MA Feiyue, WEI Ying, LI Longqi, WANG Daqi, XIANG Bin, WANG Dongyu, DU Huixin, LIU Zhiyuan
The rapid detection of short-circuit fault initiation, accurate estimation of critical fault current parameters, and precise prediction of fault current zero-crossing points are essential for achieving phase-controlled interruption of short-circuit faults. With the continuous expansion of power grids, the increasing decay time constant of the non-periodic component in short-circuit currents, exceeding 150 ms in some grids, presents challenges, yet research on zero-crossing prediction for high DC component decay remains limited. Despite this, there is limited research on predicting the zero-crossing point of short-circuit currents with a high DC component decay time constant. This study focuses on using the Prony algorithm to predict zero-crossing points for short-circuit fault currents with a high DC component. First, F0 hypothesis testing is used to detect the onset of a short-circuit fault, then the Prony algorithm is applied to predict the zero-crossing of the short-circuit current, and finally, after a delay, the circuit breaker is controlled to open quickly. The results show that the Prony algorithm can accurately predict zero-crossing points in short-circuit faults with high DC component decay, featuring small parameter calculation errors and high waveform fitting accuracy. Short-circuit current simulations, varying wave starting phases and DC decay times, reveal Prony algorithm zero-crossing prediction errors within ±0.5 ms, validated by waveform recording, confirming algorithm feasibility. Under identical parameter conditions, the Prony algorithm with a 5 ms sampling time outperforms the recursive least squares algorithm in zero-crossing point prediction.
