Wind turbine control adaptation to pitch system faults

This article introduces a novel control method for wind turbines that mitigates the adverse effects of hydraulic pitch system failures, particularly under high actuator demand. The key contribution lies in the incorporation of a memory effect within the control algorithm, which governs the pitch angle decrement limit. Simulation results using the DTU 10 MW reference wind turbine demonstrate that this approach significantly enhances resilience against safety shutdowns, completely eliminating shutdowns caused by severe leaks in the piston and pumps. This results in improvements of over 31% in some loads while producing almost the same power (barely 2% below) compared to a healthy system.

Additionally, the study shows that the effectiveness of this method can be further enhanced by modifying generator torque and minimum pitch schedules, especially in scenarios requiring rapid pitch angle increases. These modifications directly impact the elimination of shutdowns due to pre-charge loss and rod leak and reduce shutdowns caused by excessive bearing friction. As a result, in the presence of faults, improvements of over 24% are obtained in some loads, with an increase in power produced ranging from 8% to 36%, depending on the type of fault. Remarkably, these improvements are achieved with a minimal reduction of around 2% in energy production with a non-faulty system.