基于B样条二进小波变换的故障选相研究

Ｒesearch of Fault Phase Selection with Dyadic B － spline Wavelet Transform

摘要:

利用暂态行波的特征提出了一种基于小波变换的故障选相方法。该方法的实现原理是通过解耦变换将不独 立的三相故障电流变换为解耦的零模电流分量和 3 个线模电流分量，并运用 B 样条二进小波对解耦变换得到的模电 流分量进行分析，计算得到零模电流分量和线模电流分量初始行波的模极大值; 并根据 4 个模电流分量极大值在不同 故障类型下的不同特征进行对比分析选出故障相。所提出的故障选相方法充分运用了故障时电流初始行波中的模 电流分量特征，克服了现有选相方法选相速度慢、受波形畸变影响等缺点，采用所提方法可得到准确、可靠的选相结 果。最后通过 PSCAD 软件进行了仿真，运用 Matlab 分析了各种故障时的数据，验证了所提选相方法在选相方面的准 确性和优越性。

关键词:电流行波; 故障选相; B 样条二进小波变换; 解耦变换; 模极大值

Abstract:

A fault phase selection method is put forward according to the characteristics of transient travelling wave． The proposed method is implemented based on the difference of fault features of transient current travelling waves，whose modulus maxima of B － spline wavelet transform is obtained by the decoupled transform of non － independent three － phase fault current． The fault phase selection method fully considering the features of the four modular fault components remedies the defects of conventional fault phase selection methods． Compared with the traditional fault phase selection methods，the correctness and reliability of fault phase selection method based on the dyadic B － spline wavelet transform are improved，which is verified by the simulation of PSCAD and data analysis of Matlab．

Key words:current travelling waves; fault phase selection; dyadic B － spline wavelet transform; decoupled transform; modulus maxima