Create TI statistics

[FINN]

Hello, 
I have questions about a tool "create TI statistics"
I'd like to make all sector TI graph in excel.
But when I saved the result in excel format, I could have results by sector only.
I want to know how to calculate the result of each sector to the result of the all sector.
I calculated it by applying the counting value by sector, but it didn't work.

[Morten]

Maybe you right-click a mast or turbine site object and select Export TI data from the popup menu. As you say, the resulting file will only include statistics per sector and no column for all directions. As I remember, this is because extrapolation to high wind speeds with no turbulence data only is calculated per sector since WAT does not need omni-directional TI statistics for the calculations.  If you are interested in observed TI statistics only, you can copy data from the last step in the WAT TI Analyst window to clipboard and paste that into an excel sheet. That table of observed statistics will include a column for omni-directional TI statistics.   

[FINN]

On 15/11/2022 at 9:13 PM, Morten said:

Maybe you right-click a mast or turbine site object and select Export TI data from the popup menu. As you say, the resulting file will only include statistics per sector and no column for all directions. As I remember, this is because extrapolation to high wind speeds with no turbulence data only is calculated per sector since WAT does not need omni-directional TI statistics for the calculations.  If you are interested in observed TI statistics only, you can copy data from the last step in the WAT TI Analyst window to clipboard and paste that into an excel sheet. That table of observed statistics will include a column for omni-directional TI statistics.   

There is no way to calculate the omni-directional TI statistics with statistics per sector?

[Morten]

It is not an output of WAT, but in principle you could calculate it in an Excel sheet based on 1) per-sector TI statistics mean for a specific wind speed bin and 2) conditional sector frequencies for the same wind speed bin. You can calculate the latter by ordinary per-sector sector frequencies and Weibull distributions. 

Maybe you can tweak WAT to do this if you tentatively set the Wöhler exponent to m=1 and deactivate IEC 61400-1 added turbulence modelling> Include wake effect and IEC 61400-1 complex terrain turbulence factors> Apply complex terrain turbulence factors in the project options. Column Ieff,site in Reports for selected site>Effective turbulence table should then equal the omni-directional TI as function of wind speed. Please check for yourself mean TI.pdfmean TI.pdfmean TI.pdfmean TI.pdfmean TI.pdfand remember that several project options may affect the results.