On-line distance measurement method of protection fault information management system

The present invention relates to an on-line distance measurement method of a protection fault information management system. The method comprises the following steps that: S1, after a power grid malfunctions, a fault line is judged according to remote signaling shift, SOE and protection action signals; S2, the recording file of a specified fault recorder of a two-side plant station to which the fault line belongs is called; S3, a specific fault time point and a corresponding failure device are determined according to the phase current sudden change quantity of the recording file, and eight analog quantity channels, namely three-phase voltages, a zero-sequence voltage, three-phase current and zero-sequence current of the failure device are further determined; S4, as for disperse sampling points of a cyclic wave before the fault and a cyclic wave after the fault, the complex values of the three-phase voltages, the zero-sequence voltage, three-phase current and zero-sequence current before and after fault are calculated through using a differential Fourier series algorithm according to the fault time point and the eight analog quantity channels; S5, positive-sequence, negative-sequence and zero-sequence current values after the fault are calculated through phase sequence conversion, and a fault phase is determined through the comparative analysis of sequence current fault components; and S6, after the fault phase is determined, distance measurement calculation at a single end side or two end sides is performed.