Reliability analysis of wind turbine system using importance measures

Recent study on wind turbine system reveals that most of the failure in the system occurs due to the failure of generator, shaft and power converter etc. so maintenance of these components is necessary for proper functioning of the system. In this paper we study the reliability analysis of wind turbine (WT) system considering four components named as bearing, shaft, gear box and generator and also prioritize the component according to their effect on system performance using importance measure analysis. There exist number of measures like Birnbaum, fussell vesely importance measure, risk reduction, risk achievement and partial derivative importance measure etc. to name a few. Importance measure aims at ranking the components with regards to improvement in reliability, maintenance and risk. However there exists very less literature on importance measures considering cost. Cost consideration in importance measure for wind turbine system is necessary as availability of system cost is always restricted hence cost based importance measure are more realistic and justifiable. The paper proposes a new cost based importance measure that emphasizes the use of more reliable components thus reducing maintenance cost of WTS. In this paper prioritization of wind turbine system components using existing measures (improvement potential and fussell vesely´measure) and using proposed measure is obtained.