Loads extrapolation

Discuss theory and modeling of wind-turbine structures.

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Jacob.Killerup
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Joined: Fri Feb 26, 2016 2:02 am
Organization: University of Southern Denmark
Location: Denmark

Loads extrapolation

Postby Jacob.Killerup » Wed May 18, 2016 7:48 am

Hi Everybody.

I am analyzing the NREL 5MW onshore wind turbine and want to find the loads for 1-year and 50-year recurrence in the DLC 1.1 as stated in IEC61400-1 (p. 35). I have read that one approach is to make a number of bins between the cut-in and cut-out wind speeds of the wind turbine (e.g. 2-m/s). Then it is necessary to run TurbSIM at least 15 times with different rand seeds for each bin and generate 15 separate 10 minute time series. After that the peaks of each 10 minute time series should be determined and an extrapolation can be done by applying a "3 parameter Weibull distribution function".

Does anyone have hands-on experience with this with the output files generated by FAST or can you guide me towards relevant literature or software, which can be used?

Thanks in advance

Best regards
Jacob K. Pedersen
University of Southern Denmark
Best regards

Jacob K. Pedersen
University of Southern Denmark

Neelabh.Gupta
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Organization: MECAL
Location: Netherlands

Re: Loads extrapolation

Postby Neelabh.Gupta » Tue Aug 08, 2017 4:14 am

Hello Everyone,

I see this post has not been answered. I am curious if there are any NREL post-processing routines (or any other option) that can be used for FAST (ultimate) loads output and comply with IEC61400-1 ed.3. This would include:
- Extrapolation of DLC 1.1 as Jacob mentioned
- Determining characteristic value of ultimate loads (pg. 42)
When turbulent inflow is used, the mean value among the worst case computed loads for different 10-min stochastic realisations shall be taken, except for DLC 2.1, 2.2 and 5.1, where the characteristic value of the load shall be the mean value of the largest half of the maximum loads.


Any insights on these post-processing direction would be greatly helpful.

Best Regards,
Neelabh

Jason.Jonkman
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Location: Boulder, CO
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Re: Loads extrapolation

Postby Jason.Jonkman » Tue Aug 08, 2017 7:00 am

Dear Neelabh,

MExtremes can be used to post-process ultimate loads for extreme events: https://nwtc.nrel.gov/MExtremes. MExtremes includes logic to select the mean value of the largest half of the maximum loads. However, while NREL has done a lot of research in loads extrapolation of DLC 1.1, NREL has not included this capability directly within MExtremes (or MCrunch) or otherwise released a public post-processor with this capability.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Satish.Jawalageri
Posts: 117
Joined: Sun May 31, 2020 4:57 am
Organization: University College Dublin
Location: Ireland

Re: Loads extrapolation

Postby Satish.Jawalageri » Fri Dec 04, 2020 5:04 am

Dear Jason,

I am getting following error when I run the MExtremes in matlab. I have attached the input file.

Code: Select all

Error using repmat
Replication factors must be a row vector of integers or integer scalars.

Error in ParseEESettingsFile (line 619)
      Fmt = [ '%*q %*f', repmat( ' %f', 1, NumChans ), ' %f' ];   % No commas allowed in channel list!

Error in MExtremes (line 38)
   [Settings, FileInfo, EEvTable, EEvChart, errStat, errMsg] = ParseEESettingsFile(SettingsFile);

Error in mextremes_certification_tests (line 33)
MExtremes( 'Test_01.mext' );



Thanks,
Satish J
Attachments
MExtremes_ip.rtf
(8.44 KiB) Downloaded 36 times

Jason.Jonkman
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Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
Contact:

Re: Loads extrapolation

Postby Jason.Jonkman » Fri Dec 04, 2020 7:01 am

Dear Satish,

I believe the error is that you've set NumEETables = 3 in your input file, but only included 1 row in the table.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Satish.Jawalageri
Posts: 117
Joined: Sun May 31, 2020 4:57 am
Organization: University College Dublin
Location: Ireland

Re: Loads extrapolation

Postby Satish.Jawalageri » Fri Dec 04, 2020 7:17 am

Dear Jason,

Thanks for your reply.

It is working, thanks! I am getting following error when run the tests in the cert folder.

Code: Select all

=======
Test_03
=======

  Running MExtremes (v1.01.00a-gjh, 20-Oct-2015)

  Reading ".\Data\DLC2.3_1.out" (1.409390 MB).
    Rows=1201, Cols=133
  Done
  Reading ".\Data\DLC2.3_2.out" (1.676676 MB).
    Rows=1201, Cols=133
  Done
  Reading ".\Data\DLC2.3_3.out" (1.676676 MB).
    Rows=1201, Cols=133
  Done
Error using figure
Argument must be a Figure object or a positive integer.

Error in plot_load_cases_maximums (line 14)
hfig  = figure(44000 + iPlot);

Error in GenerateCharts (line 39)
            plot_load_cases_maximums(outputFileRoot, iChart, Settings.PlotFormat, EEvChart(iChart).absMax(goodDLCs,:), {FileInfo.DLCs(goodDLCs).DLC_Name},
            FileInfo.ChanNames(EEvChart(iChart).Chans)', EEvChart(iChart).Name, EEvChart(iChart).YLabel);

Error in MExtremes (line 114)
         GenerateCharts(outputFileRoot, Settings, FileInfo, EEvChart, ChanMinAssocValues, ChanMaxAssocValues);

Error in mextremes_certification_tests (line 42)
MExtremes( 'Test_03.mext' );


Thanks,
Satish J

Jason.Jonkman
Posts: 5778
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
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Re: Loads extrapolation

Postby Jason.Jonkman » Fri Dec 04, 2020 7:56 am

Dear Satish,

I'm not sure, perhaps MATLAB has changed since MExtremes was first written. Can you debug and solve the problem?

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Satish.Jawalageri
Posts: 117
Joined: Sun May 31, 2020 4:57 am
Organization: University College Dublin
Location: Ireland

Re: Loads extrapolation

Postby Satish.Jawalageri » Fri Dec 04, 2020 8:18 am

Dear Jason,

Thanks for your reply.

I will try it and let you know if anything comes up.

Thanks,
Satish J

Vishal.Sairam
Posts: 37
Joined: Mon Aug 10, 2020 7:50 am
Organization: Power Curve ApS
Location: Denmark

Re: Loads extrapolation

Postby Vishal.Sairam » Thu Mar 11, 2021 5:22 am

Hi everybody,

I was looking into load extrapolation of DLC1.1 to Vref and I found this thread. I would greatly appreciate it if someone has literature/documentation on how to proceed down this path that you can share with me.

Many thanks in advance!

Best regards,
Vishal

Jason.Jonkman
Posts: 5778
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
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Re: Loads extrapolation

Postby Jason.Jonkman » Thu Mar 11, 2021 4:52 pm

Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Vishal.Sairam
Posts: 37
Joined: Mon Aug 10, 2020 7:50 am
Organization: Power Curve ApS
Location: Denmark

Re: Loads extrapolation

Postby Vishal.Sairam » Thu Mar 18, 2021 6:21 am

Hi Jason,

Thank you for your and Pat's replies!

Best regards,
Vishal


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