An approximate method for voltage sensitivity calculation in unbalanced distribution systems

Distribution systems in North America are typically radial and unbalanced, especially with the increasing penetration of single-phase distributed energy resources (DER). In the new technological environment, new modeling and analysis approaches need to be developed to study the reliability and economic impacts of DER on the electric distribution system operation. In this study, a novel method for approximating nodal voltage sensitivities is proposed, based on some important observations made about the radial distribution system. The proposed method can efficiently compute voltage sensitivities for all network nodes based on one topology search and one power flow solution. The results have been validated using the perturbation analysis performed on the IEEE 13-Bus Test Feeder model. The proposed method for voltage sensitivity approximation can be applied in the studies of large unbalanced radial distribution systems for supporting distribution system planning and operation decisions.