Experimental Verification of the Usefulness of G-Weighted Level in the Assessment of Infrasound Noise From a Wind Farm

Abstract

Environmental assessments of wind turbine noise commonly use microphone heights of 1.5m or 4m above ground level. However, wind turbine measurement standards recommend ground-level measurements on a board to reduce wind-induced interference. This study addresses this methodological uncertainty by comparing four microphone configurations under identical in-situ conditions and relating the obtained indicators to turbine operating parameters. Measurements were performed 250m downwind of a 2MW Vestas V90 turbine for four configurations: board-mounted microphones with single and double windscreens, and tripod-mounted microphones at 1.5m and 4m above ground level. The analysis focused on G-weighted sound pressure levels LG and their relationship with wind speed, rotor speed, and electrical power. The board-mounted configuration with a double windscreen produced the most stable time series and showed the strongest statistical relationship with turbine operation, while being less sensitive to local near-ground wind variability than the elevated configurations. The results support the use of enhanced board-mounted wind protection for robust in-situ assessment of wind turbine infrasound.