• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.1
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• pp.30-37
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• 2012

This paper assessed environmental impact of tidal power plant construction in the western sea of Korea, and diagnosed problems of the related assessment. We also proposed key assessment items (scoping) and system improvement for environmental impact assessment (EIA). The establishment of a broad consensus of the appropriateness and a clear purpose for business is an important aspect of the aptness of using the waters, and the aggressive collecting of opinions of the stakeholder and institutions will have to be fulfilled. In addition, we presented the following scoping plan in order to minimize the negative effects of the marine ecosystem and the conflict between the people who work in the fishing industry which result due to the construction of the tidal power plants. (1) the change in seawater exchange rates and the aspect of erosion/sedimentation which result from the change in the velocity of running fluid, (2) the destruction of spawns/habitats of fish due to the damage of tidal flats, (3) fishery resources, impacts of fishing grounds, and the spread of suspended sediments, etc. will have to be applied to the key assessment items(scoping). In addition, every citizen will have work hard for an establishment of an active plan which achieves the harmony and balance of environmental preservation and for the policy to be applied through changing their consciousness of environmental preservation.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.131-133
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• 2008

In this paper, the control method of extracting maximum power from the seaflow energy is proposed. This Paper describes a variable speed seaflow generation system with Permanent magnet synchronous motor, bridge rectifier, buck-boost converter and Fuzzy controller. In this Proposed seaflow generation system, the duty ratio of buck-boost converter is controlled by the fuzzy controller. An advantage of MPPT control method presented in this paper don't need to use the characteristic of seaflow turbine at various seaflow speed and measure the tidal speed and the rotating speed of tidal turbine. Therefore, the Proposed system has the characteristics of lower cost, higher efficiency and lower complexity. The effectiveness of algorithm is simulated based on Matlab Simulink.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.3
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• pp.134-141
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• 2018

Numerical simulations were carried out to investigate the flow velocity changes in the flow field due to the variation in the thickness of the upper part of the shroud tidal power generation system. In this study, it was performed under constant flow velocity condition. In addition, performance analysis of shroud was performed under the same conditions. As the height of the upper part increases, the flow velocity rate gradually increases, and it tends to decrease at a certain height. As a result of analyzing the shape of the blade and the shape of the blade combined with the shroud, the torque of the blade increased due to the increase of the flow rate by the shroud system. It is expected that the shape of the structure obtained by this study and the analysis of the flow velocity distribution in the flow field can provide the data necessary for the development of an efficient shroud tidal power generation system.

• Journal of Hydrogen and New Energy
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• v.31 no.1
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• pp.151-159
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• 2020

This study aimed to investigate the performance characteristics of vertical axis turbine of tidal energy convertor. Three-dimensional Reynolds-averaged Navier-Stokes equation with shear stress transport turbulence model has been solved to analyze the fluid flow of the vertical axis turbine. The hexahedral grids have been used to construct the computational domain and the grid dependency test has been performed to find the optimum grid system. Four steps have been carried out to design the vertical axis turbine of the 100 kW class tidal energy convertor.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.326-333
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• 2015

A tidal sandshoal, called 'Puldeung' in the Daeijackdo Marine Protected Area(DMPA), is facing erosion due to sand mining in the nearby coastal region. To monitor the morphologic change and erosion of Puldeung, a camera monitoring system was established at the top of Song-Ee Mountain in Daeijack Island. The system consists of 2 Cannon digital cameras, Eye-fi memory card/Long-Term Evolution wireless network, and solar power supply. The acquired camera images were analyzed to obtain the area of Puldeung by the following methods: geometric correction of image, identification of shoreline, areal measurement of Puldeung and its error estimation. To compare the Puldeung area with previously measured area of 1.79 km2 at tidal height of 137 cm in 2008 and of 1.59 km2 at tidal height of 148 cm in 2010, we selected images with same tidal heights. The Puldeung area was 1.37 and 1.23 km2 at the tidal height of 137 and 148 cm, respectively. The erosion at DMPA is very severe and thus it is imperative to initiate the morphodynamical study on the seasonal variation and long-term evolution of Puldeung as well as the causes and measures of Puldeung erosion.

• Journal of the Korean Society of Visualization
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• v.8 no.2
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• pp.51-55
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• 2010

Flow characteristics of a free-horizontal-axis-turbine (FHAT) current power generation system have been investigated by the use of a volumetric PTV. Three types of FHAT system (S50, SE50, S65) have been tested under the current speed 1.35 knot, 1.5 knot and 2 knot. The width of the blade installed around the body is 50 mm. Based upon the power generation characteristics of the FHAT, the flow features of the blade have been investigated. Among the three models it has been verified that the S65 is the most appropriate for power generations.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.2
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• pp.77-83
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• 2012

Numerical analyses through Computational Fluid Dynamics have been performed to investigate the seawater flow field characteristics for various shrouds used in horizontal axis tidal current turbine systems. Seawater flow characteristics are largely influenced under constant tidal current velocity by the shroud geometry and there is considerable difference in fluid velocity distributions around the shrouds. Especially the location and magnitude of maximum seawater flow velocity directly affect turbine performance for power generation. For the cylinder-diffuser type shroud system whose cylinder and diffuser parts have the same length accelerated flow region is formed in the overall cylinder part while maximum velocity in the nozzle-diffuser type whose nozzle and diffuser parts have the same length with symmetry, locally appears near the minimum sectional area. In case of cylinder-diffuser type shroud fluid velocity increases rather high compared with current velocity. And fluid velocity at the centerline gradually increases from the entrance, and then decreases rapidly after reaching a peak close to the middle of the cylinder part unlike the nozzle-diffuser while there is not much variation near the rear of the shroud. These results of the seawater flow characteristics with various shroud geometries can be applied to optimal design for the development of efficient tidal current power generation systems.

• Magazine of the Korea Institute for Structural Maintenance and Inspection
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• v.16 no.3
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• pp.10-18
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• 2012

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.12
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• pp.1209-1215
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• 2009

This paper discusses a common message protocol for green power systems such as tidal, wind, photovoltaic, and solar systems. For this investigations and analysis, existing protocols such as ELCOM-90, TASE.1, ICCP/TASE.2 and SCADA were analyzed for the application of green power systems in view of real-time property and reliability. For the analysis, the practical example of green power system using SACADA and ICCP are investigated and discussed. As a future direction of this investigations, the feasibility analysis of manufacturing message specification(ISO-9560) for green power system is discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2A
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• pp.97-108
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• 2012

Dynamic responses were measured using long-term monitoring system for Uldolmok tidal current pilot power plant which is one of jacket-type offshore structures. Among the dynamic quantities, the tilt angle was chosen because the low frequency response components can be precisely measured by dynamic tiltmeter, and the natural frequencies and modal damping ratio were successfully identified using proposed LS-FDD (least squared frequency domain decomposition) method. And the effects of tidal height and tidal current velocity on the variation of natural frequencies and modal damping ratios were investigated in time and frequency domain. Also the non-parametric models were tested to model the relationship between tidal conditions and modal properties such as natural frequencies and damping ratios.