A Feeder Investment Model for Distribution System Planning Including Battery Energy Storage

The distribution system asset (DSA) planning process for a new or existing subdivision, which entails new loads and/or distributed generation, involves a comparison of a variety of plans followed by the selection of the least costly one. The costs comprise the cost of new assets (feeders and transformers), their replacements, operation and maintenance costs, as well as customer interruption costs. For a fair comparison, all costs reflect the current year and are annualized over a specific study period. The optimal plan must be capable of addressing the connection of new loads and/or generation while satisfying performance standards at the lowest annualized cost. Current DSA planning algorithms, however, fail to take battery energy storage systems (BESSs) into account, hence impeding their inclusion as a solution in DSA plans. This paper proposes a new DSA planning algorithm that includes the installation and optimal sizing of BESS units in addition to traditional assets, such as feeders and transformers. It incorporates plan and asset lifetimes as a means of establishing the minimum total annualized costs of new and replacement assets, operation and maintenance, and customer interruptions. The algorithm is successfully validated on a 3-bus system and a 33-bus distribution system.