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| Wind Tubine Generator (WTG) : Consulting 소개 |
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풍력발전기 관련, 독일 뮐러비빕엠(MBBM)에서 수행하고 있는 업무에 대해서 소개합니다.
1. Wind Turbine Engines
The noise emitted by the WTGs consists of aerodynamically and mechanically generated noise. The mostly dominating aerodynamic noise is caused at the rotor blades by vortex shedding at the blade tips and at the leading edge. Mechanical noise can be generated in the gearbox (for gear machines), in the generator and by auxiliary systems like fans, rotator drive and power converter. Above all the gear noise is often transmitted to the hub or other structures and is then emitted as airborne noise.
By nearby residents, the noise emitted by the WTGs can be regarded as disturbing. For this reason, the expected noise immission is investigated by means of a noise immission prediction already before permission is given, and after construction and initial start-up of the WTGs or wind park the actual sound immission is measured. The sound immission can either be determined by direct sound level measurements at the affected residents (sound immission measurements) or by so-called sound emission measurements in the near field of the WTG with a subsequent sound propagation calculation.
2. Sound emission measurements
The essential target of an emission measurement is to describe the sound emission of a WTG as a function of the wind speed. The measuring microphone is arranged on an even sound-reflecting plate lying flat on the floor (boundary microphone) and is protected against wind-induced noise by a primary and secondary wind screen. The secondary wind screen is a construction developed by our affiliated company in Germany, Müller-BBM, and tested in their own reverberation room and in a wind tunnel.
3.Sound immission measurements
Also in this case, for the evaluation of the power data of the WTG, the wind speed and wind direction are considered. The weather data are recorded separately by a weather station near the measuring position for the sound pressure level. For the evaluation, only those sections are used which are free of background noise and have a high WTG power. A microphone with a secondary wind screen is used.
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