• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 연구회 합동 학술발표회 논문집
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• pp.55-59
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• 1998

By this time, Diode Rectifier or SCR has been used to gain DC Voltage for Electrolysis Power. Generally DC Voltage is produced from rectifier shall be transformed before rectifier using step-down transformer to obtain adaptable DC Voltage, rectifier output. In the same way, rectifier using SCR shall obtain output voltage after step-down voltage through transformer and control of the SCR firing angle. Transformer shall be used for this two methods to adjust the voltage. But the size and weight of the transformer are increased in accordance with the increase of capacity, and the hardships are accompanied in workspace or transportation. Besides, only the value of input voltage is possible to be regulated, and the expectation of current control is almost impossible during Electrolysis. This study has conducted Design and Simulation to reduce the size and weight of transformer and to be enable voltage and current control of Electrolysis power through high-speed switching using Inverter, Electronics device.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(II)
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• pp.135-140
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• 2003

Recently Light Rail Transit(LRT) systems, especially full automatic systems are strongly issued by many provinces and major cities due to it's own characteristic for economical, environmental and sufficient transportation capacity. But LRT design criteria should be modified according to Rolling Stock's properties. -size, arrangement of bogie and wheel, power of traction motor etc, This thesis suggest for basic standard design criteria of Rubber Tired Light Rail Transit system.

• Nuclear Engineering and Technology
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• 제49권4호
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• pp.721-733
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• 2017

When temporary spent fuel storage pools at nuclear power plants reach their capacity limit, the spent fuel must be moved to an alternative storage facility. However, radioactive materials must be handled and stored carefully to avoid severe consequences to the environment. In this study, the risks of three potential accident scenarios (i.e., maritime transportation, an aircraft crashing into an interim storage facility, and on-site transportation) associated with the spent fuel transportation process were analyzed using a probabilistic approach. For each scenario, the probabilities and the consequences were calculated separately to assess the risks: the probabilities were calculated using existing data and statistical models, and the consequences were calculated using computation models. Risk assessment software was developed to conveniently integrate the three scenarios. The risks were analyzed using the developed software according to the shipment route, building characteristics, and spent fuel handling environment. As a result of the risk analysis with varying accident conditions, transportation and storage strategies with relatively low risk were developed for regulators and licensees. The focus of this study was the risk assessment methodology; however, the applied model and input data have some uncertainties. Further research to reduce these uncertainties will improve the accuracy of this model.

• 한국수소및신에너지학회논문집
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• 제31권1호
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• pp.132-137
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• 2020

Lithium secondary batteries have become an important power source for portable electronic devices such as cellular phones, laptop computers. Presently, commercialized lithium-ion batteries use a LiCoO₂ cathode. However, due to the high cost and environmental problems resulting from cobalt, an intensive search for new electrode materials is being actively conducted. Recently, solid solution LiMn_1-xNi_xO₂ have become attractive because of high capacity and enhanced safety at high voltages over 4.5 V. The Li_1.6Ni_0.35Mn_0.65O₂ compounds were conventionally prepared by a sol-gel method, which can produce the layered Li-Ni-Mn-O compounds with a high homogeneity. And by adding a graphene 2wt% the first charge-discharge voltage profiles was increased over Li_1.6Ni_0.35Mn_0.65O₂ compound. Also, the variation s of the discharge capacities with cycling showed a higher capacity retention rater. In this study, material lifecycle evaluation was performed to analyze the environmental impact characteristics of Li_1.6Ni_0.35Mn_0.65O₂ & graphene 2wt% half-cell manufacturing process. The software of material life cycle assessment was Gabi. Through this, environmental impact assessment was performed for each process. The environmental loads induced by Li_1.6Ni_0.35Mn_0.65O₂ & graphene 2wt% synthesis process were quantified and analyzed, and the results showed that the amount of power had the greatest impact on the environment.

• 설비공학논문집
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• 제26권9호
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• pp.434-440
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• 2014

Experiments were performed to verify if performance and characteristic curves obtained from the temperature differential defrosting method, where surface temperature is measured to judge defrosting condition, can be reproduced by the photoelectric technology where defrosting condition is judged by photoelectric sensors. The output voltage of a phototransistor and heating capacity, power consumption, and surface temperature of the outdoor heat exchanger are compared. The results showed that the photoelectric sensors can be used as a defrost control device. On-off control timings in temperature differential defrosting method are in good agreement with those predicted by the high and low threshold output voltages of the photoelectric sensor.

• 한국포장학회지
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• 제28권2호
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• pp.143-149
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• 2022

PCS needs to freely switch AC and DC to connect the battery, external AC loads and renewable energy in both directions for energy efficiency. Whenever converting happens, power loss inevitably occurs. Minimization of the power loss to save electricity and convert it for usage is a very critical function in PCS. PCS plays an important role in the ESS(Energy Storage System) but the importance of stabilizing semiconductors on PCB(Printed Circuit Board) should be empathized with a risk of failure such as a fire explosion. In this study, the temperature variation inside PCS was reviewed by cooling fan on top of PCS, and the vibration characteristics of PCS were analyzed during truck transportation for reliability of the product. In most cases, a cooling fan is mounted to control the inner temperature at the upper part of the PCS and components generating the heat placed on the internal aluminum cooling plate to apply the primary cooling and the secondary cooling system with inlet fans for the external air. Results of CFD showed slightly lack of circulating capacity but simulated temperatures were durable for components. The resonance points of PCS were various due to the complexity of components. Although they were less than 40 Hz which mostly occurs breakage, it was analyzed that the vibration displacement in the resonance frequency band was very insufficient. As a result of random-vibration simulation, the lower part was analyzed as the stress-concentrated point but no breakage was shown. The steel sheet could be stable for now, but for long-term domestic transportation, structural coupling may occur due to accumulation of fatigue strength. After the test completed, output voltage of the product had lost so that extra packaging such as bubble wrap should be considered.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2317-2319
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• 1999

765kV Transformer, bank capacity is 2,000MVA, is developed of two seperated tanks per phase because transportation weight of the transformer needs to be reduced. So we will operate one tank per phase in some case, low load or black down of 1 tank, using the one phase-two tank type of 765kV transformer to cut down the cost and improve the reliability of substation.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.806-812
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• 2009

Availability of reliable and affordable energy supply is a prerequisite for economic growth. Renewables are the third largest contributor to global electricity production after coal and natural gas and account for a share of 18%. Power generating capacity from renewables has increased to around 900GW by the year 2007. Today biodiesel fuels have been in commercial use in many countries and recently the world-wide biodiesel market has experienced considerable growth, which is partly due to various tax concession programs and other financial incentives. In Korea, biodiesel has already been used for transportation fuel, but not used for power generation fuel yet. Korean government has a strategy for renewable energy propagation, especially the goal of power generation amount by renewable energy is 3% of total power production by 2012. This paper focuses on the feasibility study for adaptability and strategy of using biodiesel as power generation fuel. The study also has the plan to replace the fuel of thermal power plant, gas turbine and distributed power system. As the increase of biodiesel fuel, I look forward to environment-friendly power generation and the strategy of Renewable Portfolio Standards(RPS).

• 신재생에너지
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• 제5권1호
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• pp.32-39
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• 2009

Availability of reliable and affordable energy supply is a prerequisite for economic growth. Renewables are the third largest contributor to global electricity production after coal and natural gas and account for a share of 18%. Power generating capacity from renewables has increased to around 900GW by the year 2007. Today biodiesel fuels have been in commercial use in many countries and recently the world-wide biodiesel market has experienced considerable growth, which is partly due to various tax concession programs and other financial incentives. In Korea, biodiesel has already been used for transportation fuel, but not used for power generation fuel yet Korean government has a strategy for renewable energy propagation, especially the goal of power generation amount by renewable energy is 3% of total power production by 2012. This paper focuses on the feasibility study for adaptability and strategy of using biodiesel as power generation fuel. The study also has the plan to replace the fuel of thermal power plant, gas turbine and distributed power system. As the increase of biodiesel fuel, I look forward to environment-friendly power generation and the strategy of Renewable Portfolio Standards(RPS).

• 한국산학기술학회논문지
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• 제15권2호
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• pp.638-645
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• 2014

컨테이너 물동량 증대에 따라 항만 내 타부두 간 환적 물동량 수요가 크게 증대되었으나, 기존 YT 방식의 타부두 환적은 이를 효율적으로 뒷받침하지 못하고 있다. 본 논문은 컨테이너항만의 경쟁력 향상을 위한 컨테이너 대용량 이송장치 개발방안을 제시하였다. 시스템 대안의 장단점 분석과 국내 터미널 운영형태를 고려하여 2단적재 다중 편성시스템(DMTS)을 최종 대안으로 선정하였다. DMTS 회전반경은 13.5m로, 국내 기존 항만의 layout에서 즉시 운용 가능할 것으로 판단된다. 특허분석을 통하여 DMTS 핵심기술 항목으로서 현가 조향장치 최적설계, 동력 및 동력전달 장치, 주행제어 및 안전감시장치, 그리고 트레일러 간 연결기 등을 도출하였다. DMTS는 국내 수출입 항만에 적용하는데 문제가 없으며 단위 수송용량이 높아 운영 효율성 개선에 기여할 것으로 판단된다.