ABSTRACT
This chapter discusses a Markov model of repairable multi-stages degraded systems is developed in order to analyze the reliability of offshore wind turbine gearbox. As a complex device with a long service life, offshore wind turbine gearbox has several degraded working states, indicating that it is necessary to analyze its dynamic reliability characteristics. The Markov process approach is the commonest solution to the reliability analysis of multi-state degraded system. The accessibility of offshore wind turbines is insufficient due to strict operation requirements on transports and weather conditions, which also result in longer failure downtime. As a crucial component of offshore wind turbine, gearbox is the largest contributor to the overall failure downtime, and it is also one of the most failure-prone components during the operation of wind turbine. Due to higher wind speed and salt spray corrosion, the degradation of offshore wind turbine gearbox is severer than onshore.
