MILP Model for Reliability Optimization In Active Distribution Networks

Abstract

This paper presents a Mixed Integer Linear Programming (MILP) model for optimal allocation of Automatic Switching Devices (ASDs) and Distributed Generation (DG) in distribution networks. The model’s formulation considers the application of ASDs for protection and post-fault restoration purposes, as well as the role of DG units in the restoration process. From the reliability perspective, System Average Interruption Frequency Index (SAIFI) is used as a metric index for obtaining an optimal placement of ASDs and DG units. Decoupling the optimal allocation problems of ASDs and DG units does not provide an optimal solution, since both are inherently interdependent with system reliability. Hence, the simultaneous allocation of ASDs and DG units is considered in this work. A Goal Programming approach is used to establish the optimal trade-off between the placement of ASDs and DG units, and the improvement on SAIFI. In other words, the developed model aims to i) minimize the number of interrupted consumers due to protection operation; ii) maximize the number of consumers restored by automatic network reconfiguration, and iii) minimize costs associated with the allocation of ASDs and DG units. Restoration is ensured by a set of linear power flow equations. The model’s solutions are obtained from a Branch and Bound-based technique, and results are presented using the IEEE 123-bus system.