A Power Control Scheme for the Islanding Transition of a Microgrid with Battery Energy Storage Systems

This paper focuses on the analysis of the dynamic behavior of an AC microgrid including rotating and stationary loads and battery energy storage systems during unplanned islanding transitions. The signal necessary to switch from grid-connected to standalone control mode is not instantaneous. The delay might be so long to result in frequency and voltage transients that could lead to the instability of the microgrid. The aim of this paper is to assess the potential benefits resulting from the implementation of an active and reactive power control scheme able to allow, starting from a grid-connected operation, a successful transition to island. The influence of different percentages of rotating load connected to the microgrid is analyzed by using EMTP-RV and time domain simulations of a modified version of the IEEE 34-bus test distribution system in which two battery energy storage systems are connected to two different buses.