Study on Safety Assessment of Floating Horizontal Axis Tidal Turbine with Tank Test

The current power generation or the tidal power generation is considered to have high possibility for utilization of ocean renewable energy since the current speed or tidal speed is steady. Authors carried out scale model experiments of floating type horizontal axis tidal turbine for the study on safety assessment technology. The scale model consisted of 2 rotors on 1 crossbeam moored by 2 wires. The rotor thrust load, the rotor torque, the crossbeam load and mooring tension, and the floater motion was measured. The load conditions for the experiments were decided considering typical situation in actual sea, that is, the power generation condition, the standby condition and the accidental conditions. In the accidental conditions, a stop of a rotor, error of blade pitch angle, a loss of a blade, and a break of 1 mooring line were considered. Numerical calculations were also carried out and the accuracy of BEM (blade element & momentum method) and CFD calculations were confirmed through the comparison with the tank test results.