On the effects of pitch system faults on a wind turbine

Abstract

In this study, the hydraulic pitch system of the DTU 10 MW reference wind turbine has been modelled, including different component-level faults, and the control algorithms have been modified to influence the effect of these faults on loads, production and robustness. The simulation results show that the performance of the pitch system model is similar to others in the literature, while at the same time simulating the hydraulic supply pressure variations. The results also show the importance of these variations for overall turbine performance. The number of safety events due to low supply pressure increases with the severity of internal hydraulic leaks. This can be mitigated with a control strategy which limits negative pitch rates based on accumulator pressure. The results show that this can preserve up to 100% of power production in the face of very severe pitch system faults, with as little as 0% impact on loads.