Windfarm Assessment Tool version 4.7 released

Wind farm clusters often have multiple wind turbine types with different technical losses, e.g. turbine availability loss. In addition, individual wind turbine positions may have different similarity to position(s) of measurement masts(s), leading to variable flow model uncertainty. For these reasons, the WAT model for annual energy production now allows specific technical losses and uncertainties for individual wind turbine positions or wind turbine site groups.

WAT now supports terrain assessment for power performance measurements by nacelle-mounted lidars, as described in the IEC 61400-50-3 standard. This involves multiple terrain assessments in the sector swept by lidar beams.

WAT now accepts elevation maps in either grid or vector format. The basic terrain assessment is still using a grid map, but we included an internal vector-to-grid map routine.

We revised the method for extrapolation of observed wind statistics to sectors or wind speed bins with few data. The aim is to provide a more robust model in case of missing data.

New features

• Support for WAsP 12.9 workspace file.
• Technical loss parameters for individual turbine groups.
• Redesigned extrapolation and smoothing of observed turbulence statistics for high wind speed.
• Alignment of observed turbulence statistics in WAT and WAsP CFD result viewer.
• Support for IEC 61400-50-3 terrain assessment for nacelle-based lidar measurements.
• Synchronized display of IEC 61400-12-1 (Ed2) measurement zones in plot and table when switching between mast or turbine site.
• Import of WAsP vector maps.
• Interpolation of terrain elevation grid map by vector maps.
• Save and read IEC parameters for a wind turbine generator to and from file.
• Remember programs setting from previous WAT session.
• Show margins around wind farms scaled by turbine hub height.
• Display of 90% quantile of ambient turbulence intensity with no wake effects.
• List of project model parameters.