Abstract: During fault occurrence at the large-scale power grid,all kinds of related fault wave recording data can be timely uploaded to the dispatching centre.However,operators are unable to determine the nature of the fault rapidly,accurately,and intuitively based on numerous discrete fault data such as circuit breaker,fault recorder analog and action events of protection devices alone,greatly influencing the speed of grid recovery and safe operation of large-scale power grids.By adopting advanced technology such as station equipment unified model mapping,sampling frequency normalization and sampling synchronization to effectively integrate fault recorded data and initiating fault intelligent diagnosis on differential principle,exact fault location just using fault recorded data to calculate the differential current is realized,the results of which can be automatically displayed on the screen.The proposed system played a significant role in handling several faults of a large-scale power grid.