# Pitch Control Rates

Hi, my query is regarding pitch increase/decrease rates.

I’ve read that the max pitch rate for 5 MW turbine is 8 degrees/sec. I’m working on a 1.5MW turbine model and I want to choose a value that is close to reality. What would the value be? (considering contemporary wind turbine control systems) Would 5-6 degrees/sec be a reasonable assumption?

Also, I’ve read elsewhere (not in our forum) that there could be different limits for pitch increments and decrements. It was mentioned that the limit for pitch increments was 4 degrees/sec and for decrements, it was a mere 0.7 degrees/sec. Is there such a vast difference in both usually?

Edit: What is the general time lag between the pitch control signal and the physical implementation of the signal?

Regards,

Sarat

Hi Sarat,

I’m struggling to find an answer for this as well. ECN in their wind turbine control algorithms assume 4 deg/s as pitch rate in normal operation and 10deg/s in emergency shutdown.They also have a saturation for pitch accelerations. But I’m not sure as to what is the right pitch rate n normal operation. Please let me know if you get some answers.

Regards,
Surya.

Sources :ECN/ 1. Wind turbine control algorithms , DOWEC-F1W1-EH-03-094/0 E.L. van der Hooft; P. Schaak; T.G. van Engelen and 2. Exploring the Limits in Individual Pitch Control S.K. Kanev T.G. van Engelen