This paper presents the study of the behavior of the system used to feed the warning lights of the 400 kV overhead lines towers that cross the Orinoco River. The feeding of this system is through an isolated ground wire in the section of the crossing. An analysis of the performance of the Balizaje substation is presented from the point of view of their behavior when switching overvoltages appears, with the purpose of evaluating quantitatively some conditions that could be risky for the integrity of the equipment and to obtain data for the adjustment of the substation protection system. This study was made by means of the electromagnetic transient program ATP and it is demonstrated that the Balizaje substation allows to control and to stabilize the voltage levels, guaranteeing the normal operation of the system during different fault and switching scenarios that could appear in the electrical system