• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.4
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• pp.274-281
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• 2015

Thermal and nuclear power plants on shore commonly use the sea water for cooling facility. Discharged cooling water has the high kinematic energy potential due to amount of water flux. Numerical analysis was made to find the suitable combinations between the arrangement of tidal turbines and the overall dimensions of the discharged channel. Several parameters such as the turbine diameter to inlet size, and the axial distance to turbine size were investigated. Power coefficients for various test conditions were also compared to see the effect of inlet configurations such as single inlet and dual inlet. For the single inlet, the mean power coefficient appeared to be gradually decreased with increasing distance, and the maximum power was obtained when the turbine diameter was same as the inlet diameter. For the dual inlet, the tendency was similar so that the better result when the turbine diameter was same as the inlet diameter. It is expected that the present methodology can be extensively utilized to harness the high kinetic energy flow of the discharge channel of power plant.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.112-114
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• 2006

과거 국내 접지설계는 요구 접지저항값 중심의 설계로 위험전압에 대한 접근은 미흡한 실정이었으나 최근에는 국외에서 중요시하고 있는 접지계의 안전전압에 중점을 둔 접지설계가 이루어지고 있다. 이에 시화호 조력발전소 건설공사의 접지설계를 모델로 하여 최근접지설계 기법을 정리하였다.

• Journal of the Korean Professional Engineers Association
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• v.37 no.1
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• pp.43-47
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• 2004

The purpose of this article is to introduce ocean energy and its application. In recent years, the energy consumption and requirement of fossil resources are increased due to the advanced life style. But, the amount of fossil fuels have limitation. Also, it is difficult to construct new large power plant facilities for the production of electric energy. Therefore, the necessities to study and to find out other energy resources are increased more and more. In the ocean, the efforts of using tide, wave, tidal current and thermal energy are should be attempt. To satisfy the needs, corporation is required among the government, research institute, university and company.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.121-124
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• 2006

국내외에 아직 적용 실적이 없는 발전소의 해수방류수를 이용한 조류식발전시스템의 개발을 위하여 하동화력발전소 방수로에 시험용 조류식 발전시스템을 설계 및 제작하여 현장시험이 진행 중이며, 이를 확장하여 상업용 발전을 위한 총 개발 규모를 산정하고 경제성을 분석하였다. 조류식발전구조물의 형상 설계, 가이드 베인을 이용한 출력 조정을 통하여 방수로의 수류상태를 적절히 조절하여 설계하는 것이 가능할 것으로 판단되며, 조류식발전구조물 설치시 방수로의 수류특성 수치계산 결과로 판단할 때 발전출력에 의한 에너지 회수뿐만 아니라 조류식발전구조물의 단면축소 효과 및 수두손실이 방수로의 수위 변화에 상당한 규모로 영향을 주고 있음을 확인하였다. 조류식발전구조물 설치 이전의 유속 관측 결과를 이용하여 발전량을 산정한 경우 소수력발전 단가 적응시 경제성이 떨어지지만, 조류식발전시스템의 설치시 유속 증가 효과가 나타날 뿐만 아니라 가이드 베인 등을 이용하여 발전량 증대를 꾀하면 충분한 경제성을 확보할 수 있는 조류식발전시스템의 설치가 가능할 것으로 판단된다.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.509-512
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• 2006

국내 대형 기력발전단지에서 냉각수로 사용되고 방류되는 해수는 약 150cms로 (100Mwe 당 약 5cms) 약 3,000kW 이상의 수력에너지를 보유하고 있으나, 현재 활용되지 못하고 그대로 해양으로 방류되고 있다. 발전소 방수로는 흐름조건이 비교적 균일하고, 파랑 내습이 없으며 부유사 해조류, 부유물 충돌 등의 문제가 발생하지 않아 자연 해양조건보다 조류력 발전에 매우 유리하나 수심이 낮고, 순환수 계통에의 영향으로 다수의 수차를 설치하기는 어려운 조건을 지니고 있다. 따라서, 인공수로의 균일하고 양호한 흐름조건에 적합한 보다 경제적인 수차를 개발하고, 발전량을 증대하기 위한 수차 배치 기술, 수차 및 발전기 지지구조물의 설계 기술, 계통 연결기술 등을 개발할 필요가 있으며, 이를 위하여 시험용 조류식 발전시스템을 제작하여 수차의 성능 및 전체 발전시스템의 성능을 평가하여 발생되는 문제점을 해결하고자 한다. 본 연구에서는 시험용 조류식 발전시스템을 하동화력발전소 방수로에 적용하기 위하여 현장 특성 분석, 형식 선정, 발전량 산정 등의 시스템 설계를 수행하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.1
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• pp.73-80
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• 2008

An hydraulic experiment was carried out in an open channel flume in order to improve the technique of designing shape of the sluice used for tidal power generation, which greatly affects the economical efficiency of the construction of a tidal power plant. To predict the influence of change in the major design parameters relating to the sluice shape on the water discharge capability of the sluice, it was necessary to perform a precise experiment that is discriminated to previous feasibility studies or design projects. For this purpose, by installing various flow straighteners and rectifying structures inside the water supply system and the rectifying tank, the flow in the flume was stabilized as tranquil as possible. In addition, the measuring instruments and the location of installing them were carefully determined so as to minimize the errors intervened during the measurement of water discharge and water level. The method of estimating head difference between upstream and downstream of the sluice was also developed by taking account of the head loss due to the friction at the bottom and side walls in the flume.

• Journal of Ocean Engineering and Technology
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• v.28 no.4
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• pp.261-267
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• 2014

Because a change in the natural frequencies of a structure indicates structural health problems, monitoring the natural frequencies crucial. Long-term measurement for the Uldolmok tidal current power plant structure has shown that its natural frequencies fluctuate with a constant cycle twice a day. In this study, lab-scale tests to investigate the causes of these natural frequency fluctuations were carried out in a circulating water channel. Three independent variables in the tests that could affect the fluctuation of the natural frequencies were the water level, current velocity, and boundary condition between the specimen and the bottom of the circulating water channel. The experimental results were verified with numerical ones using ABAQUS. It was found that the fluctuation of the natural frequencies was governed by a decrease in stiffness due to the boundary condition much more than the effect of added mass. In addition, it was found that the natural frequency would decrease with an increase in the tidal current velocity because of its nonlinearity when the boundary condition was severely deteriorated due to damage.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.474-481
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• 2011

The discharge coefficient and spatial velocity distribution were clarified by carrying out a physical experiment to assess the performance of sluice for tidal power generation. The physical experiment was performed by manufacturing 10 sluce models whose scale is 1/70 of the prototype and installing it in the planar open channel, which has apron sections in front of and behind the sluice models. In particular, it was attempted to reasonably determine the locations and method of measuring water levels that may affect estimation of the discharge coefficient. Based on the experimental results for various conditions of discharges and tidal levels, the discharge coefficient of the sluice in the experiment was estimated as 1.3 to 1.4. Meanwhile, it was found that velocities were 2~3% faster at the sluices near the central region whereas 4~5% slower at the sluices on both sides, in comparison to the average value of the mean velocities of the ten sluices.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.456-459
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• 2005

삼천포 보령 당진 등 국내 대형 기력발전단지에서 냉각수로 사용되고 방류되는 해수는 약 150cms로 (100Mwe당 약 5cms) 약 3,000kW 이상의 수력에너지를 보유하고 있으나, 현재 활용되지 못하고 그대로 해양으로 방류되고 있어 이 소수력에너지의 개발 방안을 검토하였다. 발전소 온배수의 원활한 배수를 위한 설계 낙차와 함께 남서해안의 조위변화에 따른 낙차를 이용하는 것으로 소수력 발전 방식과 조력 발전 방식의 특징을 동시에 활용하는 것이다. 국내의 기력발전소 가운데 삼천포, 보령, 하동화력발전소에 대하여 소수력에너지 개발방안을 검토하였으며, 배수로에 댐을 축조하여 방류수 전량을 발전에 이용하는 댐식, 배수로 중간에서 방류수 일부를 취수하는 수로식, 배수로의 빠른 유속을 이용하는 조류식 발전 방안을 중심으로 각 발전소의 구체적 적용여건에 따라 다양한 대안을 검토하여 기술적 가능성 및 경제성이 충분함을 입증하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.547-555
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• 2007

In order to transmit energy generated through the stator winding of a doubly-fed induction generator (DFIG), we need to synchronize the generated voltage vector with the grid voltage vector. However, the existing synchronization methods work only when the encoder is installed at a specific position and equivalent constant is precise. In order to solve this problem, a new synchronization method has been proposed and a way of applying the method to existing doubly-fed induction generator control algorithm has been also proposed. The validities of the methods proposed were verified by using a prototype converter for a 1.5MW-class doubly-fed induction generator and experimental results showed the validity of that against variation of an encoder positions, generator parameters, and grid voltages.