Planning a flexible distribution network with energy storage systems considering the uncertainty of renewable sources and demand

This study proposes a stochastic model for multi-stage distribution system expansion planning to enhance the network flexibility via the optimal installation of energy storage systems. In this model, installation of new substations and feeder sections, as well as reinforcement of the existing ones alongside investing in energy storage systems are considered as various alternatives for the network expansion. Uncertainty of customer-owned renewable generation and electricity demand is captured through considering several scenarios for daily patterns of nodal demand and generation. The model is then cast as a mixed-integer linear optimisation problem. Implementation of the proposed model on an 18-node distribution grid reveals the significant impact of energy storage systems on network flexibility. The obtained results show that incorporating flexibility requirements into the planning problem improves the grid performance in presence of uncertain renewable generations through reducing power curtailment of renewable sources, decreasing operational costs, and lowering necessities for network capacity enhancement.