雷电冲击电压下油纸绝缘气隙模型的局部放电测量与分析

Partial Discharge Measurement and Analysis of Gap in Oil-Paper Insulation Model under Lightning Impulse Voltage

介绍了冲击电压下油纸绝缘气隙局部放电的机理与过程,构建了油纸绝缘气隙模型,设计了冲击电压下油纸绝缘气隙局部放电的测量系统,采用ORIGIN数值分析软件进行局部放电脉冲的分析与处理,并分析了冲击电压下局部放电主脉冲及波尾多次脉冲的波形特征,探讨了雷电冲击电压下油纸绝缘气隙模型的局部放电起始电压和平均放电重复率等参数性质.试验结果表明:油纸绝缘气隙模型在雷电冲击电压下的局部放电脉冲分为波头时间的主放电脉冲和波尾时间的多次低幅值脉冲,冲击电压的等效频率很高,在测量信号中存在一个幅值很高的由容性电流引起的电压信号叠加在局部放电信号之上,要进行滤波处理;冲击电压波形的随机性与局部放电信号的随机性导致冲击电压下的局部放电信号分散性很大,需要采用统计的方法进行分析.这些试验结论为油纸绝缘类电力设备绝缘状态评估奠定了基础.

To investigate the partial discharge （PD） characteristic of the gap in oil-paper insulation model under lightning impulse voltage, the PD mechanisms of the gap in oil-paper insulator under impulse voltage are analyzed with three-capacitor model. The gap in oil-paper insulation model and PD measurement system under impulse voltage are designed. The PD pulses are analyzed and processed by ORIGIN numerical analysis software. The waveform feathers of the main PD pulse in the front time and other PD pulse during wave tail time are described. The parameters of the partial discharge inception voltage（PDIV） and discharge repetition rate on average are discussed. The results indicate that there are main PD pulse and repeated PD pulses in the front and tail time under lightning impulse voltage, the waveform of lightning impulse voltage is of high frequency and random so PD pulses are always superimposed by a voltage from the capacitive current. This study may provide theoretical and practical bases for the insulation evaluation of power equipment.