ELECTRIC DISCHARGE ASSESSMENT DEVICE AND METHOD THEREFOR

To more easily assess whether there is occurrence of an electric charge to a winding.SOLUTION: The present invention includes: measuring a first electric discharge occurrence estimated time slot Rt1 on the basis of first time-series voltage data obtained by applying an impulse voltage Vi to both ends of a winding 20 and Fourier-transforming the first time-series voltage data so as to find a frequency spectrum (steps S100-S106); extracting only an electric discharge-specific frequency component from the frequency spectrum (step S108); and reverse-Fourier-transforming the extracted frequency spectrum so as to find second time-series voltage data (step S110). The present invention further includes: finding a maximum voltage value Vmax1 and first time T1 from the first electric discharge occurrence estimated time slot Rt1 of the second time-series voltage data (step S112); estimating that there is occurrence of electric discharge when the first time T1 falls within a threshold range (step S114); and comparing the maximum voltage value Vmax1 with a threshold Vth so as to assess the occurrence of the electric discharge (steps S116-S120).SELECTED DRAWING: Figure 2 【課題】巻線に放電が発生しているか否かをより簡易に判定すること。【解決手段】巻線２０の両端にインパルス電圧Ｖｉを印加して得られる第１時系列電圧データに基づき第１放電発生推定時間帯Ｒｔ１を計測すると共に、当該第１時系列電圧データをフーリエ変換して周波数スペクトルを求め（ステップＳ１００～Ｓ１０６）、周波数スペクトルから放電特有の周波数成分のみを抽出し（ステップＳ１０８）、抽出した周波数スペクトルを逆フーリエ変換して第２時系列電圧データを求める（ステップＳ１１０）。第２時系列電圧データの第１放電発生推定時間帯Ｒｔ１から、最大電圧値Ｖｍａｘ１と、第１時間Ｔ１を求め（ステップＳ１１２）、第１時間Ｔ１が閾値範囲内であれば放電が発生していると推定し（ステップＳ１１４）、最大電圧値Ｖｍａｘ１と閾値Ｖｔｈとを比較して放電の発生の有無を判定する（ステップＳ１１６～Ｓ１２０）。【選択図】図２