دانلود رایگان مقاله انگلیسی تحلیل درخت خطای توربین های بادی دریایی شناور - الزویر 2018

ABSTRACT

With the development of offshore wind power, the reliability analysis of offshore wind turbines is increasingly significant due to the system complexity and negative impacts in harsh operating conditions. In this study, the Fault Tree Analysis method is adopted for both qualitative and quantitative evaluation of semi-submersible floating offshore wind turbine failure characteristics. The floating offshore wind turbine is divided into several assemblies, including support structures, pitch and hydraulic system, gearbox, generator and the other systems. Failure rates of relevant offshore structures are collected from previous studies, reports and reliability databases. On this basis, the quantitative assessment of Minimum Cut Sets and Importance Measures are achieved. The calculated results are generally in conformity with statistical data, indicating that most of the failures are caused by several basic factors. Marine conditions, especially the salt-spray and high wind speed, show the most significant impact on floating offshore wind turbine performance.

CONCLUSIONS

The present work develops a FT for a generic FOWT. According to this FT, both qualitative and quantitative FTA are analysed based on a set of generic failure information. In order to identify high-risk failure modes and failure causes, MCS probabilities and IMs values of several critical assemblies, namely, support structures, pitch and hydraulic system, generator, gearbox and the other systems, are calculated. IMs values suggest that extreme sea conditions are the main causes of structural malfunction. Stress caused by strong wind and wave predominates the other failure reasons. Pitch and hydraulic system is mostly affected by leakage and over pressure. Nearly 68% malfunctions are induced by 383 these two events. Leakage is also the largest contributor of generator failures, followed by parameter deviation and asymmetry. Corrosion and wear, which caused by harsh operation environment, are primary issues of the gearbox failures and most of the failures are comprised by bearings. It can be concluded that most of the failures are caused by several basic factors, e.g. storm, corrosion and leakage. It can be concluded that marine conditions, especially the salt-spray and high wind speed, show the most significant impact on FOWT reliability and availability. These two issues ought to be stressed for the improvement of system performance. Since FOWT is a multi-components equipment with numerous failure modes and failure causes, the riskbased design, condition monitoring and Reliability Centered Maintenance (RCM) efforts should concentrate on these critical factors in order to enhance the analysis efficiency.