Towards a new effective strategy to obtain optimal radial structure in power distribution networks: Graph theory-based topology assessment

Power distribution networks (PDNs) are principally operated and planned in a radial—open-loop—structure to satisfy several techno-economic goals. It is, therefore, indispensable to develop new practical strategies to rigorously investigate the radial structure-related limitation in the operation and planning of the PDNs. In this study, after a thorough and critical review of existing strategies in the literature, a new effective graph theory-based topology assessment strategy (GT-ToST) is outlined to examine the radial structure-related limitation. Then, both the distribution branch reconfiguration (DBR) problem and the multi-stage joint distributed generation and distribution network expansion planning (DG&DNEP) problem (most appropriate for the short and long-term horizons, respectively) are employed to explore the feasibility and practicality of the newly proposed strategy compared to the existing ones. The proficiency of the proposed strategy is investigated for the DBR problem with a modified 33-bus PDN and a modified real-world 177-bus PDN in Rio de Janeiro, as well as for the DG&DNEP problem with a modified 27-bus PDN and a modified real-world 104-bus PDN in the northeast part of Brazil. The obtained results from the illustrative examples and case studies prove the effectiveness of the proposed GT-ToST compared to the existing strategies.