Model-free inertia estimation in bulk power grids through O-splines

Abstract

This paper proposes a novel methodology to precisely estimate the generation units’ inertia constant by using the wide-area monitoring systems (WAMS) information of bulk power grids. The method accurately estimates the rate of change of frequency (RoCoF) and the amplitude of active power deviations through the multivariate O-splines-based differentiators of the discrete-time Taylor–Fourier transform (DTTFT). The proposal utilises active power and frequency measurements that are synchronously collected from WAMS after load changes or generation trips. In the first stage, the Teager–Kaiser energy operator (TKEO) detects the right disturbance instant. Then, the first-order and zero-order O-splines differentiators are applied to the frequency and active power deviation measurements to simultaneously estimate the RoCoF and the amplitude of active power deviations in a sole stage. Thus, the inertia constants of all generation units derived from the second Newton law are estimated using all time-synchronised signals and processing in an exclusive step by the O-splines of the DTTFT in a short time. The attained results and their comparison with a state-of-the-art technique confirm the effectiveness and performance of the proposed strategy for inertia estimates, where simulated signals of two well-known benchmark power grids are tested.