考量國內離岸風電產業發展剛起步，相關保險業者對於離岸風機損率尚無法準確評估，大多數保單皆交由國際再保公司進行再保，導致我國資金外流，為促進我國產業發展，本研究以巨災風險評估角度切入，針對離岸風機易損性模組，建立適用於台灣颱風極端風況塔柱易損性曲線。 本研究選用額定功率 5MW 及 10MW 參考風機，以美國 NREL 開發之 OpenFAST軟體執行模擬，假設三種情境分別為機艙轉向 8 度、機艙轉向 15 度及單支扇葉旋向 70度，分析風速 30m/s 至 100m/s 區間內，離岸風機整體結構受力行為。同時藉由 R 語言以拉丁超立方模擬 200 個相似塔柱斷面，根據歐洲規範 EN 1993-1-6【49】計算塔柱軸向特徵挫曲應力，判斷 200 個塔柱斷面在各種情境下之損壞程度，建立離岸風機塔柱 易損性曲線，藉此推估不同尺寸、不同情境及不同風速作用下，離岸風機塔柱結構發生損壞之機率。 考量台灣地理位置每年約有 3 至 4 個颱風侵襲，我國規範 CNS15176-1【19】除採納國際規範 IEC 61400-1 既已訂定之等級指標，將風力機劃分三級，另外增設 T 級基準，將原本規定承受 10 分鐘基準風速，由最高規格之第 I 級 50m/s 提升至 T 級57m/s。根據本研究最終結果顯示，在機艙轉向錯位 8 度且風速達至 57m/s 以後，離岸風機塔柱結構才開始發生挫曲損壞，說明目前參考風機之設計規格皆滿足 T 級基準風速所規定之要求；在機艙轉向錯位 15 度之情境模擬結果，顯示風速在 40m/s 便開始出現塔柱挫曲損壞；在單支扇葉旋向 70 度之情境模擬結果，顯示風速 35m/s 左右塔柱挫曲損壞已開始發生。三種情境作用下，單支扇葉旋向 70 度造成之損壞情況最為嚴重，且在相對較低風速時損壞率已達至 100%。;Taiwan’s offshore wind energy industry just begun in past few years. Most of the insurers in Taiwan have difficulty to estimate the failure rate of offshore wind turbines due to wind excitation, as the consequence they cede most of the premium to international reinsurance companies. This situation causes the capital outflow of our country. In this study, we develop the fragility curves of the wind turbines due to strong wind for the fragility module which is one of the five modules of catastrophe risk model of offshore wind turbines. Two reference wind turbines (RWT) are selected with rated power of 5MW and 10MW respectively. We choose three scenarios to be simulated using OpenFAST software developed by NREL to obtain the response of the wind turbines excited by wind. The combinations of conditions are wind speed from 30 m/s to 100 m/s, yaw of nacelle 8 degree and 15 degree and blade pitch 70 degree. Latin Hypercube Sampling is used to simulate 200 cross section of towers with similar RWT specifications. Based on the European standard EN 1993-1-6 【49】, tower characteristic buckling stress are calculated and compared with strength of cross section of towers. The failure situation was analyzed and the fragility curves of wind turbine tower are built accordingly. Fragility curves can be used to predict the failure rate of tower structure in different conditions which include different power rating of wind turbines, different type of machinery malfunctions, different weather conditions and different wind speeds. There are three to four typhoons hit Taiwan every year. Our country’s standard CNS 15176-1【19】which is based on international standard IEC 61400-1, divides wind turbines into three levels and adds T class. The highest level was class I in the past with 10 minutes average wind speed of 50 m/s. The current highest level is class T with average speed of 57 m/s. This study concludes that the buckling of tower occurs always after the wind speed reaches 57 m/s with yaw of nacelle of 8 degree; yaw of nacelle of 15 degree, tower bucking occurs after the wind speed reaches 40 m/s. In the case of one of blade’s pitch is set to 70 degree, tower buckling occurs after wind speed reaches 35 m/s. The fragility curves of offshore wind turbine are built which can be used in the vulnerability module of catastrophe risk mode of wind turbine for risk management purpose.
