基於三維風場觀測與大渦流模擬之風機尾流特性研究

Abstract

近年台灣離岸風電工程快速發展，但風機所產生的尾流效應常導致整體場區發電效率低於預期，甚至會波及下游風場的功率推估。然而，實務上對於尾流真實特性的研究仍不充分，特別是缺乏三維空間風速場的實測資料。本研究以丹麥開發商沃旭（Ørsted）在竹南外海風場所部署的雙多普勒雷達觀測資料為基礎，針對冬季東北季風條件下風電場尾流的三維結構進行分析。同時，透過美國國家再生能源實驗室（NREL）所開發之SOWFA模擬工具，重現一段短時間尺度（小於1小時）且高可信度的尾流風場，並將其結果與觀測資料進行比較。藉由此對照，本研究進一步探討真實風況中影響三維尾流不確定性的因子，包括風向擺動、風切變化與海陸風效應等，並檢視模擬在短時尾流變化上可能欠缺的修正項。最終，本研究目標是建立一套完善的三維尾流分析方法，期能為未來台灣離岸風場的效能評估與營運管理提供實質助益。

In recent years, offshore wind power development in Taiwan has grown rapidly. However, wake effects generated by wind turbines often reduce the overall power output of a wind farm below expectations and may even influence the power forecasts of downstream farms. Despite this, comprehensive studies on the actual characteristics of wind farm wakes remain limited, particularly with respect to three-dimensional wind field measurements. This study utilizes dual-Doppler radar data deployed by Ørsted at the Zhunan offshore wind farm to investigate the three-dimensional wake structure under northeast monsoon conditions in winter. In parallel, the Simulator fOr Wind Farm Applications (SOWFA), developed by the U.S. National Renewable Energy Laboratory (NREL), is employed to reproduce a short-duration (less than one hour) but highly reliable wake field. The simulation results are compared against the radar observations to examine factors contributing to wake uncertainties in real atmospheric conditions, such as wind direction variability, wind shear, and land–sea breeze effects. Furthermore, the study evaluates potential missing correction terms in the simulations related to short-term wake dynamics. Ultimately, this research aims to establish an effective methodology for three-dimensional wake analysis, with the expectation of providing significant benefits for performance assessment and operational management of future offshore wind farms in Taiwan.