Equivalent Inertia Estimation of Power System Based on Kinetic Energy Theorem

The accurate estimation of power system equivalent inertia is crucial for rational planning of grid-connected capacity for new energy and for ensuring the safety and stability of the system frequency. This study proposes a novel method for estimating the equivalent inertia of the power system using the kinetic energy theorem of the generator. The principle of power system inertia estimation is first analyzed based on the kinetic energy of the generator rotor and the swing equation, taking into account the impact of new energy integration on the inertia of the power system. Next, based on the kinetic energy theorem, the power variation of a single generator after disturbance is analyzed and the expression of inertia of a single generator, including the angular frequency of the generator, is derived. The proposed method uses a PMU synchronous vector measuring device to measure the frequency of the generator outlet busbar instead of the angular frequency to estimate the inertia of the generator and subsequently the equivalent inertia of the system. Finally, a four-machine two-zone Kundur power system model is built in Matlab/simulink simulation software to verify the effectiveness of the proposed method.