臺灣離岸風電潛力場址半潛式浮動平台性能研究

Abstract

本研究以四種浮式風機為目標，其特徵尺寸約為60公尺，搭載DTU 10MW風機，浮式平台則參考 OC4 DeepCwind、Windfloat、Cruse和DampingPool的設計概念，分別設計浮式風機A、B、C和D。使用軟體AQWA計算水動力係數。使用OrcaFlex以葉片動量元素理論模擬風機氣動力特性，利用有限元素法模擬繫纜系統，並求解運動方程式，風機控制系統參考NREL 5MW風機的控制策略並調整參數使其適用於DTU 10MW風機。本研究模擬條件為波高6米週期10秒的規則波，以及台灣海峽最常見和最極端的不規則波況，分別是以有義波高1.5米、零上切週期5.5秒和有義波高4.5米、零上切週期7.5秒的JONSWAP波譜加以描述。規則波中以浮式風機 A的功率響應最佳，不同運動模式的相位差會影響功率響應。不規則波中，以浮式風機輪轂的運動速度和發電功率的標準差作為評斷標準，在最常見的波況中以浮式風機 B的表現最佳，標準差分別為0.079 m/s和0.259%的額定功率。在最極端的波況中則以浮式風機 A的表現最佳，標準差分別為0.229 m/s和0.900%的額定功率。因此，浮式風機 B在運維經濟性上具有優勢，浮式風機A則在設計安全性考量上具有優勢。

This study examines four types of floating wind turbine platforms, for which the characteristic sizes are approximately 60 meters. Four target floating platforms, i.e., A, B, C, and D, refer to the design concept of OC4 DeepCwind, Windfloat, Cruse, and DampingPool, respectively. These floating platforms are all equipped with a DTU 10MW wind turbine. The aerodynamics and mooring systems are simulated by OrcaFlex using BEM and FEM, respectively. Hydrodynamic coefficients are calculated by panel method through AQWA and the equations of motion are also solved by OrcaFlex. The wind turbine control system references the control strategy of NREL 5MW wind turbine and the parameters are adjusted to make them suitable for DTU 10MW wind turbine. The target simulation conditions are a regular and two irregular wave conditions in Taiwan Strait, while the inflow wind speed is calculated from the Beaufort Scale. Under the regular wave condition (wave height = 6m, wave period = 10s), the phase difference between different motions obviously affects the power, and the platform A performs the best. Under the irregular wave conditions, taking the standard deviations of generator power and velocity at hub height as the evaluation criterion, the performance of platform B is the best under the wave condition of the highest probability (significant wave height = 1.5m, zero-crossing period = 5.5s), where the standard deviation of rotor plane wind speed is 0.079 m/s and that of generated power is 0.259% of the rated mechanical power. Platform A has the best performance under the extreme sea state (significant wave height = 4.5m, zero-crossing period = 7.5s), where the standard deviation of rotor plane wind speed is 0.229 m/s and that of generated power is 0.9% of the rated mechanical power.