配电网单相故障多频带奇异量选线方法

采用3次B样条小波包提取各线路故障奇异量模极值,根据模极值能量分布最大原则,提出各线路特征频带的选取方法.当各线路特征频带一致时,以各线路零序电流模极值的幅值关系、相位关系构造选线判据;当各线路特征频带不一致时,分别在各线路的特征频带上构建各线路零序电流模极值的大小和极性关系矩阵,构造选线判据.解决了现有故障奇异量选线方法中因频带选择不合适而造成的误判问题.通过2组现场实录故障算例验证了选线判据的有效性和实用性.

Singularity Detection for Phase-to-ground Fault in Non-effective Grounded Power Networks Based on Multi-frequency Bands Analysis

The cubic B-apline wavelet packet transform is adopted to detect the singularity of single-phase-to-ground fault signals. By means of such transform, the maximal module in wavelet domain is obtained. The characteristic frequency band of each line, in which the maximal module is most concentrated, is chosen according to the view of maximum energy. For each case that the characteristic frequency band of each line lies in or out a same one, two types of numerical fault detecting criteria are proposed. The proposed method overcomes the blindness in determining the feasible frequency band that conventional methods cannot avoid. The effectiveness and practicality of the method proposed are demonstrated via field test results.