Dynamic Influence Analysis of Virtual Inertia on Reconnection of Microgrid

The microgrid is useful in integrating renewable energy sources and distributed generation. Due to the inrush current, voltage harmonics and stability issue, microgrid cannot directly switch from the islanded mode to the grid-connected mode. Moreover, virtual inertia has proven to effectively improve the dynamic performance of the microgrid, which also influence the characteristics of mode switch. However, the influence of virtual inertia on microgrid reconnection has not been sufficiently studied. In this paper, the transient process in microgrid reconnection is modeled to analyze the inrush current. Based on the model, the influence of the virtual inertia on reconnection is analyzed, including the magnitude and response speed of the inrush current, and the stability of the reconnection of microgrid. Therefore, the proposed method for optimization of virtual inertia can improve the reconnection performance of microgrid, which eliminates the inrush current, and hence smooth the reconnection process. Finally, the simulation result verifies the effectiveness of the proposed method.