Toward Optimal Active Distribution Network Planning: A Critical Review of Conductor Size Selection Methods

Conductor size selection (CSS) is critical for the optimal design and operation of distribution networks. CSS, like other aspects of network planning, has become increasingly sophisticated as the prevalence of distributed energy resources (DERs) increases. This complexity is linked to DER operational and planning uncertainties, which often exacerbate network issues. Increased uncertainty and uncontrolled DER penetration can result in increased conductor loading and extreme voltage performance concerns (rise, drop, and unbalance) that lower the quality of supply (QoS). Traditional CSS techniques, which were developed for passive systems, do not take DERs into account. Therefore, continued application of these methodologies in CSS for modern networks is untenable. As a result, the shift towards active network design and planning requires new CSS techniques that can enhance the adoption of DERs and facilitate optimal long-term network planning. This paper presents a review of CSS methodologies, focusing on the advances made to accommodate DERs, particularly the adaptation of modeling processes to cater to DER planning and operational uncertainties, and its impacts on other key aspects of CSS. Key CSS processes, including the choice of the CSS objectives, input (loads, generation, and feeder) modeling, load flow assessment, optimization, as well as the incorporation of risk in DER analysis are discussed. Informed by the review, the paper scopes the requirements for a robust CSS methodology for active networks with high DER penetration. The findings of the paper are relevant to future research in the field of active distribution network design with a focus on optimizing the integration and utilization of DERs and the related technical performance of networks.