Hi,

I am a little bit confused because the gustoutput from IECWind v5.01.02 and my calculations are showing differences.

The “IEC.ipt” whih is included in IECWind with give me this result for EOGR-2.0 (8m/s):

```
!This file was generated by IECwind v5.01.02 (13-Sep-2012).
! Wind condition defined by IEC 61400-1 3rd EDITION.
! for IEC Turbine Class 2 and IEC Turbulence Category b
!----------------------------------------------------------
! Rotor diameter = 80.0 m.
! 80.0 m hub-height yields 42.0 m turbulence scale.
!----------------------------------------------------------
! IEC Condition: Extreme Operating Gust.
! Stats for this wind file:
! The transient occurs over 10.5 seconds.
!
! The maximum gust speed is 3.331 m/s.
! The maximum total wind speed is 11.331 m/s.
! This maximum occurs at 45.250 seconds.
!
! The wind inflow inclination angle is 0.0 degrees to the horizontal.
```

This is my calculation:

Sigma1 = Iref*(0.75*Vhub+b) = 0.14*(0.75*8+5.6) = 1.62 m/s

Vgust = 3.3 (Sigma1/(1+0.1(D/Lambda1))) = 3.3 (1.62/(1+0.1(80/42))) = 4.5 m/s

The other Vgust formula is higher then this one, thats why i only write the formula.

Can someone see the failure?

Greetings,

Your study on EOG in IECWind was helpful. Is there any means to simulate EOG50 (i.e.) with 50 years recurrence time period using IECWind?

Thanks in advance.

With regards,

Akheel

Dear Akheel,

What do you mean by EOG50, which is not defined in the IEC design standards?

Best regards,

Greetings Sir,

Thanks for your response.

I have been referring to IEC 61400-1(ed 2) in which DLC 1.6 is of extreme operating gust with a recurrence of 50 years, which I mentioned as EOG50.

With regards,

Akheel

Dear Akheel,

Actually, I’m not very familiar with Ed. 2 of IEC 61400-1. I guess the version of IECWind that I sent you in the following forum topic solves your issue: https://forums.nrel.gov/t/iecwind-previous-version/2978/3; is that correct?

Best regards,

Greetings Sir,

Thanks for your reply. Yes, the file (IECWind_v4) you sent through mail, solved the issue.

Thanks again.

With regards,

Akheel

Hi jason

in the IEC 61400-2 Standard (for small wind turbine) one of the design load cases (DLC) described with ECG (Extreme coherent gust) wind condition thats all of description of standard is in the image bellow

Can IECWind software produce such wind?

note that in IEC 61400-1 standard

Note that in the IEC61400-1 standard, a type of wind is described as ECD (Extreme coherent gust with direction change) , but it is accompanied by a change in direction

Can I somehow use the ECD that comes in 61400-1?

Dear @Ali.Rouhbakhsh,

I don’t see that ECG is included in IECWind. I would guess that this load case, which looks like a simplification of the ECD load case, was introduced after IECWind was last changed. It appears that you could generate the equivalent ECD case and zero-out the wind direction column from the uniform wind data file by hand. Alternatively, IECWind is a very simple software, so, it should not be difficult to upgrade the source code to support the ECG case directly. You could also write your own simple script to generate such a wind file.

Best regards,

Hi Jason

I have a question

In working conditions, my turbine produces power between 3 and 25 m/s wind speed, which reaches 260 rpm at 25 m/s speed. And with a series of safety coefficients, it is set so that the speed of the generator does not exceed 280 rpm, or if it increases, the generator is short-circuited… Now I want to get the extreme loads of this turbine

In DLC1.3, gust wind is used according to the image below

In this type of wind, when the wind speed suddenly increases from 25 m/s to 37 m/s, naturally, the speed of the generator increases.

Now my question is whether I should consider short circuit or not

Because if I take into account the short circuit, the speed of the generator will reach more than 280 rpm, the circuit will be short circuited, and it will not experience the wind gust, and due to the forces it gives, it will smell less.

Actually, my question is that when we are looking to get extreme loads, when we have an EOG wind at the moment when the wind is at its maximum speed, should the turbine control systems try to control the turbine or at that time These systems should be ignored

Dear @Ali.Rouhbakhsh,

The DLC 1.X cases assume the controller is fully operational. So, if you have a control and protection system that mitigates the effect of the gust, you should use such load cases to demonstrate that effect. The DLC 2.X cases require you to assume faults in the control and protection system.

Best regards,

Hi dear Mr Jonkman

My turbine control system is set in such a way that if the generator speed (rpm) reaches 275, the pitch angle of the blades will go to 90 degrees (pitch to feather). I checked my FAST model and found that when the pitch angle is It goes 90 degrees, after a short delay, the speed of the generator reaches zero, and I want to reduce this short delay to zero, so that immediately after the step angle reaches 90, the speed of the generator reaches zero. How can I do this?

Dear @Ali.Rouhbakhsh,

I’m not sure I fully understand your question. The rate at which the generator decelerates during a shutdown will be driven by the torques applied and the inertia of the drivetrain. It sounds like you want the torques to be applied in such a way such that a specific timing is achieved?

Best regards,