形态学与HHT检测相结合的行波波头准确标定方法

Accurate traveling-wave front detection based on morphology and HHT

由于长输电线路高阻故障和线路色散等因素使得故障行波波头高频成分衰减较大,提出并实现了一种将形态学与Hilbert-Huang变换(HHT)相结合的行波检测及其波头到达时刻准确标定方法。行波暂态信号经形态学滤波之后,再对其做经验模态分解(EMD)提取其高频部分IMF1和IMF2分量,藉此实现对行波波头到达时刻的精确标定。若由于线路雷电冲击电晕和线路参数频变等因素引起行波波头较大衰减,使得故障行波反射波头在IMF1表现不明显时,则可采用IMF2分量对其反射波头到达时刻进行准确标定。该方法对行波波头的时间标定可以精确到采样点。电磁暂态仿真数据和实际工程数据验证表明,该方法正确、有效,并已应用于故障行波分析与测距装置。

The high frequency components of traveling- wave front attenuate greatly because of the high resistance and dispersion of long transmission line,to which,an accurate detection method of traveling-wave front arriving time based on mathematical morphology and HHT is presented. The traveling-wave signals are filtered with mathematical morphology and the high frequency parts,IMF1 and IMF2 components,are picked up by EMD to detect precisely position the arriving time of traveling-wave front. If IMF1 component can not clearly represent the reflected traveling wave front because of bigger wave attenuation caused by lightning strike corona and transmission line parameter frequency variation,IMF2 component is then applied. The detection resolution is one sampling point. Digital simulative data and practical engineering data show that, the proposed method is correct and effective,and has been applied in the traveling-wave analysis and fault locating equipment.