Synthetical Control Strategy for Smooth Switching Between Grid-Connected and Islanded Operation Modes of Microgrid Based on Energy Storage System

Microgrid is an effective approach to solve the grid-connection of distributed generations,and the hybrid microgrid composed of wind farm,photovoltaic generation and energy storage system possesses the feature that the clean energy can be fully utilized and its operation is reliable.The smooth switching between grid-connected operation mode and islanded operation mode of microgrid is an important measure to ensure the secure and reliable operation of microgrid.For this reason,a synthetical control strategy integrating new type of master-slave control with peer-to-peer control is adopted to control the operation mode transition between grid-connected operation mode and islanded operation mode of microgrid.A model of microgrid composed of complementary wind farm,photovoltaic generation and energy storage system is constructed on DigSILENT/PowerFactory platform,and the feasibility of the proposed control strategy is verified by simulation results.Besides,simulation results also show that the improved control strategy can ensure power balance of microgrid before and after the switching and keep the voltage of the bus connected with microgrid and frequency of the microgrid within the allowed range.