本文提出田口方法應用於被動式諧波濾波器最佳化設計。直交表已廣泛應用於解決實際問題的之重要實驗程序，主要原因是直交表具有幾何平衡特性，使用較少的實驗獲得更可靠的濾波器最佳化組合。配合信號雜訊比，衡量最佳化濾波器品質的穩健性；濾波器設計時，有些不確定因素，例如系統阻抗變化及不同負載產生諧波電流，本研究中則視之為雜訊因子，並以探討其對濾波器最佳化設計的影響程度，並藉此瞭解何種濾波器組合，可以對諧波有最佳濾波效果。在濾波器的設計規劃中，一般是考慮虛功率補償與各次諧波限制條件下，以電壓總諧波失真、電流諧波總需量失真、濾波器損失與濾波器成本最小化等為設計良窳之評估準則；本研究則同時考量上述四項目標，藉由多目標特性正規化，轉換為單一目標函數；其中各單一目標函數間權重的決定，使用模糊理論之重心法，求得模糊數的幾何中心。為驗證所提方法有效性，本文以裝設交流、直流電弧爐負載及靜態虛功率補償器之某鋼鐵廠為例，模擬結果顯示能有效降低系統之諧波失真，提昇供電系統的電力品質。

This report shows the use of the Taguchi method to investigate the planning of large-scale passive harmonic filters. Orthogonal arrays are widely employed in experimental processes to solve practical problems encountered because such arrays are geometrically balanced in their coverage of the experimental region after only a few representative experiments have been implemented. The signal-to-noise ratio (SNR) is employed to investigate the robust design of harmonic filters. In the design of harmonic filters, some uncertainties should be considered. Noise factors have been considered to present the effects of filter parameter detuning, loading uncertainty and changing of system impedances. In order to determine a set of weights of objective functions to represent the relative importance of each term, the centroid method has been considered. The purposes are to minimize the total demand distortion of harmonic currents, total harmonic distortion of voltages, filter loss and cost. Reactive power compensation and constraints of individual harmonics should also be considered. A search for a global optimal solution is applied to the harmonic problems in a steel plant, where both AC and DC arc furnaces are used and a static var compensator (SVC) is installed. Additional results related to the Taguchi method are also reported and discussed as well.