絕緣材料老化為電力設備運轉過程中的必然現象，為了避免絕緣崩潰造成設備的突發故障，絕緣狀態診斷的技術研發，便顯得特別重要。
　　本文利用不同的試驗條件對交鏈聚乙烯進行劣化試驗，試驗期間以固定的時間間隔擷取試驗電壓與局部放電訊號，擷取的試驗資料經過濾波與化簡後，再以特徵萃取方式找出有效的特徵參數，並利用Pearson相關係數計算各特徵曲線的相似度，冀望藉由此方法找出較能代表絕緣劣化趨勢的特徵曲線。
　　由相似度計算結果得知，各試驗之區域平均放電量特徵曲線的變化趨勢最為相近，因此藉由此特徵參數找出可代表絕緣狀態變化的特徵樣板曲線，其斜率變化情形可作為絕緣狀態的判斷依據。劣化初期時，正、負半週曲線斜率大於1.2與1.1。劣化中期時，正半週曲線斜率介於0.3至1.2之間，負半週介於0.3至1.1之間。劣化末期時，正、負半週曲線斜率皆小於0.3。

　　The aging phenomenon of insulation materials during running period is a natural property. In order to avoid the sudden failure of equipments by insulation breakdown. The R&D of techniques for insulation status diagnosis has apparently become imperative.
　　The thesis applies different experimental conditions to the cross-linked polyethylene deterioration test. The experiment voltage and signal of partial discharge are measured at a fixed time interval during experiment. The data acquired from experiment are filtered and simplified, and then the effective characteristic parameters are found by feature extraction methods. Finally, the similarity of characteristic curves is calculated by Pearson correlation coefficient method looking forward to finding a representative curve of the trend of insulation deterioration.
　　From the result of calculation, the trends of change of district average discharge amount are most alike, therefore, the characteristic template which can represent the change of insulation status is found by this parameter. The status of insulation can be judged in accordance with the change of slope of the characteristic template. In the early stage of degradation, the slopes of positive half and negative half cycle are larger then 1.2 and 1.1 respectively. While during the middle stage of degradation, the slopes of positive half cycle are between 0.3 and 1.1 and that of negative half cycle are between 0.3 and 1.1. The slopes are smaller than 0.3 for both positive half and negative half cycle during the final stage of degradation before insulation breakdown.

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