Distance measurement method for power distribution network single-phase earth fault on the basis of aerial mode traveling wave mutation

The invention discloses a distance measurement method for a power distribution network single-phase earth fault on the basis of aerial mode traveling wave mutation. The method includes the following steps that (1) the same voltage pulse is simultaneously injected to three phases of a head end of a power distribution network, and voltage traveling waves returned from the three phases are detected; (2) the voltage traveling waves of each phase, which are obtained in the step (1), are transformed to modulus by a phase-mode transformation matrix, and further, aerial mode voltage traveling waves are obtained; (3) the aerial mode voltage traveling waves obtained in the step (2) are subjected to difference derivation to obtain first nonzero mutational point time, and thereby, travel time of the traveling waves can be obtained; (4) the travel time obtained in the step (3) is substituted into a distance measurement formula to obtain fault distance. According to the method, high voltage pulse is simultaneously injected to the three phases of the head end to detect aerial mode voltage traveling wave mutation so as to perform fault distance measurement, and thereby, the problem of fake fault points caused by unbalance three-phase loads of the distribution network is solved.