变电站二次电缆瞬态电磁骚扰的特征统计方法与不确定度分析

Statistical analysis method and uncertainty of transient electromagnetic disturbance measured on secondary cables in substations

针对瞬态电磁骚扰数据样本量小和分散性强的特点,结合自助统计法,提出了偏差矫正的自助置信区间估计法和多次测量不确定度的B类评估方法。首先在变电站测量了开关操作时二次电缆端口的瞬态电磁骚扰,其次应用基于自助法的随机加权原理和偏差矫正的自助置信区间估计法,得到特征参数的统计均值和置信区间。然后应用瞬态电磁骚扰多次测量不确定度的B类评估方法,得到了特征参数的不确定度。最后评估标准波形特征参数与实测波形的符合性。分析结果表明:多次测量骚扰电压峰峰值的分散性是产生不确定度的主要因素;100~300 kHz区间实测骚扰电压的上升时间显著长于100 kHz慢速阻尼振荡波;6.5~10 MHz区间实测骚扰电压的上升时间显著长于快速阻尼振荡波;实测骚扰电压波形随区间频率的增加,持续时间缩短。

Because of the characteristics of transient electromagnetic disturbance characteristics like small sample and large dispersion,and combined with Bootstrap method,a bias-corrected bootstrap confidence interval estimation method and the B-type uncertainty evaluation method for multiple measurements are proposed.First,the transient electromagnetic disturbance of the secondary cable port during a switching operation is measured in the substation.Then,a random weighting method based on the Bootstrap and a self-confidence interval estimation method for deviation correction are applied to obtain the statistical mean and confidence interval of the characteristic parameters.Then the B-type uncertainty evaluation method for multiple measurements is applied to obtain the uncertainty of the characteristic parameters.Finally,the compliance between the standard waveform characteristic parameters and the measured waveform is evaluated.The results show that the dispersion of the peak-to-peak disturbance voltage from multiple measurements is the major factor in the uncertainty;the rise time of the measured disturbance voltage in the 100~300 kHz range is significantly longer than that of the 100 kHz slow damping oscillation wave;the rise time of the measured disturbance voltage in the 6.5~10 MHz range is significantly longer than that of the fast damping oscillating wave;the duration of measured disturbance voltage waveform decreases with increasing frequency of the interval.