Acoustic evaluation: microphone array measurements on a multi-megawatt individual pitch control wind turbine

As rotor diameters of wind turbines approach 200 m, aerodynamic noise becomes a significant issue, especially for onshore turbines. The rapid expansion of wind energy has led to increased concerns regarding the noise generated by wind turbines particularly in proximity to residential areas. This study investigates the noise emissions from a full-scale multi-megawatt individual pitch control (IPC) onshore wind turbine, with rotor diameter of 158 m and a hub height of 120 m, across 12 scenarios - six upstream and six downstream. The wind turbine under investigation operates under both IPC and non-IPC modes. Utilizing a microphone array and beamforming algorithm techniques, we conducted comprehensive acoustic measurements to analyses the noise sources and their characteristics. Our findings indicate that turbine operating in IPC mode produces higher sound pressure levels dB (A-weighted) as compared to the turbine under non-IPC modes. This observation emphasizes the need for a balanced approach in wind turbine operations, considering both load reduction and noise mitigation.