Condition Monitoring of Rotor Blades: Approaches, Algorithms, Experiences

Company / Unternehmen: Bosch Rexroth Monitoring GmbH
Speaker / Referent: John Reimers

The currently executed monitoring of rotor blades by visual inspections on a period basis with long intervals in-between can be problematic, because a small and easily rectifiable defect can grow to become a serious problem. Besides damages particular environmental conditions such as icing and overloads can also influence the operational state of the rotor blades and therefore the entire wind turbine. Since these phenomena are of temporary nature they can only the detected by a continuous surveillance of the blades.
Where sensor-based gearbox condition monitoring has become more and more common over the years, rotor blade condition monitoring is currently less widely used, but with rotors growing larger and larger the pressure for continuous rotor blade monitoring increases.

The experience of combined 600 operational years of rotor blade monitoring will be summarized and a view on future developments will be given.
Central Objectives of the presentation
– Overview and comparison of methods used for condition based monitoring of wind turbine rotor blades
– Description of the of natural frequency analysis approach
– Illustration of how natural frequencies can be utilized for early damage and ice detection for rotor blades of wind turbines
– Description of the technical equipment required to build a rotor blade condition monitoring system
– Demonstration of how different damages and other changes affect the frequency spectrum
– Provide an experience based overview of the challenges of condition monitoring