Method for improving positioning of fault section of power distribution network including distributed power supply through directional elements

The invention discloses a method for improving positioning of a fault section of a power distribution network including a distributed power supply through directional elements. The method comprises the steps that (1) after the power distribution network including the distributed power supply breaks down, whether a fault occurs in an area with a T joint or an area without a T joint is judged according to the direction of fault current reported by switches around a fault point; (2) if the direction information of the fault reported by the directional element on the side with the fault current supplied by a main power supply is in the positive direction, and the direction information of the fault reported by the directional element on the side with the fault current supplied by the distributed power supply is in the negative direction, it is accordingly judged that the fault occurs in the area with the T joint, and thus the fault isolation is conducted; (3) if the direction information of the fault current provided by feeder line switches around the fault point is identical, it is judged that the fault occurs in area without the T joint. The amplitude values of the fault current of the switches on the two sides of the fault point are different, the fault current crossing the switches on the same side of the fault point is approximately identical, and thus the specific area where the fault occurs can be judged and fault isolation can be conducted accordingly.