• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.188-190
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• 2008

In this paper, it proposes a the high efficiency tracking system regarding power loss when operating a tracking system for environment variable such as a rapidly changing insolation to improve the power of PV tracking system. In case of tracking an azimuth and altitude of the sun in realtime, therefore, the actual PV power is less increasing than the power of tracking system fixed a specific position. To reduce the power loss, this paper proposes a nonel control algorithm of the tracking system. The paper is analyzed efficiency about conventional PV tracking method, comparing proposed algorithm with high performance method. We show propriety of proposed algorithm by means of the demonstrable study.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 춘계학술대회 논문집
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• pp.403-406
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• 2008

In this paper proposes a novel tracking algorithm regarding the power loss when operating a tracking system for a rapidly changing insolation to improve the power of PV tracking system. In case of tracking an azimuth and altitude of the sun in realtime, therefore, the actual PV power is less increasing than the power of tracking system fixed a specific position. To reduce the power loss, this paper proposes a nonel control algorithm of the tracking system. The paper is analyzed efficiency about conventional PV tracking method, comparing proposed algorithm with high performance method. We show propriety of proposed algorithm by means of the demonstrable study.

• 동력기계공학회지
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• 제14권5호
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• pp.30-35
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• 2010

Recently, the large capacity draft fans in power plants had been changed to variable speed type to educe the power consumption. But the fan experienced the unexpected vibration at specific speed regions. In this study, the high vibration frequency of the fan was confirmed and the natural frequency of the rotor were measured and analyzed by FEM programs. It was analyzed that the vibration was caused by the resonance at the frequency, 30.7Hz. So, the rotor vibration characteristic was changed by adjusting the distance between the shaft bearings. It was conformed the high vibration was disappeared over the all operation speeds.

• Nuclear Engineering and Technology
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• 제29권1호
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• pp.85-91
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• 1997

Cross-flow existing in a shell-and-tube steam generator can cause a tube to vibrate. There are four regions subjected to cross-flow in Yonggwang units 3 and 4 (YGN 3 and 4) steam generators, which are of the same design as the steam generators for Palo Verde nuclear power plant Palo Verde units 1 and 2 steam generators have experienced localized oar at the comers of the cold side recirculating fluid inlet regions. A number of design modifications were made to preclude tube failure in specific regions of YGN 3 and 4 steam generators. Therefore, flow induced vibration experiments were done to determine the vibration magnitude of tubes in the economizer tube free lane region. The objective of this experiment is to demonstrate that the tube displacement is less than 0.01 inch rms at 100% of full power flow and to quantify the remaining design margin at 120ft and 140% of full power flow.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 추계학술대회
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• pp.248-249
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• 2010

This paper describes development of hardware simulator for the PMSG(Permanent Magnet Synchronous Generator) wind power system, which was designed using real wind data. The simulator consists of a realistic wind turbine model using anemometer, vector drive, induction motor. The turbine simulator generates torque and speed signals for a specific wind turbine with respect to given wind speed. This torque and speed signals are scaled down to fit the input of 3kW PMSG. The PMSG-side converter operates to track the maximum power point and the grid-side inverter controls the active and reactive power supplied to the grid. The operational feasibility was first verified by computer simulations with PSCAD/EMTDC. The feasibility of real system implementation was confirmed through experimental works with a hardware set-up.

• 무역학회지
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• 제45권5호
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• pp.55-74
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• 2020

This study examines the policy direction and specific countermeasures for addressing possible port labour issues from the perspective of Just Transition which may be raised by closing coal fired power plants in Korea. Current energy transition policy and port labour policy in Korea are reviewed and case studies in the countries which has experienced closure of coal fired power plants are undertaken. Although it varies from country to country, a similar approach was found that the employment problem of coal fired power plant closures and measures based on Just Transition regime to mitigate the negative impacts that occur in the region are the key to successful transition. It is suggested that countermeasures for port labour should be institutionalized for providing stakeholders with legal stability covering labours not only directly employed by the plants but also employed in entities in the whole supply chains.

• 한국중재학회지:중재연구
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• 제30권2호
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• pp.165-184
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• 2020

In this study, the factors affecting opportunism in the relationship between suppliers and key accounts were analyzed from the viewpoint of transaction cost theory, market power theory, and relationship marketing theory. As a result of the hypothesis test, Hypothesis 1 stating that demand volatility will have a positive effect on opportunism and Hypothesis 2 that transaction-specific investment will have a positive effect on opportunism were also supported. In addition, Hypothesis 3 stating that channel power will have a positive effect on opportunism was also supported. Lastly, Hypothesis 4 stating that relational commitment will have a negative effect on opportunism was not supported, along with Hypothesis 5 stating that transaction satisfaction will have a negative effect on opportunism. The theoretical and practical implications of this study are as follows. This study has identified the antecedents of opportunism by comprehensively applying the transaction cost theory, market power theory, and relationship marketing theory. In addition, this study can identify what a company should manage specifically to lower opportunism by identifying the antecedents of opportunism. The limitations of this study and the directions for future studies are as follows. First, not all of the antecedents of opportunism of key accounts have been extensively investigated from the viewpoint of the transaction cost theory, market power theory, and relationship marketing theory. In the future, it is necessary to identify additional factors. Second, the study was conducted only in the supplier's viewpoint. In future studies, it is expected that more accurate research results can be obtained by simultaneously examining not only the supplier's point of view but also the buyer's point of view.

• 한국전자파학회논문지
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• 제16권8호
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• pp.810-814
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• 2005

TEM 셀 내에 있는 혈액에 대한 삽입 손실과 반사율을 측정하여, 원하는 혈액 흡수 SAR(Specific Absorption Rate) 선택에 따른 TEM셀 입력 전력을 구하였다. 혈액 세포는 피부 세포와 함께 전자파 영향을 연구하기 위한 기준 세포이다. 따라서 SAR에 따른 혈액 세포에 인가할 전력 산출은 정확해야 함은 물론 타당성이 있어야 한다. 이 연구에서는 g당 혈액 세포가 받는 전력을 산출하기 위해 50 g의 혈액을 이용하여 전달 전력 감소를 측정하였다. 측정된 데이터로부터 휴대폰 전자파 생체 흡수율 SAR 0.8, 1.6, 3, 4 mW/g에 해당하는 TEM셀 입력 전력을 계산하였다. 이 연구 결과는 배양 세포의 전자파 방사 장치에 응용함을 목적으로 하고 있다.

• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2652-2659
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• 2020

The methyl iodide (CH₃I) removal performance of tri-ethylene-di-amine impregnated activated carbon (TEDA-AC) used in the air cleaning unit of nuclear power plants (NPPs) should be maintained at least 99% between 24 month-performance test period. In order for evaluating the effectiveness of TEDA-AC on the removal performance of CH₃I in nuclear power plant during the operation of NPPs, the long-term test for up to 15 months was carried out under the simulated operating conditions (e.g., 25 ℃, RH 50%, ppb level poisoning gases injection) at nuclear power plants (NPPs). The TEDA-AC samples were analyzed with the Brunauer-Emmett-Teller (BET) specific surface area and TEDA content as well as CH₃I penetration test. It is clearly evident that more than 99% of CH₃I removal performance of TEDA-AC was observed in the TEDA-AC samples during 15 months of long-term operation under the simulated NPP operating conditions including the ppb level of organic and oxide form of poisoning gases. BET specific surface area and TEDA content that can affect the CH₃I removal performance of TEDA-AC were also maintained as those in new TEDA-AC during 15 months of long-term operation.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2005년도 추계 학술대회 논문집
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• pp.126-133
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• 2005

국내 중${\cdot}$저준위 방사성폐기물 처분을 위한 처분부지 확보 및 관련업무가 활발히 진행 중이다. 방사성폐기물 처분을 위해서는 방사성폐기물의 물리화학적, 방사학적 상태 및 건전성 등을 확보하여야 하며 폐기물 발생자는 이러한 정보를 처분사업자에게 제공해야한다. 또한 처분 안전성을 확보하기 위하여 방사성폐기물 인수기준(Waste Acceptance Criteria : WAC) 및 처분부지 특성을 고려한 세부인수기준(Site Specific Waste Acceptance Criteria : SWAC)이 필요하며 방사성폐기물을 이 기준에 적합하게 처리${\cdot}$생성${\cdot}$관리 및 인도하여야 한다. [1] 이를 위해서는 각각의 방사성폐기물에 대한 특성평가를 수행하여야 하나 원자력발전소의 경우 방사성폐기물 발생량이 많아 현실적으로 어려움이 있다. 이러한 문제점을 해결하기 위해 IAEA 및 해외 주요 국가는 방사성폐기물 인증체계(Waste Certification Program : WCP) 및 품질보증체계(Quality Assurance Program : QAP)를 개발하여 활용하고 있으며[2,3] 이를 바탕으로 국내 방사성폐기물의 안전한 처분을 위해 과기부고시 2005-18호 '중저준위 방사성폐기물 인도규정' 및 세부인수기준(시안)을 만족할 수 있는 방사성폐기물 인증프로그램을 개발하였다. 또한 방사성폐기물 인증체계 조기 도입 및 운영을 위해서 상용원전 관련 절차서 개정 및 실무자 교육을 추진 중이다.