For controlled fault current interruption

rapid prediction of zero-cross point of objective current is a key factor

however a difficult problem.Two major rapid algorithms for predicting the zero-cross point

i.e.the safe-point algorithm and the adaptive self-checking algorithm

were hence proposed.This paper discussed the two algorithms via theoretical analysis and simulation.A single-phase short circuit fault current model was established to analyze and compare the suitability of two algorithms.The results show that for the short circuit fault current model without harmonics

the adaptive self-checking algorithm can predict the zero-cross point of objective current with higher precision

and for the short circuit fault current model with harmonics

the safe-point algorithm works easier and can achieve better waveform.However

both algorithms can only be applied to the system with single-phase fault.