Distributed Secondary Voltage Control For Autonomous Microgrids Under Additive Measurement Noises And Time Delays

This study addresses the secondary voltage restoration problem of ac autonomous microgrids with additive measurement noises and time delays. Existing distributed control methods commonly assume ideal communication among distributed generators (DG), however, the channels are prone to additive noises (i.e. caused by environmental causes, such as rain etc.) and time delays, then each DG obtains noisy and delayed measurements of the states of its neighbouring DGs. The proposed distributed cooperative control strategy will achieve voltage restoration of DGs through a sparse communication network subject to noisy and delayed measurements. The theoretical concepts and necessary conditions for stability and robust performance of the proposed distributed secondary voltage control strategy are outlined by the graph theory, stochastic theory, and Lyapunov functional approach. Furthermore, the proposed control strategy is fully distributed and therefore the central controller is no longer required bringing about several advantages, e.g. plug-and-play property. Simulation results on an autonomous ac microgrid test system are obtained to evaluate the performance of the proposed control method to achieve voltage restoration in the MATLAB/SimPowerSystems Toolbox.