Estimation of Dynamic Grid Flexibility Using Matrix Perturbation Theory

In this letter, a numerically-based method is proposed to estimate the metrics of dynamic grid flexibility, namely the inertial index, and the flexibility index. The novelty of the proposed method lies in using matrix perturbation theory, through which the sensitivity of a system to any perturbation is determined quantitatively. This notion is applied to the power system scenario under small disturbances, through which the inertial and the flexibility indices are calculated directly from the system matrix. This makes the proposed method immune to modeling complexities, and enables to implicitly understand the impact of any used generator or controller model. The applicability of the method is tested for the IEEE 39-bus system.