風力機之設計壽命通常為20年，現今台灣使用中的陸域風力機於2020年後將面臨使用壽命到期的問題。由於早期風力機設計時採用較高的安全因子，以至於風力機可能會超過所預估的20年壽命。
本研究分為兩部分。第一部分為收集並探討已發表的風力機延壽評估方法，建立適用於台電風力機組的具體方案，提出的方法包含資料收集、分析評估及檢查項目。
第二部分針對Vestas V80風力機塔架進行疲勞壽命評估，參照IEC 61400-13進行負載量測，於塔架底部黏貼應變規，量測短時間的負載訊號。根據有限元素分析及應變量測結果，可得到中下法蘭截面的負載。風力機所受之負載頻譜為使用短時間負載量測及運轉資料來重建。再應用FAMOS軟體分析疲勞損傷。研究結果顯示，在IEC 61400-1之疲勞設計負載下，Vestas V80風力機塔架之中下法蘭截面不會發生疲勞失效。

In general, the life of a wind turbine is designed to be 20 years. In 2020, some of onshore wind turbines in Taiwan will reach the end of their planned service life. Due to the higher safety factor that adopted in the original design of wind turbine, the life of wind turbine may be longer than 20 years.
This research is divided into two parts. The first part is to collect and discuss the published assessments of lifetime extension of wind turbine. Then, the author constructed a specific one that is suitable for Taipower Company’s wind turbine. The proposed method includes data collection, assessment analysis, and inspections.
The second part is to start a fatigue life assessment, the author chose a Vestas V80 wind turbine tower. According to IEC 61400-13 standard, we stuck some strain gauges at tower bottom, and measured short-time loading. Based on the results of finite element analysis, the loading at the cross-section of middle-lower flange can be obtained from the strain measurement. The wind turbine’s endured load spectrum was reconstructed using a short-time load measurement and operational data. Then the fatigue damage was analyzed with FAMOS software. The results showed that fatigue failure will not occur at the middle-lower flange cross-section of Vestas V80 wind turbine tower if it is operated under the design fatigue load cases of IEC 61400-1 standard.

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