Load response of a two‐rotor floating wind turbine undergoing blade‐pitch system faults

Abstract Multi‐rotor floating wind turbines are among the innovative technologies proposed in last decade effort to reduce cost of energy. These systems able offer advantages terms smaller blades deployed offshore, cheaper operations, fewer installations, and sharing platform. As blade‐pitch actuation system is prone failures, assessment associated load scenarios commonly required. Load fault has only been performed for single‐rotor solutions. In this work, we address effect faults emergency shutdown on dynamics loads a two‐rotor turbine. The concept considered employs two NREL 5‐MW baseline OO‐Star semi‐submersible investigated blade blockage runaway, that is, seizure at given pitch angle uncontrolled one blades, respectively. Blade‐pitch lead significant increase structural system, especially runaway conditions. Emergency significantly excites platform motion, tower‐bottom bending moment, tower torsional loads, while suppressing faulty flapwise moment after short peak. Shutdown delay between rotors increases maxima acting tower. Comparison with data from spar‐type study show great similarity, highlighting not affected by (1) type used (2) multi‐rotor deployment.