Virtual Inertia a must for mitigation of frequency instability in Microgrids: A Comprehensive Review

In this paper, a comprehensive review of microgrids frequency control by using the Virtual Inertia (VI) is presented. Due to the widespread penetration of renewable energy sources (RESs) and distributed generators (DGs), a new system stability issue has been recently emerged. This issue is associated with the reduction and variation of inertia in the microgrid that is triggered by the utilization of power electronics interfaces to connect the RESs and DGs into the system. This leads to a higher system uncertainty requiring more complex system operation and control. To maintain microgrid reliability and to provide efficient use of RESs and DGs, the synthesis and control of virtual inertia should be a key technology to achieve a flexible operation in current and future microgrids. This paper provides a comprehensive survey on the fundamental aspects of synthesis and control of the virtual inertia for microgrid control. More specifically, an overview of the low inertia issue in microgrids with a high share of RESs and the role of virtual inertia are highlighted. Moreover, this paper reviews the role of battery energy storage system (BESS), as one of the novel VI emulated techniques, in enhancing system inertia.