The electric power system has undergone numerous changes over the years. The transformation of the end-users from passive actors to active actors brings implications for the electric power system. The distribution system operator will be able to guide its operations in the function of the active role of the end-users. In many situations, the distribution system operator is carried out to avoid congestion in the distribution networks, and when it happens the distribution system operator is obliged to compensate the affected end-users. This paper presents a model in which distribution system operator can take advantage of the flexibility of the end-users in order to minimize the costs of the investments in distribution network expansion. The investment cost with the presented methodology as show the results has a reduction of 5.77%.