Investigation of Sub-Synchronous Control Interactions with Grid Forming Inverters

As the electric grid increasingly incorporates renewable energy resources, traditional inertia-providing synchronous generators are being retired. This presents a challenge in ensuring stability in the system, leading to the exploration of alternatives to traditional inertia-providing power plants. Presently, Grid Forming Inverters (GFM) have emerged as a solution to address this critical issue. The growing share of Inverter Based Resources (IBRs) in the grid has resulted in a critical challenge within modern power systems known as Sub-Synchronous Control Interaction (SSCI). This challenge poses a significant obstacle in maintaining the grid's stability. It is primarily caused by the interaction between IBR controls and series compensated transmission lines, leading to potential damage to system equipment, a reduction in power generation capacity, and an overall decline in grid stability. Addressing SSCI has become a requirement to maintain the resiliency of power grids. This study aims to investigate the impact of GFMs on SSCI and their overall impact on power system stability and reliability.