An MVDC Based Meshed Hybrid Microgrid Enabled Using Smart Transformers

Decentralized integration of distributed generation (DG) units and loads are increasing in the modern distribution grid. Maintaining the power flow and power quality within their accepted limits is a challenging task. The formation of meshed hybrid microgrids is an effective method to improve the power system. The smart transformer (ST) is a promising solution to establish meshed hybrid microgrids in the distribution system. This paper analyzes the performance of an ST based meshed hybrid microgrid interconnected to the main grid feeder through medium voltage (MV) dc link of a second ST. The coordinated operation of interconnected ST system is proposed to explore the features of the configuration. During normal operation, the MVDC bus voltage is controlled by one ST, and this reduces the complexity of the overall control. The main grid and microgrid MVAC source failure and converter fault conditions are explored to analyze the reliability of the proposed microgrid structure. Moreover, the reactive power support capability and active power losses for the proposed system are compared with the existing solutions. Simulation and experimental results are presented to show the operation of the proposed system.