Nowadays, the situation of the electric energy markets has required distribution and transmission companies to improve the efficiency of their services and thus reduce costs to a minimum. In the case of ENAP, which owns its substations, the competition of its dependent markets also obliges it to have a reliable energy supply at the lowest possible cost, since the economic factor is always relevant. That is why preventive maintenance costs and the cost of lost production in the event of a power supply failure are of vital importance, with adequate preventive maintenance plans and testing techniques as advanced as possible to determine with the greatest certainty the condition of a substation's equipment. The objective is to analyze, using the Digsilent program, the possible interconnection of the substations to reduce the load of S/E N°1 and thus have the possibility in the future to disconnect each of the transformers to perform comprehensive maintenance on the transformers of S/E N°1, using the power of the transformer of S/E N°2.