Fast and accurate prediction of zero-crossing points of fault current lays the foundation of the phasecontrolled fault interruption. In this paper

a new algorithm is proposed to predict the zero-crossing points based on Prony method. By calculating the frequencies

amplitudes

phases

etc.

the original waveform is obtained through fitting the sampled signal to calculate the objective zero points. An ideal signal is set in MATLAB to test the effectiveness of the proposed algorithm

and the result shows that the algorithm gains high SNR and very small margin of error. Moreover

compared with the safe-point algorithm

Prony algorithm demonstrates better fitting degree of waveform and higher stability to harmonics in the condition of 1/4 sampling cycle and triple-frequency harmonics.