典型缺陷的直流局部放电波形测量与特性分析

为深入了解直流局部放电特性,在直流下分别测量了气隙、表面和电晕放电模型的局部放电,比较3种模型的放电脉冲波形和直流电压施加不同阶段的放电情况,并从放电机理角度分析了直流电压施加不同阶段局部放电特性的差异。结果表明,3种放电模型的直流局部放电能量分布频段多<10 MHz,放电脉冲波形与频谱分析图存在区别,可以此分辨3种放电类型。气隙放电模型在直流电压移除后,因空间电荷作用,绝缘介质中存在较强的内电场会引起较多的反极性放电;而表面放电模型与电晕放电模型在直流电压移除后无此现象。

Partial Discharge Pulse Shape Detection and Analysis Under DC Condition in Typical Defect Models

The partial discharge(PD) under DC condition was obtained by internal discharge models,surface discharge models and corona discharge models.Discharge pulse shapes,Fourier analysis of the discharge pulse shapes and PD characteristics under DC condition in three kinds of typical defect models were compared.According to the fast Fourier analysis of the discharge pulse shapes,the frequency bands of the energy of discharges in three kinds of defect models are below 10MHz.The discharge pulse shapes of three kinds of models are different.Three kinds of discharges can be distinguished by analysis of pulse shapes and the fast Fourier analysis of the pulse shapes.There are a large amount of space charges accumulated in internal models,of which polarity is opposite to the applied DC voltage.When DC voltage being removed,these space charges may result in the opposite polarity discharges.But few space charges could be stored in surface discharge models and corona discharge models.Therefore,when DC voltage is removed,partial discharges,of which polarity is opposite to the discharges at DC voltage applied,occur in internal defect models.But there is no discharge occurring in surface defect models and corona defect models.