Seamless transition of microgrid between islanded and grid-connected mode of operation

Microgrids and their smart interconnection with utility are the major trends of development in the present power system scenario. Inheriting the capability to operate in grid-connected and islanded mode, the microgrid demands a well-structured protectional strategy as well as a controlled switching between the modes. This challenging task is dealt with in this study, by the proposed centralized smart mode transition controller (CSMTC). The controller embarks upon two major microgrid protection aspects, by incorporating the protectional strategy against unintentional islanding and auto-reclosing. Subsequent to the protection of the microgrid, the smooth operation of the microgrid has also been a major focus of the proposed study. Therefore, the switching of microgrids between the modes (i.e. grid-connected to islanded or vice-versa) has been engaged in the proposed controller. Energy storage-based distributed static synchronous compensator (E-STATCOM) is integrated at the point of common coupling to support the performance of the controller. E-STATCOM performs to compensate the switching transients, along with maintaining the steady-state system stability. The CSMTC integrated with E-STATCOM protects the microgrid against unwanted system faults and supports a seamless transition between the modes by controlling the interconnecting static switch. To verify the operation of the proposed control strategy, the microgrid test model is simulated on the podium of MATLAB 2015b/Simulink.