Strategic Placement of Grid-Forming Inverters Considering Spatiotemporal Dynamics and Composite Stability Index

Abstract

The strategic deployment of grid-forming inverters (GFMIs) is imperative to fully leverage their potential to stabilise the grid. Otherwise, poorly planned spatial allocation of GFMIs could threaten the overall system stability under network disturbances. There is an urgent need to develop a robust and multidimensional framework for GFMI placement and evaluation, considering various stability and spatiotemporal aspects of modern power systems. This article addresses this need by introducing a new GFMI placement framework considering spatiotemporal aspects of converter-interfaced renewables and a newly proposed GFMI placement index. The practical range of spatiotemporal aspects with a high probability of occurrence is captured by a reduced number of scenarios derived from a novel hybrid scenario reduction algorithm. Furthermore, the proposed composite GFMI placement index encapsulates distinct aspects of network stability, precisely, frequency and voltage stiffness/stability represented by the frequency deviation index (FDI) and the damping ratio index (DRI), respectively. The performance of the proposed GFMI placement strategy is validated through dynamic simulations by deploying GFMIs at strategic locations in a modified IEEE-39 bus network with converter-interfaced wind generators. The dynamic simulation results revealed that the proposed GFMI ranking system effectively identifies the best GFMI positions in contrast to relying solely on FDI or DRI and, thereby, can assist in preserving the stability of modern power systems with high RE penetration levels.