Expansion planning of joint medium- and low-voltage three-phase distribution networks considering the optimal integration of distributed energy resources

Abstract

This article proposes a novel hybrid approach based on the three-phase bus impedance matrix to solve the medium and low voltage planning problem of three-phase distribution systems considering the optimal integration of battery energy storage systems (BESSs) and different renewable energy sources (RESs). The mathematical formulation to describe the problem involves a mixed-integer non-linear model that considers the allocation and selection problem of distribution substations and transformers, medium and low voltage branches, RESs, and BESSs. Furthermore, the optimal operation of BESSs, the load balancing among low voltage system phases, the upgrading of existing elements, and the uncertainty of RESs, demands, and energy prices are considered. To solve the investment problem, an Iterated Local Search algorithm with neighborhood structures is applied, which uses the electrical information from the three-phase bus impedance matrix to generate new solutions. In addition, a two-step decomposition stochastic optimal power flow is proposed to solve the operational problem considering the stochastic scenarios. The performance of the new methodology is tested on a real distribution system. The numerical results show that integrating RESs and BESSs in the planning problem minimizes the cost of energy losses by 14.16% and the energy purchased from substations by 18.78%.

Keywords

• Distribution systems planning
• Medium and low voltage networks
• Distributed energy resources
• Three-phase bus impedance matrix