  A major concern associated to the massive connection of distributed energy
resources is the increasing share of power electronic interfaces resulting in
the global inertia reduction of power systems. The recent literature advocated
the use of voltage source converter (VSC) interfaced battery energy storage
system (BESS) as a potential way to counterbalance this lack of inertia.
However, the impact of VSCs on the dynamics of reduced-inertia grids is not
well understood especially with respect to large transmission grids interfacing
a mix of rotating machines and resources interfaced with power electronics. In
this regards, we propose an extension of the IEEE 39-bus test network used to
quantify the impact of VSCs on reduced-inertia grids. In this respect, a
reduced-inertia 39-bus system is obtained by replacing 4 synchronous generators
in the original 10-synchronous machine system, with 4 wind power plants modeled
as aggregated type-3 wind turbines. Then, a large-scale BESS is integrated into
the reduced-inertia network via a three-level neutral-point clamped (NPC)
converter, thereby to be used for studying the impact of VSC on the dynamics of
the inertia-reduced power system, as well as for comparing different VSC
controls. The proposed models are implemented on a real-time simulator to
conduct post-contingency analysis, respectively, for the original power system
and the reduced-inertia one, with and without the BESS-VSC.
