Wind Turbine Derate Analysis
Customer Problem: A wind turbine owner was experiencing a high rate of very expensive gearbox failures. The customer wanted to derate the turbines in order to reduce the loads on the gearbox. However, derating the turbines also reduces the amount of revenue produced by the turbines, and the owner needed to know how to balance the increase in gearbox reliability with the loss in revenue.
Our Approach: RBB Engineering created an analytical model of the gearbox calculating the failure probability of each component at several maximum power ratings. The reliability of each component was used to evaluate the system reliability of the gearbox and the expected yearly cost of failure at each maximum power rating. The value of the revenue lost for each of the derated power levels was also calculated. The reduction in maintenance expenses due to the increase in gearbox reliability was compared with the loss of revenue due to the decrease in power production, and we calculated an optimal level of maximum operating power.
Outcome and benefit to customer: The RBB Engineering analysis quantified the costs and benefits of reducing the maximum operating power level of the turbines, allowing the customer to select an optimal derated power level that best balanced the gains from increased gearbox reliability with the costs of reduced energy production.