# 15MW control behaviour rated wind

**URL:** <https://forums.nlr.gov/t/15mw-control-behaviour-rated-wind/2393>\
**Category:** Controls\
**Created:** [January 26, 2021, 6:24pm UTC](https://forums.nlr.gov/t/15mw-control-behaviour-rated-wind/2393 "2021-01-26T18:24:44Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Peter.Veldman](https://avatars.discourse-cdn.com/v4/letter/p/cdc98d/32.png) [@Peter.Veldman](https://forums.nlr.gov/u/Peter.Veldman)\
**Post date:** [January 26, 2021, 6:24pm UTC](https://forums.nlr.gov/t/15mw-control-behaviour-rated-wind/2393/1 "2021-01-26T18:24:44Z")

</div>

Dear NREL team,

I am running an openFAST simulation of the 15-MW offshore reference turbine in an under rated, rated and above rated turbulent condition (8, 10.6 and 14 m/s) generated with the use of Turbsim (V2.00.08 64-bit). For verification purposes, I fixed all translations and rotations of the floater, as well as I am ignoring structural deformation of the wind turbine tower and wind turbine blades.

When using the DISCON.dll wind turbine controller (+ DISCON-UMaineSemi.IN obtained from GitHub) with correction for the floating application, only the wind turbine responses for the rated condition (10.6 m/s) seem to behave incorrect with respect to the steady state value (see figure). The turbine responses for the under (8.0 m/s) and above rated (14 m/s) conditions behave like expected around the steady-state values.

Is there a reason for this control behavior at rated wind speed?

Best regards,

Peter Veldman

 ![WTG_timetrace_FAST.png](https://europe1.discourse-cdn.com/nrel/original/2X/7/7b2fcc23cebb249dae894c6fc6f06356d28acabd.png)

---

<div class="post-metadata">

**Author:** ![Nikhar.Abbas](https://avatars.discourse-cdn.com/v4/letter/n/3da27b/32.png) [@Nikhar.Abbas](https://forums.nlr.gov/u/Nikhar.Abbas)\
**Post date:** [January 26, 2021, 6:54pm UTC](https://forums.nlr.gov/t/15mw-control-behaviour-rated-wind/2393/2 "2021-01-26T18:54:43Z")

</div>

Hi Peter,  
This definitely is not expected behavior for ROSCO. Just to be clear, are you using the DISCON.dll available here?  
[github.com/IEAWindTask37/IEA-15 … /ServoData](https://github.com/IEAWindTask37/IEA-15-240-RWT/tree/master/OpenFAST/IEA-15-240-RWT-UMaineSemi/ServoData)

If so, this looks like it might be an outdated version of ROSCO. There were some bug fixes that should hopefully address the issues that you are seeing. Do you mind re-running your simulations with ROSCO v2.1.1 found here: [github.com/NREL/ROSCO/tags](https://github.com/NREL/ROSCO/tags). I suspect that this might fix your issues. If not, we can certainly do some more digging.

Best,  
Nikhar

---

<div class="post-metadata">

**Author:** ![Peter.Veldman](https://avatars.discourse-cdn.com/v4/letter/p/cdc98d/32.png) [@Peter.Veldman](https://forums.nlr.gov/u/Peter.Veldman)\
**Post date:** [January 29, 2021, 9:36am UTC](https://forums.nlr.gov/t/15mw-control-behaviour-rated-wind/2393/3 "2021-01-29T09:36:39Z")

</div>

Dear Nikhar,

Thanks a lot for quick and helpful reply. The controller that I was using from [url][https://github.com/IEAWindTask37/IEA-15-240-RWT/tree/master/OpenFAST/IEA-15-240-RWT-UMaineSemi/ServoData[/url]](https://github.com/IEAWindTask37/IEA-15-240-RWT/tree/master/OpenFAST/IEA-15-240-RWT-UMaineSemi/ServoData%5B/url%5D) turned out to be outdated, indeed.

Re-running the simulations with ROSCO v2.1.1 resulted in the expected behavior.

Again, thank you very much.

Regards,

Peter Veldman