Distributed Secondary Control for Islanded MicroGrids - A Networked Control Systems Approach

This paper presents a novel approach to conceive the secondary control in droop-controlled Micro Grids. The conventional approach is based on restoring the frequency and amplitude deviations produced by the local droop controllers by using a MicroGrid Central Controller. A distributed networked control system is used in order to implement a distributed secondary control thus avoiding the use of a MicroGrid Central Control. The proposed approach is not only able to restore frequency and voltage of the MicroGrid but also ensures reactive power sharing. The distributed secondary control do not relies on a central control, so that the failure of a single unit will not produce the fail down of the whole system. Experimental results are presented to show the feasibility of the distributed control. The time latency limits of the communication systems are studied as well.