A Series Arc Fault Protection Method Based on Time and Frequency Domain Characteristics of Current

In view of the problems of misrecognition and missed identification caused by nonlinear load in arc fault identification, this paper proposes an arc fault protection method based on current similarity and high-frequency wavelet energy. Db 5 wavelet is selected for arc current preprocessing. The difference of the cosine similarity of the low-frequency approximation coefficients of adjacent periodic currents is used as the low-frequency characteristic quantity of the arc current, and the wavelet energy in the frequency band of 3125 Hz ~ 6250 Hz is used as the high-frequency characteristic quantity of the arc current. An arc fault protection algorithm based on threshold comparison is proposed. The results show that the method can realize the accurate identification of the arcing fault under a single load and combined loads. There is no error identification during the startup of the nonlinear loads.