直流下局部放电序列信号检测与特性分析

Measurement and Analysis for Pulse Sequence of Partial Discharge Signals Under DC Voltage

介绍了用于分析直流下局部放电序列信号的时间等待恢复模型及其假设,总结了基于基本参数放电幅值q和放电时间点t用于分析直流局部放电序列信号的多种放电谱图。利用自行研制的直流局部放电宽带检测系统获取了缺陷模型(空气中电晕、油纸绝缘的尖板、内部缺陷和沿面放电)在直流电压下的大量局部放电脉冲波形-时间序列。并对获取的脉冲波形-时间序列,使用脉冲群快速分类技术进行随机干扰脉冲剔除。在上述工作基础之上,进行了直流局部放电幅值-时间序列信号的相关性统计分析,给出了各缺陷模型对应的典型q-t、n-q、n-Δt和qsuc-q等多种直流局放谱图。试验结果分析表明,四种典型缺陷具有各自的放电特性,直流下局部放电发展过程符合时间等待恢复模型及其假设。这为基于幅值-时间序列的直流局放检测、识别提供了理论和试验依据。

A time recovery and lag model with its hypothesis to analysis partial discharge （PD） pulse sequence signals under DC voltage is introduced in this paper. A group of histograms to analysis DC PD are deduced from the two basic parameters, the discharge magnitude and arrive time which can be recorded by the PD measurement system. Three basic defect models of oil-paper insulation including corona, bounded cavity and surface discharge, and a typical discharge model of corona in air are described after the DC PD test and measurement system are shown. The PD measurement system has a special anti-noise technique which resorts to the characteristic of pulse waveshape signals in time and frequency domain to achieve fast separation of random pulsed noise signals. Test results of those defect models are analyzed and discussed respectively, which show that PD pulse sequence under DC voltage has its own characteristic with different defect models. Some of analyze results can be explained well with the time recovery and lag model with its hypothesis. This provides a test and theoretical evidence for study of detection and identification of PD pulse sequence under DC voltage.