離岸風電打樁水下噪音模擬與統計分析

Simulation and Statistical Analysis of Pile Driving Noise from Offshore Wind Turbine Installation

黃晉德(Chin-Te Huang)

指導教授 ： 陳琪芳

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2022年)

https://doi.org/10.6342/NTU202200318

摘要

臺灣海峽風場具有極大發展的潛力，全球最好的 20 座離岸風場，台灣就佔了其中 16 座，為了提高台灣再生能源電量比例，政府亦推動「千架風機」計畫，期許於 2025 年以前離岸風電裝置容量達5.7 GW。然而台灣西半部海域規畫之施工風場緊鄰於瀕危海洋哺乳類「中華白海豚」之棲息地，風機打樁所產生之水下噪音可能會對其造成行為改變或者聽力受損。因此本研究目標於預估打樁水下噪音，使用有限元素法於頻域模擬衝擊式打樁噪音聲源，結合拋物線音傳模式所計算之傳播損失，預估傳播至遠場之噪音聲曝值。模擬比對分為兩部分。第一部分為台灣苗栗海洋風場 21 號示範風機，於 2016 年 9 月所量測不同貫入深度之打樁噪音聲曝值結果，量測距離為 230 公尺，模擬結果顯示不同貫入深度下聲曝值誤差落於 2 dB以內。第二部分為國外海域量測之不同樁徑下打樁噪音聲曝值趨勢，其統計超過300 隻施工基礎，量測距離為 750 公尺，結果顯示本研究於不同樁徑尺寸下所產生之聲曝值與其趨勢相近。
與實海域量測結果比對後，本研究之打樁噪音模擬有一定之參考性，後續將選用可能影響水下噪音之相關參數，進行變異數分析與回歸分析，其參數如「樁槌能量」、「基樁長度」、「基樁直徑」、「樁壁厚度」、「貫入深度」與「當地水深」，透過變異數分析獲得聲曝值之回歸公式，利用此公式可用於預估打樁噪音於 750 公尺處之聲曝值，可做為將來欲開發之離岸風場施工前噪音之參考。並利用國外實際量測氣泡幕於不同頻段之插入損失進行減噪模擬，利用不同案例進行減噪模擬，結果顯示減噪效果與量測結果相近有一定之參考性，因此可將此減噪模擬配合前述噪音模擬，預估打樁噪音經減噪後於750 公尺處是否超過法律規範之 160 dB re 1 μPa2s。

關鍵字

有限元素法 ； 拋物線方程 ； 力道函數 ； 打樁噪音 ； 變異數分析

並列摘要

Taiwan Strait wind farms have great potential for development. Among the top 20 offshore wind farms in the world, Taiwan accounts for 16 of them. Offshore wind installations will have a capacity of 5.7 GW by 2025. However, the planned construction wind farm in the western half of Taiwan is close to the habitat of the endangered marine mammal "Chinese White Dolphin", and the underwater noise generated by the wind turbine piling may cause behavioral changes or hearing damage. Therefore, the objective of this study is to estimate the underwater noise of piling. The finite element method is used to simulate the sound source of the impact piling noise in the frequency domain. Combined with the propagation loss calculated by the parabolic sound transmission model, the acoustic exposure level of the noise propagating to the far field is estimated. The simulated alignment is divided into two parts. The first part is the No. 21 demonstration fan in the Miaoli Ocean Wind Farm, Taiwan. The sound exposure level of piling noise at different penetration depths were measured in September 2016. The measurement distance was 230 meters. The simulation results showed the acoustic exposure level at different penetration depths. The error falls within 2 dB. The second part is the trend of sound exposure level of pile driving noise under different pile diameters measured in foreign sea areas. It counts more than 300 construction foundations and the measurement distance is 750 meters. The sound exposure level is close to its trend.
After comparing with the measurement results in the real sea area, the simulation of piling noise in this study has a certain reference. In the future, relevant parameters that may affect underwater noise will be selected for variance analysis and regression analysis. The parameters such as "pile hammer energy" , "pile length", "pile diameter", "pile wall thickness", "penetration depth" and "local water depth", the regression formula of sound exposure level is obtained through variance analysis, and this formula can be used to estimate pile driving noise The sound exposure level at 750 meters can be used as a reference for the noise before construction of the offshore wind farm to be developed in the future. The noise reduction simulation is carried out by using the actual measurement of the insertion loss of the bubble curtain in different frequency bands abroad, and the noise reduction simulation is carried out by using different cases. The results show that the noise reduction effect is similar to the measurement result, which has certain reference. The simulation cooperates with the aforementioned noise simulation to estimate whether the piling noise at 750 meters after noise reduction exceeds the legal norm of 160 dB re 1 μPa2s。

並列關鍵字

finite element method ； parabolic equation ； forcing function ； pile driving noise ； analysis of variance

參考文獻

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