Reliability analysis assessment of the wind turbines system under multi-dimensions

Aiming at the frequent occurrence of the wind turbines failures, a set of analytical methods was developed to carry out the reliability assessment from multi-dimensions, considering the fault characteristics of the wind turbines subsystems, the variation of its failure process, and the wind turbines reliability indexes. Through classification processing of failure data, the Pareto diagram was applied to search the weak subsystem. A fault tree model is constructed, which can figure out the logical relationship between its failure events by the Fussell-Vesely algorithm. According to various characteristics of the bathtub curve, the failure process based on power law process (PLP) model was proposed, it has been discussed that the change criteria of the wind turbines failure with the running time. At last, reliability indexes such as availability were solved and compared to judge the wind turbine performance status. A case study was given in which the failure data are from a wind farm in China. The results indicate that electrical control and pitch subsystems are weak subsystems, and the minimum bottom event in their fault tree model may lead to system failure. Besides, the PLP model can describe the failure process of wind turbines.