XWaveform identification of oscillation current and fault current in DC traction network

Due to the frequent malfunctions of relay protection system caused by low-frequency oscillation current of Metro DC traction network, more effective feature extraction methods are in need to improve the reliability of protection system. The extraction method combined empirical mode decomposition(EMD) and energy weight can effectively distinguish oscillation current and fault current of traction network, and achieve the extraction of dynamic feature information in traction network current. In this method, the traction network current is decomposed by EMD and the energy weight of each intrinsic mode function(IMF) is calculated, and the feature vector of fault pattern recognition is obtained by constructing the multi-scale feature entropy based on energy weight. The actual measurement data illustrates that the new method not only can accurately identify oscillation current and fault current of traction network, but also has the advantages of clear concept and simple algorithm.