An Approach for Condition-Based Maintenance Optimization Applied to Wind Turbine Blades

A sound maintenance planning is of crucial importance for wind power systems. There is a large potential in cost savings by optimizing maintenance decisions to make the projects more cost-efficient. This paper presents an approach to optimize condition-based maintenance strategies for components which degradation can be classified according to the severity of the damage. The approach is applicable to inspection-based maintenance as well as maintenance based on online condition-monitoring systems. This enables us to compare the maintenance strategies within a unified framework. First decisions associated with the different maintenance strategies are optimized, then the expected life cycle maintenance costs of the strategies are compared. The model is applied to blades of wind turbine in order to compare three maintenance strategies: visual inspection, inspection with a condition-monitoring technique (e.g., ultrasonic or thermography), and online condition monitoring (e.g., fiber optic). It is shown that online condition monitoring is the optimal maintenance strategy for high failure rate and low crack time to failure. In other cases, inspection with condition-based maintenance is slightly more beneficial.