暂态信号分析中小波基的选择与应用

暂态信号的识别、处理和利用是新一代继电保护(暂态保护技术)发展的基础。处理非平稳信号时,小波变换在时域和频域内均有局部化能力。研究和描述小波分析理论,探讨小波基的特性,为电力系统常见暂态信号分析的小波基选择提供了依据。利用Matlab对1条500 kV输电线路发生单相接地时进行故障定位仿真结果表明,选择Db4小波进行信号分析是准确的;建立单相接地短路、雷击输电线路2种暂态类型,得到多尺度能量统计能反映不同暂态的特性。

Selection and application of mother wavelet in the analysis of transient signals

The identification,processing and utilization of transient signals are the foundation of a new protection theory-transient based protection.Wavelet transform has location-resolve ability in time and frequency domain when processing the non-stationary signals.The wavelet analysis theory was described and the characteristic of mother wavelets was discussed.The basis of the selection of mother wavelet in analysis transient signals that are common seen in power system was provided.Simulation to the single-phase grounding fault of a 500 kV transmission line verified the correctness of the proposed method.The MATLAB simulated models were built about the single-phase grounding and the lightning strike.The results indicate that multi-scales energy statistic can reflect the characteristics of different transient signals.