seenu

When estimating the AEP of a wind turbine / farm, it is recommended to use the blade pitch angle information. However, some commercial turbines do not make this information available. Is there a way to identify the level of deviation or uncertainty this imposes on the AEP calculation? Further, would you know if a site (url) that identifies the level of error or deviation at each stage of WAsP’s calculation, if the calculations are within the operational envelope?

Thank you.

The wind turbine data sheets do not have the density used for the power curves. So I presumed it to be 1.225 kg/m3 as most turbines data sheets are estimated using that density. However, the density of my site is 1.17 kg/m3. WAsP says that it cannot calculate AEP due to the density differences when I use two different densities. (1) Changing the WTG density to 1.17 kg/m3 is an option to estimate AEP. But that power curves were not estimated at that density. This would also lead to overestimation of AEP. (2) Using 1.225kg/m3 for reference site is another method, which would again overestimate AEP at the reference sit. Is there any methods to solve this problem? Thank you

Thank you. That would be really a big deal.

Thank you Andreas. I shall check them.

WAsP CFD is not free. However, if you are a student at DTU then please ask your supervisor to contact the WAsP group about your needs. Does not WAsP student Package has two free simulation?

Issue #1: Sorted, I guess. I removed few polygons from the kml file (especially the borders) so there are not many cross points. Issue #2: Problem not solved. But since the cross points and nodes are less, the map image refreshing is not a big deal. Issue #3: Would really appreciate if you could assure that those warnings are handled correctly by me. Last issue: Add and replace function did not work when I tried to combine KML file and the SRTM file. So I converted the KML file as a standard map file. Then added that file to the SRTM file. And simply saved it. Oh I have reduced the SRTM map size. So the process is faster. New doubts: I have digitalized the map in GE (drawing polygons - the terrain was disabled) and created a KML file. I have fed roughness info to the downloaded KML file - after converting it to a standard map file. My issue is, the polygons do not contain orography information (assuming since the terrain is disabled while drawing those polygons). So my question is, should I enable terrains while drawing those polygons on GE? Or no need?

The wind turbine data sheets do not have the density used for the power curves. So I presumed it to be 1.225kg/m3 as most turbines data sheets are estimated using that density. However, the density of my site is 1.17kg/m3. WAsP gives error when I use two different densities. How do we estimate AEP for 1.17kg/m3. Changing the WTG density to 1.17 is an option. But that power curves were not estimated at that density. So I am kind of lost here. I am worried about the errors in estimation. Any methods to solve this?

Thank you.

It is extremely difficult to get power curves and thrust coefficient curves for wind turbines - especially for small wind turbines. The manufacturers do not respond to the emails nor attend the calls if they know we are students / researchers. IT would be great if WAsP team could include small wind turbine generators too. Thank you.

For some commercial turbines, the blade pitch angle is unavailable. Could you please help me identify the level of uncertainties or errors in estimating power because of this? Further, how do we calculate wind farm efficiency? Is there a link / site that I could refer to the best practices for each of the WAsP calculation and the level of uncertainty / error that could arise at each stage – even if the calculations are within the operational envelope? Thank you.

For an island that we are exploring, the dRIX is very high, due to mountainous terrain with steep slopes. There is however relatively flat land to the center-left of this island. Would you recommend a way to explore the potential to install wind turbines in the flat areas? We attempted to focus the grid only on this flat surfaces, but yet recorded high dRIX. Why is that?

An undo button would help - especially when you are dealing with cross points and dead ends. Thanks

I am not able to post the URL. I have elaborated my issue under this topic -- ""Map Editor Nodes / Cross Points / Dead Ends"" Issue #1: Sorted, I guess. I removed few polygons from the kml file (especially the borders) so there are not many cross points. Issue #2: Problem not solved. But since the cross points and nodes are less, the map image refreshing is not a big deal. Issue #3: Would really appreciate if you could assure that those warnings are handled correctly by me. Last issue: Add and replace function did not work when I tried to combine KML file and the SRTM file. So I converted the KML file as a standard map file. Then added that file to the SRTM file. And simply saved it. Oh I have reduced the SRTM map size. So the process is faster. New doubts: I have digitalized the map in GE (drawing polygons - the terrain was disabled) and created a KML file. I have fed roughness info to the downloaded KML file - after converting it to a standard map file. My issue is, the polygons do not contain orography information (assuming since the terrain is disabled while drawing those polygons). So my question is, should I enable terrains while drawing those polygons on GE? Or no need?

Hi, I posted an elaborated message as a new thread.

Hi, I'm having some trouble with Map Editor, could I please get some help with the following issues I face: Issue #1: I have over 200 cross points in a SRTM 3-arc file. How do we remove them? I have tried right-clicking the map image file and editing the point, this tends to not yield the desired result. Issue #2: Editing the points on the map image is quite cumbersome as the map image keeps refreshing, I've read elsewhere in the forum that disabling the consistency checks will resolve this, but this has not worked in our case. Issue #3: I receive the following warnings when I open a SRTM 3-arc .map file and my responses for these warnings are typed in inverted commas. Could you please help identify if they are critical issues? a) Consecutive points in polylines/polygons closer than a horizontal resolution of 2.0m encountered. Do you want such repeated points to be removed as the map file is opened? "YES" //If we respond "NO", the number of dead ends seem to decrease with no effect on cross points and error b) does not show up but error 'c' does.// b)Contour #85065 Convert single point to spotheight-circle? "ALL" c) Curves with missing or invalid height/roughness properties encountered. Use manual editing in the display window or the Menu change options to supply valid properties. Is there a way to identify where the curves with missing height/roughness properties are on the map image? And how would we supply valid properties for these curves--would it be right click-->edit point properties? Finally, I've read elsewhere in the forum that the SRTM imported data may be incomplete and need to be supplemented by user-fed roughness classes. I imported the kml file created from google earth, saved this as a '.map' file and used the add and replace function to overlay this over the SRTM generated map. This method after a lengthy processing time (about 3 hours) leads to the google earth created data not being present. Could I please check whether I have done something incorrectly? How can I add these two maps--one from SRTM and the other that we marked on Google Earth to be used in tandem in the maps editor? Thanks in advance! PS: The SRTM data is from the version 2_1 3-arc files.