Short-time fourier transform based analysis to characterization of series arc fault

Considering the non-periodic and non-stationary signatures of series arc fault current signals, a time-frequency analyzing method for series arc faults detection is presented based on short-time Fourier transform. The algorithm of STFT using the Hanning window function is described in detail, in which the length of the window function and the sliding step parameters are discussed to obtain 20 ms time-resolution and 25 Hz frequency-resolution. The relationship between the variations of even order harmonics, odd order harmonics and the 50 Hz fundamental component under series arcing faults is obtained. The results of testing data verified the feasibility of the new method proposed by this paper.