• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.589-592
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• 2011

In this paper, bidirectional DC-DC converter is designed to cover up defects of fuel cell generating system like as low dynamic characteristic, unstable output and lack of storage ability by using bidirectional DC-DC Converter and supercapacitor that available to charge & discharge quickly, high efficient at charge & discharge and semi-permanent. Operating efficiency has been analyzed through simulation and examination. According to these design and data, hybrid system has been made and operation test, evaluation and results evaluation have been performed.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.1
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• pp.11-18
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• 2011

Wave overtopping reef system with guide vanes convert incident wave energy on the reef type structures into electric power. Previous studies decided shape parameters likes slope, height of the sloping arm and shape of guide vane. In this paper, using these shape parameters produce 1/7 scale model and construct integration scale model system combining water pressure head turbine, power generation, power control, operating control and monitoring system. In these systems, we measure the overtopping and power generation with different wave heights and periods and compare the results with the previous studies. This was confirmed designed overtopping and power generation, then we suggest efficient control system.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2000-2002
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• 2004

한류형 휴즈는 크게 저압, 고압 및 초고압 한류형 퓨즈의 3종류로 분류할 수 있다. 저압형(정격전압 200/380/660V)은 주로 전원장치 보호용으로 인버터 및 UPS에 적용되고 있으며, 고압형(정격전압 3600/7200v)은 전력계통에서 수변전설비의 고압에 적용되어 VCB, 변압기, MOTOR 및 MOLD PT 등을 보호할 목적으로 사용되고 있다. 또한 초고압형(정격전압 24000/25800v)은 수배전설비의 고압에 적용되어 발전기 및 변압기 둥을 보호할 목적으로 사용되고 있다. 한편, 한류형 퓨즈의 성능 및 수명을 결정하는 요인은 용단시간, 동작 특성 및 내습성에 의해 결정된다. 따라서, 환경요인(온도, 습도 및 전류)을 변화시켜 성능을 저하시킨 후 과전류를 인가하면 수명저하의 경향을 분석할 수 있다. 국내에서 생산하고 있는 저압, 고압 및 초고압 한류형 퓨즈의 신뢰성이 향상되면 전력계통에서의 신뢰성을 확보할 수 있고 따라서 대형사고로의 발전 가능성을 줄일 수 있다.

• Journal of the KSME
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• v.29 no.3
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• pp.317-325
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• 1989

광학시 비접촉 미소 변위 계측 장치의 응용예는 앞서 소개한 응용 외에도 여러 분야에서 많이 활용되고 있다. 즉, 주행 중인 차량 바퀴의 얼라이먼트(alignment) 계측에 이용되기도 하며, 파괴 역학 분야에서 크랙 개구단부(COD)의 변위량 측정에도 이용되며, 충격 역학 분야에서는 변위의 출력 응답 특성이 경시적으로 대단히 복잡하게 변하는 동적 파괴 현상의 원인 규명의 목적으 로도 많이 활용되고 있다. 더욱이 눈부신 발전을 거듭하고 있는 재료 요소 기술 및 센서 기술의 도움으로 앞으로는 이러한 비접촉식 미소 변위 측정 시스템이 보다 더욱 다양하게 사용되어질 것으로 기대되며, 또한 점차 성능 및 가격적 측면에서도 고성능의 계측 시스템을 손쉽게 큰 부 담이 없이 구입 가능할 수 있으리라 믿는다. 그러나 한편으로는 고정도의 물리량의 계측은 꼭 최신의 고가의 장비로만 되는 것이 아니라는 점과, 이러한 계측 시스템의 활용 시에는 기본 검출 원리 및 특성의 이해와 더불어 각 시험 경우에 따른 측정치에 대한 검증 작업을 게을리 하지 말아야 된다는 점도 아울러 당부하고자 한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.191-200
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• 2009

This paper, which consists of two parts, dealt with the parameter tuning of the power system stabilizer for a 612[MVA] thermal power plant in KEPCO system and its validation in field test. In Part 1 of the paper, the selection of parameters such as lead-lag time constants for phase compensation, system gain was optimized by using linear & eigenvalue analyses and they were verified through the time-domain transient stability analysis. In part 2, the performance of PSS was finally verified by the generator's on-line field test. Through the comparisons of simulation results and measured data before and after tuning of the PSS, the models of generator and its controllers including AVR, Governor and PSS used in the simulation are validated and confirmed.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.4
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• pp.349-356
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• 2012

For smooth implementation of the IMO Ballast Water Management Convention that is to come into effect in the near future, IMO and Member States are working on the development of various technologies and establishment of legislative action. Ballast water treatment systems are essential, yet difficult technologies, as they need not only to treat living organisms, but also define whether they are viable or not, count the number of viable organisms, and present quantitative results of the concentration of active substances. Despite the fact that the Convention is looming in the near future, the issues mentioned above obstruct the setup of consensual technologies for performance reliability of the treatment system and analysis method of efficacy test results. This paper considers the unsolved issues of the ballast water treatment technologies, and presents guidelines to solve these issues.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.666-671
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• 2023

As international environmental regulations on ship emissions are gradually strengthened, interest in electric propulsion and hybrid propulsion ships is increasing, and various solutions are being developed and applied to these ships, especially stabilization of the power system and system efficiency. The direct current distribution system is being applied as a way to increase the power. In addition, verification and testing of safety and performance of marine DC distribution systems is required. As a result of establishing a DC distribution test bed, verifying the performance of the DC distribution (variable speed power generation) system, and analyzing fuel consumption, this study applied a variable speed power generation system that is applied to DC power distribution for ships, and converted the power output from the generator into a rectifier. A system was developed to convert direct current power to connect to the system and monitor and control these devices. Through tests using this DC distribution system, the maximum voltage was 751.5V and the minimum voltage was 731.4V, and the voltage fluctuation rate was 2.7%, confirming that the voltage is stably supplied within 3%, and a variable speed power generation system was installed according to load fluctuations. When applied, it was confirmed through testing that fuel consumption could be reduced by more than 20% depending on the section compared to the existing constant speed power generation system.

• Journal of IKEEE
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• v.25 no.4
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• pp.703-709
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• 2021

As drone technology advances, the risks of drones are increasing, then technology to detect drones is becoming important. In this thesis, it was verified that miniaturized and lightweighted active array antenna could be used for radar system to detect drones in reality. The transmit-receive module was designed in the form of tile-type to simplify interconnections between devices. The waveform generation module and the down conversion module were miniaturized to include in one body too. As a result of verifing the detection performance through test, it was confirmed that the detection range was over 3.7Km.

• Journal of the Korean Geotechnical Society
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• v.19 no.3
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• pp.23-31
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• 2003

Over the past half century, borehole seismic surveys have been diversified into the three techniques such as crosshole, downhole, and suspension logging according to their devices and testing configurations. These field techniques have been improved, in terms of equipment and testing procedures, and are very valuable in the evaluation of ground characteristics for geotechnical and earthquake engineering problems. Yet, despite the importance and significance of the techniques as engineering tools, the techniques are not much used as standard penetration test (SPT) by practicing engineers. The possible explanations are cost and operational difficulties of the surveys as well as sophistication and complexity of the devices. An in-hole seismic method has been developed to meet the requirement of economical testing cost and practicality in engineering practice to measure dynamic soil properties. The prototype in-hole probe developed herein is small and light enough to be fit in three-inch boreholes and to be handled with bare hands. The performance of the source has been evaluated through extensive crosshole tests at various sites. The in-hole seismic method was adopted at three test sites and verified by comparing with crosshole results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.413-419
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• 2011

Diagnosis X-ray equipment localized at 1950's but it is developed suddenly at 1960's with demand together. Manufacture of Diagnostic X-ray equipment is controled by the KS regulation and the Ministry of Health and Welfare because of hazardous element etc. exposure by radiation. Most of diagnostic X-ray equipment ware single phase and three phase full-wave rectification but from 1980's it transforms it was exchanged in inverter type X-ray equipment. Inverter type X-ray equipment produces approximately 50~80% more average photon intensity then single phase full-wave rectification and the accuracy is high. But from a clinic it dose not use because expensive therefor the efficiency improvement of single phase full-wave rectification is necessary. We produced single phase full-wave rectification X-ray equipment control unit, high tension transformer, filament heating transformer, rectification circuit, high tension cable and others and evaluated efficiency, in result which is excellent compare with Rule of Safety Management and KS regulation.