Fault positioning method of complicated distribution line

The present invention discloses a fault positioning method of a complicated distribution line. The method comprises a step 1 of carrying out the mathematical modeling on the distribution line, and establishing the T nodes, wherein the T nodes comprise the actual T nodes established by the connection points of the actual branch lines and the virtual T nodes established by the parameter segments of different lines; a step 2 utilizing a database to store the mode information of the plant-stations of a power grid, the system equivalent impedance and the parameter information of the distribution network lines; a step 3 determining the possible positions of the fault points in a main line according to a fault current, a system parameter and the electrical circle of each T node; deciding the branch line in which the fault concretely and possibly occurs according to the branch line impedance. The fault positioning method of the present invention realizes the distribution line fault accurate positioning just by the system equivalent impedance and a line virtual T node model, enables the distribution line patrol efficiency to be improved greatly, the distribution network scheduling instructions to be enriched and the fault patrol time to be shortened, and has the important significance for improving the distribution network power supply reliability and reducing the distribution network potential safety hazards.