Small Signal Interactions Involving a Synchronous Machine and a Grid Forming Converter

Interactions between synchronous machines (SMs) and grid forming converters (GFMs) will become increasingly relevant as the power system transitions from a conventional fossil fueled synchronous based system to a renewable generation rich and converter-based system. This paper investigates and confirms the possibility of electromechanical oscillatory modes between conventional SMs and converter connected generation using a GFM control algorithm as well as between two GFMs. The study employs small-signal models and performs small-signal eigenvalue analysis. Moreover, parametric sweeps are performed, to investigate the impact of network and GFM control parameters in controlling the electromechanical modes.