Power distribution network failure data self-synchronizing method based on instantaneous amplitude change

The invention discloses a power distribution network failure data self-synchronizing method based on instantaneous amplitude change. According to the power distribution network failure data self-synchronizing method, the instantaneous amplitude of the failure current is calculated by use of the instantaneous sampled values of three-phase currents at the same moment, failure synchronization is realized according to the characteristic that the instantaneous amplitude of the currents after a failure changes suddenly, and whether the failure exists is determined according to whether the magnitude of the sudden change of two cycle current instantaneous amplitudes before and after the failure exceeds a certain threshold; the power distribution network failure data self-synchronizing method has the characteristics of high sensitivity and high speed, and is capable of effectively overcoming the defects of an existing fault detection method, such as slow start, high failure moment detection error and poor self-synchronizing effect in case of failures occurring near a current zero-crossing point; without increasing the construction cost, the clock synchronization accuracy is improved to meet the requirements of the line longitudinal differential protection of the power distribution network.