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IEA 15 MW design load cases #218
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Hello, thanks for your questions. Some comments:
I hope this helps! |
Thanks for your quick response and for sharing the information! That's why DLC 1.4 from IEC 61400-1 standards was the extreme event for the tower base moment and forces, blade root moment, out-of-plane blade tip deflection in my calculations which enables ROSCO during ECD. 1- regarding point#4, as I understand from a quick reading of the reference you provided, to run DLC 1.4 from IEC 61400-1 standards effectively, I have to change the source code of ROSCO and provide a closed loop response characteristics of the rotor for shutdown and recompile it? is this shutdown trigger publicly available or I have to write it? 2- another question please, Does ROSCO support emergency shutdown DLC 5.1 and fault case DLC 2.X from IEC 61400-1 standards or not, I read before that DISCON for NREL 5MW doesn't support emergency shut down DLC 5.1 IEC 61400-1 standards. 3- In my calculations, for tower top displacement in for aft and side to-side, the governing load cases were 2.x and 5.x. I calculated the displacement from all DLCs and then weighted them by multiplying the displacement* partial safety factor specified in IEC 61400-1 standards for every load case. is that a correct approach or not? Regards, |
hello again, |
Thanks for your quick reply, I appreciate your help. |
Hello again, Sorry for asking a lot of questions. 1- For DLC 5.x from IEC 61400-1 standards, Can I simulate emergency shut down at specific time by using ServoDyn input file instead of manipulating the input signal to the shutdown ROSCO controller? For example, I simulate shutdown at 200 sec by changing ServoDyn as PCMode=VSContrl=5 Is that an acceptable approach or not? 2-The same thing for DLC 2.1 from IEC 61400-1 standards, I used the approach from (Loads Analysis of a Floating Offshore Wind Turbine Using Fully Coupled Simulation by J.M. Jonkman and M.L. Buhl, Jr.)."For DLC 2.1, we simulated a fault in the collective blade-pitch control system where one blade ignores its command and runs away to the minimum set point of 0º at the full pitch rate of 8º/s. We assume that the turbine’s protection system detects this fault in this situation by simulating a shut down of the turbine; the shut down is initiated after a 0.2-s delay (to account for the time it takes the protection system to detect the fault and take action) by feathering the other two blades at full pitch rate to the maximum pitch setting of 90º." Can I use the same approach with ROSCO or not? Thanks for your consideration Regards, |
@abhineet-gupta can you please help here? |
Hi @marwa023
Abhineet |
Thanks @ptrbortolotti and @abhineet-gupta for your help and response. |
Dear Dr. @ptrbortolotti May I ask you a question please? Regards, |
I chose 120 deg somewhat arbitrarily, it seemed to work well given the ECD conditions prescribed by the standards. I'm sure industrial controllers have more sophisticated logics to deal with real world conditions, which however do not usually climb up to the thresholds specified by the IEC standards (wind speed and direction changes, but not as bad as an ECD with a coherent gust, at least not at NREL Flatirons Campus...) As for your point 2, choose your best judgement. I say you should make sure the controller works well across conditions, and not well just for one specific inflow |
Thanks, Dr. @ptrbortolotti for your detailed reply. |
Description
_I model IEA 15 MW on monopile support under different design load cases. I used Open Fast v3.5.1, I used ROSCO 2.8. My question is why there is no mention in the IEA 15 MW manual for design load cases with faults like 2.x or 7.x or emergency shutdown?
When I tried to simulate DLC 6.2 with yaw errors -180 to 180, I had instabilities between angles +- (20 to 60 ), I read the same problem in (Loads Analysis of a Floating Offshore Wind Turbine Using Fully Coupled Simulation by J.M. Jonkman and M.L. Buhl, Jr.). when I tried to apply the brake, it didn't change anything (maybe I did something wrong).
But when I tried the solution mentioned in DTU 10 MW manual, which is changing vibration direction to improve the aerodynamic damping by considering the pitch sequence as 70-90-90 or 90-70-90 or 90-90-70, it efficiently removed the instability.
My questions are:
1- I understand the solution of changing the pitch sequence to improve the aerodynamic damping because at idling conditions it is minimum, but why specifically 70, not 80 or 60, etc, is there a specific reason? or why the recommended position for blades in parked is feathered not 90,70,90?
2- DLC 6.2 combined extreme wind and wave with a return period 50 years, but the lifetime of the turbine itself of 20 to 30 years, on the same time there are critical yaw errors that give instabilities are between +-(20 to 60) and the remaining yaw errors +-(80-180) results in minimum loads compared to normal operation conditions DLC1.X, so should I excluded DLC 6.2 from the calculations from the beginning
3-The solution of (bypass it by choosing yaw errors that don’t result in the instability) is it practical? I mean when designing monopile of turbine?
4- when I calculated the out of plane blade tip deflection it was= 36.8 m! (including PSF of 1.35) from DLC 1.4-ECD+r but in the report it was 22.8 m and the tower clearance is 30 m. what made my calculations incorrect?
Thanks in advance and sorry if my questions are basic
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