Inertia Estimation of a Power System Area Based on Iterative Equation Error System Identification

This paper proposes an area inertia estimator based on an iterative equation error (EE) system identification (SI) approach. The inertia value can be accurately extracted for areas of different compositions with different penetrations of converter-interfaced generators. Firstly, the internal frequency variation of the generator units is computed by means of a frequency divider-based estimator. Subsequently, these internal frequency variations are used to carry out a generator clustering, which provides groups of coherent generators to the proposed inertia estimator. Finally, the iterative EE SI approach provides a joint inertia estimation for each of these coherent groups. Numerical results on a properly modified version of both the IEEE 39-bus and the IEEE 118-bus test systems highlight the accuracy of the proposed method using both ambient measurements and ringdown signal measurements (power imbalance events). Furthermore, the proposed method presents a low computational burden that allows fast estimation updating times.