Method of determining the place where a single-phase ground fault occurs in circuits with transitions overhead lines - underground cable, where the screens (11) of the cables (12) are connected transposed and to ground at both ends thereof basically it comprises: - receive a signal (8) of triggering of some of the protections of the line with air-underground transition. - evaluate the relations between the modules of the currents that circulate through the screens (11) of the power cables (12), direct sequence and homopolar on one side, and reverse and homopolar on the other. - evaluate the angular differences between the intensities that circulate through these screens (11). - compare the relationships between the intensity modules with a value of reference module x, and the angular differences with a reference angular value z and, based on these results. - allow or block the reclosing maneuver. (Machine-translation by Google Translate, not legally binding)