A Reliability Case Study of the Impact of Tribology on Wind Turbine Gearboxes

Abstract This work shows the impact of reliability influencing factors related to tribology on the monetary saving potential. The gearbox reliability was evaluated using an extended Fault Tree Analysis (FTA) with added connections focusing on the tribological influences on the failure rate. A modified Failure Mode and Effect Analysis (FMEA) without accurate reliability connections related to tribology was evaluated for comparison. A 10% improvement in all tribology-related factors in the extended FTA yields 14.96% higher annual failure cost savings, which relates to reduced costs of 22937 €/turbine/year for a 2.5 MW reference turbine. The extended FMEA estimates the saving potential to be 4.99%. The study demonstrates the importance of integrating tribology expertise and cooperation between park owners, manufacturers, suppliers, and academia. Our results demonstrate that even marginal tribological improvements significantly increase wind turbine reliability and monetary savings confirming that tribology, despite being overlooked, is a powerful reliability enhancement tool.