Robust frequency control for a wind/hydro autonomous microgrid

This paper presents a robust frequency control method for autonomous small-scale microgrids (MG) based on hydro and wind powers. The proposed solution includes a smart load (SL) on the control side, which acts on the MG power loading to maintain the frequency constant. The thermal energy produced by SL is used for the local consumers. An isochronous frequency controller is optimally designed and the proposed control technique is validated by experiments on a laboratory test-bench. The study was focused on frequency control under variable load and wind power, and the experimental results showed that the proposed solution provides good results, the MG frequency being kept in a narrow band. The system is also investigated under overload conditions, when a load-shedding method overcomes the system outage.