An Optimization-based Method for Estimating Critical Inertia in Smart Grids

The great diffusion of renewable energy sources is substituting traditional power plants, based on synchronous generators. This is leading to lower levels of inertia in modern power systems, thus reducing their frequency stability. In the context of future low-inertia systems, this paper introduces the novel concept of critical inertia, i.e. the minimum inertia needed at each network bus, in order to ensure the transient stability of the power system, and describes a methodology based on parametric identification for its assessment. The method is tested on a nine-bus power system and results related to different case studies are presented.