100kW floating PV system is operating with 15% average capacity factor.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.4
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• pp.10-20
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• 2022

The performance analysis test of the scramjet engine intake was conducted under the Mach 5 condition of the scramjet engine test facility, a free-jet ground test facility of the Korea Aerospace Research Institute. A pitot/static pressure rake installed at the rear of the isolator was designed and manufactured to measure the total pressure recovery rate and mass capture ratio, which are typical performance factors of the scramjet engine intake. The effect of the rake mounted at the rear of the isolator on the intake, the performance analysis measured by the rake, and the change in wall static pressure distribution according to the angle of attack were performed. Finally, the point at which the intake unstart occurred was confirmed by using the rear back pressure adjusting device, which simulates pressure rise in the combustor, and the results are summarized in this paper.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.2
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• pp.127-132
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• 2010

The standards of demand, diversity and load density are necessary to create the design of a transformer capacity that is seldom presented in terms for academic study. At the moment, both legal and institutional standards for such a transformer are insufficient both at home and abroad. The works described in this thesis strongly support more reasonable standards for calculating transformer capacity by correlating the analysis between the maximum utilization factors of a given transformer with those of a transformer capacity whose power consumption has been investigated within a lease apartment. In this dissertation, it is necessary to analyze the key features and general trend from the investigated data. It made an analysis of the feature parameters, such as average, standard deviation, median, maximum, minimun and thus it was carried by the linear and nonlinear regression analysis.