絕緣材料老劣化是設備運轉時產生的自然現象，目前無有效的抑制措施，只能靠平時的維護保養，因此研發各種絕緣狀態診斷技術更為重要。對於液態絕緣材料而言，目前已知的診斷技術中以油中氣體分析發展最為長久且數據庫也最為齊全，亦是目前業界使用率較高的檢測方式；局部放電是當今最具發展潛力的檢測方式，透過放電訊號相位圖譜可迅速分析設備故障類型及形式。雖然油中氣體檢測已廣泛使用，但高檢測費用及費時是此技術的缺點，相較之下，局部放電檢測更快速且方便，為了使局部放電檢測方式替代油中氣體檢測方式，本論文根據法規IEC60599中大偉三角形法分類放電訊號相位圖譜，並分析不同故障形式間圖譜的差異，從單次油樣檢測中發現其分類出的故障形式與油樣的放電面積有關聯。透過階段性的油樣檢測，發現當油樣中有能量波動時，絕緣狀態圖中亦可發現其能量變動，其可說明油中氣體分析結果與局部放電的絕緣狀態圖間有關聯。

Nowadays, one of the most useful and widely used conditions assessment techniques involves sampling and analysis of gasses dissolved(DGA) in the oil immersed transformers. This technique is sensitive to a wide range of malfunctions, both thermal and electrical. Another detected method partial discharge (PD) is one of the most potential test item in the field detection. The engineer can determine the type of failure through phase resolved partial discharge (PRPD) pattern, and observe the trend of partial discharge. DGA is very popular but the technique is expensive and takes time. In contrast, PD technique is faster, more convenience in the test process and results can be distinguished electrical failures more clearly. The main issue in the thesis is tried to find the correlation between PD and DGA in the dielectric liquid through comparison with the results of the PRPD and Duval triangle. From the experimental results, the energy variation is correlated to the results of DGA and PD.

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