The invention discloses a method and a
system for studying, judging and handling a single-phase grounding fault of a power distribution network. The method comprises the following steps: acquiring a line selection
alarm signal and a line selection result of a low-current
grounding line selection device in a
station; according to the line selection result, calculating the zero-sequence current variation of all the off-
station terminals of the corresponding line; if the line topological structure passes the
verification, replacing a specified terminal in the line topological structure with a lead to obtain a new line topological structure;
hierarchical clustering is carried out on the out-of-
station terminals according to the zero-sequence current variable quantity, the class with the large arithmetic mean value in the clustering result is a
fault class, and the class with the small arithmetic mean value in the clustering result is a normal class; marking a fault point in the new line topological structure according to the out-of-station terminal corresponding to the
fault class and the normal class; and isolating the fault points, and if the line selection
alarm signal is not reset after all the fault points are isolated, iteratively executing the steps until the line selection
alarm signal is reset. According to the method, iterative clustering is carried out in combination with the fault reset condition, and the single-phase earth fault can be accurately handled.