Research on Fault Recording Data Synchronization Algorithm Based on Prony Fitting and Zero Crossing

In the application of relay protection in active distribution network, data synchronization is of great significance to system protection. As the structure and composition of the power grid system become more and more complex, its fault characteristics also tend to be complicated. However, the traditional data self-synchronization algorithm ignores the start-up delay of the starting component, which will bring large synchronization errors in some complex fault conditions. Therefore, a zero-crossing point (ZCP) synchronization algorithm based on Prony fitting is proposed. The accurate fault time of the recorded signal on the load side is found by Prony fitting, and the fault time is used as the starting point of the load side to find the zero-crossing point, without considering the invalid zero-crossing point, so that the synchronization error is reduced to less than one sampling period. Through simulation verification, the algorithm in this paper can correctly identify the first zero-crossing point before fault under different fault types, different fault distances and different transition resistances, and achieve high-precision synchronization, which has good applicability and stability.