Active and Reactive Power Flow Control in a Grid Connected and Autonomous Microgrid

These paper proposes real and reactive power management strategies of electronically interfaced distributed generation (DG) units in the context of multiple-DG of microgrid systems. In autonomous mode of microgrid, the power demand in the microgrid is supplied by the distributed generators (DGs) and controlled with the help of voltage source converters (VSCs), which control the desired real and reactive power flow between DGs to reach different load conditions. An arrangement of DGs in the microgrid is proposed to achieve load sharing in both grid connected and autonomous modes. This system can work as grid connected and autonomous mode depends on power requirement of microgrid, where power flow form grid to microgrid and vice-versa. The back-to-back converters also provide total frequency isolation between the grid and the microgrid. It is shown that the voltage or frequency fluctuation on the grid side has no impact on voltage or power on microgrid side. Different loads are considered to verify the system stability. All system model and daily load demand of microgrid has been simulated in PSCAD.