Optimal Inertia Emulation via Adaptive Grid-forming Inverter Selection in Active Distribution Networks

This paper presents an optimization algorithm that estimates the equivalent inertia and damping factor required to support the power electronics dominated grids (PEDG) in response to severe load and generation disturbances. The proposed algorithm emulates optimal inertia by adaptively selecting grid-forming inverters (GFMIs) at various locations given their battery energy storage system (BESS) capacities as well as their state-of-charge (SOC) in an active distribution network. The proposed algorithm is implemented in the tertiary layer controller or supervisory controller (SC) of the considered control architecture. Various constraints including maximum frequency deviation which represents the frequency Nadir, rate of change of frequency (ROCOF), and SOC of the batteries are considered for real-time optimization to ensure optimality of emulated inertia and damping factor via GFMIs. Various case studies have been implemented MATLAB/Simulink environment to demonstrate the practicality of the proposed approach.