A
transmission line single-phase grounding fault single-end
ranging method belongs to the field of
power system protection and control. According to the method of the invention, positive, negative and zero sequence
voltage and current phasors of a line during the time section between the occurrence of a
single phase grounding fault and
single phase tripping and the time section between
single phase tripping and reclosing are measured at a substation protection installation site and are used as input. The initial value of fault distance is set from 0 to the overall length of the line with
delta1 as the step length, and the initial value of transition resistance starts from 1
ohm and increases to 1000 ohms with 1
ohm as the step length. For each combination of the values of fault distance and transition resistance, the equivalent
electromotive force values of a
system at the opposite end of the line during the time section between the occurrence of the single phase grounding fault and single phase
tripping and the time section after single phase tripping are respectively calculated, the sum of absolute errors of the equivalent
electromotive force values is calculated, and the fault distance value corresponding to the minimum value of the sum of absolute errors is selected as the fault
ranging distance. The method is high in precision, is not affected by distributed
capacitive current, transition resistance, load and
system impedance and has very high practical values.