According to studies carried out, it is estimated that electrical losses due to ohmic effect in conductors can reach up to 70% of the total losses in electrical systems. In the work, a mathematical model is established for the evaluation of technical losses in subtransmission networks of the Holguín province, which considers the effective length of the circuit, the resistance in the conductors and the number of clients connected to said circuit. This calculation model allows, on the basis of the general information available from the circuit (global information), to evaluate the losses, establishing certain simplifications with respect to traditional methods. The results obtained were verified with those of the Radial software. The statistical results indicate that there are no significant differences in means, so the model calculates practical results similar to Radial.