  One of the fundamental concerns in the operation of modern power systems is
the assessment of their frequency stability in case of inertia-reduction
induced by the large share of power electronic interfaced resources. Within
this context, the paper proposes a framework that, by making use of linear
models of the frequency response of different types of power plants, including
also grid--forming and grid-following converters, is capable to infer a
numerically tractable dynamical model to be used in frequency stability
assessment. Furthermore, the proposed framework makes use of models defined in
a way such that their parameters can be inferred from real-time measurements
feeding a classical least squares estimator. The paper validates the proposed
framework using a full-replica of the dynamical model of the IEEE 39 bus system
simulated in a real-time platform.
