About the main frequency control issues in microgrids with renewable energy sources

This paper provides a brief look over the main frequency control issues related to the operation of microgrids with renewable energy sources. Starting from the regulation of the classical power systems regarding the frequency control, the MGs can use similar control techniques adapted to the typical units that can be found in such systems. On this line, this paper analyzes the main frequency-controlling units, including RES-based and classical generators, as well as energy storage systems and active loads. The distributed units are evaluated from the view of frequency control performances, using several criteria, while also investigating the power-frequency characteristics, which cover the first two frequency control levels, i.e. primary and secondary.