風機系統之可靠度設計與運轉維護策略研究

Abstract

本論文探討風機系統的可靠度設計，以及風機系統設置後之運轉維護策略，其中特別著重失效模式與影響性分析、失效樹分析、以及在適當可靠度要求下最小成本之運維等議題。本論文將風機系統拆分為基底與塔架、葉片、傳動、電力四個子系統。在失效模式與影響性分析裡，將各子系統分出許多組件，而組件又可再細分出多個零件。本研究首先依據物理原則，搭配國內外學者專家的經驗與建議，製作出前述子系統之失效模式與影響性分析表格，讓人得以快速看出哪些失效模式是屬於比較重要的模式，及爾後運維時需要特別注意的組件。在失效樹分析裡，本研究將四個子系統可能失效的情況以「頂層事件」來表示，而後參考國內外文獻，將導致子系統失效之潛在肇因細分出一些「中間事件」與「基本事件」。洞悉以上事件後，即可作出風機系統的失效樹圖，讓工程設計或爾後之運維人員快速看出每個子系統與基本事件的關聯性。本論文更依據以上建構之系統失效樹圖，搭配布林代數法則，定量分析各基本事件對風機系統失效的影響，據以探討基本事件的重要性。本論文最後所作運轉維護研究則是根據前述可靠度設計結果，在考量一些不確定及成本因素下，建構一套維修模擬程式。透過該模擬程式，可獲得風機系統與子系統可靠度、維修時間與維修成本間的關係，讓業界能依照自己制定的維修期間擬定各種運轉維護策略，並模擬在特定策略下之風機可靠度與維修成本。

This thesis discusses the reliability design of wind turbine system and the operation and maintenance strategy after a wind turbine is set up. With regard to the reliability design, failure mode and effect analysis, failure tree analysis, and several other methods are employed. As for the operation and maintenance strategy, a maintenance period resulting in the minimum cost under appropriate reliability requirement of a turbine is the major target. This thesis divides a wind turbine system into four subsystems namely foundation and tower, blade, drive, and an electrical subsystem. In the failure mode and effect analysis, each subsystem is divided into several assemblies; and an assembly consists of several components. Based on principles of physics and experiences and recommendations from experts, this study develops failure mode and effect analysis tables for the above mentioned subsystems, allowing people to understand quickly the importance of each failure mode and pay more attention to those critical failure modes during maintenance. In the failure tree analysis, this study considers possible failures of subsystems as top events. For a top event, its potential causes are identified and addressed to be intermediate and basic events subsequently. After understanding the above events, the failure tree diagram of a wind turbine system can be constructed. The result is helpful for engineers to know potential failures of subsystems and their causes. Based on the system’s failure tree diagram, this thesis also employs Boolean algebraic rule to analyze quantitatively the impact of each basic event on the failure of a wind turbine system and discusses the importance of each basic event. The operation and maintenance study conducted in this study is based on results of the reliability design. A simulation computer program for maintenance strategy is developed in consideration of parameter uncertainties as well as maintenance cost. Through the simulation program, the relationship between the reliability of a wind turbine system and its subsystems, the maintenance time, and the maintenance cost are obtained. The results allow people to find the maintenance cost as well as the wind turbine reliability for a selected operational maintenance strategy in which the maintenance period is emphasized.