expansion planning of automated sub-transmission and distribution networks integrated by distributed generations

This paper presents sub-transmission and distribution network expansion planning (s dep) including distributed generation (dg) and distribution automation (da) considering reliability indexes. the objective function is to minimize investment, operation, maintenance and reliability costs subjected to ac power flow, system operation and generating units and dg limits, reliability, and distribution automation constraints (including the constraints of protection devices and volt/var control mechanism). the proposed model is a mixed integer non-linear programming (minlp) model which is hard to solve. for this reason, a minlp problem is transformed to mixed integer linear programming (milp) model. the validity of the proposed method is investigated in the two synthetic test networks.