A New Prospective of Smart Transformer Application: Dual Microgrid (DMG) Operation

With the significant increase in renewable energy sources (RES) and storage elements, power distribution system needs new services for reliable and continuous operation. Smart transformer (ST) based on power electronics, control, and communication has been proposed for improving the performance of power system. However, operational capabilities and applications of ST with RES and energy storage in distribution system are still not explored in detail. In this paper, a new prospective of ST application, dual microgrid (DMG) operation, is proposed. In normal medium voltage (MV) grid operation, the ST supplies power to loads connected to its low voltage side and injects into the MV grid depending upon the available RES and load demand. During the voltage disturbances, the ST feeds power to the sensitive loads connected to the other feeders equipped with the conventional power transformers. In this case, the distribution loads are isolated from the MV utility grid. This ability of the smart transformer to isolate from the utility grid and provide continuous power to the sensitive loads of other feeders has potential to significantly improve the performance of power system as well as ST. With simulation results based on PSCAD/EMTDC software, this paper introduces for the first time an unexplored feature of the smart transformer.