Aeroacoustic Assessment of Wind Plant Controls
Wind plant control strategies are used more and more to mitigate wake losses within wind plants. The most commonly implemented strategy for wake loss mitigation is that of wake steering---introducing lateral deflections to the momentum-deficit characterizing the wake by intentionally yawing a wind turbine with respect to the incoming wind direction. Wake steering has been shown experimentally and computationally to increase annual energy production (AEP) of a wind plant by 1-2% reliably, with the potential for much greater gains under conditions where wake losses are most pronounced. As wake steer becomes a common and accepted operational strategy for large wind plants, external effects must be quantified to ensure that the strategy remains viable moving forward.
External or secondary effects of wake steering include the potential for increased structural loads, which could increase operations and maintenance costs, and increased aeroacoustic noise generation, which could impose additional operational constraints. To meet local constraints on noise generation, wind turbines may be operated at a reduced tip speed, impacting the mechanical efficiency of the machine and the levelized cost of energy (LCOE). For wake steering to be widely applied as a strategy to mitigate wake losses, changes in the aeroacoustic noise emissions of utility scale wind turbines under yawed operation must be quantified.
All work in the Aeroacoustic Assessment of Wind Plant Controls project was conducted by researchers from the National Renewable Energy Laboratory at the Flatirons Campus. Aeroacoustic data was collected behind the DOE-owned GE 1.5 MW SLE wind turbine.
National Renewable Energy Laboratory
The Aeroacoustic Assessment project aims to quantify changes in aeroacoustic noise generation by a utility scale wind turbine operating under imposed yaw offsets common for wake steering and wind plant control strategies. Yawed operation of a wind turbine changes the three-dimensional aerodynamic interaction between the rotor blades and the incoming atmospheric flow, leading to changes in noise generation. This work quantifies the extent to which active control induces additional aeroacoustic emissions from additional separation and other flow interaction dynamic effects. Given public concerns about wind turbine noise and the need for observational data required for regulators to establish noise restrictions, we must understand potential acoustic emissions resulting from active control prior to commercial deployment and the development of practical noise reduction methods and technology.
A document containing the details of the data will be attached to the data registration page. Go to the Browse Data link.