Wind Power Class Window

This feature is coming soon to Windographer 5.

This window helps to clarify how Windographer determines the wind power class. The wind power classes are defined by ranges of mean wind power density at 50m above ground. The prerequisite to determining the wind power class is therefore the calculation of the mean wind power density at 50m.

For a dataset that contains wind speed measurements at multiple heights above ground, Windographer calculates the mean wind power density at each height. If two or more wind speed sensors have the same height, Windographer will average them to find the mean wind power density at that height. The resulting mean wind power densities appear in the table on the left side of the window and as diamonds in the graph.

Windographer uses linear least squares regression to find the straight line that best fits the graph of the natural logarithm of mean wind power density versus the natural logarithm of height. The graph shows this line of best fit.

To find the best estimate of the mean wind power density at 50m, Windographer calculates the value of mean power density at which the line of best fit crosses 50m above ground.

Note: Windographer calculates the mean wind power density at 50m from the line of best fit even if the dataset contains one or more wind speed sensors at 50m.

You can use the Filter by section to choose the data on which Windographer bases its calculation of the wind power class in this window. However, this will not change the value of wind power class displayed in the Summary tab and elsewhere; this will always be calculated from the entire dataset subject to default flag filtering. For more information on filtering see the article on filtering data.

Tip: You can use the Wind Power Class window only if you have the Professional or higher edition of Windographer. Please visit www.windographer.com for information on the pricing and capability of each edition.