Enhancing the unbalanced distribution network’s hosting capacity for DERs via optimal load re-phasing

Abstract

Maximizing the distribution systems’ hosting capacity (HC) for distributed energy resources (DERs) is an integral part of the efforts to increase the share of renewable energy sources (RES) in electricity grids. Hence, a novel strategy is proposed in this paper to enhance the network’s HC for DERs, which considers the technical issues such as voltage unbalance caused by the high share of DERs. Through a novel three-stage optimization model, this paper shows that the HC for DERs such as solar photo-voltaics (PV), residential and public electric vehicle chargers (EVCs), and heat pumps (HPs) can be increased. The proposed approach uses a novel re-phasing strategy to determine the optimal network configuration, which can decrease the voltage unbalance, and hence the available network capacity can accommodate more DERs. In the first stage, the network’s HC for DERs is maximized without any further structural modifications on the existing network. In the second stage, the best configuration of the system is obtained to mitigate the voltage unbalance caused by the DER penetration. Finally, at the third stage and based on the obtained optimal configuration of the network, the HC of the modified system is maximized by adding more DER capacity. The results show that using the proposed re-phasing technique can improve the network’s HC for DERs, without any need to reinforce the existing network.