Estimation of Inertia in Power Systems Using Law of Conservation of Energy

One of the fundamental challenges for powering the grid with a significant share of renewable sources is to operate the grid securely with low levels of inertia. Hence, it has become imperative for the grid operator to monitor the inertia of the power grid to optimize the share between conventional and renewable sources and plan for frequency reserves. This paper details the formulation of a novel method to monitor the inertia of the grid and its areas using measurements from PMUs (Phasor Measurement Units). The method uses the Law of Conservation of Energy and Kinetic Energy to devise the problem. Upon detection of frequency events, i.e., power imbalance events, a system of linear equations is formed using PMU measurements, which is then solved by the least-squares algorithm to obtain inertia. The method is tested in Kundur two-area system and modified IEEE 39 bus system.