高压输电线路单相故障性质诊断方法

Method to Diagnose Property of Single-phase Fault on High-voltage Transmission Lines

输电线路单相接地故障性质识别方法是自适应重合闸实现的关键。依据故障相首端电压在瞬时性故障和永久性故障下二次电弧阶段高频能量特性的不同,提出了基于小波包变换和支持向量机的输电线路单相故障性质诊断方法。首先,对故障相首端电压信号进行小波包分解,为反映高频能量特性去除低频频带,再将剩下频带的能量归一化后作为支持向量机的特征向量;通过训练学习样本使分类器建立特征向量和故障类型的映射关系,达到区分故障性质的目的。与已有的判据相比,该方法简单、易于实现,适用于带并联电抗器和不带并联电抗器的输电线路。

The key point of realizing the adaptive reclosure is to find a way to distinguish the fault property of the trans- mission line when it happens the single-phase grounding fault. Based on wavelet packet transform and support vector machine technique, a new method is proposed to distinguish permanent fault and transient fault according to their dif- ferent energy properties under high frequency during the period of the second arc of the fault phase voltage at the first end. The Voltage signal of the fault phase at the first end is decomposed by wavelet packet at first, and the band with a low frequency is removed from the original signal in order to highlighting the characteristics of high frequency energy, Then. the remaining energy is normalized to form the feature vector of the support vector machine. Through training samples, the mapping relationship of classifier is built between the feature vectors and the fault types. In this way, the property of the single-phase grounding fault can be easily distinguished. Compared with the existing criterion, the pro- posed method is more simple, easy to implement and is suitable for applying on transmission line with and with-outshunt reactors.