基于单相电流行波的配电线路单相接地故障选线方法

A Method of Single Phase to Ground Fault Feeder Selection Based on Single Phase Current Traveling Wave for Distribution Lines

为解决现有单相电流行波选线方法有效时间窗短、存在死区,且受到现场电流互感器(current transformer,CT)配置方式的制约等问题,提出一种利用故障暂态单相电流和母线三相电压构造方向行波并进行故障方向识别的配电线路接地选线新方法。该方法选取一定数据窗内各线路单相电流和母线三相电压,利用单相电流与模量电压的线性组合,构造模量上的特征方向行波(characteristic directional traveling wave,CDTW)。通过二进小波变换求取CDTW在特定频带内的分解系数,进而计算出特征正、反向行波积分关系实现接地选线。数学证明与仿真结果表明,所提方法选线可靠性高,在故障全过程均有效,特征方向行波定义合理,且不受中性点接地方式等因素的影响。

To solve the problems of short effective time span, dead zone existence, and being highly restricted by the practical current transformers （CTs） configuration, a novel fault line selection method based on the construction of directional traveling wave is proposed, which adopts transient signals of single phase current and bus phase voltages. By using the linear combination of single phase current and bus phase voltages, characteristic directional traveling wave （CDTW） in mode domain is established. Dyadic wavelet transform is applied to calculate the decomposition coefficient of CDTW in certain frequency span. The integral relationship between forward and backward directional traveling wave is obtained and the fault line selection is accomplished. Mathematical deduction and simulation results prove that the proposed method has high accuracy and long effective time span. The definition of characteristic directional traveling wave is reasonable. The performance of the proposed method is not affected by the neutral point grounding type.