基于改进的广义谐波小波包分解和混沌振子的小电流接地系统故障选线

Application of Improved Generalized Harmonic Wavelet Packet Decomposition and Chaos Oscillator to Fault Line Detection in Small Current Grounding System

小电流系统发生故障时,各线路零序电流具有非平稳、非线性等复杂特性。本文提出一种基于改进的广义谐波小波包分解算法和混沌振子检测的小电流接地系统故障选线方法。广义谐波小波包分解算法经过扩频,能进行任意频段及任意频宽的信号特征提取,且计算量小,实现信号的快速无混叠分离。Duffing振子系统不受噪声影响且对于与内驱动力同频的外界信号具有高度敏感性,对Duffing振子系统进行时标变换,可以适应不同频率信号的检测要求,通过观察相图的变化可以准确选出故障线路。数值仿真验证了该算法的准确性及可靠性。

As the small current grounding system fails, the zero-sequence current of each line appears complicated characteristics of non-stationary and nonlinear. A small current grounding system fault line selection method based on improved generalized harmonic wavelet packet decomposition and chaos oscillator detection algorithm is given in this paper. Through spread spectrum, the generalized harmonic wavelet packet decomposition algorithm could extract features of any frequency band and arbitrary bandwidth signal with less calculation, realizing fast and anti-aliasing separation to signals. Duffing oscillator system is unaffected by noise and presents highly sensitive to external signals which have the same frequency as the internal driving force. By time-scale transformation, Duffing oscillator could be adapted to the detection of different frequency signals. The fault line could be accurately selected by observing the changes in the system's phase diagram. Numerical simulation showes the reliability and accuracy of the algorithm.