• Journal of the Korean institute of surface engineering
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• v.51 no.5
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• pp.316-324
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• 2018

Harsh seawater environment is subdivided into marine atmosphere, splash zone, tidal zone, submerged zone and bottom of sea depending on the exposed part. Since corrosion rate depends on the conditions of the exposed parts, proper protection and maintenance for each parts are essential for long-term use of steel structures in seawater environment. For steel structures which were installed in Shiwha Lake, a special maintenance system is required to guarantee its long-term durability and safety. As the tidal power plant has recently been operated, the salinity has risen due to the rapid influx of seawater upstream into Sihwa Lake and the corrosion tendency of the structure is variable according to the water level fluctuation. In this study, corrosion properties of steel structures under water level fluctuation was evaluated by corrosion rate measurement, visual inspection and natural potential measurement and their durability and life management were discussed in view of the effect of variation in of seawater level fluctuations in Shihwa Lake.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.61-62
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• 2018

시화호는 1994년에 완공된 인공호수로, 완공 이후 심각한 오염에 직면하여 방조제 건설 후 4년째인 1998년부터 바닷물을 일부 유통하기 시작하여 2001년 10월부터 해수의 상시 유통이 확정되었다. 또한, 시화호 조력발전소는 2011년 11월에 착공되어 본격적인 전력생산에 들어 갔으며, 2018년 1월 현재 전력공급량은 29억kWh를 달성하였다. 시화호는 환경적 오염으로 인하여 많은 문제가 야기된 곳이기 때문에 환경적 또는 재해적인 검토를 통한 기초자료의 분석 및 공개는 필수적이라 판단된다. 이러한 목적 하에 수행된 시화호 수리수문 해석결과, 시화호 수리특성은 시화호 조력발전소 운영조건과 시화화 유입하천에 의해 결정되는데, 시화호 조력발전소 관리수위 조건 하에서 고조위는 -1.5m~-0.94m의 분포를, 제한수위 조건하에서 -0.76~0.48m의 분포를 보인다. 또한, 장기하상변동 결과는 수로 부근은 침식이, 그 외의 구간은 퇴적이 우세하게 나타났다. 이러한 결과로, 시화호는 내측으로 갈수록 재해적 환경적으로 불리한 지역임이 확인하였다.

• Korean Journal of Environment and Ecology
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• v.30 no.3
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• pp.320-327
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• 2016

Intertidal zone has been restored by the Sihwa Lake tidal power plant is operating in 2012. After restoration, to check the difference of bird group's community change out, the examination has been carried out from 2009 to 2014 when sea dike sluicer runs, the intertidal zone area was increased to $20.3km^2$ after restoring in $5.3km^2$. There was no significant difference in the number of individuals congestion of the whole, but the results of analysis of the differences between the six bird group by number of individuals, it showed a significant difference in Diving ducks(p = 0.237) the Herons (p<0.001), Swans and Geese (p<0.01), Dabbling ducks (p<0.001), showed a significant difference in the Shore birds (p<0.001) gulls (p<0.001) except for diving of ducks. Sihwa Lake intertidal zone was only just been restored, but environment and the improvement of benthic ecosystem has been carried out, It is determined that waterfowls that living based on intertidal zone are also affected. This study is a good example of the restoration of the intertidal zone that disappeared, which hard to find a similar case. It will be utilized as basic data of ecological monitoring for the conservation and management of the future of the intertidal zone later.

• Journal of the Korean Geotechnical Society
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• v.26 no.5
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• pp.37-48
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• 2010

In this study, the seepage flow monitoring method by the hydraulic head loss rate was developed for the purpose of application to offshore construction site enclosed by cofferdams in which seepage force varies periodically. The amount of the hydraulic head loss rate newly defined in this graph was in a range between 0 and 1. The zero of the rate means the existence of flow with no seepage resistance. The 1 of the rate means no seepage flow through the ground. The closer to 1 the coefficient of determinant in the hydraulic head loss graph is, the more the ground through which seepage water flows is stable. The closer to 0 the coefficient of determinant in the hydraulic head loss graph is, the more the ground through which seepage water flows was unstable and the higher the possibilities of existence of empty space or of occurrence of piping on the seepage flow pass in the ground is. The hydraulic head loss graph makes it possible to monitor sensitively the situation of seepage flow state, and the graph helps to understand easily the seepage flow state at the specific section on the whole cofferdam.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.110-111
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• 2006

본 논문은 시화 방조제상에 공사중인 국내최초, 세계 최대설비용량인 254,000kW의 벌브형 수차발전설비가 수중에 설치되도록 설계되어 있어 해수에 의한 설비부식으로부터 설비를 보호하기 위한 전기방식설비 설계의 적정성과 시스템 구성에 대해서 고찰하기 위한 것이다. 시화조력발전소에 적용될 전기방식설계의 적정성을 사전 예측하기 위하여 전문 프로그램을 활용하여 시뮬레이션을 시행하였으며 방식전위 실시간 감시 및 제어기능은 물론 수차발전설비 운전상태와 연동하여 방식전위를 자동제어 할 수 있는 최적제어시스템 설계내용을 제시하였다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1615-1617
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• 2007

시화 방조제상에 공사중인 국내최초, 세계최대용량의 조력발전소에 25,400kW의 벌브형 수차발전기 10대를 설치함에 따라서 해수에 의한 부식으로부터 설비를 보호하기 위한 전기방식을 적용하였다. 전기방식 설계는 설비의 재질에 따라 요구되는 단위 면적당 전류밀도가 상이하고 발전기의 운전상태에 따라 소요되는 각기 다른 수량의 양극과 수차발전기를 제어하는 주 제어시스템과의 통신이 필수인 지능화된 정류기가 요구되어진다. WEB 기반의 감시제어시스템 구성시 외부 또는 장소에 제한없이 전기방식 설비의 정상 가동여부, Alarm, Fault 상태 등을 실시간 접속하여 확인이 가능하고 담당 직원 또는 지정된 사람의 휴대폰에 문자메세지를 통한 상태 알림 기능을 자동으로 제공할 수 있도록 구성하였다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.184-186
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• 2007

절연물의 열화가 진행되면 최초로 1선 지락사고가 발생할 가능성이 많고 1선 지락사고는 2선 지락 및 단락사고로 파급되어 설비에 심각한 손상으로 이어지게 된다. 따라서, 1선지 락 사고에 대한 완전한 보호방식의 적용은 설비 신뢰성 증대라는 측면에서 매우 중요한 사항이라고 판단된다. 이에 시화호조력 발전소에 설치될 수차발전기는 고정자권선의 지락사고에 대한 100%보호방식을 적용하였으며 이 설계사례를 토대로 실제적으로 적용가능한 발전기 고정자권선의 지락보호증대방식을 공유코자 한다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.336-337
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• 2011

접지시스템 구축의 근본 목적은 인체의 안전(Safety)과 설비의 안정(Stability)을 목적으로 하며, 보호목적에 따라 전력설비용 접지와 약전용 접지로 크게 나눌 수 있다. 전력설비용접지(Frame Earth)는 감전이나 설비의 피해를 방지하기 위한 것으로서 주로 보안용접지에 속하며 평상시에는 접지선에 전류가 흐르지 않는 것이 일반적이다. 이에 반하여 약전용접지(Signal Earth)는 전자통신 회로의 안정된 동작을 확보하기 위한 것으로 평상시에도 전류가 흐르는 것이 일반적이다. 이와 같이 접지시스템은 인축의 안전과 설비의 안정적 가동확보를 위해 대단히 중요한 설비이며, 특히 전력설비용 접지의 목적은 대지면의 국부적 전위상승에 따른 인체의 감전사고방지와 1선지락사고시 전위상승억제 및 보호계전기의 확실한 동작을 도모하기 위하여 실시한다. 본 연구에서는 2011. 10월 준공예정인 시화조력발전소의 전력설비용 접지시스템을 대상으로 IEEE에서 제시하는 목표접지저항값 유지여부를 평가하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.10
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• pp.1532-1539
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• 2017

The floating photovoltaic system is a new concept in the renewable energy technology. That is similar to land based photovoltaic technology except floating system. So the system needs buoyant objects, mooring, ect, besides modules and supports, and that is able to withstand in water level changes and wind strength. Therefore the floating photovoltaic system is much different from land photovoltaic system. K-water (Korea Water Resources Corporation) has been operating two floating photovoltaic system that's capacity is 100 kW and 500 kW respectively since in summer 2011 for commercial generation, and have construction project for 2,000 kW in Boryeong multipurpose Dam and other areas. Furthermore K-water was developing a tracking-type floating photovoltaic system at Daecheong multipurpose Dam and developed and installed an ocean floating photovoltaic demonstration plant at Sihwa Lake in October 2013 for R&D. In this paper, we introduce that structure of floating photovoltaic system include buoyant structure, mooring system and auxiliary device. Especially the rope which is in part of mooring should be always maintain tension under any water level. Also we explain about structure design concept to wind load in an every loading condition and a kind of structure materials and PV structure types used in water environment. Especially ocean floating PV system is affected by tidal current and typhoon. So there are considering the elements in design. Finally we compare with floating and land photovoltaic on power amount. As a result of that we verified the floating photovoltaic system is more about 6.6~14.2 % efficiency than a general land photovoltaic system.

• Korean Journal of Environment and Ecology
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• v.30 no.5
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• pp.837-847
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• 2016

In this study, the bird fauna of Sihwa Lake in Gyeonggi Province were investigated from 2009 to 2014 to identify the effect of the restored intertidal zone on bird community. Based upon the analysis of the habitat status and distribution change of water birds in the intertidal zone, the following conclusions were obtained. The number of water bird individuals increased by approx. 40 thousand after the restoration. Most of water bird species increased, but diving ducks decreased. Analysis of the number of individuals of water birds before and after the intertidal zone restoration showed that there was a significant increase in the number of shorebird individuals. There is a habitat use pattern change in the southern tideland intertidal zone that includes the largest area of widened intertidal zone and the inland waters of the intertidal zone. This is related to the change of benthic ecosystem which is the food source of birds. The benthic ecosystem in restoring Sihwa Lake has been stabilized with a decrease in opportunistic species and consistent increase in equilibrium species that are sensitive to pollution. As a result, the environmental conditions for shorebirds have been improved. The restoration of intertidal zone affected the habitat use and distribution patterns of water birds in a short period of time. Compared to before restoration, all the water birds now use the wide area of the intertidal zone with no partiality and it is confirmed that the restoration greatly affected the distribution of shorebirds and swan & geese. This study was conduced to identify the effects of an artificial restoration of intertidal zone due to tidal power generation of bird species. In terms of maintaining and improving biodiversity, the intertidal zone restoration was recognized to be important and still shows positive results. This study is expected to provide a direction when an alternative is required to maintain and improve biodiversity in a similar situation in the future.