• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.74.5-74
• /
• 2001

The wave power plant is a generating system to convert the wave energy resources to electric energy. ´CHUJEON A´, which is a prototype of wave power plant developed by KORDI(Korea Ocean Research and Development Institute), has been launched for its performance test. A wound rotor induction machine is adopted as a generator for the power plant to acquire constant frequency and voltage over wide range of rotor speed. Because the generator of ´CHUJEON A´ has no connection to the power grid line on land, all of the processes to generate and consume the electricity have to be conducted on the floating plant. This paper deals with the design and implementation of the unmanned control system for ´CHUJEON A´. The system includes generator control system, power conversion and charging system, data acquisition and wireless communication system ...

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.19 no.3
• /
• pp.185-193
• /
• 2016

In this study, the present deployment of the multiple wave energy converters (WECs) in a floating wind-wave hybrid power generation platform was estimated considering the interaction effect among WEC buoys. The interaction processes of multiple buoys were very complex, since scattered and radiated waves from each buoy affected the others in the array. The interaction analysis of the diffraction and radiation problem by the array of WECs was applied by matched eigenfunction expansion method (MEEM). The analytical solutions were compared with the results of numerical calculation based on WAMIT. The overall performance of 24 WECs installed in the hybrid power generation platform was evaluated by the q-factor representing the interaction effect among buoys.

• Proceedings of the KSME Conference
• /
• 2002.08a
• /
• pp.373-376
• /
• 2002

The drift force acting on a floating OWC chamber in waves is studied taking account of fluctuating air pressure in the air chamber. A velocity potential in the water due to the free surface oscillating pressure patch is added to the conventional radiation-diffraction potential problem. The potential problem inside the chamber is formulated by making use of the Green integral equation associated with the Rankine Green function while the outer problem with the Kelvin Green function. The drift forces as well as the chamber motions are calculated taking account of the air pressure in the chamber.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.26 no.4
• /
• pp.225-243
• /
• 2014

As the economic matters are involved, applying the WEC, which is used for controlling waves as well as utilizing the wave energy on existing breakwater, is preferred rather than installing exclusive WEC. This study examines the OWC mounted on a pressurized air chamber floating breakwater regarding the functionality of both breakwater and wave-power generation. In order to verify the performance as a WEC, the velocity of air flow from pressurized air chamber to WEC has to be evaluated properly. Therefore, numerical simulation was implemented based on BEM from linear velocity potential theory as well as Boyle's law with the state equation to analyze pressurized air flow. The validity of the obtained values can be determined by comparing the previous results from numerical analysis and empirically obtained values of different shapes. In the actual numerical analysis, properties of wave deformation around OWC system mounted on fixed type and floating type breakwaters, motions of the structure with air flow velocities are investigated. Since, the wind power generating system can be hybridized on the structure, it is expected to be applied on complex power generation system which generates both wind and wave power energy.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.5
• /
• pp.811-818
• /
• 2016

This paper suggests a structure of power control system in floating wave-offshore wind hybrid power generation system. We have developed an unified SCADA(Supervisory Control and Data Acquisition) system which can be used to monitor and control PCS(Power Conversion System) based on IEC61850. The SCADA system is essential to perform the algorithm like proportional distribution and data acquisition, monitoring, active power, reactive power control in hybrid power generation system. IEC61850 is an international standard for electrical substation automation systems. It was made to compensate the limitations of the legacy industrial protocols such as Modbus. In order to test the proposed SCADA system and algorithm, we have developed the wind-wave simulator based Modbus. We have designed a protocol conversion device based on real-time Linux for the communication between Modbus and IEC61850. In this study, SCADA system consists of four 3MW class wind turbines and twenty-four 100kW class wave force generator.

• Ocean Systems Engineering
• /
• v.9 no.3
• /
• pp.219-240
• /
• 2019

This paper presents the comparison between SFT response with linear and nonlinear cables. The dynamic response analysis of submerged floating tunnel (SFT) is presented computationally with linear and nonlinear tension legs cables. The analysis is performed computationally for two wave directions one at 90 degrees (perpendicular) to tunnel and other at 45 degrees to the tunnel. The tension legs or cables are assumed as linear and non- linear and the analysis is also performed by assuming one tension leg or cable is failed. The Response Amplitude Operators (RAO's) are computed for first order waves, second order waves for both failure and non-failure case of cables. For first order waves- the SFT response is higher for sway and heave degree of freedom with nonlinear cables as compared with linear cables. For second order waves the SFT response in sway degree of freedom is bit higher response with linear cables as compared with nonlinear cables and the SFT in heave degree of freedom has higher response at low time periods with nonlinear cables as compared with linear cables. For irregular waves the power spectral densities (PSD's) has been computed for sway and heave degrees of freedom, at $45^0$ wave direction PSD's are higher with linear cables as compared with nonlinear cables and at $90^0$ wave direction the PSD's are higher with non-linear cables. The mooring force responses are also computed in y and z directions for linear and nonlinear cables.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.1
• /
• pp.77-83
• /
• 2011

In this study, the dynamic modeling of floating offshore wind turbine system is reported and the dynamic behavior of the platform for the offshore wind turbine system is analyzed. The modeling of the wind load for a floating offshore wind turbine tower is based on the vertical profile of wind speed. The relative Morison equation is employed to obtain the wave load. ADAMS is used to carry out the dynamic analysis of the floating system that should withstand waves and the wind load. Computer simulations for four types of tension leg platforms are performed, and the simulation results for the platforms are compared with each other.

• Journal of Power System Engineering
• /
• v.18 no.3
• /
• pp.36-41
• /
• 2014

The structure of a variable liquid column oscillator(a VLCO) is analogous to that of the tuned liquid column damper used to suppress oscillatory motion in large structures like tall buildings and cargo ships. The VLCO is a system absorbing high kinetic energy of accelerated motions of the multiple floating bodies in the effect of air springs occurred by installation of inner air chambers. Thus, VLCO can improve the efficiency of energy than wave energy converters of the activating object type made in Pelamis Company. In this research, the experiment was performed in two models of same draft. The one is that weights were filled, and the other is that water was filled. The numerical results were estimated by assuming that do not exist internal flow, and the results were compared with the results of experiments.

• KEPCO Journal on Electric Power and Energy
• /
• v.2 no.3
• /
• pp.461-467
• /
• 2016

In order to install the floating transport type wind-turbine foundation, water pumping is used to sink the foundation. During this process, its mass and center of gravity, and buoyancy center become continuously changed so that the dynamic stability of the floating foundation become unstable. Dynamic stability analysis of the floating foundation is a complex problem since it should take into account not only the environmental wave, wind, and current loads but also its weight change effect simultaneously considering six-degree-of-freedom motion. In this study, advanced numerical method based on the coupled computational fluid dynamics (CFD) and multi-body dynamics (MBD) approach has been applied to the dynamic stability analysis of the floating foundation. The sloshing effect of foundation internal water is also considered and the floating dynamic characteristics are numerically investigated in detail.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.40 no.6
• /
• pp.557-563
• /
• 2016

The energy absorption efficiency of a wave power generation system is calculated as the ratio of the wave power to the power of the system. Because absorption efficiency depends on the dynamic behavior of the wave power generation system, a dynamic analysis of the wave power generation system is required to estimate the energy absorption efficiency of the system. In this study, a dynamic analysis of the wave power generation system under wave loads is performed to estimate the energy absorption efficiency. RecurDyn is employed to carry out the dynamic analysis of the system, and the Morison equation is used for the wave load model. According to the results, the lower the wave height and the shorter the period, the higher is the absorption efficiency of the system.