DOFF-RLS-Based Equivalent Inertia Estimation for Power System with PV

With the use of photovoltaic (PV) generation, a large number of synchronous generation units have been replaced, resulting in obvious decline in the equivalent inertia of power system. Facing a lack of inertia, virtual inertia control techniques are applied to PV, but there is a lack of methods to estimate the equivalent inertia of PV in real time, making it difficult to quantitatively estimate the effect of control method with virtual inertia. Therefore, this paper adopts the controlled autoregressive (CAR) identification model and the recursive least square algorithm of dynamic optimal forgetting factor (DOFF-RLS) to estimate the PV equivalent inertia, in order to address the time varying characteristics of the PV equivalent virtual inertia. The proposed identification model and solution algorithm have superior tracking capability and good convergence. All that is required is to obtain the disturbance data of frequency and active power from the point of common coupling from the phasor measurement unit (PMU). Finally, the accuracy and suitability of the identification model and method are verified by simulation.