Motion of twin type ocean current turbine at the time of startup and accident

Recently, the movement of promoting renewable energy is increasingly growing all over the world. In this paper, ocean current power generation is treated as a potential new generation system. Ocean current turbines need to adopt a floating type because of deep seabed. Since it is only tied by mooring line and there is nothing that restricts movement, it is concerned that this equipment shows unstable motion. Thus, in this study, as a particular situation, the motion at the time of startup and accident is investigated. For the accidental situation, an experiment using a small scale model is conducted and compared with computer simulation. As a result, validity of the computer simulation is shown and by using this simulation it became clear that minor displacement takes place in the accidental case at the realistic scale. With respect to the startup situation, the simulation is improved to revive the motion of the startup and prediction is performed for an experiment which will be carried out in the near future.