接触网腕臂绝缘子泄漏电流特征研究

Research on Characteristics of Leakage Current for Cantilever Insulators in Overhead Contact Lines

基于电气化铁路用QB-25系列接触网腕臂绝缘子在饱和湿度下的泄漏电流试验数据,采用小波包与经验模态分解相结合的时频分析方法、Welch功率谱计算法、谐波分析等分析方法,从时域分析和频域分析两个角度研究了绝缘子表面泄漏电流特性,分析了泄漏电流有效值、有效值标准差、有效值均值、3次谐波有效值、谐波含量等5个特征量随绝缘子表面污秽度的不同而变化的规律。结果表明,5个特征量均随绝缘子表面污秽度的增加而增大,其中,泄漏电流有效值最大值的波动能够最显著地反映腕臂绝缘子表面污秽度的变化,其次是泄漏电流有效值标准差、有效值均值。连续测得的泄漏电流谐波含量在绝缘子临近闪络时会出现下降。本论文的研究成果可为电气化铁路腕臂绝缘子表面污秽度监测提供诊断与评价的依据,可直接用于工程实践,具有重要的应用价值。

Series of QB-25 cantilever insulators in overhead contact lines serve as test samples in this paper,based on testing data of leakage current on the condition of saturation humidity and operating voltage,Wavelet Packets and Empirical Mode Decomposition method,Power Spectrum Calculation with the Welch method,Harmonic Current Analysis are applied to analyze the leakage current characteristic of time domain and frequency domain for cantilever insulators. The paper focuses on leakage current effective value,standard deviation of effective value,the mean effective value,and the effective value of third harmonic,harmonic content,to figure out how these five leakage current characteristic values are changing when it comes to different contamination criteria. The results show that the five leakage current characteristic values respectively have a positive relationship with contamination level. As far as the degree of correlation concerned,the leakage current effective value is the top influence factor on reflecting the contamination level changing of cantilever insulators,standard deviation of leakage current effective value is the second influence factor and the mean effective value is the third one. Harmonic content of leakage current measured continuously would decrease when the cantilever insulator is in the state of closing to polluted flashover. The research results could be used as scientific basis for diagnosis and evaluate of contamination monitoring with an important application value and could be applied to contamination on-line monitoring system practically.