Model for the expansion planning problem of distribution systems considering reliability

This paper presents a mixed-integer linear programming model for the expansion planning problem of power distribution systems (PDS). The objective function considers the investment costs of reconductoring existing branches and adding new branches, and operation costs, accounting for maintenance, energy losses, and voltage violations costs. Reliability is considered in the optimization model through the energy not supplied, system average interruption duration, and system average interruption frequency indexes, using a reward-penalty formulation. Numerical results are presented for a 54-node distribution system, comparing the expansion plans obtained when reliability assessment is considered or not in the objective function. The obtained results show the relevance of considering reliability indexes in the expansion planning of PDS.