Abstract: The power performance measurement (PPM) of wind turbine is an objective method to evaluate the performance of wind turbine, which is the basis for the optimization of the wind turbine, the calculation of annual energy production and other related topics. Traditional testing method usually installs the ground-based equipment, such as the meteorological mast or ground-based lidar, which are more constrained by the on-site conditions. The nacelle mounted Lidar (NML), which can be installed on the top roof on wind turbine nacelle, could overcome the constraints of the on-site conditions. In recent years, NML starts to be used in PPMs, especially for offshore wind turbines. In this paper, the PPM had been conducted by using NML, and the differences were analyzed. The results showed that the wind speed accuracy of NML was consistent with the meteorological mast, the correlation coefficient of the two devices was 0.994, and the slope and offset by linear regression were 0.979 and 0.084, respectively; the scattering point of PPM by NML was more concentrated, and NML was always measuring the wind speed exactly in front of the wind turbine with the yawing of the wind turbine nacelle, which was better representative of the wind speed. The AEP assessment results showed that the NML was 1.73% overestimated relative to the met mast, and the overall evaluation error range was smaller due to the lower dispersion of NML. The NML had a better representation of wind speed than met mast, with less uncertainty, and had value for the application of PPM of wind turbine.

Key words: power performance measurement (PPM), nacelle-mounted Lidar (NML), meteorological mast, annual energy production (AEP)