Airborne Noise Emission Characteristics of Wind Turbines in Iran

Abstract

Introduction: Wind-turbine noise emission and its environmental impact are considerable issues nowadays. Considering the importance of the issue, the purpose of this study was to prepare noise map and wind turbines sound characteristics on the largest wind farm of Iran. Method: This study was carried out in two phases:1) In order to prepare the daytime sound level (Ld) noise map, environmental noise measurement was done using LAeq for 10 minutes three times daily according to the ISO9612 method. 2) On the basis of IEC 61400-11.2006, sound characteristics and wind speed were measured concurrently at the back and front of the wind turbines using TES-1358 Sound Level Meter and vane anemometer. Discussion: The average daytime sound level (Ld) of wind farm was 63dBA which is 3 dB higher than the recommended level. Wind speed has a significant non-linear relationship with the wind turbine noise emissions (p<0.05) which is valid with increasing wind speed up to 17 m/s. Frequency analysis showed that the wind turbine noise is in the range of low noise frequencies(below 1000 Hz). There is a significant relationship between the power generation, wind turbine blade length and sound level (p<0.05). Sound pressure levels in frequencies lower than 250 Hz are equal at the back and front of the wind turbines. Wind turbine characteristics specifies model of noise emission. Result: Daytime sound level around the wind farm is more than the recommended values. The sound level of wind turbines is sensitive to Wind speed changes and it is in a range of low frequencies and fluctuation once.

Keywords

• Wind Turbine
• Noise
• Airborne Emission
• Wind Farm