Differential Game-based Safety Operation of Microgrids Including Virtual Synchronous Generator

Abstract

Microgrids are new power supply systems expected to expand the introduction of Distributed Energy Resources (DER) using Renewable Energy Sources (RES). There are some challenges in a microgrid. First, DERs are power sources with no mechanical inertia. Second, synchronous generators have risks at step-out because of the perturbation of DER using RES. To suppress the angular frequency variation of power sources is necessary, it is valid to introduce a Virtual Synchronous Generator (VSG) and smooth power flow using batteries. For a safe operation in a microgrid with VSG, differential games-based analysis and control are used. The reachable set-based transient analysis represents sufficient conditions for the system to become unsafe. The control based on Iterative Linear Quadratic (ILQ) Games derives an optimal trajectory avoiding unsafe sets of the system. Finally, the numerical solution shows that reachable set-based analysis for microgrids and ILQGames-based control of power sources keep microgrids safe.