Optimal Design of Virtual Inertia and Damping for Grid-Forming Inverters Considering Spatiotemporal Frequency Distribution in New Power Systems

With the high penetration of renewable energy, the inherent inertia of new power systems has significantly decreased, which might cause nodal frequency violations. To address this issue, this paper has proposed an optimization design method for virtual inertia and damping in grid-forming inverters. Firstly, by introducing the power disturbance distribution matrix and the synchronized power coefficient matrix into the state-space equation, the coupling effects among disturbance nodes and source nodes can be characterized. As a result, the nodal frequency deviations under power disturbances can be precisely estimated. On this basis, the minimum nodal frequency can be determined and an optimization cost function considering both frequency nadir and reserve energy costs is established. Afterwards, optimized design results of virtual inertia and damping are iteratively calculated through an improved particle swarm optimization algorithm. Finally, the case study result verifies that the proposed optimization method can improve economic efficiency while ensuring frequency limit compliance.