基于特征频带相电流提取的故障选相和选线方法

为有效提高故障选相和选线的准确率,提出基于三相暂态电流信号小波分析的故障选相和选线方法。通过母线处故障相和两健全相的暂态电流差异判断出故障相;对各条线路的暂态电流进行小波包的分解和重构,计算各条线路暂态电流在特征频带内的重构系数比值,利用此值的差异辨识故障线路;在PSCAD仿真软件中搭建包含架空线-电缆混合线路的10 kV典型配电网模型,考虑不同中性点接地方式和过渡电阻大小,利用多组仿真算例验证了所提出故障选相和选线方法的正确性。

Faulty phase and line selection method based on the feature extraction of the phase current in the selected frequency band

In order to improve the accuracy of the faulty phase and faulty line selection, a method of faulty phase selection and faulty line selection is proposed based on the wavelet analysis of the three phase transient current signal. The fault phase was identified by the difference of transient current correlation between faulty phase and healthy phase. Then the transient current of each line was decomposed and reconstructed by wavelet packet, the reconstruction coefficient ratio is calculated for each line based on the transient current energy in the selected frequency band, and the ratio difference was used to identify the faulty line. A 10 kV distribution network consisting of overhead-cable hybrid line was built in PSCAD software, several simulation cases were used to verify the correctness of the proposed scheme considering different neutral grounded mode and fault resistance.