On-line inertia estimation of Virtual Power Plants

This paper presents an on-line estimation method to track the equivalent, time-varying inertia provided by Virtual Power Plants (VPPs). The proposed method relies on the estimation of the rate of change of the active and reactive power at the point of connection of the VPP with the rest of the grid and provides, as a byproduct, an estimation of the VPP's internal equivalent reactance. The accuracy of the proposed method is first validated by estimating the rotational inertia of Synchronous Machines (SMs), and then tested for a VPP, based on a comprehensive case study carried out based on the WSCC 9-bus test system.