WIND power noise systematically underestimated in Sweden

This paper outlines a numerical study of measurement faults in regard to wind power turbines in Sweden. For this purpose, seven (7) reports of noise level from four (4) wind power stations, with between seven (7) and 47 on shore turbines, and between 145 m and 230 m high, were examined. Parallel studies were performed with analytic methods. Technically the noise level was undervalued by more than five (5) dB(A). The effect of the wind speed at 10 m height, according to the IEC64100-11 regulations, was generally not taken into account. In some cases, only the wind speed at the turbine hub was regarded. Thereby the correct wind speed at 10 m height was overstated by up to five (5) meters per second. In one case the measurement of wind power noise was measured at wind speed between three (3) and four (4) meters without the wind turbine blades moving at all. In summary the wind power noise levels were suppressed by about 5 dB(A) for the wind power stations analyzed in Sweden. The study results in a differentiated model as compared to the required rule in IEC64100-11. The projects were carried out between the years 2012 and 2024.