Optimal Dispatch with Transformer Dynamic Thermal Rating in ADNs Incorporating High PV Penetration

Abstract

Under the high penetration of distributed photovoltaic (PV) resources, distribution networks face great transfer capacity and voltage rise challenges, which drives the transformation to active distribution networks (ADNs). Transformers are critical and costly components that are generally hard to reinforce or replace. Dynamic thermal rating (DTR) is an effective strategy that can enhance the transfer capacity of existing transformers according to the thermal condition of the equipment. In this article, an optimal dispatch model of ADNs incorporating transformer DTR and active management strategies is proposed. The thermal ratings of transformers are determined by the hot-spot temperature and loss of life (LOL) instead of the nameplate rating. Both the operation cost and transformer LOL are cooptimized in the model to avoid considerable insulation damage while enhancing the transfer capacity. The optimization model is transformed into a mixed-integer second-order cone programming (MISOCP) that can be easily solved. Numerical results demonstrate that the proposed model can significantly promote distributed PV accommodation by the synergy of transformer DTR and active management strategies and effectively address the tradeoff between higher utilization of transfer capacity and increased transformer insulation damage.