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变压器油纸绝缘老化是影响变压器正常运行的重要因素.现阶段,基于时域检测的去极化电流法被广泛应用于变压器油纸绝缘状态诊断,但对于去极化电流谱线的特征量提取仍处于初始阶段.根据介电响应和陷阱理论,提出绘制去极化陷阱密度谱,并从中提取峰值大小Smax和峰值时间常数Tmax这两个新特征量,用以评估变压器油纸绝缘老化状态.首先采用不同极化电压测试,分析去极化陷阱密度谱线新特征量与极化电压间的关系.其次对检测出不同糠醛质量浓度的绝缘油纸变压器的陷阱密度谱线作对比分析.最后对大量变压器实例进行验证分析.研究结果表明:峰值大小Smax与糠醛检测质量浓度呈正相关,峰值时间常数Tmax与糠醛检测质量浓度呈负相关;随着油纸绝缘老化程度的加深,陷阱密度谱的特征量Smax逐渐增大,而特征量Tmax逐渐减小;所提出的两个特征量取值范围可作为今后诊断变压器油纸绝缘老化状态的依据.“,”Transformer oil-paper insulation aging is an important factor affecting the normal operation of transformers.At present,the depolarization current (PDC) method based on the time domain detection is widely used in transformer insulation condition diagnosis,but the feature extraction of depolarizing current line is still in the initial stage.According to the dielectric response and trap theory,we put forward a method to draw the depolarizing trap density spectrum,extract two features including peak value Smax and peak time constant Tmax,and then use them to evaluate the state of transformer insulation.Firstly,different polarization voltage tests are used to analyze the relationship between new characteristic value and polarization voltage.Secondly,the trap density of transformers with different furfural concentration are comparatively analyzed.Finally,a large number of instances on oil-paper insulation aging diagnosis are verified and analyzed.The research results show that the peak value is positively related with furfural content,and peak time constant is negatively related with furfural content.With the deepening of oil-paper insulation aging,the peak value Smax increases gradually,but the peak time constant Tmax decreases gradually.The value range of two characteristics proposed can be used as the basis of the diagnosis of transformer insulation aging status.