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This PULSE software determines the official sound power of a wind turbine when making acoustic measurements according to the latest versions of the measurement standards of the British Wind Energy Association (BWEA), American Wind Energy Association (AWEA), and IEC 61400-11, ed.3.0, Annex F. It works together with a microphone placed at the downwind reference position of the turbine, and interfaces to the turbine’s data to incorporate the turbine’s power output. A weather station provides wind direction and speed. The software guides the user through the measurement procedure required to fulfil the relevant standard.

USE SCENARIOS

• Manufacturers determining sound power and tonality
• Checking the expected specified noise levels of new or refurbished units
• Calibrating and validating environmental noise maps for single wind turbines or extensive wind farms

SMALL WIND TURBINES

This software allows measurements of wind turbines with a maximum rated power of 100 kW, or a rotor swept area of 200 m2 or less (rotor diameter 16 m or 52 ft for horizontal axis turbines). These turbines have lighter demands on noise measurement. One is that wind speed and direction do not have to be measured on the nacelle. Instead, a portable weather station is used.

Once you have made the measurement, the results are exported to Excel® to calculate emission noise maps, sound power levels, rated sound levels and tonal audibility (depending on standard used) ready for the report.

The information reported depends on the standard being followed:

• IEC-61400-11-Annex F: an emission map showing sound pressure level contours as a function of wind speed vs distance from the rotor centre
• AWEA: rated sound level calculated at 60 m from rotor hub, with prominent tones observed and reported
• BWEA: noise label containing a noise map from the cut-in wind speed up to the cut-out wind speed for the given turbine

CAPABILITIES

• Emission noise mapping for BWEA standards and IEC standards
• Rated sound level for AWEA standards
• Measures operational and background noise with simultaneous CPB and FFT analysis
• Determines tonality
• Interfaces to turbine and weather data
• Emission maps of sound pressure contours as a function of wind speed vs distance from turbine tower

COMPLETE SYSTEM

A typical system incorporates a portable LAN-XI data acquisition unit, one Type 4189 microphone and preamplifier, a DC signal converter box to interface the turbine parameters to the auxiliary channels in the PULSE software, a weather station, and a laptop PC.