Extreme Event Control

Extreme Event Control (EEC) is one of the four major control components of the integrated wind turbine control concept SucCon, which is being developed in the SenterNovem research project number EOS LT02013 “Sustainable Control: A new approach to operate wind turbines”. The aim is to improve the certainty of power production and reduce the loads during extreme wind conditions, such as extreme wind gusts and wind direction changes. 

Extreme wind conditions can lead to very large turbine loads causing fatigue or even damage to some turbine components. Moreover, large gusts can accelerate the rotor too much with the consequence of the wind turbine getting shutdown by the supervisory system, giving rise to unnecessary missed production. Such effects can sometimes be circumvented by means of timely recognition of the extreme event (extreme event recognition), followed by a prompt and proper control system reaction (extreme event control). An EEC algorithm has been developed in which extreme wind gust and direction change recognition is performed by means of estimating the wind direction (rotor yaw misalignment) together with three blade-effective wind speed signals. For this estimation, rotor speed and blade root bending moment measurements are used. These estimates are used to recognize extreme wind gusts and/or wind direction changes. The EEC aims at

• preventing rotor overspeed (which can make the supervisory system trigger a turbine shutdown) by collectively pitching the blades toward feathering position, and
• reducing blade loads by individually pitching the blades (individual pitch control).

Publications

1. Wind Turbine Extreme Gust Control 
   S. Kanev and T. van Engelen
   ECN-E--08-069; oktober 2008; 56p.
2. Wind Turbine Extreme Gust Control
   S. Kanev and T. van Engelen, , to appear in Wind Energy.