Improvement of Microgrid Systems Using Synchronverters

Abstract

In typical electrical power system, enormous synchronous generators (SGs) driven by different types of prim-movers generate the major bulk of electrical power. Virtually the individual inertia of separate SGs are summed to give an equivalent huge inertia rotating at synchronous speed. In case of a fault or disturbance, the kinetic energy reserved in this huge inertia is injected to the power system to maintain the energy balance, prevents sudden changes in frequency, and enhances the stability of power system. The contribution of renewable energy sources is gradually taking a remarkable share of the total electrical power generated. The trend is to inject the energy obtained from these resources in main grid or small local grids using inverter-based systems. With this trend, these renewable sources have no contribution to rotating inertia, and stability problems may arise specially in small power networks -called micro grids- or when the total share of renewable resources reaches a remarkable percent of the total power generated (case of distributed generation DG).