Power distribution network fault fixed-point detection device and method

The invention provides a power distribution network fault fixed-point detection device and method. The detection device comprises a signal source and a detector. The signal source is connected to a fault section of a power distribution network and is used for injecting characteristic signals into grounding phases of a plurality of branch lines and sending characteristic signal voltage and frequency information to the detector when the plurality of branch lines to which the fault section belongs are shut down, and the characteristic signals form a loop through grounding points of the pluralityof branch lines; and the detector is connected with the plurality of branch lines, and is used for measuring the characteristic signals flowing through the plurality of branch lines based on the loop,receiving information sent by the signal source to obtain resistive current of each branch line in the fault section, and determining a grounding point of the fault section based on the resistive current. The method is high i