Load Step Pre-announcement and Bang-Bang controller Implemented in Islanded Microgrids to Improve Frequency Stability

Abstract

Unlike large traditional electrical power systems, islanded Microgrids usually have a low inertia, especially when a high share of inverter coupled generation is integrated. Frequency stability is one main concern in islanded Microgrid operation. Load step preannouncement and a bang-bang controller are introduced and implemented to improve the frequency response of islanded Microgrids. In order to achieve the best performance of the proposed control method, two parameters, preset and total time, have to be optimized. In this paper, an islanded Microgrid, including a conventional generator, a photovoltaic generator and a lumped load, is used as a study case. Three optimization criteria regarding the two parameters are presented, analyzed and compared. Furthermore, the effectiveness of the implementation of load step pre-announcement and bang-bang controller is validated using simulation results.